Encyclopedia
Tinnitus is a common and disabling symptom often associated with hearing loss. While clinical practice frequently shows that a certain degree of psychological discomfort often characterizes tinnitus suffers, it has been recently suggested in adults as a determining factor for cognitive decline affecting attention and memory domains.
- tinnitus
- cognition
- psychological aspects
- auditory pathways
- elderly
1. Introduction
Tinnitus consisting of the perception of sounds in the absence of external stimuli is a very common and disabling condition with pervasive effects on health and wellbeing. In 95% of cases, tinnitus is subjective and described as a buzz, click, hiss, ring, roar, hum, or pulsatile. The prevalence increases with age, affecting 24–45% of the elderly [1], where tinnitus is frequently associated to hearing impairment. Noise exposure, which is the greater risk factor for the development of both hearing loss and tinnitus [2,3], contributes to the increase in prevalence among the elderly. Tinnitus can occur as an isolated idiopathic symptom or in association with otologic disease, such as otosclerosis [4] and Meniere disease [5], drug ototoxicity [6], cerebrovascular diseases, hypertension, dyslipidemia, metabolic diseases [7], chronic kidney disease, and diabetes mellitus [8]. On the other hand, it could be associated with any type of deafness as well as with a normal hearing threshold as in the case of ototoxicity from aspirin and quinine [9] or migraine [10]. Cochlear mechanism and involvement of central auditory and non-auditory pathways thought to underlie tinnitus with or without hearing loss are still controversial. Major evidence suggests that tinnitus is related to a failure of the central auditory pathway to adapt to the loss of afferent peripheral fibers due to peripheral damage [11,12], leading to plastic neuronal changes in the tonotopic map of the auditory cortex, as a “maladaptive plasticity”, which concurs in maintaining tinnitus in a sort of “vicious circle” [13,14,15,16,17]. All these changes in the central auditory pathway, together with the neuroplastic reorganization within the thalamus and the structures of the limbic and paralimbic circuits [18], induced us to speculate about a possible relationship between tinnitus, psychological distress, and cognitive impairment, with a positive correlation to tinnitus severity [19,20].
2. Possible Links between Tinnitus and Neuropsychological Dysfunction in the Elderly
3.1. Psychological Distress
It is largely demonstrated that psychiatric discomfort is present in a large number of tinnitus suffers, with a higher prevalence of anxiety rather that depression [35,36] (Table 1). Tinnitus may directly determine a psychiatric condition; even if sleep disorders and insomnia evoked by tinnitus could induce emotional distress or unmask a pre-existing but compensated disorder. Aazh H et al. [24] retrospectively verified a strong association between tinnitus annoyance, depression level, and insomnia score in the elderly.
| Author, Year [Ref] | Inclusion Criteria | Exclusion Criteria | N° of Cases, Age | Type of Study | Objective | Methods (Outcome Evaluation) |
Results | Level of Evidence | Evidence of Association |
|---|---|---|---|---|---|---|---|---|---|
| Fetoni AR, 2021 [23] |
-Chronic tinnitus -Age ≥ 55 y -With or without HL |
-History of neurological diseases -Psychiatric disorders -Otologic diseases-Antipsychotic drugs use |
102 patients ≥55 y; 70.4 ± 9.6 y (range 55–94 y |
Prospective cross-sectional study | To assess the value of self-administered screening tests in comparing severity of tinnitus perception with emotional disorders and cognitive status | THI, HADS, MMSE (questionnaires) |
THI score related to HADS-A score, HADS-D score, there was no relationship between tinnitus severity and MMSE | II | Yes |
| Aazh H, 2017 [24] |
-Age ≥ 60 y -Tinnitus sufferers with/without hyperacusis -With/without HL |
History of neurologic and psychiatric diseases, or sleep disorders | 184 patients ≥60 y; mean age of 69 y |
Retrospective cross-sectional study | To assess issues associated with tinnitus and hyperacusis handicap | HADS, HQ, ISI, THI, VAS (questionnaires) |
THI was significant in predicting tinnitus annoyance. Hyperacusis handicap and insomnia were both predicted by level of depression | III | Yes |
