There is no consensus regarding the outcome measures necessary to assess upper limb function in post-stroke patients [1]. In the acute and subacute phases, patients within six months after a stroke undergo a comprehensive and specialized evaluation of their health [2]. This process, held in hospital clinics, involves determining the rehabilitation and treatment goals, selecting therapeutic interventions, and evaluating progress [3]. The successful rehabilitation of post-stroke patients relies on effective motor deficit assessments, accurate diagnoses and therapy choices, proper outcome evaluations, and prolonged treatment and rehabilitation to maintain recovery in the chronic phase [4]. There are multiple perspectives from which hand outcome measures can be examined, highlighting the complexity of assessing rehabilitation progress. These perspectives include physiological measures that focus on the physical changes and improvements, quality of life measures that assess the impact on the patients’ daily lives and well-being, phase of stroke recovery to determine the appropriate stage-specific interventions, and the type of hospital care the patient requires, which may vary based on individual needs and progress. The motor impairment of the upper limb after a stroke contributes to weakened muscle strength. Low muscle strength is associated with fatigue phenomena, reduced endurance, and ineffective task performance by the patient [5]. These are the main problems that occur in hemiparesis [6]. The image of a patient with hemiparesis after stroke is heterogeneous [7]. Static and isokinetic dynamometers are used to obtain objective results of muscle endurance as well as muscle strength itself [5]. Patients in the chronic phase with paresis receive reeducation of the number of motor units and long-term denervation of paresis muscles, which contributes to muscle weakness [8]. Manual dexterity can be a valuable predictor of motor impairment after stroke [9]. The impairment of the above function leads to reduced manual dexterity, limiting activities of daily living and worsening quality of life. After a stroke, it turns out that there are difficulties with basic activities, such as cooking, laundry, cleaning, and many others [10]. In particular, two-handed activities that require a high degree of manual dexterity are difficult to perform [11]. Hand grip strength (HSG) is another parameter that checks the return of muscle strength. It is a useful measurement and a prognostic biomarker after stroke. It is performed using the Jamar dynamometer along with a standardized test protocol approved by the American Society of Hand Therapists (ASHT) [12,13]. Impaired motor function after stroke often occurs with muscle spasticity, resulting in poorer motor recovery of the affected limb. In this case, the main problems are increased muscle tension, which requires checking the resistance of the muscles to stretching but also the range of motion of the joints (ROM) and pain due to deformities and contractures [14,15]. The failure of the joints to move individually is among the features of hemiparesis of the upper limb. There is difficulty in controlled movement of the limb during reaching, which is caused by abnormal torque production and impaired interjoint coordination [16,17]. Understanding and considering these different perspectives can help healthcare professionals develop a more comprehensive and tailored approach to hand rehabilitation for stroke patients. In physiotherapy diagnostics, instruments are used in addition to tests and scales. Centimeter tapes and a goniometer designed for measurement are widely available and simple in service [18]. The need to obtain accurate results led to the development of many tools used in the diagnosis of stroke patients, including hand dynamometers, haptic sensors, position tracking systems, leap motion, and the use of artificial intelligence. Hand measurement is essential in the diagnostic process in the context of enabling individualization of therapy [19,20,21,22].

To maintain a stroke patient’s health, it is crucial to start rehabilitation as soon as possible and, once the inpatient rehabilitation process is complete, to continuously monitor the patient’s condition and rehabilitate after leaving the hospital [23]. The intensity of rehabilitation is correlated with better inpatient rehabilitation outcomes. Higher doses of therapy (increased intensity) during inpatient rehabilitation have a positive impact on the functional independence measure (FIM), leading to an increase in its levels [24]. Despite widespread access to hand and arm measurement scales and tests, there is no general agreement on which measures are best for evaluating therapy for post-stroke patients in the chronic phase. Bushnell et al. recommend using the Fugl-Meyer Upper Extremity scale, the Wolf Motor Function Test, and the Action Research Arm Test for upper limb and hand measurements [25]. They emphasize that the Fugl-Meyer Upper Extremity scales should be the primary outcome measure in the chronic phase of stroke. In the acute and subacute phases of stroke, there are no clear procedures regarding which measures should be performed to assess outcomes. This lack of clarity leads to discrepancies between evidence and practice in making hand diagnoses [26]. Furthermore, Murphy et al., 2021 endorsed the use of the Fugl-Meyer Upper Extremity scale and the Action Research Arm Test measures for patients [26].

