Postural Control and Balance Performance in Patients With Carpal Tunnel Syndrome

Adults without clinical symptoms suggestive of CTS

Electrophysiologically confirmed CTS, Bland grades 1-2

Electrophysiologically confirmed CTS, Bland grade 3

Electrophysiologically confirmed CTS, Bland grades 4-6

Center-of-pressure (COP) sway area will be measured in square millimeters (mm²) using the TecnoBody ProKin posturography system during 30-second bipedal static standing assessments under eyes-open and eyes-closed conditions. We will calculate the within-participant difference in log-transformed COP sway area between the two visual conditions. We will compare this difference across four groups: healthy controls and participants with mild, moderate, or severe carpal tunnel syndrome.

Center-of-pressure (COP) total path length will be measured in millimeters (mm) using the TecnoBody ProKin posturography system during 30-second bipedal static standing assessments under both eyes-open and eyes-closed conditions. Total COP path length represents the cumulative distance traveled by the COP during each assessment. Values obtained under both visual conditions will be recorded separately and compared across healthy controls and mild, moderate, and severe carpal tunnel syndrome groups.

Mean anteroposterior center-of-pressure (COP) velocity will be measured in millimeters per second (mm/s) using the TecnoBody ProKin posturography system during 30-second bipedal static standing assessments under both eyes-open and eyes-closed conditions. This parameter quantifies COP movement velocity along the anteroposterior axis. Values obtained under both visual conditions will be recorded separately and compared across healthy controls and mild, moderate, and severe carpal tunnel syndrome groups.

Mean mediolateral center-of-pressure (COP) velocity will be measured in millimeters per second (mm/s) using the TecnoBody ProKin posturography system during 30-second bipedal static standing assessments under both eyes-open and eyes-closed conditions. This parameter quantifies COP movement velocity along the mediolateral axis. Values obtained under both visual conditions will be recorded separately and compared across healthy controls and mild, moderate, and severe carpal tunnel syndrome groups.

The anteroposterior stability index (APSI) will be measured using the movable platform of the TecnoBody ProKin posturography system during a standardized bipedal dynamic balance assessment. The APSI quantifies postural instability in the anteroposterior direction. Values will be compared across healthy controls and participants with mild, moderate, and severe carpal tunnel syndrome.

The mediolateral stability index (MLSI) will be measured using the movable platform of the TecnoBody ProKin posturography system during a standardized bipedal dynamic balance assessment. The MLSI quantifies postural instability in the mediolateral direction. Values will be compared across healthy controls and participants with mild, moderate, and severe CTS.

The total stability index (TSI) will be measured using the movable platform of the TecnoBody ProKin posturography system during a standardized bipedal dynamic balance assessment. The TSI provides an overall measure of dynamic postural instability. Values will be compared across healthy controls and participants with mild, moderate, and severe CTS.

Clinical symptoms and functional impairment will be assessed using the Boston Carpal Tunnel Questionnaire (BCTQ), consisting of the Symptom Severity Scale (BCTQ-SSS; 11 items) and Functional Status Scale (BCTQ-FSS; 8 items). Each item is scored from 1 to 5, and the mean score for each subscale ranges from 1 to 5. Higher scores indicate greater symptom severity or functional impairment. Associations between BCTQ scores and postural control parameters will be evaluated in participants with CTS.

Median nerve function will be assessed using nerve conduction studies. Sensory nerve conduction velocity (m/s), sensory nerve action potential (SNAP) amplitude, distal motor latency (ms), and compound muscle action potential (CMAP) amplitude will be recorded. Electrophysiological CTS severity will be classified according to the Bland grading system. Associations between electrophysiological parameters and postural control measures will be examined in participants with CTS.

Cutaneous sensory function will be assessed using Semmes-Weinstein monofilament testing and static two-point discrimination. Testing will be performed over the distal pulp of the thumb, index finger, and middle finger. Monofilament testing will determine the lowest reliably perceived mechanical stimulus, while two-point discrimination will measure the minimum distance (mm) at which two simultaneous tactile stimuli can be distinguished. Higher thresholds indicate greater sensory impairment. Associations with postural control parameters will be examined.

Handgrip strength will be measured using a hand dynamometer, and pinch strength will be assessed using a hydraulic pinch gauge. Pinch measurements will include tip-to-tip, lateral, and three-point pinch strength. Three measurements will be obtained for each hand, and the mean value will be recorded in kilograms (kg). Associations between hand strength and postural control parameters will be examined in participants with CTS.