Cervical dystonia: Normal auditory mismatch negativity and abnormal somatosensory mismatch negativity

Clin Neurophysiol. 2018 Sep;129(9):1947-1954. doi: 10.1016/j.clinph.2018.05.028. Epub 2018 Jul 4.

Abstract

Objective: Previous electrophysiological and psychophysical tests have suggested that somatosensory integration is abnormal in dystonia. Here, we hypothesised that this abnormality could relate to a more general deficit in pre-attentive error/deviant detection in patients with dystonia. We therefore tested patients with dystonia and healthy subjects using a mismatch negativity paradigm (MMN), where evoked potentials generated in response to a standard repeated stimulus are subtracted from the responses to a rare "odd ball" stimulus.

Methods: We assessed MMN for somatosensory and auditory stimuli in patients with cervical dystonia and healthy age matched controls.

Results: We found a significant group ∗ oddball type interaction effect (F (1, 34) = 4.5, p = 0.04, ρI = 0.63). A follow up independent t-test for sMMN data, showed a smaller sMMN amplitude in dystonic patients compared to controls (mean difference control-dystonia: -1.0 µV ± 0.3, p < 0.00, t = -3.1). However the amplitude of aMMN did not differ between groups (mean difference control-dystonia: -0.2 µV ± 0.2, p = 0.24, t = -1.2). We found a positive correlation between somatosensory MMN and somatosensory temporal discrimination threshold.

Conclusion: These results suggest that pre-attentive error/deviant detection, specifically in the somatosensory domain, is abnormal in dystonia. This could underlie some previously reported electrophysiological and psychophysical abnormalities of somatosensory integration in dystonia.

Significance: One could hypothesize a deficit in pre-conscious orientation towards potentially salient signals might lead to a more conservative threshold for decision-making in dystonia.

Keywords: Dystonia; Mismatch negativity (MMN); Somatosensory integration.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acoustic Stimulation
  • Aged
  • Attention / physiology
  • Auditory Cortex / physiopathology*
  • Auditory Perception / physiology*
  • Electroencephalography
  • Evoked Potentials, Auditory / physiology*
  • Evoked Potentials, Somatosensory / physiology*
  • Female
  • Humans
  • Male
  • Middle Aged
  • Physical Stimulation
  • Reaction Time / physiology
  • Torticollis / physiopathology*
  • Touch Perception / physiology*