PARAKINESIAS

PARAKINESIAS, a term proposed by Jacob to denote a special, not yet sufficiently studied form of hyperkinesias, namely involuntary complex coordinated motor acts sometimes observed in organic diseases of the brain. A patient with P. constantly performs a series of natural movements, in their motor formula fully corresponding to habitual voluntary movements, e.g., fingers fidgeting, rubbing fingers against each other, stroking or kneading a piece of blanket held, swinging a leg, etc., but cannot stop this involuntary gesture by force of will or can only hold it back for the shortest time. The character of complex coordination inherent in these movements distinguishes them from choreatic and athetotic movements. Their independence from the primary disorder of the psyche is evidenced among other things by the fact that this syndrome is usually developed on one side. For the most part, P. are combined with more or less pronounced phenomena of central paralysis, sometimes preceding the development of hemiplegia. The anatomical substrate of P. is not yet fully clear. Disease of the frontal lobes and their connections is assumed, or possibly the striatal system; however, the latter, as well as the assumption of a special hypothetical 'center of instinctive mobility' in the brainstem, is less probable.