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Reiss, A.B.; Greene, C.; Dayaramani, C.; Rauchman, S.H.; Stecker, M.M.; De Leon, J.; Pinkhasov, A. Neurologic Symptoms of Long COVID. Encyclopedia. Available online: (accessed on 05 December 2023).
Reiss AB, Greene C, Dayaramani C, Rauchman SH, Stecker MM, De Leon J, et al. Neurologic Symptoms of Long COVID. Encyclopedia. Available at: Accessed December 05, 2023.
Reiss, Allison B., Caitriona Greene, Christopher Dayaramani, Steven H. Rauchman, Mark M. Stecker, Joshua De Leon, Aaron Pinkhasov. "Neurologic Symptoms of Long COVID" Encyclopedia, (accessed December 05, 2023).
Reiss, A.B., Greene, C., Dayaramani, C., Rauchman, S.H., Stecker, M.M., De Leon, J., & Pinkhasov, A.(2023, July 11). Neurologic Symptoms of Long COVID. In Encyclopedia.
Reiss, Allison B., et al. "Neurologic Symptoms of Long COVID." Encyclopedia. Web. 11 July, 2023.
Neurologic Symptoms of Long COVID

SARS-CoV-2, a single-stranded RNA coronavirus, causes an illness known as coronavirus disease 2019 (COVID-19). Long-term complications are an increasing issue in patients who have been infected with COVID-19 and may be a result of persistent viral-associated systemic and central nervous system inflammation or may be attributed to virus-induced microvascular blood clots. COVID-19 may incite changes in brain function with a wide range of lingering symptoms. Patients often experience fatigue and may note brain fog, sensorimotor symptoms, headaches and sleep disturbances. Prolonged neurological and neuropsychiatric symptoms are prevalent and can interfere substantially in everyday life, leading to a massive public health concern.

COVID-19 long COVID syndrome brain fog fatigue myalgia

1. Fatigue

Fatigue is considered a fundamental core symptom of long COVID and occurs after infection with many other viruses [1][2][3][4][5]. This symptom has been reported in a third or more of COVID-19 patients and commonly persists for upwards of 6 months and is an indicator of worse prognosis [6][7][8]. Stefanou et al. conducted a longitudinal analysis of 1733 acute COVID-19 patients and found that, at 6 months, 63% had fatigue or muscle weakness [9]. Fatigue is a somewhat subjective experience that is not easily quantified. In long COVID patients, fatigue has been defined as an energy deficit that may be physical, mental, and/or emotional that makes normal daily activities difficult, frequently leaving the patient with post-exertional malaise [10][11]. The acute COVID-19 illness may not have been severe, but ramifications, such as intractable fatigue can be profound.
A qualitative study by Ladds et al. explored the experience of fatigue as described subjectively by patients [12]. They recount a need to adjust their performance of basic activities and disruption of work life with a major decline in functional status due to exhaustion. Self-reported fatigue is associated with impaired quality of life after COVID-19 and this link was also found in studies where fatigue was assessed using more quantitative screening tools [13][14][15].
The decrease in physical and/or mental performance that results from fatigue may be traced back to changes in CNS provoked by COVID-19 infection and postulated to be a result of both systemic and neuro-inflammatory processes within the brain itself [16][17]. Systemic inflammation and surging cytokine levels can cause or exacerbate tiredness [18].
Diminished neurotransmitter levels in the CNS post-COVID-19 may be responsible for at least some of the fatigue [19][20][21]. A study of 12 post-COVID-19 patients who had recovered from severe pneumonia, but had sustained profound fatigue and 10 healthy controls found neurophysiological indications of disruption of the primary inhibitory neurotransmitter GABA, with evidence of overall reduced GABAergic cortical activity in the post-COVID-19 group [22]. Depleted levels of serotonin may also contribute to fatigue [23][24].
Neuropsychological factors that can contribute to fatigue include anxiety, confusion, depression, apathy, and anger [25][26]. Neuropsychiatric aspects of long COVID are covered in greater detail in the next section.
Nevertheless, another factor that may contribute to the experience of fatigue is the effect of COVID-19 on skeletal muscle which is vulnerable to the ACE2 surface protein [20][27]. Patients may note muscle pain and muscle weakness which limit endurance [28].

2. Neuropsychiatric Sequelae

The most common long-term neuropsychiatric manifestations of COVID-19 are anxiety, PTSD, and depression and may include pain disorder, delirium, mood swings, and, at the extreme, psychosis [29][30][31][32] [Figure 1]. Anxiety and depression symptoms have been positively correlated with COVID-19 disease severity and decline in function post-COVID-19 [33]. Alghamdi et al. corroborated these findings with an online survey of 2218 COVID-19 patients finding mood alteration and depression to be common symptoms, which were positively correlated with female sex and disease severity [34]. Recovery is possible as percentage reporting depression decreased over time, but for many patients, symptoms persist for a year and beyond [35].
As with fatigue, inflammatory cytokines are thought to play a pathophysiological role in COVID-19-related depression [36][37]. In a retrospective cohort study of 236,379 patients conducted by Taquet et al., 17.4% were diagnosed with anxiety disorder and 13.7% with a mood disorder in the 6 months following a COVID-19 diagnosis [38]. Long COVID may cause metabolic dysregulation, including the new onset of insulin resistance [39]. Al-Hakeim et al. found an association between insulin resistance and depression in long COVID patients, which they link to the neurotoxicity of oxidative stress in an insulin-resistant milieu [40].
External circumstances, such as isolation, extended quarantines, financial distress, and the stress inflicted by living through the pandemic have all been documented to raise anxiety, incite behavioral changes, increase loneliness, and provoke avoidance behaviors [41][42][43]. Adding to these environmental factors are the physical changes in permeability of the BBB discussed previously which lead to cytokine overload, inflammation, and direct viral neuronal invasion with subsequent CNS damage that may mediate neuropsychiatric sequelae [44].
Obsessive-compulsive disorder (OCD) has been reported in many studies with up to 20% of screened patients experiencing symptoms at follow-up [45][46]. OCD symptoms may worsen in persons who already have the disorder, possibly due to the added stressors of masking, hygiene, and isolation and may also appear in those who have not had the diagnosis previously [47][48][49].
For some patients, neuropsychological symptoms are accompanied by PTSD with potentially debilitating flashbacks, hyperarousal, and intrusive thoughts [50][51][52]. PTSD occurs in both hospitalized and non-hospitalized patients. In a cohort of 238 patients who were hospitalized in Italy with COVID-19, 17% had PTSD at 4 months post-discharge as assessed by the Impact of Event Scale-Revised [53]. In a study from the Netherlands, Houben et al. found that among 239 patients (62 hospitalized, 177 not hospitalized), PTSD symptoms at 3 months of follow-up were found in 43.5% of patients who had been hospitalized versus 35% of those who had not been hospitalized (p = 0.23) while at 6 months of follow-up PTSD symptoms were found in 30.6% of patients who had been hospitalized versus 25.4% of those who had not been hospitalized (p = 0.42) [54]. Savarraj et al. found an association between pain and PTSD in a prospective study of hospitalized COVID-19 patients in Texas. Patients who were experiencing pain were seven times more likely to have PTSD at 3 months after hospitalization [55].
Psychosis was also found at higher rates in COVID-19 cohorts than in controls [56][57]. Though a relatively uncommon neuropsychological symptom, multiple case studies have reported patients with sudden onset psychosis both with and without prior medical history after presenting with SARS-CoV-2 [58]. An analysis from Smith et al. of 2396 papers found 48 patients with psychosis lasting between 2 and 90 days, most commonly experiencing delusions [59].
Delirium has also been noted in some COVID-19 patients, especially in older persons and those who are hypoxic or have high fever [60][61]. A study of 516 patients across four Italian medical centers found 73 patients presenting with delirium on admission. Delirium was found to correlate to older age and in-hospital mortality.
Figure 1. Neuropsychiatric symptoms of long COVID. Long COVID can profoundly affect mental health and mood and cause substantial suffering. Psychological and pharmacological intervention may help. Abbreviations: Obsessive compulsive disorder (OCD); Post-traumatic stress disorder (PTSD).

3. Sleep Disorders

Among the most commonly reported neurological long COVID symptoms are sleep disturbances [63]. In a study by Huang et al., of 1733 patients suffering from long COVID symptoms, 26% had sleep disturbances [64]. In another study on 251 survivors, 41.8% experienced insomnia at 1 month post-discharge and at 3 months 25.5% still had insomnia. It is estimated that half of patients, even months after acute COVID-19 infection, report sleep-related problems. There is also a bidirectional association between mental health problems and sleep disturbance which may contribute to the mental health complications related to COVID-19 [65]. Patients have reported both trouble sleeping, nightmares and lucid dreaming, which may be a long COVID symptom or a reflection of the stress of life-altering pandemic circumstances [66].

4. Sensorimotor Deficits

4.1. Prevalence and Spectrum of Symptoms

Sensorimotor symptoms of COVID-19 can take a number of forms, including peripheral neuropathy, paresthesias, neuropathic pain, myalgia, and persistent weakness [67][68][69][70] (Figure 2). Pilotto et al. found that, at the 6 month follow-up appointment, 40% of previously hospitalized COVID-19 patients had neurologic deficits and that 7.6% of these survivors had subtle motor or sensory deficits [71]. However, an online survey of 3762 patients with COVID-19 from multiple countries found that in the initial 6 months following acute infection, sensorimotor deficits were among the most commonly reported symptoms (91%), exceeding the percentage reporting emotional/mood disorders (88%), headache (77%), and smell/taste disorders (58%). The same study revealed that 55.7% of patients experienced those symptoms for at least 6 months and that 53.7% were still experiencing those symptoms after 6 months [7]. There are many factors that could be contributing to the difference in numbers seen in these publications, most prominently the variability in defining the spectrum of sensorimotor symptoms as well as the method of collecting data, but it is clear that more work needs to be carried out to assess accurately the prevalence of sensorimotor symptoms following COVID-19.
Figure 2. Sensorimotor effects of long COVID. Long COVID can cause multiple symptoms in the periphery affecting nerves and muscles as depicted in this figure. Patients may experience nerve pain or paresthesias, most often due to involvement of small nerve fibers. Muscle pain and weakness and joint pain can also be part of long COVID syndrome. Causes of these manifestations are not completely understood, but may result from inflammation and infection-triggered immune system dysregulation. Vasculitis with microclots may also damage nerve and muscle.

