The Effect of Upper Extremity Motor Function, Trunk Control and Motor Imagery Ability on Turkish Language Skills in Individuals With Stroke

A large number of people have a stroke each year and it is a major cause of disability worldwide. Upper limb motor impairments, aphasia, body control problems and decreased motor imagery ability are common after stroke. Although there are studies showing that these impairments may be related to each other, there is no comprehensive study examining the relationship between Turkish language skills and these motor functions. The aim of this study was to evaluate the relationship between Turkish language skills and upper extremity motor function, trunk control and motor imagery ability in stroke patients.

Each year, approximately 800,000 individuals experience a new or recurrent stroke. Although mortality rates have declined in recent years, the number of stroke survivors has increased, making stroke the third most common cause of disability worldwide.

In stroke patients, both upper extremity (UE) motor impairment and language function disorders are frequently observed. These two types of post-stroke dysfunctions are among the most prominent neuropsychological deficits: UE motor impairment occurs in approximately 80% of stroke patients, aphasia in 21-38%, and both conditions co-occur in about 24% of cases. Upper extremity motor impairment combined with aphasia affects social participation and quality of life and is also associated with many comorbidities, potentially leading to a poor prognosis. Due to their anatomical proximity, ischemia or hemorrhage in the middle cerebral artery (MCA) often results in UE motor impairments and non-fluent aphasia. Hybbinette et al. confirmed through a small sample study that apraxia of speech and aphasia commonly co-occur with hand motor deficits in patients with left hemisphere stroke.

Aphasia is defined as acquired neurological damage to areas of the brain responsible for understanding and producing language and symbols. This damage disrupts the connection between speaking, thinking, and interpreting. A recent prospective study by Grönberg and colleagues revealed that despite a decrease in ischemic stroke rates over the last decade, 30% of patients with acute ischemic stroke still experience aphasia.

Post-stroke aphasia is a major disability that negatively impacts rehabilitation and overall stroke outcomes. It is one of the most detrimental conditions affecting health-related quality of life, associated with high risk of depression and reduced likelihood of returning to work. Accurate knowledge of the symptoms and factors associated with aphasia is essential for optimal care.

One of the most common issues in stroke patients is upper extremity motor dysfunction. One-third of stroke survivors continue to experience deficits even six months post-stroke. Another disabling consequence of stroke is impairment in trunk motor control and balance. One of the main roles of the trunk is to support limb movements by activating before or during goal-directed actions. However, in stroke patients, motor impairment leads to decreased or delayed trunk muscle activation, which causes deviations in limb movements and postural abnormalities. These abnormal movement patterns and posture, resulting from stroke, are the primary cause of early trunk control disorders. Trunk dysfunction also affects respiration and, consequently, phonation, which is known to impact speech abilities in stroke patients. This suggests that trunk control plays an important role in predicting the efficiency of post-stroke rehabilitation and functional recovery.

Imagery refers to mentally creating or recreating an experience or knowledge. Motor imagery (MI) is the process of mentally simulating a movement without physically performing it. During imagery, the neuronal activity that occurs between the cerebral cortex, cerebellum, and brainstem is similar to that during actual movement.

One major challenge in using motor imagery is determining the extent to which a person can form mental representations of movement. After stroke, this becomes more problematic. The slowing down of imagery after stroke suggests that the temporal characteristics of imagery may be altered. These findings indicate that some patients may not be able to use motor imagery at all. Therefore, evaluating imagery ability in stroke patients is crucial.

One study comparing stroke survivors and a control group found that stroke patients experienced difficulties in understanding and performing tasks related to motor imagery.

Cayol et al. (2020) aimed to investigate the relationship between performance on a motor imagery task and word-definition task in adolescents. The results indicated that MI ability predicts language processing skills. This finding aligns with literature suggesting the role of MI in representing action-related concepts in the brain. The correlation between MI ability and language processing skills implies that the brain can represent action-related information more effectively.

Additionally, Taub and colleagues observed that stroke patients often fail in upper extremity motor function tasks, leading them to avoid using the affected limb-a phenomenon known as "learned non-use." In such cases, both the willingness to move and the memory of movement imagery for the affected limb may be impaired. Patients make repeated errors, which reduces motivation to use the limb, hindering recovery of motor function.

The collected evidence indicates that language skills, upper extremity motor function, trunk control, and motor imagery ability are all affected in stroke patients. Several studies suggest potential relationships between these domains. However, no comprehensive research has been conducted examining the relationship between these three domains and language skills in Turkish.

This study aims to contribute to multidisciplinary rehabilitation approaches by offering new perspectives and supporting the development of combined evaluation and treatment methods in the future.

Although there are studies in various languages examining the relationship between upper extremity motor function and language ability in stroke patients, there is a lack of research involving Turkish-speaking individuals. Exploring how these two areas interact specifically in Turkish speakers may provide important insights for recovery.

Furthermore, no studies have examined the impact of language skills on trunk control and motor imagery ability. To fill this gap, our study aims to evaluate the relationship between Turkish language skills and upper extremity motor function, trunk control, and motor imagery in stroke patients. Understanding this connection will be a valuable guide in rehabilitation processes.

Therefore, our goal is to assess the impact of upper extremity motor function, trunk control, and motor imagery ability on Turkish language skills in individuals who have experienced a stroke.

Eligibility Criteria:
Inclusion Criteria:

* 18 years of age or older
* Stroke onset more than 1 week
* Not having practiced imagery before
* Being a native speaker of Turkish
* Standardized Mini Mental Test (SMMT) Score of 24 and above
* History of cerebrovascular events
* Not having any neurological disorder other than stroke
* The ability to grasp and hold a 2.5 cm cube

Exclusion Criteria:

* No consent from the family or person
* Having had a stroke before
* Severe hearing or vision loss
* Individuals are excluded if they have other primary medical conditions that may affect language and motor functions (e.g. brain tumor, Parkinson's disease, severe post-stroke depression, Alzheimer's disease) or have undergone surgery.