Objective: The aim of the present study was to assess the temporal discrimination and motion processing in DYT-SGCE myoclonus-dystonia as well as its’ neuronal correlates using structural neuroimaging.

Background: Similarly to other dystonic syndromes  abnormal sensori-motor integration  has been shown in DYT-SGCE. However,  temporal discrimination and motion perception has not been studies in this form of dystonia. We hypothesized that DYT-SGCE patients,  known to share some common pathophysiological features with other dystonic syndromes, will have an abnormal sensory processing of temporal discrimination and motion.

Method: Using  computerized tasks, we tested temporal discrimination, discrimination of the speed and the direction of the motion in 37 DYT-SGCE patients (with n = 24 and without n = 13 deep brain stimulation of GPI) compared to controls (n = 25). To further assess how visual perception are generated in this form of dystonia, the behavioral data were analyzed using computational “race model”. In this  model, an accumulation of sensory “evidence” for a hypothesis occurs in a linear fashion. Once enough sensory evidence for a certain response is accumulated (at a rate μ), signified by the decision signal reaching its threshold (θ), then this hypothesis is accepted and a decision to respond is made.  We also performed the region of interest analysis for the structural changes within the neuronal network that underpin the performance in the behavioral tasks.

Results: Computational analysis of the behavioral performance in tasks pointed to a slower rate of sensory accumulation in DYT-SGCE patients compared to the healthy volunteers in both temporal discrimination and motion evaluation tasks. Structural brain analysis showed a thicker primary visual cortex in the DYT-SGCE patients, which predicted severity of myoclonus and a lower rate of sensory accumulation in the visual Temporal discrimination task.

Conclusion: Our findings suggested that visual sensory information processing is altered in DYT-SGCE.  The abnormalities of brain morphology and correlations with clinical severity scores, suggest that abnormalities of sensory processing is likely a part of the pathogenesis of myoclonus-dystonia.

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MDS Abstracts - https://www.mdsabstracts.org/abstract/visual-sensory-processing-is-altered-in-myoclonus-dystonia/