4.2. COVID-19-Associated Neuropathic Pain and Neuropathies

Neuropathic pain in long COVID patients may involve sensations of itching, tingling, or burning. Although neuropathic pain can have central or peripheral etiologies, neuropathic pain persisting for 3 months after acute COVID-19 infection has been attributed to peripheral neuropathy [72][73][74][75]. Although both small and large fiber nerves are affected, recent evidence has shown that it is the small diameter, lightly myelinated or unmyelinated nerves that are most susceptible to damage [76]. The lack of myelination leaves axons subject to local stressors, including those produced by immune dysregulation. Fortunately, these fibers grow continuously throughout a person’s lifetime. If the stressful stimulus is removed, reinnervation may occur to a degree sufficient to alleviate symptoms. Although small fiber neurons have been classically thought of as having sensory functions, these nerves are also responsible for innervation of sweat glands, bone, and small blood vessels. Sweat dysfunction has been reported in some post-COVID-19 patients [77]. Interestingly, a small study of 90 patients revealed that patients suffering from neuropathic pain were 4.9 times more likely to have experienced headache during the acute phase of COVID-19 than those suffering from non-neuropathic pain [78].
Paresthesias, experienced as abnormal sensations of tingling, burning, cold, or itch that often occur in the upper or lower extremities, may indicate peripheral neuropathy following COVID-19 infection [79]. A meta-analysis of 36 studies with over 9900 patients found that 33.3% of those with long COVID symptoms reported paresthesias [80]. In agreement with this result, an observational study from Mexico of 280 patients (median age 55) who had been hospitalized with the diagnosis of COVID-19 infection were evaluated up to 6 months after discharge and 35% reported paresthesias [81].
Small fiber peripheral neuropathy may develop within a month of COVID-19 onset [67]. Ser et al. screened patients with a history of COVID-19 infection at least 4 weeks prior to evaluation, and based on an online survey, selected those with high scores in autonomic and neuropathic complaints for further evaluation with electrophysiologic studies [82]. Thirty-eight patients (35.8%) had neuropathic and/or autonomic symptoms and 13 had neuropathic complaints only. The neuropathic symptoms were patchy, mostly proximal, and not symmetrical. An abnormally high cutaneous silent period suppression index (p  =  0.002) compared to a healthy control group indicated small-fiber dysfunction.
Mononeuropathies that persist have been reported following COVID-19 in many parts of the world [83][84]. New York Presbyterian and Columbia found an association between long COVID and the development of mononeuropathy multiplex [85]. A respiratory clinic in Scotland found elevated hemidiaphragm on chest X-ray in about 3% of patients after COVID-19 pneumonia, likely due to phrenic nerve mononeuritiis. The hemidiaphragm elevation persisted for an average of 7 months after diagnosis of COVID-19 [86].
There has been evidence that COVID-19 infection is associated with demyelinating polyneuropathies, such as Guillain–Barré syndrome (GBS) and Miller–Fisher syndrome [87][88][89]. Time lapse between COVID-19 onset and symptoms of GBS vary, but may develop in under 2 weeks and generally respond well to standard treatment—either IVIG or plasma exchange [90].
Neuropathy resulting from COVID-19 may be falsely attributed to the state of critical illness seen in some severe acute infections or to compression and traction from prolonged immobility [91]. The treatment options for neuropathy related to COVID-19 are those used for inflammatory neuropathy: Intravenous immunoglobulin (IVIG) and/or corticosteroids [67][68][92]. A short course of steroids is a relatively safe empirical option [93]. Utrero-Rico et al. used prednisone at a dose of 30 mg per day for 4 days while McWilliam used prednisolone at a starting dose of 60 mg per day with tapering over about 8 weeks [94][95]. Dosage of IVIG is generally 2.0 g/kg or higher over a period of 5–7 days, but Thompson et al. used a course of 0.5 g/kg given every 2 weeks, with a plan to continue for between 6 months and 1 year to alleviate symptoms in a small highly subjective study of six long COVID patients [96]. A randomized clinical trial “Immunotherapy for Neurological Post-Acute Sequelae of SARS-CoV-2” is in progress using 0.4 g/kg/day for 5 days versus normal saline with an estimated completion date of April 2024 (NCT05350774).
Gabapentinoids and antidepressants can also be tried [97][98]. Moreover, patients may improve without intervention. COVID-19 can cause a variety of long-lasting sensorimotor symptoms that may not always be reported. Symptoms of neuropathy that linger in long COVID patients are distressing and sometimes disabling and can be difficult to treat pharmacologically [99].
In addition to being an issue for patients as a symptom itself, sensorimotor neuropathy can have profound adverse effects on quality of life. Lasting deficits can make return to work difficult or impossible, cause pain, and impair the ability to perform activities of daily living. The sensorimotor aspect of long COVID is one that may be overlooked, underdiagnosed, and cause lasting problems for patients. More study is needed to grasp the full extent of the problem in order that effective rehabilitation can ensue [100].

4.3. Myalgias

The long COVID syndrome frequently includes chronic pain commonly in the form of neuropathic pain, but also in the form of myalgias. New onset pain following acute infection with COVID-19 has been seen most frequently in the lower back, the joint space, the neck, and the calf. Risk factors for chronic pain after COVID-19 infection include increasing age and female gender. Older age was positively correlated with the development of non-neuropathic pain [78].
A meta-analysis of over 25,000 COVID-19 patients showed that the prevalence of long COVID myalgias, joint pains, and chest pain ranged from 5.65% to 18.15%, 4.6% to 12.1%, and 7.8% to 23.6%, respectively. Numbers were obtained at onset, as well as 30 days, 60 days, and <180 days after acute infection. The prevalence of musculoskeletal pain decreased between onset and 30 days of infection, increased between 30 and 60 days following infection, and decreased between 60 and <180 days of follow-up [101]. A cohort study at a single center in Turkey showed that, amongst patients with rheumatic or musculoskeletal symptoms after acute infection, at the 3 month follow-up 40.6% had myalgias. Whereas at the 6 month follow-up, only 15.1% had myalgias. Of note, this study also found a significant association between female gender and the development of myalgias following COVID-19 infection [102]. A cross-sectional study from Northern Spain also found female gender to be associated with post-COVID-19 myalgias [103]. Moreover, this study observed that those suffering from post-COVID-19 myalgias had a higher fibrinogen level than those without myalgias (510  ±  82 mg/dL vs. 394  ±  87 mg/dL; p = 0.013) [103]. A number of studies have found that higher BMI was associated with the persistence of myalgias in the setting of COVID-19 [104][105].
There is limited data on the effective treatment of long COVID myalgias and more work is needed in this area. Physical activity may be helpful in reducing myalgia [106].

4.4. Pathophysiology of Long COVID Effects on the Peripheral Nerves

The mechanisms by which neurologic damage occurs have yet to be determined definitively, but current theories include infiltration of the virus into the nerves directly or indirect effects from toxic processes that change the neural environment. Direct toxicity could occur via invasion of the virus into nerve cells via the angiotensin-converting enzyme 2 (ACE2) receptor or other means, followed by replication and possibly neuronal spread [107][108].
Indirectly, COVID-19 may leave in its wake a milieu of increased cytokine production and release contributing to chronic inflammation and oxidative stress [109]. COVID-19-induced vasculitis may also cause neuropathy since it can lead to microthrombosis within the vasa nervorum [110][111][112]. A known cause of autoimmune neuropathy seen with other viruses is induction of auto-immunogenicity, possibly by molecular mimicry leading to breaking of self-tolerance. A post-infectious autoimmune cascade could then lead to nerve damage [113].

5. Cognitive Impairment and Brain Fog

Cognitive deficits are a debilitating symptom experienced between 20 and 35% of patients with post-COVID-19 syndrome following resolution of acute COVID-19 [18][114][115][116][117]. Cognitive deficits may be seen in multiple domains compromising concentration, attention, and frontal/executive function [118][119].
A systemic review by Llana et al. of 13 studies of mostly middle-aged adults who had required hospitalization found that one third had subjective cognitive complaints and a highly variable but significant portion had objective deficits in verbal memory at 4–6 months post-COVID-19 [120]. The severity and clinical course of acute COVID-19 infection do not correlate consistently with the appearance or persistence of cognitive symptoms [121][122]. The lack of consistency makes it difficult to predict risk or gain insight into contributing factors and underlying causes of cognitive problems in long COVID patients [123].
Although the term “brain fog” does not have a universally accepted definition, it is a hallmark of long COVID widely used by the lay public and the medical community to describe difficulty thinking and focusing with confusion and lack of mental clarity [44]. Brain fog is generally one part of a symptom cluster, often correlated with decreased psychological and psychomotor performance [124]. A study of 1680 patients aged 18–55 from hospitals in Iran with long COVID symptoms found that 7.2% reported brain fog. Brain fog was positively correlated with factors including female sex, ICU admission, and respiratory problems at the onset of disease [125]. An analysis of retrospective cohort studies including nearly 1.3 million patients showed that up to 2 years after COVID-19 infection, risk of brain fog continued to be elevated [126]. Other long COVID symptoms (discussed further in other sections), such as fatigue, sleep disturbances, and mood disorders are known contributors to cognitive deficits and may worsen the feeling of brain fog [127]. Neuropsychiatric symptoms, such as depression are connected to cognitive impairments in the realms of global cognition, episodic memory, executive functioning, processing speed, visuospatial memory, attention, and working memory [128]. In a study from Whiteside et al. conducted on 49 patients diagnosed with COVID-19 with self-reported cognitive concerns, neuropsychological tests were administered to observe different areas of cognition: Performance validity, attention/working memory, processing speed, memory, language, visual-spatial, executive functioning, motor, and emotional functioning. Mean scores on objective cognitive measures were not in the impaired range, but there were elevated mean scores for mood measures [129]. The association between depressed mood and brain fog was corroborated in 137 patients in a year-long follow-up after COVID-19 recovery where depression was found to be the strongest predictor of brain fog, leading the authors to suggest that brain fog is a depressive state or the same neuroinflammation is responsible for both symptoms [130]. This study also found that the patients did not have severe cognitive deficits despite brain fog. The link between brain fog and depression is considered an indication that clinical treatment of brain fog would be most effective using a multidisciplinary approach taking neuroinflammation, mental health, sleep quality, stress management, and lifestyle adjustments into account in order to properly address all possible contributing factors [128][131].
While no single pathological hypothesis fully explains brain fog, the presumed etiology is cytokine-mediated during a prolonged immune response in which inflammatory cells and mediators cross the blood-brain barrier, inciting neuroinflammation [132][133]. A study by Nuber-Champier et al. found that higher plasma levels of the inflammatory cytokine tumor necrosis factor (TNF)-α during the acute phase of COVID-19 infection predicted the future risk of memory problems 6–9 months later [134]. He et al. also found a relationship of TNF-α to cognitive deficits even at 15 months after recovery from acute COVID-19 infection [135].
Direct infection of neurons and brain support cells and other mechanisms are also considered as etiologic factors [136][137][138]. Irrespective of causes and objective testing, subjectively, the experience of brain fog is a difficult one for long COVID patients that causes emotional distress and changes in everyday functioning [139].

