Sensory tricks in cervical dystonia: perceptual dysbalance of parietal cortex modulates frontal motor programming.
Cervical dystonia is a disabling basal ganglia disorder characterized by an involuntary head deviation to one side. A typical but also mysterious feature is the impressive improvement of muscle spasms and involuntary head posture by application of a sensory facial stimulus (sensory trick). Here, we report the effect of a sensory trick on cortical activation patterns in 7 patients with cervical dystonia by using H2(15)O positron emission tomography. The application of the sensory trick stimulus, resulting in a near-neutral head position, led to an increased activation mainly of the superior and inferior parietal lobule (ipsilateral to the original head turn) and bilateral occipital cortex and to a decreased activity of the supplementary motor area and the primary sensorimotor cortex (contralateral to the head turn). We propose that a perceptual dysbalance induced by a sensory trick maneuver leads to a relative displacement of the egocentric midvertical reference to the opposite side and a decrease in motor cortex activity. This modulation of motor programming gives novel insights into the mechanisms involved in sensorimotor integration in movement disorders.
Naumann
M
M
Department of Neurology, University of Würzburg, Germany.
Magyar-Lehmann
S
S
Reiners
K
K
Erbguth
F
F
Leenders
K L
KL
D000328:Adult; D000368:Aged; D001931:Brain Mapping; D002574:Cervical Vertebrae; D004421:Dystonia / Q000000981:diagnostic imaging* / Q000503:physiopathology; D005260:Female; D005625:Frontal Lobe / Q000000981:diagnostic imaging* / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D010296:Parietal Lobe / Q000000981:diagnostic imaging* / Q000503:physiopathology; D013003:Somatosensory Cortex / Q000000981:diagnostic imaging* / Q000503:physiopathology; D014055:Tomography, Emission-Computed