The aim of this study was to examine the pathophysiological mechanisms underlying co-contraction in @entity1 with @entity3519 (n = 6) and @entity3520 (n = 5). Multi-unit needle and surface EMGs were recorded from extensor carpi radialis (ECR) and flexor carpi radialis (FCR) muscles during motor tasks that elicited @entity3519 or @entity3520 . The EMGs from ECR and FCR were recorded simultaneously and analysed using cross-correlation analysis. Similar recordings were obtained from healthy age- and sex-matched control subjects (n = 8). Despite co-contraction of the muscles, cross-correlograms from the healthy subjects did not reveal evidence of motor unit synchronization. Cross-correlograms from the dystonic subjects revealed a central peak with a median duration of 37 ms, indicating broad-peak motor unit synchronization. Cross-correlograms from @entity1 with @entity3520 were either flat or modulated by a 11-12-Hz @entity400 . Frequency-domain analysis of ECR and FCR EMGs demonstrated significant coherence in the @entity1 with @entity3519 and @entity3520 . These results indicate that co-contraction in @entity3519 is neurophysiologically distinct from voluntary co-contraction and is produced by abnormal synchronization of presynaptic inputs to antagonist motor neuron pools. ECR and FCR co-contraction in @entity3520 may be a compensatory process under voluntary control.

Abnormal motor unit synchronization of antagonist muscles underlies pathological co-contraction in XXXX .

@entity1 :: ('9606', 'Species') :: ['patients'] @entity3520 :: ('MESH:D020821', 'Disease') :: ["writer's cramp"] @entity3519 :: ('MESH:D004421', 'Disease') :: ['dystonia'] @entity400 :: ('MESH:D014202', 'Disease') :: ['tremor']
@entity3519 :: (MESH:D004421,Disease) :: ['upper limb dystonia']