6. Hyposmia, Hypogeusia, Hearing Loss

A decline in sensory function has been reported as a symptom associated with long COVID presenting as varying levels of hyposmia (dulled sense of smell), hypogeusia (dulled sense of taste), and hearing loss [9][140]. Although the cause of these symptoms is not fully understood, it is thought that damage to nasal and tongue epithelium due to inflammation as well as viral antigen persistence contribute [141][142]. In relation to smell, olfactory receptor neurons that normally turnover rapidly, exhibit diminished regenerative capability after COVID-19 infection [143]. In a recent meta-analysis, Trott et al. found that about 12.2% of patients experience complete loss of smell (anosmia) and 11.7% lose all sense of taste (ageusia) that continues beyond 12 weeks after COVID-19 infection [144]. A study from Poland conducted from September 2020 to September 2021 of 2218 patients (36.4% female, 63.6% male, mean age 53.8 ± 13.5 years) who had recovered from COVID-19 found that 98 patients (4.4%) reported smell and taste disorders up to 3 months after COVID-19 infection with no difference in the incidence of smell and taste disorders related to disease severity [145]. A study from Wuhan China of 1733 long COVID patients discharged from the hospital between January and May of 2020 found that 11% reported impairment of smell and 7% reported impairment of taste at 6 months [64]. A recent meta-analysis encompassing time-to-event data from 3699 patients in 18 studies utilized self-reported recovery of smell and taste over time after infection to project a likely outcome and predicted that, similar to the study from Poland, about 5% of patients who had problems with smell and taste initially were likely to suffer persistent dysfunction [146]. Helmsdal et al. performed phone interviews on 170 people who had been diagnosed with COVID-19 between March 2020 and April 2020 in the Faroe Islands and found that by a median of 22.6 months after infection 9% still described symptoms affecting smell and taste [147].
A study from the University of Vienna enrolled 102 patients with COVID-19-related olfactory dysfunction for an in-person evaluation at an average of 216 days after symptom onset. They used not only questionnaires, but also applied chemosensory testing of orthonasal, retronasal, and gustatory function. In this group, recovery proved to occur slowly with only 23.5% returning to normosmia after 216 days. However, only 4% had persistent anosmia, indicating that for most patients, olfactory neurons resume function [148][149]. Some patients who have experienced hyposmia or anosmia as a result of COVID-19 infection also report parosmia, where olfactory response is negatively altered. In one case series, the distortion in smell was reported as reminiscent of sewage, with others reporting rotten meat, rotten eggs, moldy socks, and citrus odors [150]. For the majority of patients, most odors triggered parosmia, but some only experienced this phenomenon for one specific smell, such as perfume, frying smell, or meat. The majority of these patients also experienced dysgeusia, distorted taste. Patients with dysgeusia have described food that was previously appealing as tasting “bland and metallic” [151]. For a significant period after the initial infection, viral presence was found in tongue epithelial cells and taste receptor cells, disrupting taste response. Mucosal inflammation leads to a reduction in epithelial cells and these cells are replenished slowly, causing dysgeusia to be a persistent long COVID symptom [152][153].
Treatment of decreased and distorted sense of smell after COVID-19 infection may encompass olfactory training through exposure to smell essences or oils and odor identification [154][155]. Training can be self-administered or given by a health professional.
Hearing loss is less well-documented after COVID-19 even though it is relatively rare [156][157]. Tinnitus is also reported [158]. In an online survey of over 3700 people, 5.2–6.4% reported hearing loss between months 4–7 after COVID-19 infection [7]. How SARS-CoV-2 affects the auditory pathway is not fully elucidated, but hearing problems may result from epithelial damage and vascular issues, such as microthrombosis [158][159][160].
Newer variants of COVID-19, such as Delta and Omicron are less likely than the original to cause chemosensory problems. A study by Coelho et al. using a dataset of over 3.5 million cases of COVID-19 found that the probability of smell and taste loss was only 17% for Omicron [161]. The effects of future variants are unknown and the problem may resurge with BA.5. Studies are ongoing to understand the mechanisms through which COVID-19 affects sensory systems and particularly how it may inflict damage to cells that are not specifically infected [162].

7. Ocular Symptoms

Ocular complications, such as epiphora, hyperemia, and chemosis have occurred in patients who were diagnosed with COVID-19, presumably due to the ACE2 receptors on the cornea, limbus, and conjunctiva. COVID-19 can in turn cause damage to cranial nerves, pupils, lacrimal system, conjunctiva, sclera, retina, choroid, and other parts of the eye [163]. These complications are uncommon, but the virus has been found in tears at low prevalence. In a study performed at a hospital in Turkey, ophthalmologists examined 359 patients hospitalized with a diagnosis of COVID-19 and found that four developed conjunctivitis, five developed subconjunctival hemorrhage, and one experienced vitreous hemorrhage [164]. These complications can develop during infection or at a later time during follow-up. In a study from Egypt, 100 patients who had recovered from an acute COVID-19 infection and 100 control patients who did not have COVID-19 were given ophthalmologic screens. The results of the screening found higher levels of retinal vascular occlusion, uveitis, central serous chorioretinopathy, and anterior ischemic optic neuropathy in those who had been infected with COVID-19 [165]. Retinal microvascular changes may also be detected after recovery from COVID-19 [166][167]. Endogenous endophthalmitis and ocular surface abnormalities, such as dryness and different tear osmolarity have been reported, as well [168]. Inflammation and elevated coagulation after infection are implicated in significantly higher levels of ocular morbidities due to COVID-19 [167].

8. Conclusions

Long COVID-associated neurocognitive impairment is a serious public health concern. It can affect those with mild or severe initial infection and spans all age groups. Persons with long COVID may find their quality of life compromised and their productivity reduced. Fatigue and brain fog are common. Anxiety, depression, poor sleep quality, and myalgias can add to the quality of life issues. There are no proven effective treatments for the multitude of neuropsychiatric symptoms of long COVID. A multi-pronged approach is often desirable and addresses the array of symptoms to support recovery through rehabilitation, good nutrition and psychiatric care. An individualized care plan can yield maximum benefit. More research is clearly needed to improve our understanding of the etiology of long COVID and provide a road map toward effective therapies.


