Altered sensory system activity and connectivity patterns in adductor spasmodic dysphonia

Sci Rep. 2020 Jun 23;10(1):10179. doi: 10.1038/s41598-020-67295-w.

Abstract

Adductor-type spasmodic dysphonia (ADSD) manifests in effortful speech temporarily relievable by botulinum neurotoxin type A (BoNT-A). Previously, abnormal structure, phonation-related and resting-state sensorimotor abnormalities as well as peripheral tactile thresholds in ADSD were described. This study aimed at assessing abnormal central tactile processing patterns, their spatial relation with dysfunctional resting-state connectivity, and their BoNT-A responsiveness. Functional MRI in 14/12 ADSD patients before/under BoNT-A effect and 15 controls was performed (i) during automatized tactile stimulus application to face/hand, and (ii) at rest. Between-group differential stimulation-induced activation and resting-state connectivity (regional homogeneity, connectivity strength within selected sensory(motor) networks), as well as within-patient BoNT-A effects on these differences were investigated. Contralateral-to-stimulation overactivity in ADSD before BoNT-A involved primary and secondary somatosensory representations, along with abnormalities in higher-order parietal, insular, temporal or premotor cortices. Dysphonic impairment in ADSD positively associated with left-hemispheric temporal activity. Connectivity was increased within right premotor (sensorimotor network), left primary auditory cortex (auditory network), and regionally reduced at the temporoparietal junction. Activation/connectivity before/after BoNT-A within-patients did not significantly differ. Abnormal ADSD central somatosensory processing supports its significance as common pathophysiologic focal dystonia trait. Abnormal temporal cortex tactile processing and resting-state connectivity might hint at abnormal cross-modal sensory interactions.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Botulinum Toxins, Type A / therapeutic use
  • Brain Mapping / methods
  • Dysphonia / drug therapy
  • Dysphonia / physiopathology*
  • Dystonic Disorders / drug therapy
  • Dystonic Disorders / physiopathology*
  • Female
  • Hand / physiopathology
  • Humans
  • Magnetic Resonance Imaging / methods
  • Male
  • Middle Aged
  • Motor Cortex / drug effects
  • Motor Cortex / physiopathology
  • Phonation / drug effects
  • Phonation / physiology
  • Sensory Receptor Cells / drug effects
  • Sensory Receptor Cells / physiology*
  • Speech / drug effects
  • Speech / physiology

Substances

  • Botulinum Toxins, Type A