Upper limb limitations, motor deficits, and hemiplegia are present in more than 80% of post-stroke patients [27]. These impairments impact coordination and manual dexterity, which play a crucial role in daily life and functioning [28]. About 67% of individuals who have experienced a stroke with complications still cannot use their hand, even four years after the event [29]. Upper limb spasticity, which can develop following a stroke, affects 17–40% of people [30,31]. During the restoration of motor function after a stroke, cortical reorganization and synaptic plasticity mechanisms occur in the brain. Both cerebral hemispheres are involved in these reorganization processes [32]. Their activity is highest within the first few months following the disease [27,32]. The unique critical period, also referred to as the sensitive period, comprises the first three months after a stroke, during which complete recovery is possible [33].

Reduced hand mobility is linked to difficulties in performing daily tasks. Challenges with grasping objects, transferring, manipulating, coordinating hand-finger movements, and maintaining dexterity are both rehabilitation obstacles and targets [34,35]. Even up to 12 months post-stroke, daily use of the affected upper limb is three times less frequent compared to the healthy limb [36].

There is a need to understand the assessment of the physical and physiological conditions and associated measurements of a stroke patient’s hand. There are different degrees of spontaneous improvement in arm paresis within the first months after stroke. An assessment of the patient’s improvement in physical condition and hand function after 6 months can be predicted based on the results of motor deficits occurring after 1 month of hospitalization, despite a further 5 months of routine rehabilitation [30]. The hand’s biomechanical complexity is reflected in the large portion of the brain’s motor cortex dedicated to controlling hand movements. The precision of hand movement control is highly dependent on the intact corticospinal tract [37,38,39]. Hand rehabilitation is based on motor movement, which plays an important role in the brain’s motor cortex [40]. The corticospinal tract (the compensatory corticoreticulospinal tract branches) branches in many segments in the spinal cord and innervates more proximal muscles than distal ones, with a predominance of flexors, but it lacks resolution and also innervates the extensors of the fingers and hands. This causes abnormal involuntary coupling between shoulder visitation and wrist/finger flexion (flexion synergy), as well as weakness in the muscles that are the extensors of the distal joints. This results in a significant limitation of hand opening movement [41,42].

The ability to actively extend the fingers up to 7 days after a stroke is part of the prognosis for recovery of upper limb mobility. Independent extension of the wrist and each finger is also key, which is associated with the integrity of the corticospinal tract. Also, a prognostic factor is the movement of visiting the absence within 72 h, thumb extension, and the movement of closing and opening the hand [43,44,45,46,47]. The latter movement represents multi-finger movement, which is important because of the frequent impairment of multi-finger coordination in post-stroke patients [48]. Carpinella et al. showed that inadequate finger extension is due to two concurrent causes: altered neurophysiological control mechanisms and mechanical limitation of the extension movement [49]. Mechanical limitations can be caused by atrophy of the extensor muscles, contracture of the flexor muscles, increased passive stiffness of the muscle tissue, or the shortening of muscle fibers. Neurophysiological disorders can result from flexor muscle spasticity, a weakness of the extensor muscles, or excessive contraction of the extensor and flexor muscles [49,50,51,52,53,54]. Robotic rehabilitation can lead to the alleviation of the occurrence of spasticity in the wrist joint [55]. Restoration of normal muscle tone is a predictive factor, marking the first stage of recovery from the onset of the disease [56]. Researchers indicate that the Brunnstrom Stages of Stroke Recovery are useful in assessing motor recovery in post-stroke patients.