  1. Townsend, L.; Dyer, A.H.; Jones, K.; Dunne, J.; Mooney, A.; Gaffney, F. Persistent fatigue following SARS-CoV-2 infection is common and independent of severity of initial infection. PLoS ONE 2020, 15, e0240784.
  2. Healey, Q.; Sheikh, A.; Daines, L.; Vasileiou, E. Symptoms and signs of long COVID: A rapid review and meta-analysis. J. Glob. Health 2022, 12, 05014.
  3. Aucott, J.N.; Rebman, A.W. Long-haul COVID: Heed the lessons from other infection-triggered illnesses. Lancet. 2021, 397, 967–968.
  4. El Sayed, S.; Shokry, D.; Gomaa, S.M. Post-COVID-19 fatigue and anhedonia: A cross-sectional study and their correlation to post-recovery period. Neuropsychopharmacol. Rep. 2021, 41, 50–55.
  5. Mudgal, S.K.; Gaur, R.; Rulaniya, S.; Latha, T.; Agarwal, R.; Kumar, S.; Varshney, S.; Sharma, S.; Bhattacharya, S.; Kalyani, V. Pooled Prevalence of Long COVID-19 Symptoms at 12 Months and Above Follow-Up Period: A Systematic Review and Meta-Analysis. Cureus 2023, 15, e36325.
  6. Logue, J.K.; Franko, N.M.; McCulloch, D.J.; McDonald, D.; Magedson, A.; Wolf, C.R.; Chu, H.Y. Sequelae in adults at 6 months after COVID-19 infection. JAMA Network Open 2021, 4, e210830.
  7. Davis, H.E.; Assaf, G.S.; McCorkell, L.; Wei, H.; Low, R.J.; Re’em, Y.; Redfield, S.; Austin, J.P.; Akrami, A. Characterizing long COVID in an international cohort: 7 months of symptoms and their impact. EClinicalMedicine 2021, 38, 101019.
  8. Verveen, A.; Wynberg, E.; van Willigen, H.D.G.; Boyd, A.; de Jong, M.D.; de Bree, G.; Davidovich, U.; Lok, A.; Moll van Charante, E.P.; Knoop, H.; et al. Severe Fatigue in the First Year Following SARS-CoV-2 Infection: A Prospective Cohort Study. Open Forum Infect. Dis. 2022, 9, ofac127.
  9. Stefanou, M.I.; Palaiodimou, L.; Bakola, E.; Smyrnis, N.; Papadopoulou, M.; Paraskevas, G.P.; Rizos, E.; Boutati, E.; Grigoriadis, N.; Krogias, C.; et al. Neurological manifestations of long-COVID syndrome: A narrative review. Ther. Adv. Chronic Dis. 2022, 13, 20406223221076890.
  10. Harenwall, S.; Heywood-Everett, S.; Henderson, R.; Godsell, S.; Jordan, S.; Moore, A.; Philpot, U.; Shepherd, K.; Smith, J.; Bland, A.R. Post-Covid-19 Syndrome: Improvements in Health-Related Quality of Life Following Psychology-Led Interdisciplinary Virtual Rehabilitation. J. Prim. Care Community Health 2021, 12, 21501319211067674.
  11. Azzolino, D.; Cesari, M. Fatigue in the COVID-19 pandemic. Lancet Healthy Longev. 2022, 3, e128–e129.
  12. Ladds, E.; Rushforth, A.; Wieringa, S.; Taylor, S.; Rayner, C.; Husain, L.; Greenhalgh, T. Persistent symptoms after COVID-19: Qualitative study of 114 “long covid” patients and draft quality principles for services. BMC Health Serv. Res. 2020, 20, 1144.
  13. Rass, V.; Ianosi, B.A.; Zamarian, L.; Beer, R.; Sahanic, S.; Lindner, A.; Kofler, M.; Schiefecker, A.J.; Mahlknecht, P.; Heim, B.; et al. Factors associated with impaired quality of life three months after being diagnosed with COVID-19. Qual. Life Res. 2022, 31, 1401–1414.
  14. Tabacof, L.; Tosto-Mancuso, J.; Wood, J.; Cortes, M.; Kontorovich, A.; McCarthy, D.; Rizk, D.; Rozanski, G.; Breyman, E.; Nasr, L.; et al. Post-acute COVID-19 Syndrome Negatively Impacts Physical Function, Cognitive Function, Health-Related Quality of Life, and Participation. Am. J. Phys. Med. Rehabil. 2022, 101, 48–52.
  15. Twomey, R.; DeMars, J.; Franklin, K.; Culos-Reed, S.N.; Weatherald, J.; Wrightson, J.G. Chronic Fatigue and Postexertional Malaise in People Living With Long COVID: An Observational Study. Phys. Ther. 2022, 102, pzac005.
  16. Spudich, S.; Nath, A. Nervous system consequences of COVID-19. Science 2022, 375, 267–269.
  17. Mackay, A. A Paradigm for Post-Covid-19 Fatigue Syndrome Analogous to ME/CFS. Front. Neurol. 2021, 12, 701419.
  18. Ceban, F.; Ling, S.; Lui, L.M.W.; Lee, Y.; Gill, H.; Teopiz, K.M.; Rodrigues, N.B.; Subramaniapillai, M.; Di Vincenzo, J.D.; Cao, B.; et al. Fatigue and cognitive impairment in Post-COVID-19 Syndrome: A systematic review and meta-analysis. Brain Behav. Immun. 2022, 101, 93–135.
  19. Boldrini, M.; Canoll, P.D.; Klein, R.S. How COVID-19 Affects the Brain. JAMA Psychiatry 2021, 78, 682–683.
  20. Rudroff, T.; Fietsam, A.C.; Deters, J.R.; Bryant, A.D.; Kamholz, J. Post-covid-19 fatigue: Potential contributing factors. Brain Sci. 2020, 10, 1012.
  21. Ortelli, P.; Ferrazzoli, D.; Sebastianelli, L.; Maestri, R.; Dezi, S.; Spampinato, D.; Saltuari, L.; Alibardi, A.; Engl, M.; Kofler, M.; et al. Altered motor cortex physiology and dysexecutive syndrome in patients with fatigue and cognitive difficulties after mild COVID-19. Eur. J. Neurol. 2022, 29, 1652–1662.
  22. Versace, V.; Sebastianelli, L.; Ferrazzoli, D.; Romanello, R.; Ortelli, P.; Saltuari, L.; D’Acunto, A.; Porrazzini, F.; Ajello, V.; Oliviero, A.; et al. Intracortical GABAergic dysfunction in patients with fatigue and dysexecutive syndrome after COVID-19. Clin. Neurophysiol. 2021, 132, 1138–1143.
  23. Sadlier, C.; Albrich, W.C.; Neogi, U.; Lunjani, N.; Horgan, M.; O’Toole, P.W.; O’Mahony, L. Metabolic rewiring and serotonin depletion in patients with postacute sequelae of COVID-19. Allergy 2022, 77, 1623–1625.
  24. Eroğlu, İ.; Eroğlu, B.Ç.; Güven, G.S. Altered tryptophan absorption and metabolism could underlie long-term symptoms in survivors of coronavirus disease 2019 (COVID-19). Nutrition 2021, 90, 111308.
  25. Calabria, M.; García-Sánchez, C.; Grunden, N.; Pons, C.; Arroyo, J.A.; Gómez-Anson, B.; Estévez García, M.; Belvís, R.; Morollón, N.; Vera Igual, J.; et al. Post-COVID-19 fatigue: The contribution of cognitive and neuropsychiatric symptoms. J. Neurol. 2022, 269, 3990–3999.
  26. Baslet, G.; Aybek, S.; Ducharme, S.; Modirrousta, M.; Nicholson, T.R. Neuropsychiatry’s Role in the Postacute Sequelae of COVID-19: Report From the American Neuropsychiatric Association Committee on Research. J. Neuropsychiatry Clin. Neurosci. 2022, 34, 341–350.
  27. Hejbøl, E.K.; Harbo, T.; Agergaard, J.; Madsen, L.B.; Pedersen, T.H.; Østergaard, L.J.; Andersen, H.; Schrøder, H.D.; Tankisi, H. Myopathy as a cause of fatigue in long-term post-COVID-19 symptoms: Evidence of skeletal muscle histopathology. Eur. J. Neurol. 2022, 29, 2832–2841.
  28. Pires, R.E.; Reis, I.G.N.; Waldolato, G.S.; Pires, D.D.; Bidolegui, F.; Giordano, V. What Do We Need to Know About Musculoskeletal Manifestations of COVID-19?: A Systematic Review. JBJS Rev. 2022, 10, e22.00013.
  29. Khraisat, B.; Toubasi, A.; AlZoubi, L.; Al-Sayegh, T.; Mansour, A. Meta-analysis of prevalence: The psychological sequelae among COVID-19 survivors. Int. J. Psychiatry Clin. Pract. 2021, 26, 234–243.
  30. Putri, C.; Arisa, J.; Hananto, J.E.; Hariyanto, T.I.; Kurniawan, A. Psychiatric sequelae in COVID-19 survivors: A narrative review. World J. Psychiatry 2021, 11, 821–829.
  31. Jackson, C.; Stewart, I.D.; Plekhanova, T.; Cunningham, P.S.; Hazel, A.L.; Al-Sheklly, B.; Aul, R.; Bolton, C.E.; Chalder, T.; Chalmers, J.D.; et al. Effects of sleep disturbance on dyspnoea and impaired lung function following hospital admission due to COVID-19 in the UK: A prospective multicentre cohort study. Lancet Respir. Med. 2023; Advance online publication.
  32. Zakia, H.; Pradana, K.; Iskandar, S. Risk factors for psychiatric symptoms in patients with long COVID: A systematic review. PLoS ONE 2023, 18, e0284075.
  33. Gramaglia, C.; Gattoni, E.; Gambaro, E.; Bellan, M.; Balbo, P.E.; Baricich, A.; Sainaghi, P.P.; Pirisi, M.; Binda, V.; Feggi, A.; et al. Anxiety, Stress and Depression in COVID-19 Survivors from an Italian Cohort of Hospitalized Patients: Results from a 1-Year Follow-Up. Front. Psychiatry 2022, 13, 862651.
  34. Alghamdi, H.Y.; Alrashed, A.M.; Jawhari, A.M.; Abdel-Moneim, A.S. Neuropsychiatric symptoms in post-COVID-19 long haulers. Acta Neuropsychiatr. 2022, 34, 318–329.
