Effects of Vagus Nerve Stimulation on Motor Function, Respiratory Muscle Strength, and Quality of Life in Stroke Patients

We will use the Fugl-Meyer Upper Motor Assessment score, which is the most sensitive for treatment outcomes in stroke patients presenting with unilateral paresis in the post-stroke period. It measures upper extremity use and impairment, measuring shoulder, elbow, forearm, wrist, finger, and reflex movements from proximal to distal, synergistic to extrinsic. The score ranges from 0 to 66 and consists of 33 items. 0-28 indicates severe motor impairment; 29-42 indicates moderate motor impairment; and 43-66 indicates mild motor impairment. Higher scores indicate better performance. The FM-UE consists of one component, each rated on a 3-point ordinal scale (0=not achieved, 1=partially contributed, 2=completely contributed). The minimum clinically meaningful change on the FM-UE for chronic stroke has been determined to be 4.25 to 7.25. Consistent with the literature, we define an improvement of at least 6 points or more as significant.

The SIS 3.0 assesses function and quality of life based on subjective report in eight clinically important domains. It consists of two parts. The first part is the main scale of the IAS, which assesses multidimensional health-related quality of life (QOL) including strength, hand function, ADL/instrumental ADL, mobility, communication, emotion, memory/thinking, and social participation. It consists of 59 items, and each item is subjectively rated by stroke patients on a 5-point Likert-type scale according to their perceived difficulty with the item in the past week. The score for each domain is converted to a score out of 100, and the average scores for all domains are used to represent stroke patients' multidimensional health-related quality of life. The formula Domain Score = [(Average Item Score -1) / (5 -1) x 100] is used to convert each domain score. SIS 3.0 also includes assessment of post-stroke recovery using a 0-100 visual analog scale (0: no recovery, 100: complete recovery)

This is the pressure measured when the patient tries to breathe as forcefully as possible into their lungs (inspiration). It assesses the strength of the diaphragm and accessory respiratory muscles-in other words, the inspiratory capacity of the respiratory muscles. The measurement is taken through the mouth. A nose clip is applied. After maximum exhalation near the residual volume (RV), the patient tries to breathe in as forcefully as possible for 1-2 seconds. Three repetitions are performed, and the average is calculated. (The higher the pressure value, the greater the muscle strength.)

This is the pressure measured during the patient's strongest possible exhalation (expiration). This indicates the strength of the respiratory muscles that assist exhalation, such as the abdominal muscles and internal/external intercostal muscles. The measurement is taken orally. A nose clip is applied. After taking a maximum inspiration (close to TLC), the patient attempts to exhale as forcefully as possible for 1-2 seconds. Three repetitions are performed, and the average is calculated. (The higher the pressure value, the greater the muscle strength.)

It is a brief and practical self-report instrument developed to measure the severity of fatigue experienced by individuals. It consists of 10 items, and each item is rated subjectively on a 5-point Likert-type scale used to assess overall fatigue level over the past week. The lowest score is 10, and the highest is 50. (≤ 21 points: None/low fatigue, 22-34 points: Moderate fatigue, ≥ 35 points: High fatigue)