| Park SY, 2017 [25] |
-Age < and ≥ 65 y -With/without HL |
History of psychiatric or neurologic diseases | 76 patients ≥65 y |
Retrospective cohort study | To assess differences between tinnitus-related features and psychological aspects between younger and older tinnitus sufferers | THI, BDI, and BEPSI (questionnaires) |
No differences in tinnitus severity, depression, and stress between younger and older subjects | III | Yes/No |
| Gopinath B, 2010 [26] |
-Age ≥ 50 y -With/without tinnitus -With/without HL |
History of psychiatric diseases | 1214 participants (602 with tinnitus) ≥50 y |
Longitudinal cohort study | To evaluate the risk factors and effects of tinnitus (depression) | SF-36; MHI for depression and/or CES-D (questionnaires) |
Lessened quality of life and wellbeing in patients with tinnitus | II | Yes |
| Lasisi AO, 2010 [27] |
-Age ≥ 65 y -With/without tinnitus; -With/without HL |
History of neuropsychologic diseases | 184 patients ≥65 y; mean age of 77.3 y |
Longitudinal cohort study | To establish the prevalence of tinnitus in the elderly and its influence on their life quality | WHOQOL (questionnaire) |
Tinnitus sufferers had a lower perception of their overall health and a worse life quality; twofold likelihood to suffer activities impairment in daily living | II | Yes |
| Loprinzi PD, 2013 [28] |
-Age ≥ 70 y -With/without tinnitus -With/without HL |
Age < 70 years old | 696 patients 76 ± 0.2 y (range 70–85 y) |
Prospective cross-sectional study | To evaluate the association between tinnitus and depression | Patient Health Questionnaire-9 (questionnaire) |
Positive association between tinnitus (at least a moderate) and depression; patients bothered by tinnitus before going to bed were nearly 3 times more likely to be depressed | II | Yes, in moderate/severe tinnitus |
| Beukes EW, 2018 [29] |
-Age< and > 60 y -Chronic tinnitus -With/without HL who completed therapy |
History of neuropsychiatric diseases | 146 patientsstratified for age (> 60 y) | A randomized, delayed intervention efficacy trial | To establish if an internet-based cognitive behavioral therapy is useful in reducing tinnitus severity and associated comorbidities | ISI, Generalized Anxiety Disorder-7, Patient Health Questionnaire-9, Hearing Handicap Inventory for adults, HQ, Cognitive Failures Questionnaire, Satisfaction with Life Scales (questionnaires |
Significant reduction in tinnitus and comorbidities (insomnia, depression, hyperacusis, cognitive failures) and improving of life quality |
I | Yes |
| Park HM, 2020 [30] |
-Age ≥ 60 y -With/without tinnitus -With/without HL |
History of neurologic or psychiatric diseases | 5129 patients ≥60 y (range 60–79 y) |
Retrospective cross-sectional study | To find a possible association of tinnitus, mental health, and health-related quality of life | Stress was tested asking: “How much stress do you usually feel in your daily life?”; depression was tested using CIDI-SF; suicide ideation with the question: “Have you ever thought about committing suicide within 12 months?” (questionnaires) |
The annoying tinnitus patients had more depression, psychological stress, and suicidal ideation if compared to control group | III | Yes |
3.2. Cognitive Impairment
Based on behavioral evidence, psychological markers of attention switching (i.e., cognitive and emotional control) are impaired in chronic tinnitus suggesting that the reduced cognitive control may be pivotal in maintaining the awareness of tinnitus. According to the literature (Table 2), tinnitus patients have poor cognitive performance, but it is still unclear whether cognitive impairment is a response to tinnitus manifestations or a feature of it, especially in the elderly. By using MMSE as a screening tool for cognitive impairment hearing threshold and anxious–depressive traits measured with hospital anxiety depression scale (HADS) questionnaire, scores for cognitive dysfunction were slightly increased by age and gender [23] (Table 1). Few other reports suggest the relationship between neurocognitive abilities and tinnitus severity [38,39], even if its mechanism remains controversial [5]. Thus, a key point in the elderly population is whether cognitive impairment is related to age-related hearing loss (ARHL) or to tinnitus per se.