  35. Rass, V.; Beer, R.; Schiefecker, A.J.; Lindner, A.; Kofler, M.; Ianosi, B.A.; Mahlknecht, P.; Heim, B.; Peball, M.; Carbone, F.; et al. Neurological outcomes 1 year after COVID-19 diagnosis: A prospective longitudinal cohort study. Eur. J. Neurol. 2022, 29, 1685–1696.
  36. da Silva Lopes, L.; Silva, R.O.; de Sousa Lima, G.; de Araújo Costa, A.C.; Barros, D.F.; Silva-Néto, R.P. Is there a common pathophysiological mechanism between COVID-19 and depression? Acta Neurol. Belg. 2021, 121, 1117–1122.
  37. Matits, L.; Munk, M.; Bizjak, D.A.; Kolassa, I.T.; Karrasch, S.; Vollrath, S.; Jerg, A.; Steinacker, J.M. Inflammation and severity of depressive symptoms in physically active individuals after COVID-19—An exploratory immunopsychological study investigating the effect of inflammation on depressive symptom severity. Brain Behav. Immun. Health 2023, 30, 100614.
  38. Taquet, M.; Geddes, J.R.; Husain, M.; Luciano, S.; Harrison, P.J. 6-month neurological and psychiatric outcomes in 236 379 survivors of COVID-19: A retrospective cohort study using electronic health records. Lancet Psychiatry 2021, 8, 416–427.
  39. Khan, S.; Karim, M.; Gupta, V.; Goel, H.; Jain, R. A Comprehensive Review of COVID-19-Associated Endocrine Manifestations. South. Med. J. 2023, 116, 350–354.
  40. Al-Hakeim, H.K.; Al-Rubaye, H.T.; Jubran, A.S.; Almulla, A.F.; Moustafa, S.R.; Maes, M. Increased insulin resistance due to Long COVID is associated with depressive symptoms and partly predicted by the inflammatory response during acute infection. Braz. J. Psychiatry 2023. Advance online publication.
  41. Bonati, M.; Campi, R.; Segre, G. Psychological impact of the quarantine during the COVID-19 pandemic on the general European adult population: A systematic review of the evidence. Epidemiol. Psychiatr. Sci. 2022, 31, e27.
  42. Dos Santos, E.R.R.; Silva de Paula, J.L.; Tardieux, F.M.; Costa-E-Silva, V.N.; Lal, A.; Leite, A.F.B. Association between COVID-19 and anxiety during social isolation: A systematic review. World J. Clin. Cases 2021, 9, 7433–7444.
  43. Pietrabissa, G.; Simpson, S.G. Psychological Consequences of Social Isolation During COVID-19 Outbreak. Front. Psychol. 2020, 11, 2201.
  44. Crook, H.; Raza, S.; Nowell, J.; Young, M.; Edison, P. Long covid—Mechanisms, risk factors, and management. BMJ 2021, 374, n1648.
  45. Ahmed, G.K.; Khedr, E.M.; Hamad, D.A.; Meshref, T.S.; Hashem, M.M.; Aly, M.M. Long term impact of Covid-19 infection on sleep and mental health: A cross-sectional study. Psychiatry Res. 2021, 305, 114243.
  46. Jain, A.; Bodicherla, K.P.; Bashir, A.; Batchelder, E.; Jolly, T.S. COVID-19 and Obsessive-Compulsive Disorder: The Nightmare Just Got Real. Prim. Care Companion CNS Disord. 2021, 23, 20l02877.
  47. Loosen, A.M.; Skvortsova, V.; Hauser, T.U. Obsessive-compulsive symptoms and information seeking during the Covid-19 pandemic. Transl. Psychiatry 2021, 11, 309.
  48. Abba-Aji, A.; Li, D.; Hrabok, M.; Shalaby, R.; Gusnowski, A.; Vuong, W.; Surood, S.; Nkire, N.; Li, X.M.; Greenshaw, A.J.; et al. COVID-19 pandemic and mental health: Prevalence and correlates of new-onset obsessive-compulsive symptoms in a Canadian Province. Int. J. Environ. Res. Public Health 2020, 17, 6986.
  49. Linde, E.S.; Varga, T.V.; Clotworthy, A. Obsessive-Compulsive Disorder During the COVID-19 Pandemic-A Systematic Review. Front. Psychiatry 2022, 13, 806872.
  50. Kaseda, E.T.; Levine, A.J. Post-traumatic stress disorder: A differential diagnostic consideration for COVID-19 survivors. Clin. Neuropsychol. 2020, 34, 1498–1514.
  51. Mazza, M.G.; De Lorenzo, R.; Conte, C.; Poletti, S.; Vai, B.; Bollettini, I.; Melloni, E.M.T.; Furlan, R.; Ciceri, F.; Rovere-Querini, P.; et al. Anxiety and depression in COVID-19 survivors: Role of inflammatory and clinical predictors. Brain Behav. Immun. 2020, 89, 594–600.
  52. Mao, J.; Wang, C.; Teng, C.; Wang, M.; Zhou, S.; Zhao, K.; Ye, X.; Wang, Y. Prevalence and Associated Factors of PTSD Symptoms After the COVID-19 Epidemic Outbreak in an Online Survey in China: The Age and Gender Differences Matter. Neuropsychiatr. Dis. Treat. 2022, 18, 761–771.
  53. Greene, T.; El-Leithy, S.; Billings, J.; Albert, I.; Birch, J.; Campbell, M.; Ehntholt, K.; Fortune, L.; Gilbert, N.; Grey, N.; et al. Anticipating PTSD in severe COVID survivors: The case for screen-and-treat. Eur. J. Psychotraumatol. 2022, 13, 1959707.
  54. Houben-Wilke, S.; Goërtz, Y.M.; Delbressine, J.M.; Vaes, A.W.; Meys, R.; Machado, F.V.; van Herck, M.; Burtin, C.; Posthuma, R.; Franssen, F.M.; et al. The Impact of Long COVID-19 on Mental Health: Observational 6-Month Follow-Up Study. JMIR Ment. Health 2022, 9, e33704.
  55. Savarraj, J.P.J.; Burkett, A.B.; Hinds, S.N.; Paz, A.S.; Assing, A.; Juneja, S.; Colpo, G.D.; Torres, L.F.; Cho, S.M.; Gusdon, A.M.; et al. Pain and Other Neurological Symptoms Are Present at 3 Months After Hospitalization in COVID-19 Patients. Front. Pain Res. 2021, 2, 737961.
  56. Schou, T.M.; Joca, S.; Wegener, G.; Bay-Richter, C. Psychiatric and neuropsychiatric sequelae of COVID-19—A systematic review. Brain Behav. Immun. 2021, 97, 328–348.
  57. Ferrando, S.J.; Klepacz, L.; Lynch, S.; Tavakkoli, M.; Dornbush, R.; Baharani, R.; Smolin, Y.; Bartell, A. COVID-19 Psychosis: A Potential New Neuropsychiatric Condition Triggered by Novel Coronavirus Infection and the Inflammatory Response? Psychosomatics 2020, 61, 551–555.
  58. Chaudhary, A.M.D.; Musavi, N.B.; Saboor, S.; Javed, S.; Khan, S.; Naveed, S. Psychosis during the COVID-19 pandemic: A systematic review of case reports and case series. J. Psychiatr. Res. 2022, 153, 37–55.
  59. Smith, C.M.; Gilbert, E.B.; Riordan, P.A.; Helmke, N.; von Isenburg, M.; Kincaid, B.R.; Shirey, K.G. Covid-19-associated psychosis: A systematic review of case reports. Gen. Hosp. Psychiatry 2021, 73, 84–100.
  60. O’Hanlon, S.; Inouye, S.K. Delirium: A missing piece in the COVID-19 pandemic puzzle. Age Ageing 2020, 49, 497–498.
  61. Otani, K.; Fukushima, H.; Matsuishi, K. COVID-19 delirium and encephalopathy: Pathophysiology assumed in the first 3 years of the ongoing pandemic. Brain Disord. 2023, 10, 100074.
  62. Rebora, P.; Rozzini, R.; Bianchetti, A.; Blangiardo, P.; Marchegiani, A.; Piazzoli, A.; Mazzeo, F.; Cesaroni, G.; Chizzoli, A.; Guerini, F.; et al. Delirium in patients with SARS-CoV-2 infection: A multicenter study. J. Am. Geriatr. Soc. 2020, 69, 293–299.
  63. Premraj, L.; Kannapadi, N.V.; Briggs, J.; Seal, S.M.; Battaglini, D.; Fanning, J.; Suen, J.; Robba, C.; Fraser, J.; Cho, S.M. Mid and long-term neurological and neuropsychiatric manifestations of post-COVID-19 syndrome: A meta-analysis. J. Neurol. Sci. 2022, 434, 120162.
  64. Huang, C.; Huang, L.; Wang, Y.; Li, X.; Ren, L.; Gu, X.; Kang, L.; Guo, L.; Liu, M.; Zhou, X.; et al. 6-month consequences of COVID-19 in patients discharged from hospital: A cohort study. Lancet 2021, 397, 220–232.
  65. Efstathiou, V.; Stefanou, M.-I.; Demetriou, M.; Siafakas, N.; Makris, M.; Tsivgoulis, G.; Zoumpourlis, V.; Kympouropoulos, S.; Tsoporis, J.; Spandidos, D.; et al. Long Covid and neuropsychiatric manifestations (review). Exp. Ther. Med. 2022, 23, 363.
  66. Scarpelli, S.; Nadorff, M.R.; Bjorvatn, B.; Chung, F.; Dauvilliers, Y.; Espie, C.A.; Inoue, Y.; Matsui, K.; Merikanto, I.; Morin, C.M.; et al. Nightmares in People with COVID-19: Did Coronavirus Infect Our Dreams? Nat. Sci. Sleep 2022, 14, 93–108.
  67. Oaklander, A.L.; Mills, A.J.; Kelley, M.; Toran, L.S.; Smith, B.; Dalakas, M.C.; Nath, A. Peripheral Neuropathy Evaluations of Patients With Prolonged Long COVID. Neuroimmunol. Neuroinflamm. 2022, 9, e1146.
