Placebo application using the Hypervolt 2 Pro device for 40 minutes per session (10 min paraspinal, 10 min flexor retinaculum, 10 min extensors, 10 min flexors), 2 sessions per week for 6 weeks. It mimics the physical vibration and head shape of the matrix rhythm therapy device to maintain blinding.

Participants use a night splint holding the wrist in neutral position. On clinic days, conservative physiotherapy sessions are administered immediately following the active or sham matrix rhythm therapy sessions, 2 days per week for 6 weeks. These supervised sessions include median nerve sliding exercises (3 sets, 5 reps) and passive stretching for wrist flexors/extensors (15-sec hold, 3 sets, 5 reps). In addition to clinical sessions, the same exercise protocol is performed at home twice daily and continued independently up to the 12th-week follow-up. Compliance with both splint wear and home exercises is strictly monitored using participant usage logs and exercise diaries.

Assessed using a pinch gauge to measure tip pinch strength. The participant is seated with the shoulder adducted at 0 degrees, elbow flexed at 90 degrees, and forearm/wrist in neutral position, and asked to squeeze the device with maximum effort using the tips of the thumb and index finger. The measurement will be repeated three times for the affected hand with 5-second intervals, and the arithmetic mean will be recorded. Higher values indicate greater pinch strength measured in kilograms (kg).

Evaluated using the EuroQol (EQ-5D-5L) scale, which covers 5 dimensions: mobility, self-care, usual activities, pain/discomfort, and anxiety/depression. Each dimension has 5 response levels. These responses are converted into a single health-state index score using the country-specific value set. Index scores typically range from less than 0 to 1, where higher scores indicate a better health-related quality of life.