Sensory tricks in cervical dystonia: Perceptual dysbalance of parietal cortex modulates frontal motor programming

Abstract

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.

Dystonia Pathophysiology: A Critical Review

“…These abnormalities were also found in non-symptomatic patients carrying the DYT1 gene (149). In line with electrophysiological studies, abnormal sensory processing was reported in focal hand dystonia (150), blepharospasm (151), and cervical dystonia (152). Similar results were also obtained in non-manifesting DYT1 carriers (153,154).…”

Endophenotyping in idiopathic adult onset cervical dystonia

“…The fact that the latter research group found the largest differences in the visual and tactile compared to mixed (visuo-tactile) paradigm is intriguing and hard to explain. (Bradley et al, 2009;Kimmich et al, 2014) (Tinazzi et al, 2002)patients with IAOCD multimodal (visuo-tactile) temporal discrimination might be more affected compared to the unimodal temporal discrimination; i) the parietal lobe as an important center of multimodal sensory integration is part of the dystonia network (Lacruz et al, 1991;Leon and Shadlen, 2003;Neychev et al, 2011;Pastor et al, 2004), ii) this notion receives support by the finding that patients with a good effect to a sensory trick perform significantly better in the visuo-tactile sensory discrimination and that the parietal lobe is activated while performing an effective sensory trick (Kagi et al, 2013;Naumann et al, 2000), iii) the superior colliculi, where multisensory (visual, tactile, auditory) inputs converge are involved in head-turn generation with its cephalomotor premotor neurons (Hutchinson et al, 2014).…”

History of the ‘geste antagoniste’ sign in cervical dystonia

“…In the 1980s, Charles David Marsden clearly established the organic origin of cervical dystonia and other dystonic syndromes [33,37]. Currently, the proposition of a psychological origin has given way to the modern view of dystonia as a disease of sensorimotor integration [38,39]. The exact mechanisms of the geste antagoniste phenomenon remain unknown.…”

“…Positron emission tomography for patients suffering from cervical dystonia has shown that the application of a sensory trick stimulus leads to increased activation of the superior and inferior parietal lobule ipsilateral to the original head turn and to a decreased activity of the supplementary motor area and the primary sensorimotor cortex contralateral to the head turn [39]. This reinforces the idea that the application of a geste antagoniste could exert a modulation of the sensorymotor intergration that is disturbed in dystonia [38][39][40][41]. This effect could be age dependent [17].…”