| Author, Year [Ref] | Inclusion Criteria | Exclusion Criteria | N° of Cases, Age | Type of Study | Objective | Methods (Outcome Evaluation) |
Results | Level of Evidence | Evidence of Association |
|---|---|---|---|---|---|---|---|---|---|
| Lee SY, 2020 [31] |
-Age > 60 y -Diagnosed for MCI -With/without tinnitus |
-Moderate or severe hearing loss -Otologic diseases -History of psychiatric or neurologic disorders |
23 patients (12 with tinnitus) 74.0 ± 6.1 y (range 63–83 y) |
Retrospective cohort study | To examine the glucose metabolism and gray matter volume in patients with MCI and tinnitus | MCI with or without tinnitus: FDG-PET and magnetic resonance imaging were performed (imaging) |
Specific brain regions are associated with cognitive decline and increased tinnitus severity | III | Yes |
| Lee SY, 2020 [32] |
-Age ≥ 65 y -With/without HL |
History of psychiatric or neurologic disorders | 58 patients68.1 ± 5.1 y (range 65–82 y) |
Prospective cohort study | To examine the cognitive domains and the association between tinnitus severity and cognitive functions | K-PHQ-9, K-IADL, MoCA-K (questionnaires) |
THI score in the MCI group was higher than in the non-MCI | II | Yes |
| Yun Y, 2020 [33] |
-Age > 50 y -Chronic tinnitus |
-History of Alzheimer’s disease or neurologic diseases -Hearing loss or otologic diseases |
55 patients > 50 y | Cross-sectional study | To examine plasma c-proteasome activity in association with cognitive functions in chronic tinnitus patients | Plasma c-proteasome activity was achieved with fluorogenic reporter substrate; MoCA (cut-off score of 22/23) to assess MCI (markers and questionnaires) |
Circulating proteasomes were lower in patients with chronic tinnitus and MCI | III | Yes |
| Fetoni AR, 2021 [23] |
-Chronic tinnitus -Age ≥ 55 y -With/without HL |
-History of neurological diseases -Psychiatric disorders -Otologic diseases-Antipsychotic drugs use |
102 patients ≥ 55 y | Prospective cross-sectional study | To evaluate the use of self-administered screening tests to correlate the severity of tinnitus with emotional disorders and the overall cognitive status | THI, HADS, MMSE (questionnaires) |
THI score was directly related to HADS score, there was no relationship between tinnitus severity and MMSE | II | No |
| Beukes EW, 2018 [29] |
-Age < and > 60 y -Chronic tinnitus-With/without HL -Who completed therapy |
History of neuropsychiatric diseases | 146 patients stratified for age (>60 y) |
Randomized delayed intervention efficacy trial | To establish if an internet-based cognitive behavioral therapy is useful to lessen tinnitus severity and associated comorbidities | ISI, Generalized Anxiety Disorder, Patient Health Questionnaire, Hearing Handicap Inventory for Adults Screening version, HQ, Cognitive Failures Questionnaire, Satisfaction with Life Scales (questionnaires) |
Significant reduction in tinnitus and comorbidities (insomnia, depression, hyperacusis, cognitive failures) and a significant rise in life quality | I | Yes |
| Ruan Q, 2021 [34] |
-Age ≥ 58 y -With/without frailty -With/without HL -With/without tinnitus |
No history of disability, cophosis, and vision loss | 429 patients ≥58 y |
Longitudinal cohort study | To study whether cognitive frailty is associated with HL and tinnitus | To assess MCI: with executive and attention domain (TMT A and B); language domain (BNT and animal list generation); memory domain (HVLT-R) (questionnaires) |
Cognitive frailty patients had higher risks of severe HL and tinnitus. Cognitive impairment in tinnitus patients involved executive, memory, and attention domains; altered processing speed | II | Yes/No |
How chronic tinnitus causes cognitive deficits might be found in functional and structural brain alterations that were studied by Lee et al. [31]. Patients with MCI were divided in two groups (tinnitus and non-tinnitus groups) and were tested through FDG-PET to evaluate glucose metabolic connectivity. The tinnitus–MCI group showed a lower metabolism in the right superior temporal pole (which comprises the auditory cortex and is associated with the cognitive social processes interacting with limbic areas) and in the fusiform gyrus (which is altered in semantic dementia), if compared with non-tinnitus group. Furthermore, they exhibited significantly lower gray matter volume in the right insula (which is involved in the emotional reaction to tinnitus), and the THI was inversely correlated with it. Thus, the evidence for a causal link between tinnitus and MCI might be found in the pathophysiology of tinnitus and in the central neural changes that it determines. Surely, future studies in this direction could help to establish the causal link.
3. Summary
The association between tinnitus and psychological distress has been demonstrated, although only a few studies addressed this topic to the elderly. More difficult is the task of proving the association between cognitive dysfunction and tinnitus. Patients with chronic tinnitus (with or without hearing impairment) refer attention and memory failures, which reflects the dropped ability to shift attention away from phantom sounds in order to achieve proper cognitive performances [39].
A current key point is to evaluate if tinnitus-related comorbidities effectively depend on tinnitus or the hearing loss that is often associated. Limitations of this systematic review are that there are no reports on the effect of tinnitus on specific cognitive domains and its impact in older patients with good hearing.
Another limit is that, even if some studies (i.e., those of Lee and Yun) evaluated the relationship with MCI, which is a common dysfunction in older patients [45], results are hardly comparable, as they use different methods to validate cognitive impairment. Therefore, it is hard to understand if tinnitus matters as an independent risk factor.
Tinnitus is a common and disabling symptom especially in adults, and it is often associated with hearing loss in older people. Elderly patients affected by chronic tinnitus have dysfunctional traits, such as anxiety and depression, and demonstrate reduced cognitive functions. In older patients affected by hearing loss, tinnitus seems to worsen cognitive dysfunction. However, further studies are required to improve the evidence supporting the relationship between cognitive dysfunction and tinnitus.
This entry is adapted from the peer-reviewed paper 10.3390/jcm10091881
