Sensorimotor inhibition in Dystonia
Final Report Abstract
One key finding in primary dystonia is insufficient cortical inhibition. Abnormalities in several different cortical inhibitory functions have been reported for different phenotypes of primary dystonia, including spatial spread of motor inhibition, temporal properties of motor inhibition, somatosensory spatial inhibition and temporal properties of somatosensory inhibition. However, some of these domains have produced inconsistent findings. Moreover, few studies have investigated two or more inhibitory functions within the same patient group. Therefore, current knowledge does not clarify whether there exists a dystonic deficit in inhibitory processing, common to different functions and phenotypes, or whether the deficit is more specific. We, therefore, developed a systematic battery consisting of 6 different tests, assessing both spatial and temporal cortical inhibitory processing, in both motor and somatosensory systems. We tested 17 cervical dystona patients and 19 healthy controls. We found a significant deficit in the dystonic group, compared to the control group, in two tests of somatosensory spatial inhibition (Tactile Grating Orientation Task, Lateral Feedforward Subliminal Inhibition). In contrast, somatosensory temporal inhibition tests (Tactile Temporal Discrimination Task, Feedforward Subliminal Inhibition) and tests of motor inhibition (Short-interval Intra-Cortical Inhibition, Surround Inhibition) showed comparable results between the two groups. Our findings point to a key role of somatosensory, rather than motor inhibitory mechanisms in dystonia. Using this extensive, theory-based test battery, we have confirmed the concept of a somatosensory core of dystonia pathophysiology, and placed it on a clear experimental footing. Importantly, these results demonstrate for the first time a specific inhibitory deficit for spatial somatosensory functions in CD.
Publications
- Dystonic Tremor and Spasmodic Dysphonia in Spinocerebellar Ataxia Type 12. Movement Disorders Clinical Practice. 04/2014
Christos Ganos, Tabish A. Saifee, Panagiotis Kassavetis, Roberto Erro, Amit Batla, Carla Cordivari, Kailash P. Bhatia
(See online at https://doi.org/10.1002/mdc3.12006) - Paroxysmal Kinesigenic Dyskinesia May Be Misdiagnosed in Co-occurring Gilles de la Tourette Syndrome. Movement Disorders Clinical Practice. 04/2014
Christos Ganos, Niccolo Mencacci, Alice Gardiner, Roberto Erro, Amit Batla, Henry Houlden, Kailash P. Bhatia
(See online at https://doi.org/10.1002/mdc3.12001) - The Phenomenology of Functional (Psychogenic) Dystonia. Movement Disorders Clinical Practice. 04/2014
Christos Ganos, Mark J. Edwards, Kailash P. Bhatia
(See online at https://doi.org/10.1002/mdc3.12013) - Feedforward somatosensory inhibition is normal in cervical dystonia. Parkinsonism & Related Disorders 01/2015
Elisa R. Ferre, Christos Ganos, Kailash P. Bhatia, Patrick Haggard
(See online at https://doi.org/10.1016/j.parkreldis.2014.12.026)
