Paroxysmal dyskinesia on awakening: A new familial form of non- kinesigenic dyskinesia

Background

The sleep-to-wake and wake –to –sleep transitions known also as post and pre- dormitum are short events resulting from fine activation and deactivation of brain-stem and forebrain modulatory systems. Although sleep related movement disorders (SRMD) were recognized as a new category of sleep disorders since the 2nd version of the International Classification of Sleep Disorders, (ICSD-2), the mentioned list of those disorders did not include movement disorders occurring just before falling asleep or on awakening. Moreover, in a review of sleep-to-wake transitional movement disorders, only propriospinal myoclonus was mention as occurring during awakening.

Case presentation

we describe a brother and sister with chronic short events of dyskinesia occurring exclusively on awakening from nocturnal as well as daytime sleep, without evidence of additional neurological or medical abnormalities. Both siblings showed a prompt response to low dose of clonazepam (clonex^R), with long term and complete remission and without ill side effects. The clinical characteristics of this particular movement disorder are unique. A short video clip of the brother is included.

Conclusion

Our patients suffer from paroxysmal non-kinesigenic dyskinesia. The relation to sleep suggests that the disorder in our patients represents a new and unique form of familial paroxysmal hypnogenic dyskinesia responsive to clonazepam.