title: Recovery function of somatosensory evoked brain response in patients with carpal tunnel syndrome: A magnetoencephalographic study.
abstract: The recovery function of somatosensory evoked magnetic fields (SEFs) was recorded to investigate excitatory and inhibitory balance in the somatosensory cortex of patients with carpal tunnel syndrome.
  
  
  
  SEFs were recorded in patients and controls. Recordings were taken following median nerve stimulation with single and double pulses with interstimulus intervals of 10-200ms. The root mean square for the N20m component following the second stimulation was analyzed. SEFs following stimulation of the first and middle digits were also recorded and the location for the equivalent current dipoles was estimated in three-dimensional planes.
  
  
  
  Distances on the vertical axis between the equivalent current dipoles for the first and third digits were shorter in patients than in control participants. The root mean square for the N20m recovered earlier in patients compared to controls; this was statistically significant at an interstimulus interval of 10ms. There was no relationship between N20m recovery and the equivalent current dipole location in the primary somatosensory cortex.
  
  
  
  Carpal tunnel syndrome was associated with functional disinhibition and destruction of the somatotopic organization in the primary somatosensory cortex.
  
  
  
  Disinhibitory changes might induce a maladaptation of the central nervous system relating to pain.
authors.affiliation: Department of Hand Surgery, Graduate School of Medicine, Nagoya University, Nagoya, Japan. Electronic address: kiwatsuki@med.nagoya-u.ac.jp.
authors.forename: Katsuyuki
authors.initials: K
authors.lastname: Iwatsuki
authors.affiliation: Department of Hand Surgery, Graduate School of Medicine, Nagoya University, Nagoya, Japan; Department of Rehabilitation, Nagoya University Hospital, Nagoya, Japan.
authors.forename: Akihito
authors.initials: A
authors.lastname: Yoshida
authors.affiliation: Hand Surgery Center, Chunichi Hospital, Nagoya, Japan.
authors.forename: Takaaki
authors.initials: T
authors.lastname: Shinohara
authors.affiliation: Department of Hand Surgery, Graduate School of Medicine, Nagoya University, Nagoya, Japan.
authors.forename: Tomonori
authors.initials: T
authors.lastname: Nakano
authors.affiliation: Department of Physical and Occupational Therapy, Graduate School of Medicine, Nagoya University, Nagoya, Japan.
authors.forename: Jun-Ichi
authors.initials: JI
authors.lastname: Uemura
authors.affiliation: Department of Pathophysiological Laboratory Sciences, Graduate School of Medicine, Nagoya University, Nagoya, Japan.
authors.forename: Sae
authors.initials: S
authors.lastname: Goto
authors.affiliation: Department of Pathophysiological Laboratory Sciences, Graduate School of Medicine, Nagoya University, Nagoya, Japan.
authors.forename: Masaaki
authors.initials: M
authors.lastname: Hirayama
authors.affiliation: Department of Physical and Occupational Therapy, Graduate School of Medicine, Nagoya University, Nagoya, Japan; Brain and Mind Research Center, Nagoya University, Nagoya, Japan.
authors.forename: Minoru
authors.initials: M
authors.lastname: Hoshiyama
authors.affiliation: Department of Hand Surgery, Graduate School of Medicine, Nagoya University, Nagoya, Japan.
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Hirata
mesh_terms: D000368:Aged; D001931:Brain Mapping; D002349:Carpal Tunnel Syndrome / Q000503:physiopathology*; D004558:Electric Stimulation; D005073:Evoked Potentials, Somatosensory / Q000502:physiology*; D005260:Female; D006801:Humans; D015225:Magnetoencephalography; D008297:Male; D008475:Median Nerve / Q000503:physiopathology*; D008875:Middle Aged; D011930:Reaction Time / Q000502:physiology; D013003:Somatosensory Cortex / Q000503:physiopathology*
keywords: Carpal tunnel syndrome; Magnetoencephalography; N20m; Pain; Somatosensory cortex; Somatosensory evoked magnetic field