Study showing how the brain reacts differently to acupuncture in subjects with carpal tunnel disease and healthy controls.

Acupuncture Evoked Response in Contralateral Somatosensory Cortex Reflects Peripheral Nerve Pathology of Carpal Tunnel Syndrome.

Author information 

  • 1Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital , Harvard Medical School, Charlestown, MA. ; Department of Radiology, Logan College of Chiropractic/University Programs , Chesterfield, MO.
  • 2Department of Radiology, Logan College of Chiropractic/University Programs , Chesterfield, MO.
  • 3Department of Biomedical Engineering, Kyung Hee University , Yongin, Korea.
  • 4Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital , Harvard Medical School, Charlestown, MA.
  • 5Department of Physical Medicine and Rehabilitation, Spaulding Rehabilitation Hospital , Medford, MA.
  • 6Department of Physical Medicine and Rehabilitation, Harvard Medical School , Spaulding Rehabilitation Hospital, Boston, MA.
  • 7Department of Pain Medicine, Harvard Vanguard Medical Associates , Atrius Health, Boston, MA.

Abstract

BACKGROUND:

Most neuroimaging studies exploring brain response to different acupoints have been performed in healthy adults.

OBJECTIVE:

The aim of this study was to compare brain responses to acupuncture at local versus distal acupoints in patients with carpal tunnel syndrome (CTS), who have chronic pain, versus healthy controls (HC) and correlate these responses with median nerve function.

MATERIALS AND METHODS:

Brain response to electroacupuncture (EA; 2Hz) was evaluated with event-related functional MRI (fMRI) in patients with CTS (n=37) and age-matched HC (n=30). EA was applied at acupoints local (PC 7 to TW 5) and distal (SP 6 to LV 4) to the CTS lesions.

RESULTS:

Brain response in both groups and acupoints included activation of the bilateral secondary somatosensory cortex (S2) and insula, and the contralesional primary somatosensory cortex (cS1). Deactivation was noted in ipsilesional primary somatosensory cortex (S1). A significant difference between local and distal acupoints was found in cS1 for HC, but not CTS. Furthermore, cS1 activation by EA at local acupoints was negatively correlated with median nerve peak sensory latency in HC, but was positively correlated in CTS. No correlation was found for EA at distal acupoints for either group.

CONCLUSIONS:

Brain response to EA differs between CTS and HC and, for local acupoint stimulation, is associated with median nerve function, reflecting the peripheral nerve pathophysiology of CTS.