Abstract
The neurophysiology of aggravation or improvement of symptoms in dystonia patients due to their mental status remains unclarified. The patient is a DYT11 case (SGCE NM_003919.3 : c. 233-2A>G, de novo mutation) who developed focal dystonia at the age of 5 years. In this case, transcranial magnetic stimulation (TMS) was used during movement to measure the silent period (SP) during the affected side hand contraction and bilateral hands contraction. SP was used as an index of interhemispheric inhibition. SP was also compared in the presence or absence of distraction (mental calculation). In addition, motor related cortical potentials (MRCP) and contingent negative variations (CNV) were measured in order to investigate abnormalities in the movement preparation state. The patient’s SP in TMS was shorter in bilateral hands contraction than in the affected side hand contraction alone, as opposed to controls. SP during bilateral hands contraction was prolonged and recovered with distraction compared to that without distraction. MRCP recordings were not normal and CNV appeared. From the results in this dystonia case, it was believed that the decrease in interhemispheric inhibition was involved in abnormalities during movement, and that abnormalities in movement plan and cognitive overload were involved in abnormalities in movement preparation. It is possible that distraction improved the symptoms by eliminating the decreased interhemispheric inhibition. We consider these data to be valuable by showing some neurophysiological basis of psychological effects in dystonia.