  68. Silva-Hernández, L.; Cabal-Paz, B.; Mayo-Canalejo, D.; Horga, A. Post-COVID symptoms of potential peripheral nervous and muscular origin. Neurol. Perspect. 2021, 1, S25–S30.
  69. Munblit, D.; Bobkova, P.; Spiridonova, E.; Shikhaleva, A.; Gamirova, A.; Blyuss, O.; Nekliudov, N.; Bugaeva, P.; Andreeva, M.; DunnGalvin, A.; et al. Sechenov StopCOVID Research Team Incidence and risk factors for persistent symptoms in adults previously hospitalized for COVID-19. Clin. Exp. Allergy 2021, 51, 1107–1120.
  70. Wahlgren, C.; Forsberg, G.; Divanoglou, A.; Östholm Balkhed, Å.; Niward, K.; Berg, S.; Levi, R. Two-year follow-up of patients with post-COVID-19 condition in Sweden: A prospective cohort study. Lancet Reg. Health Eur. 2023.
  71. Pilotto, A.; Cristillo, V.; Cotti Piccinelli, S.; Zoppi, N.; Bonzi, G.; Sattin, D.; Schiavolin, S.; Raggi, A.; Canale, A.; Gipponi, S.; et al. Long-term neurological manifestations of COVID-19: Prevalence and predictive factors. Neurol. Sci. 2021, 42, 4903–4907.
  72. Di Stefano, G.; Falco, P.; Galosi, E.; Di Pietro, G.; Leone, C.; Truini, A. A systematic review and metanalysis of neuropathic pain associated with coronavirus disease 2019. Eur. J. Pain 2023, 27, 44–53.
  73. Fernández-de-Las-Peñas, C.; Nijs, J.; Neblett, R.; Polli, A.; Moens, M.; Goudman, L.; Shekhar Patil, M.; Knaggs, R.D.; Pickering, G.; Arendt-Nielsen, L. Phenotyping Post-COVID Pain as a Nociceptive, Neuropathic, or Nociplastic Pain Condition. Biomedicines 2022, 10, 2562.
  74. Burakgazi, A.Z. Small-Fiber Neuropathy Possibly Associated with COVID-19. Case Rep. Neurol. 2022, 14, 208–212.
  75. Odozor, C.U.; Kannampallil, T.; Ben Abdallah, A.; Roles, K.; Burk, C.; Warner, B.C.; Alaverdyan, H.; Clifford, D.B.; Piccirillo, J.F.; Haroutounian, S. Post-acute sensory neurological sequelae in patients with severe acute respiratory syndrome coronavirus 2 infection: The COVID-PN observational cohort study. Pain 2022, 163, 2398–2410.
  76. Grieco, T.; Gomes, V.; Rossi, A.; Cantisani, C.; Greco, M.E.; Rossi, G.; Sernicola, A.; Pellacani, G. The Pathological Culprit of Neuropathic Skin Pain in Long COVID-19 Patients: A Case Series. J. Clin. Med. 2022, 11, 4474.
  77. Hinduja, A.; Moutairou, A.; Calvet, J.H. Sudomotor dysfunction in patients recovered from COVID-19. Neurophysiol. Clin. 2021, 51, 193–196.
  78. Zis, P.; Ioannou, C.; Artemiadis, A.; Christodoulou, K.; Kalampokini, S.; Hadjigeorgiou, G.M. Prevalence and Determinants of Chronic Pain Post-COVID: Cross-Sectional Study. J. Clin. Med. 2022, 11, 5569.
  79. Abrams, R.M.C.; Simpson, D.M.; Navis, A.; Jette, N.; Zhou, L.; Shin, S.C. Small fiber neuropathy associated with SARS-CoV-2 infection. Muscle Nerve 2022, 65, 440–443.
  80. Pinzon, R.T.; Wijaya, V.O.; Jody, A.A.; Nunsio, P.N.; Buana, R.B. Persistent neurological manifestations in long COVID-19 syndrome: A systematic review and meta-analysis. J. Infect. Public Health 2022, 15, 856–869.
  81. Irisson-Mora, I.; Salgado-Cordero, A.M.; Reyes-Varón, E.; Cataneo-Piña, D.J.; Fernández-Sánchez, M.; Buendía-Roldán, I.; Salazar-Lezama, M.A.; Occupational Health and Preventive Medicine Consortium. Comparison between the persistence of post COVID-19 symptoms on critical patients requiring invasive mechanical ventilation and non-critical patients. PLoS ONE 2022, 17, e0273041.
  82. Ser, M.H.; Çalıkuşu, F.Z.; Tanrıverdi, U.; Abbaszade, H.; Hakyemez, S.; Balkan, İ.İ.; Karaali, R.; Gündüz, A. Autonomic and neuropathic complaints of long-COVID objectified: An investigation from electrophysiological perspective. Neurol. Sci. 2022, 43, 6167–6177.
  83. Needham, E.; Newcombe, V.; Michell, A.; Thornton, R.; Grainger, A.; Anwar, F.; Warburton, E.; Menon, D.; Trivedi, M.; Sawcer, S. Mononeuritis multiplex: An unexpectedly common feature of severe COVID-19. J. Neurol. 2021, 268, 2685–2689.
  84. Mahmood, S.B.Z.; Mushtaq, M.Z.; Kanwar, D.; Ali, S.A. Lower limb axonal mononeuropathies as sequelae of COVID-19: A case report and review of literature. Egypt. J. Neurol. Psychiatr. Neurosurg. 2022, 58, 22.
  85. Carberry, N.; Badu, H.; Ulane, C.M.; Beckley, A.; Rosenberg, S.J.; Brenner, K.; Brannagan, T.H. Mononeuropathy Multiplex After COVID-19. J. Clin. Neuromuscul. Dis. 2021, 23, 24–30.
  86. Law, S.M.; Scott, K.; Alkarn, A.; Mahjoub, A.; Mallik, A.K.; Roditi, G.; Choo-Kang, B. COVID-19 associated phrenic nerve mononeuritis: A case series. Thorax 2022, 77, 834–838.
  87. Palaiodimou, L.; Stefanou, M.I.; Katsanos, A.H.; Fragkou, P.C.; Papadopoulou, M.; Moschovos, C.; Michopoulos, I.; Kokotis, P.; Bakirtzis, C.; Naska, A.; et al. Prevalence, clinical characteristics and outcomes of Guillain-Barré syndrome spectrum associated with COVID-19: A systematic review and meta-analysis. Eur. J. Neurol. 2021, 28, 3517–3529.
  88. Yaqoob, A.; Dar, W.; Khuja, Z.; Bukhari, I.; Raina, A.; Ganie, H.; Chandra, A.; Wani, M.; Asimi, R.; Wani, F. Miller Fisher syndrome associated with COVID 19. J. Family Med. Prim. Care 2022, 11, 4023–4025.
  89. Malekpour, M.; Khanmohammadi, S.; Meybodi, M.J.E.; Shekouh, D.; Rahmanian, M.R.; Kardeh, S.; Azarpira, N. COVID-19 as a trigger of Guillain-Barré syndrome: A review of the molecular mechanism. Immun. Inflamm. Dis. 2023, 11, e875.
  90. Noon, A.; Malhi, J.K.; Wong, C.K. Atypical Guillain-Barré Syndrome Presenting After COVID-19 Infection. Cureus 2022, 14, e29521.
  91. Finsterer, J.; Scorza, F.A.; Scorza, C.A.; Fiorini, A.C. Peripheral neuropathy in COVID-19 is due to immune-mechanisms, pre-existing risk factors, anti-viral drugs, or bedding in the Intensive Care Unit. Arq. Neuropsiquiatr. 2021, 79, 924–928.
  92. Liu, X.; Treister, R.; Lang, M.; Oaklander, A.L. IVIg for apparently autoimmune small-fiber polyneuropathy: First analysis of efficacy and safety. Ther. Adv. Neurol. Disord. 2018, 11, 1756285617744484.
  93. Franke, C.; Berlit, P.; Prüss, H. Neurological manifestations of post-COVID-19 syndrome S1-guideline of the German society of neurology. Neurol. Res. Pract. 2022, 4, 28.
  94. Utrero-Rico, A.; Ruiz-Ruigómez, M.; Laguna-Goya, R.; Arrieta-Ortubay, E.; Chivite-Lacaba, M.; González-Cuadrado, C.; Lalueza, A.; Almendro-Vazquez, P.; Serrano, A.; Aguado, J.M.; et al. A Short Corticosteroid Course Reduces Symptoms and Immunological Alterations Underlying Long-COVID. Biomedicines 2021, 9, 1540.
  95. McWilliam, M.; Samuel, M.; Alkufri, F.H. Neuropathic pain post-COVID-19: A case report. BMJ Case Rep. 2021, 14, e243459.
  96. Thompson, J.S.; Thornton, A.C.; Ainger, T.; Garvy, B.A. Long-term high-dose immunoglobulin successfully treats Long COVID patients with pulmonary, neurologic, and cardiologic symptoms. Front. Immunol. 2023, 13, 1033651.
  97. Attal, N.; Martinez, V.; Bouhassira, D. Potential for increased prevalence of neuropathic pain after the COVID-19 pandemic. Pain Rep. 2021, 6, e884.
  98. El-Tallawy, S.N.; Perglozzi, J.V.; Ahmed, R.S.; Kaki, A.M.; Nagiub, M.S.; LeQuang, J.K.; Hadarah, M.M. Pain Management in the Post-COVID Era-An Update: A Narrative Review. Pain Ther. 2023, 12, 423–448.
  99. Córdova-Martínez, A.; Caballero-García, A.; Pérez-Valdecantos, D.; Roche, E.; Noriega-González, D.C. Peripheral Neuropathies Derived from COVID-19: New Perspectives for Treatment. Biomedicines 2022, 10, 1051.
  100. Figueroa-Padilla, I.; Rivera Fernández, D.E.; Cházaro Rocha, E.F.; Eugenio Gutiérrez, A.L.; Jáuregui-Renaud, K. Body Weight May Have a Role on Neuropathy and Mobility after Moderate to Severe COVID-19: An Exploratory Study. Medicina 2022, 58, 1401.
  101. Fernández-de-Las-Peñas, C.; Navarro-Santana, M.; Plaza-Manzano, G.; Palacios-Ceña, D.; Arendt-Nielsen, L. Time course prevalence of post-COVID pain symptoms of musculoskeletal origin in patients who had survived severe acute respiratory syndrome coronavirus 2 infection: A systematic review and meta-analysis. Pain 2022, 163, 1220–1231.
