Cerebral Changes Following Carpal Tunnel Syndrome Treated with Guided Plasticity: A Prospective, Randomized,...

Area of Science:

• Neuroscience
• Neurology
• Medical Imaging

Background:

• Carpal tunnel syndrome (CTS) alters nerve signaling, potentially affecting somatosensory brain regions.
• Unilateral CTS can lead to changes in afferent nerve signaling and subsequent cortical reorganization.
• Understanding these cerebral changes is crucial for developing effective treatments.

Purpose of the Study:

• To assess cerebral changes in patients with unilateral carpal tunnel syndrome (CTS).
• To evaluate the short-term and long-term effects of guided plasticity treatment using ipsilateral cutaneous forearm deafferentation.
• To investigate the impact of anesthetic cream (EMLA) versus placebo on brain activity and sensory function.

Main Methods:

• Twenty-four patients with mild-to-moderate unilateral CTS were randomized to receive EMLA or placebo.
• Patient-rated outcomes (Boston CTS, QuickDASH), tactile discrimination, and dexterity were assessed.
• Functional magnetic resonance imaging (fMRI) evaluated cortical activation during sensory stimulation at baseline, 90 minutes, and 8 weeks.

Main Results:

• fMRI revealed significantly less cortical activation in the primary somatosensory cortex (S1) when stimulating the CTS-affected hand compared to the healthy hand.
• Cutaneous forearm deafferentation in the CTS-affected arm led to increased S1 activation both immediately and 8 weeks post-treatment.
• The EMLA group showed improvements in QuickDASH scores and tactile discrimination over the 8-week period.

Conclusions:

• Unilateral CTS reduces contralateral S1 activation during median nerve-innervated finger stimulation.
• Forearm anesthesia on the affected side increases S1 activation, suggesting neuronal recruitment.
• Guided plasticity treatment shows potential for improving sensory function in CTS patients.