Does dystonic muscle activity affect sense of effort in cervical dystonia?

• DOI: 10.1371/journal.pone.0172019
• Publication Date: 2017-02-13T19:40:38Z
• Authors: Loïc Carment; Marc A. Maier; Sophie Sangla; Vincent Guiraud; Serge Mesure; Marie Vidailhet; Påvel G Lindberg; Jean-Pierre Bleton
• Keywords: Proprioception; Cervical dystonia; Visual feedback; Affect; Sensory cue; Neck muscles; Motor Control

Focal dystonia has been associated with deficient processing of sense effort cues. However, corresponding studies are lacking in cervical (CD). We hypothesized that dystonic muscle activity would perturb neck force control based on cues.Neck extension was investigated 18 CD patients different clinical features (7 and 11 without retrocollis) 19 subjects. Subjects performed force-matching force-maintaining tasks at 5% 20% maximum voluntary contraction (MVC). Three task conditions were tested: i) visual feedback, ii) feedback (requiring use effort), iii) but extensor vibration (modifying afferent cues). Trapezius recorded using electromyography (EMG).CD did not differ performance from healthy subjects when (ANOVA, p>0.7). In contrast, relying cues (without MVC), impaired retrocollis (p = 0.006), (p>0.2). Compared to controls, significantly affected (p<0.001), retrocollis. Extensor EMG during rest, included as covariate ANOVA, explained these group differences.This study shows biases controlling forces CD. The bias acts peripheral or central depending whether the involves muscles. This may explain why more accurately matched isometric forces. highlights need consider (pattern muscles) evaluating sensorimotor integration