  102. Karaarslan, F.; Güneri, F.D.; Kardeş, S. Long COVID: Rheumatologic/musculoskeletal symptoms in hospitalized COVID-19 survivors at 3 and 6 months. Clin. Rheumatol. 2022, 41, 289–296.
  103. Maamar, M.; Artime, A.; Pariente, E.; Fierro, P.; Ruiz, Y.; Gutiérrez, S.; Tobalina, M.; Díaz-Salazar, S.; Ramos, C.; Olmos, J.M.; et al. Post-COVID-19 syndrome, low-grade inflammation and inflammatory markers: A cross-sectional study. Curr. Med. Res. Opin. 2022, 38, 901–909.
  104. Shanthanna, H.; Nelson, A.M.; Kissoon, N.; Narouze, S. The COVID-19 pandemic and its consequences for chronic pain: A narrative review. Anaesthesia 2022, 77, 1039–1050.
  105. Azadvari, M.; Haghparast, A.; Nakhostin-Ansari, A.; Emami Razavi, S.Z.; Hosseini, M. Musculoskeletal symptoms in patients with long COVID: A cross-sectional study on Iranian patients. Heliyon 2022, 8, e10148.
  106. Galluzzo, V.; Zazzara, M.B.; Ciciarello, F.; Tosato, M.; Martone, A.M.; Pais, C.; Savera, G.; Calvani, R.; Picca, A.; Marzetti, E.; et al. Inadequate Physical Activity Is Associated with Worse Physical Function in a Sample of COVID-19 Survivors with Post-Acute Symptoms. J. Clin. Med. 2023, 12, 2517.
  107. Guerrero, J.I.; Barragán, L.A.; Martínez, J.D.; Montoya, J.P.; Peña, A.; Sobrino, F.E.; Tovar-Spinoza, Z.; Ghotme, K.A. Central and peripheral nervous system involvement by COVID-19: A systematic review of the pathophysiology, clinical manifestations, neuropathology, neuroimaging, electrophysiology, and cerebrospinal fluid findings. BMC Infect. Dis. 2021, 21, 515.
  108. Dayaramani, C.; De Leon, J.; Reiss, A.B. Cardiovascular Disease Complicating COVID-19 in the Elderly. Medicina 2021, 57, 833.
  109. Moghimi, N.; Di Napoli, M.; Biller, J.; Siegler, J.E.; Shekhar, R.; McCullough, L.D.; Harkins, M.S.; Hong, E.; Alaouieh, D.A.; Mansueto, G.; et al. The Neurological Manifestations of Post-Acute Sequelae of SARS-CoV-2 infection. Curr. Neurol. Neurosci. Rep. 2021, 21, 44.
  110. Taga, A.; Lauria, G. COVID-19 and the peripheral nervous system. A 2-year review from the pandemic to the vaccine era. J. Peripher. Nerv. Syst. 2022, 27, 4–30.
  111. Michaelson, N.M.; Malhotra, A.; Wang, Z.; Heier, L.; Tanji, K.; Wolfe, S.; Gupta, A.; MacGowan, D. Peripheral neurological complications during COVID-19: A single center experience. J. Neurol. Sci. 2022, 434, 120118.
  112. Saif, A.; Pick, A. Polyneuropathy following COVID-19 infection: The rehabilitation approach. BMJ Case Rep. 2021, 14, e242330.
  113. Mahboubi Mehrabani, M.; Karvandi, M.S.; Maafi, P.; Doroudian, M. Neurological complications associated with Covid-19; molecular mechanisms and therapeutic approaches. Rev. Med. Virol. 2022, 32, e2334.
  114. Lopez-Leon, S.; Wegman-Ostrosky, T.; Perelman, C.; Sepulveda, R.; Rebolledo, P.A.; Cuapio, A.; Villapol, S. More than 50 long-term effects of COVID-19: A systematic review and meta-analysis. Sci. Rep. 2021, 11, 16144.
  115. Hartung, T.J.; Neumann, C.; Bahmer, T.; Chaplinskaya-Sobol, I.; Endres, M.; Geritz, J.; Haeusler, K.G.; Heuschmann, P.U.; Hildesheim, H.; Hinz, A.; et al. Fatigue and cognitive impairment after COVID-19: A prospective multicentre study. EClinicalMedicine 2022, 53, 101651.
  116. Albu, S.; Zozaya, N.R.; Murillo, N.; García-Molina, A.; Chacón, C.A.F.; Kumru, H. Multidisciplinary outpatient rehabilitation of physical and neurological sequelae and persistent symptoms of covid-19: A prospective, observational cohort study. Disabil. Rehabil. 2022, 44, 6833–6840.
  117. Badenoch, J.B.; Rengasamy, E.R.; Watson, C.; Jansen, K.; Chakraborty, S.; Sundaram, R.D.; Hafeez, D.; Burchill, E.; Saini, A.; Thomas, L.; et al. Persistent neuropsychiatric symptoms after COVID-19: A systematic review and meta-analysis. Brain Commun. 2021, 4, fcab297.
  118. Delgado-Alonso, C.; Valles-Salgado, M.; Delgado-Álvarez, A.; Yus, M.; Gómez-Ruiz, N.; Jorquera, M.; Polidura, C.; Gil, M.J.; Marcos, A.; Matías-Guiu, J.; et al. Cognitive dysfunction associated with COVID-19: A comprehensive neuropsychological study. J. Psychiatr. Res. 2022, 150, 40–46.
  119. Santoyo-Mora, M.; Villaseñor-Mora, C.; Cardona-Torres, L.M.; Martínez-Nolasco, J.J.; Barranco-Gutiérrez, A.I.; Padilla-Medina, J.A.; Bravo-Sánchez, M.G. COVID-19 Long-Term Effects: Is There an Impact on the Simple Reaction Time and Alternative-Forced Choice on Recovered Patients? Brain Sci. 2022, 12, 1258.
  120. Llana, T.; Zorzo, C.; Mendez-Lopez, M.; Mendez, M. Memory alterations after COVID-19 infection: A systematic review. Appl. Neuropsychol. Adult 2022.
  121. Daugherty, S.E.; Guo, Y.; Heath, K.; Dasmariñas, M.C.; Jubilo, K.G.; Samranvedhya, J.; Lipsitch, M.; Cohen, K. Risk of clinical sequelae after the acute phase of SARS-CoV-2 infection: Retrospective cohort study. BMJ 2021, 373, n1098.
  122. Graham, E.L.; Clark, J.R.; Orban, Z.S.; Lim, P.H.; Szymanski, A.L.; Taylor, C.; DiBiase, R.M.; Jia, D.T.; Balabanov, R.; Ho, S.U.; et al. Persistent neurologic symptoms and cognitive dysfunction in non-hospitalized Covid-19 “long haulers”. Ann. Clin. Transl. Neurol. 2021, 8, 1073–1085.
  123. Wild, C.J.; Norton, L.; Menon, D.K.; Ripsman, D.A.; Swartz, R.H.; Owen, A.M. Disentangling the cognitive, physical, and mental health sequelae of COVID-19. Cell Rep. Med. 2022, 3, 100750.
  124. Jennings, G.; Monaghan, A.; Xue, F.; Duggan, E.; Romero-Ortuño, R. Comprehensive clinical characterisation of brain fog in adults reporting long covid symptoms. J. Clin. Med. 2022, 11, 3440.
  125. Asadi-Pooya, A.A.; Akbari, A.; Emami, A.; Lotfi, M.; Rostamihosseinkhani, M.; Nemati, H.; Barzegar, Z.; Kabiri, M.; Zeraatpisheh, Z.; Farjoud-Kouhanjani, M.; et al. Long Covid syndrome-associated brain fog. J. Med. Virol. 2021, 94, 979–984.
  126. Taquet, M.; Sillett, R.; Zhu, L.; Mendel, J.; Camplisson, I.; Dercon, Q.; Harrison, P.J. Neurological and psychiatric risk trajectories after SARS-CoV-2 infection: An analysis of 2-year retrospective cohort studies including 1,284,437 patients. Lancet Psychiatry 2022, 9, 815–827.
  127. Moy, F.M.; Hairi, N.N.; Lim, E.; Bulgiba, A. Long COVID and its associated factors among COVID survivors in the community from a middle-income country-An online cross-sectional study. PLoS ONE 2022, 17, e0273364.
  128. Krishnan, K.; Lin, Y.F.; Prewitt, K.-R.M.; Potter, D.A. Multidisciplinary approach to brain fog and related persisting symptoms post covid-19. J. Health Serv. Psychol. 2022, 48, 31–38.
  129. Whiteside, D.M.; Basso, M.R.; Naini, S.M.; Porter, J.; Holker, E.; Waldron, E.J.; Melnik, T.E.; Niskanen, N.; Taylor, S.E. Outcomes in post-acute sequelae of COVID-19 (PASC) at 6 months post-infection Part 1: Cognitive functioning. Clin. Neuropsychol. 2022, 36, 806–828.
  130. Cristillo, V.; Pilotto, A.; Piccinelli, S.C.; Gipponi, S.; Leonardi, M.; Bezzi, M.; Padovani, A. Predictors of “brain fog” 1 year after COVID-19 disease. Neurol. Sci. 2022, 43, 5795–5797.
  131. Taube, M. Depression and brain fog as long-COVID mental health consequences: Difficult, complex and partially successful treatment of a 72-year-old patient-A case report. Front. Psychiatry 2023, 14, 1153512.
  132. Hugon, J. Long-COVID: Cognitive deficits (brain fog) and brain lesions in non-hospitalized patients. Presse Med. 2022, 51, 104090.
  133. Kao, J.; Frankland, P.W. Covid Fog Demystified. Cell 2022, 185, 2391–2393.
  134. Nuber-Champier, A.; Cionca, A.; Breville, G.; Voruz, P.; de Alcântara, I.J.; Allali, G.; Lalive, P.H.; Benzakour, L.; Lövblad, K.O.; Braillard, O.; et al. Acute TNFα levels predict cognitive impairment 6-9 months after COVID-19 infection. Psychoneuroendocrinology 2023, 153, 106104.
