Carpal Tunnel Syndrome (CTS) is the most common peripheral entrapment neuropathy, causing pain, paresthesia, and hand dysfunction due to median nerve compression at the wrist. While physiotherapy provides symptom relief, it does not effectively address the underlying neuroplastic deficits of the median nerve. Photobiomodulation (PBM), delivered at 830 nm near-infrared wavelength, has shown potential to enhance peripheral nerve regeneration via cytochrome c oxidase activation, ATP synthesis, and upregulation of neurotrophic factors including brain-derived neurotrophic factor (BDNF). This randomized controlled trial will evaluate whether 830 nm PBM (200 mW, 4 J/cm², 12 sessions over 4 weeks) combined with routine physiotherapy produces significantly greater neuroplastic recovery of the median nerve - assessed by high-resolution ultrasound (HRUS) measurement of median nerve cross-sectional area (CSA), nerve conduction study parameters and serum BDNF - compared to sham PBM combined with identical physiotherapy in adults with mild-to-moderate CTS. Neuroplasticity was operationalised as a multimodal construct comprising: (1) functional recovery, indexed by nerve conduction study parameters; (2) structural remodelling, indexed by median nerve cross-sectional area on high-resolution ultrasound; and (3) molecular neuroplastic signalling, indexed by serum BDNF. This multimodal approach was adopted because no single measure captures the full construct of peripheral nerve neuroplasticity (Padua et al., 2020).
Age 18-60 years
Clinical diagnosis of unilateral mild-to-moderate carpal tunnel syndrome based on positive Phalen test and/or Tinel sign
Electrophysiological confirmation of CTS via nerve conduction study (NCS) meeting AANEM 2012 diagnostic criteria for mild-to-moderate CTS
No prior photobiomodulation or laser therapy to the affected wrist within the preceding 3 months
Bilateral carpal tunnel syndrome
Previous surgical release of the carpal tunnel on the affected side
Systemic peripheral neuropathy (e.g., diabetes mellitus, hypothyroidism, Charcot-Marie-Tooth disease)
Pregnancy or breastfeeding
Parallel
Photobiomodulation (Low-Level Laser Therapy)
DevicePhotobiomodulation (PBM) delivered using a 46-diode cluster probe at 830 nm wavelength, 200 mW optical output power, continuous wave mode, 4 J/cm² energy density, applied in static contact technique over the carpal tunnel (volar wrist surface, 3-5 cm proximal to distal wrist crease). Application time per session: approximately 200 seconds (\~3.3 minutes). Treatment schedule: 3 sessions per week for 4 consecutive weeks (12 sessions total). Sham device output confirmed \<1 mW by calibrated photodiode power meter.
Sham Photobiomodulation
DeviceDeactivated PBM device identical in external appearance to the active device. Applied using the same 46-diode cluster probe, contact technique, and duration (approximately 200 seconds) as the active arm. Output power confirmed \<1 mW by calibrated photodiode power meter (LaserCheck or equivalent) at baseline, session 6, and session 12 for the first five enrolled participants. No therapeutic light emission occurs.
Routine Physiotherapy Programme
Other interventionParticipants will receive an 4-week routine physiotherapy programme comprising median nerve mobilization, night splinting, and tendon-gliding exercises. Median nerve mobilization will use six sequential positions progressing from wrist-neutral finger/thumb flexion to finger, wrist, and thumb extension, forearm supination, and assisted thumb stretching. Each position will be held for 5 seconds; the sequence will be repeated 10 times, three times daily. A neutral volar wrist splint allowing free finger and thumb movement will be worn nightly for 6-8 hours. Tendon-gliding exercises will include straight hand, hook fist, full fist, tabletop, and straight fist positions. Each position will be held for 5 seconds, with 10 repetitions performed three times daily. A physiotherapist will teach and monitor the programme. Participants will receive illustrated instructions and maintain an adherence diary. Exercises will be modified or stopped if symptoms worsen.
Change From Baseline in Median Nerve Sensory Conduction Velocity at Week 4 and week 8
Median nerve sensory conduction velocity will be measured in metres per second (m/s) using a standardized nerve conduction study performed by a blinded neurophysiologist. Electrode placement, stimulation distance, equipment settings and skin temperature will be standardized across assessments. Change will be calculated as the Week 4 and 8 value minus the baseline value. A positive change indicates improvement in sensory conduction velocity.
Change From Baseline in Median Nerve Distal Motor Latency
Median nerve distal motor latency will be measured in milliseconds (ms) using a standardized nerve conduction study, with stimulation at the wrist and recording from the abductor pollicis brevis muscle. The same stimulation distance, electrode placement, equipment settings and skin-temperature controls will be used at each assessment. Change will be calculated as the follow-up value minus the baseline value. A negative change indicates reduced latency and improved motor conduction.
Change From Baseline in Median Nerve Sensory Nerve Action Potential Amplitude
Median nerve sensory nerve action potential amplitude will be measured in microvolts (µV) using a standardized nerve conduction study performed by a blinded neurophysiologist. The same recording technique and equipment settings will be used at each assessment. Change will be calculated as the follow-up value minus the baseline value. A positive change indicates an increase in sensory response amplitude.
Change From Baseline in Median Nerve Cross-Sectional Area
The cross-sectional area of the median nerve will be measured in square millimetres (mm²) using high-resolution ultrasonography at the carpal tunnel inlet at the level of the pisiform. The nerve will be traced within the hyperechoic epineurial border. Three measurements will be obtained and averaged at each assessment. The same anatomical level, participant position, ultrasound settings and blinded assessor will be used throughout the study. Change will be calculated as the follow-up value minus the baseline value. A negative change indicates a reduction in median nerve enlargement.
Change From Baseline in Boston Carpal Tunnel Questionnaire Symptom Severity Scale Score
Symptom severity will be assessed using the 11-item Symptom Severity Scale of the Boston Carpal Tunnel Questionnaire. Each item is scored from 1 to 5, and the subscale score is calculated as the mean of the completed items. Total subscale scores range from 1 to 5, with higher scores indicating more severe symptoms. Change will be calculated as the follow-up score minus the baseline score. A negative change indicates improvement
Change From Baseline in Serum Brain-Derived Neurotrophic Factor Concentration
Serum brain-derived neurotrophic factor concentration will be measured in picograms per millilitre (pg/mL) using a standardized enzyme-linked immunosorbent assay. Blood collection time, clotting duration, centrifugation, storage temperature, freeze-thaw exposure and assay procedures will be standardized across assessments. Samples from both intervention groups will be analysed in the same assay batches where feasible. Change will be calculated as the follow-up concentration minus the baseline concentration. This outcome will be interpreted as an exploratory circulating biomarker and not as a specific standalone measure of median nerve neuroplasticity.
Click on the lead sponsor to view all of their trials.
This trial is not recruiting at the moment. You can still explore other options:
