Peripheral and Central Adaptations After a Median Nerve Neuromobilization Program Completed by Individuals With Carpal Tunnel Syndrome: An Exploratory Mechanistic Study Using Musculoskeletal Ultrasound Imaging and Transcranial Magnetic Stimulation.

OBJECTIVE: Neuromobilization exercises are increasingly advocated in the conservative management of individuals with carpal tunnel syndrome (CTS), as they may mitigate CTS-related signs and symptoms via potential peripheral (ie, musculoskeletal) and central (ie, neurophysiological) adaptations. However, the mechanisms underlying these adaptations have not been studied extensively. Hence, this exploratory and mechanistic study aims to evaluate the potential peripheral and central adaptations that may result in individuals with CTS who have completed a neuromobilization program. METHODS: Fourteen individuals with CTS were evaluated before and 1 week after the completion of a 4-week neuromobilization program that incorporated median nerve sliding exercises. Pain and upper limb functional abilities were assessed using standardized questionnaires. The biological integrity and mechanical properties of the median nerve and the corticospinal excitability were quantified using musculoskeletal ultrasound imaging and transcranial magnetic stimulation, respectively. RESULTS: Upon completion of the program, participants reported both large and moderate improvements in pain (P ≤ .03) and upper limb functional abilities (P = .02), respectively. The biological integrity and mechanical properties of the median nerve remained unchanged (P ≥ .22), whereas a small significant increase in corticospinal excitability (P = .04) was observed. CONCLUSION: The proposed neuromobilization program appears promising to improve pain and upper limb functional abilities in individuals with CTS. These improvements may be preferentially mediated via central, rather than peripheral, adaptations. Future studies, especially with a larger sample size, longer intervention duration, and additional measurement times, are needed to strengthen current evidence.

Left Right Judgement Task and Sensory, Motor, and Cognitive Assessment in Participants with Wrist/Hand Pain.

The Left Right Judgement Task (LRJT) involves determining if an image of the body part is of the left or right side. The LRJT has been utilized as part of rehabilitation treatment programs for persons with pain associated with musculoskeletal injuries and conditions. Although studies often attribute changes and improvement in LRJT performance to an altered body schema, imaging studies suggest that the LRJT implicates other cortical regions. We hypothesized that cognitive factors would be related to LRJT performance of hands and feet and that sensory, motor, and pain related factors would be related to LRJT in the affected hand of participants with wrist/hand pain. In an observational cross-sectional study, sixty-one participants with wrist/hand pain participated in a study assessing motor imagery ability, cognitive (Stroop test), sensory (Two-Point Orientation Discrimination, pressure pain thresholds), motor (grip strength, Purdue Pegboard Test), and pain related measures (West Haven Yale Multidimensional Pain Inventory) as well as disability (Disability of the Arm, Shoulder and Hand). Multiple linear regression found Stroop test time and motor imagery ability to be related to LRJT performance. Tactile acuity, motor performance, participation in general activities, and the taking of pain medications were predictors of LRJT accuracy in the affected hand. Participants who took pain medications performed poorly in both LRJT accuracy (p=0.001) and reaction time of the affected hand (p=0.009). These participants had poorer cognitive (p=0.013) and motor function (p=0.002), and higher pain severity scores (p=0.010). The results suggest that the LRJT is a complex mental task that involves cognitive, sensory, motor, and behavioural processes. Differences between persons with and without pain and improvement in LRJT performance may be attributed to any of these factors and should be considered in rehabilitation research and practice utilizing this task.

Addressing Neuroplastic Changes in Distributed Areas of the Nervous System Associated With Chronic Musculoskeletal Disorders.

Present interventions utilized in musculoskeletal rehabilitation are guided, in large part, by a biomedical model where peripheral structural injury is believed to be the sole driver of the disorder. There are, however, neurophysiological changes across different areas of the peripheral and central nervous systems, including peripheral receptors, dorsal horn of the spinal cord, brain stem, sensorimotor cortical areas, and the mesolimbic and prefrontal areas associated with chronic musculoskeletal disorders, including chronic low back pain, osteoarthritis, and tendon injuries. These neurophysiological changes appear not only to be a consequence of peripheral structural injury but also to play a part in the pathophysiology of chronic musculoskeletal disorders. Neurophysiological changes are consistent with a biopsychosocial formulation reflecting the underlying mechanisms associated with sensory and motor findings, psychological traits, and perceptual changes associated with chronic musculoskeletal conditions. These changes, therefore, have important implications in the clinical manifestation, pathophysiology, and treatment of chronic musculoskeletal disorders. Musculoskeletal rehabilitation professionals have at their disposal tools to address these neuroplastic changes, including top-down cognitive-based interventions (eg, education, cognitive-behavioral therapy, mindfulness meditation, motor imagery) and bottom-up physical interventions (eg, motor learning, peripheral sensory stimulation, manual therapy) that induce neuroplastic changes across distributed areas of the nervous system and affect outcomes in patients with chronic musculoskeletal disorders. Furthermore, novel approaches such as the use of transcranial direct current stimulation and repetitive transcranial magnetic stimulation may be utilized to help renormalize neurological function. Comprehensive treatment addressing peripheral structural injury as well as neurophysiological changes occurring across distributed areas of the nervous system may help to improve outcomes in patients with chronic musculoskeletal disorders.