  135. He, D.; Yuan, M.; Dang, W.; Bai, L.; Yang, R.; Wang, J.; Ma, Y.; Liu, B.; Liu, S.; Zhang, S.; et al. Long term neuropsychiatric consequences in COVID-19 survivors: Cognitive impairment and inflammatory underpinnings fifteen months after discharge. Asian J. Psychiatr. 2023, 80, 103409.
  136. Jeong, G.U.; Lyu, J.; Kim, K.D.; Chung, Y.C.; Yoon, G.Y.; Lee, S.; Hwang, I.; Shin, W.H.; Ko, J.; Lee, J.Y.; et al. SARS-CoV-2 infection of microglia elicits proinflammatory activation and apoptotic cell death. Microbiol. Spectr. 2022, 10, e0109122.
  137. Marshall, M. COVID and the brain: Researchers zero in on how damage occurs. Nature 2021, 595, 484–485.
  138. McMahon, C.L.; Staples, H.; Gazi, M.; Carrion, R.; Hsieh, J. SARS-CoV-2 targets glial cells in human cortical organoids. Stem Cell Rep. 2021, 16, 1156–1164.
  139. Goldstein Ferber, S.; Shoval, G.; Zalsman, G.; Weller, A. Does COVID-19 related symptomatology indicate a transdiagnostic neuropsychiatric disorder?—Multidisciplinary implications. World J. Psychiatry 2022, 12, 1004–1015.
  140. Trecca, E.M.C.; Cassano, M.; Longo, F.; Petrone, P.; Miani, C.; Hummel, T.; Gelardi, M. Results from psychophysical tests of smell and taste during the course of SARS-CoV-2 infection: A review. Acta Otorhinolaryngol. Ital. 2022, 42, S20–S35.
  141. Costa Dos Santos, J.; Ximenes Rabelo, M.; Mattana Sebben, L.; de Souza Carneiro, M.V.; Bosco Lopes Botelho, J.; Cardoso Neto, J.; Nogueira Barbosa, A.; Monteiro de Carvalho, D.; Pontes, G.S. Persistence of SARS-CoV-2 Antigens in the Nasal Mucosa of Eight Patients with Inflammatory Rhinopathy for over 80 Days following Mild COVID-19 Diagnosis. Viruses 2023, 15, 899.
  142. Tsuchiya, H. Oral Symptoms Associated with COVID-19 and Their Pathogenic Mechanisms: A Literature Review. Dent. J. 2021, 9, 32.
  143. Han, A.Y.; Mukdad, L.; Long, J.L.; Lopez, I.A. Anosmia in COVID-19: Mechanisms and significance. Chem. Senses 2020, 45, 423–428.
  144. Trott, M.; Driscoll, R.; Pardhan, S. The prevalence of sensory changes in post-COVID syndrome: A systematic review and meta-analysis. Front. Med. 2022, 9, 980253.
  145. Chudzik, M.; Babicki, M.; Mastalerz-Migas, A.; Kapusta, J. Persisting Smell and Taste Disorders in Patients Who Recovered from SARS-CoV-2 Virus Infection-Data from the Polish PoLoCOV-CVD Study. Viruses 2022, 14, 1763.
  146. Tan, B.K.J.; Han, R.; Zhao, J.J.; Tan, N.K.W.; Quah, E.S.H.; Tan, C.J.; Chan, Y.H.; Teo, N.W.Y.; Charn, T.C.; See, A.; et al. Prognosis and persistence of smell and taste dysfunction in patients with covid-19: Meta-analysis with parametric cure modelling of recovery curves. BMJ 2022, 378, e069503.
  147. Helmsdal, G.; Hanusson, K.D.; Kristiansen, M.F.; Foldbo, B.M.; Danielsen, M.E.; Steig, B.Á.; Gaini, S.; Strøm, M.; Weihe, P.; Petersen, M.S. Long COVID in the Long Run-23-Month Follow-up Study of Persistent Symptoms. Open Forum Infect. Dis. 2022, 9, ofac270.
  148. Prem, B.; Liu, D.T.; Besser, G.; Sharma, G.; Dultinger, L.E.; Hofer, S.V.; Matiasczyk, M.M.; Renner, B.; Mueller, C.A. Long-lasting olfactory dysfunction in COVID-19 patients. Eur. Arch. Otorhinolaryngol. 2021, 279, 3485–3492.
  149. Boscolo-Rizzo, P.; Tofanelli, M.; Zanelli, E.; Gardenal, N.; Tirelli, G. COVID-19-Related Quantitative and Qualitative Olfactory and Gustatory Dysfunction: Long-Term Prevalence and Recovery Rate. ORL J. Otorhinolaryngol. Relat. Spec. 2023, 85, 67–71.
  150. Rashid, R.A.; Alaqeedy, A.A.; Al-Ani, R.M. Parosmia Due to COVID-19 Disease: A 268 Case Series. Indian J. Otolaryngol. Head Neck Surg. 2022, 74, 2970–2977.
  151. Melley, L.E.; Bress, E.; Polan, E. Hypogeusia as the initial presenting symptom of COVID-19. BMJ Case Rep. 2020, 13, e236080.
  152. Tuter, G.; Yerebakan, M.; Celik, B.; Kara, G. Oral manifestations in SARS-CoV-2 infection. Med. Oral Patol. Oral Cir. Bucal. 2022, 27, e330–e339.
  153. Park, G.C.; Bang, S.Y.; Lee, H.W.; Choi, K.U.; Kim, J.M.; Shin, S.C.; Cheon, Y.I.; Sung, E.S.; Lee, M.; Lee, J.C.; et al. ACE2 and TMPRSS2 immunolocalization and oral manifestations of COVID-19. Oral Dis. 2022, 28, 2456–2464.
  154. Vandersteen, C.; Payne, M.; Dumas, L.É.; Cancian, É.; Plonka, A.; D’Andréa, G.; Chirio, D.; Demonchy, É.; Risso, K.; Askenazy-Gittard, F.; et al. Olfactory Training in Post-COVID-19 Persistent Olfactory Disorders: Value Normalization for Threshold but Not Identification. J. Clin. Med. 2022, 11, 3275.
  155. Donelli, D.; Antonelli, M.; Valussi, M. Olfactory training with essential oils for patients with post-COVID-19 smell dysfunction: A case series. Eur. J. Integr. Med. 2023, 60, 102253.
  156. Ludwig, S.; Schell, A.; Berkemann, M.; Jungbauer, F.; Zaubitzer, L.; Huber, L.; Warken, C.; Held, V.; Kusnik, A.; Teufel, A.; et al. Post-COVID-19 Impairment of the Senses of Smell, Taste, Hearing, and Balance. Viruses 2022, 14, 849.
  157. Degen, C.V.; Mikuteit, M.; Niewolik, J.; Joosten, T.; Schröder, D.; Vahldiek, K.; Mücke, U.; Heinemann, S.; Müller, F.; Behrens, G.M.N.; et al. Audiological profile of adult Long COVID patients. Am. J. Otolaryngol. 2022, 43, 103579.
  158. De Luca, P.; Di Stadio, A.; Colacurcio, V.; Marra, P.; Scarpa, A.; Ricciardiello, F.; Cassandro, C.; Camaioni, A.; Cassandro, E. COVID, audiovestibular symptoms and persistent chemosensory dysfunction: A systematic review of the current evidence. Acta Otorhinolaryngol. Ital. 2022, 42, S87–S93.
  159. McFadyen, J.D.; Stevens, H.; Peter, K. The emerging threat of (micro)thrombosis in COVID-19 and Its therapeutic implications. Circ. Res. 2020, 127, 571–587.
  160. Dorobisz, K.; Pazdro-Zastawny, K.; Misiak, P.; Kruk-Krzemień, A.; Zatoński, T. Sensorineural Hearing Loss in Patients with Long-COVID-19: Objective and Behavioral Audiometric Findings. Infect. Drug Resist. 2023, 16, 1931–1939.
  161. Coelho, D.H.; Reiter, E.R.; French, E.; Costanzo, R.M. Decreasing Incidence of Chemosensory Changes by COVID-19 Variant. Otolaryngol. Head Neck Surg. 2023, 168, 704–706.
  162. Zazhytska, M.; Kodra, A.; Hoagland, D.A.; Frere, J.; Fullard, J.F.; Shayya, H.; McArthur, N.G.; Moeller, R.; Uhl, S.; Omer, A.D.; et al. Non-cell-autonomous disruption of nuclear architecture as a potential cause of COVID-19-induced anosmia. Cell 2022, 185, 1052–1064.
  163. Sanyaolu, A.; Marinkovic, A.; Prakash, S.; Zhao, A.; Balendra, V.; Haider, N.; Jain, I.; Simic, T.; Okorie, C. Post-acute Sequelae in COVID-19 Survivors: An Overview. SN Compr. Clin. Med. 2022, 4, 91.
  164. Öncül, H.; Öncül, F.Y.; Alakus, M.F.; Çağlayan, M.; Dag, U. Ocular findings in patients with coronavirus disease 2019 (COVID-19) in an outbreak hospital. J. Med. Virol. 2020, 93, 1126–1132.
  165. Tohamy, D.; Sharaf, M.; Abdelazeem, K.; Saleh, M.G.A.; Rateb, M.F.; Soliman, W.; Kedwany, S.M.; Omar Abdelmalek, M.; Medhat, M.A.; Tohamy, A.M.; et al. Ocular manifestations of post-acute covid-19 syndrome, Upper Egypt Early Report. J. Multidiscip. Healthc. 2021, 14, 1935–1944.
  166. Kazantzis, D.; Machairoudia, G.; Theodossiadis, G.; Theodossiadis, P.; Chatziralli, I. Retinal microvascular changes in patients recovered from COVID-19 compared to healthy controls: A meta-analysis. Photodiagnosis Photodyn. Ther. 2023, 42, 103556.
  167. Jevnikar, K.; Meglič, A.; Lapajne, L.; Logar, M.; Vidovič Valentinčič, N.; Globočnik Petrovič, M.; Jaki Mekjavić, P. The Comparison of Retinal Microvascular Findings in Acute COVID-19 and 1-Year after Hospital Discharge Assessed with Multimodal Imaging-A Prospective Longitudinal Cohort Study. Int. J. Mol. Sci. 2023, 24, 4032.
  168. Johansson, J.; Möller, M.; Markovic, G.; Borg, K. Vision impairment is common in non-hospitalised patients with post-COVID-19 syndrome. Clin. Exp. Optom. 2023; Advance online publication.
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