NOCTURNAL PAROXYSMAL DYSTONIA - A CLINICAL FORM OF FOCAL EPILEPSY

Different paroxysmal movements occur during sleep. They correspond eit her to epileptic seizures of sleep, or to parasomnia. Recently, other nocturnal motor phenomena have been described in the literature as noc turnal or hypnogenic paroxysmal dystonia (NPD), paroxysmal arousal, ep isodic nocturnal wanderings, etc. The NPD are involuntary nocturnal mo vements characterized by the association of dystonic postures, tonic m ovements of the four limbs and the body axis, automatisms, affective m imicry, and vocalization. In certain patients, the EEG records show ab normalities characteristic of epilepsy; in others, the EEG appears nor mal. A large proportion of the patients present epileptic seizures as antecedents. Typical generalized tonic-clonic seizures can follow an N PD. The NPD are improved with anti-epileptics. The considerable simila rity of the clinical and paraclinical signs and of the effects of anti -epileptic treatments do not seem to justify the individualization of different subgroups as a function of the EEG patterns: the NPD are alw ays the result of focal epilepsy, and never of a pathology of movement or of parasomnia. Numerous arguments based on the symptoms and the EE G suggest that these seizures involve the mesial frontal regions.