[Lafora disease (author's transl)].

On the basis of 21 personal observations as well as those (82) from the litterature, it is concluded that the progressive myoclonic epilepsy with Lafora bodies (P.M.E.) constitutes a disease on its own. The clinical features are those described in the litterature observations and completed by some characteristics; the high frequency of visual symptoms (47 p. 100 personal cases); the relatively less bad evolution of epilepsy, perhaps in relation with use of modern drugs; the relatively moderate intensity of myoclonus which becomes complete only at the end of the evolution. From E.E.G. point of view, we can distinguish three periods: an initial one at the very onset of disease, who will show the same features as observated in primary generalized epilepsy, i.e. a well preserved background activity with superimposed generalized fast spikes and waves facilitated by the I.L.S. Then follows a period of evolutive E.E.G. (1-2 years after the onset of the disease) characterized by progressive slowing of the posterior background, enlargement of posterior slow activity and appearance of diffuse theta and delta activity. Simultaneously spikes and waves are taking less typical and bisynchronous aspect. Finally after 3 to 5 years from the onset there is a diffusely slow E.E.G. with superimposed fast multiple spikes. The E.E.G. findings in litterature usually refer only to this last period (stationary or terminal period). Occipital independent multiple spikes are frequently observed and could correlate with the visual symptoms observated in the Lafora disease. Some elements of differential diagnosis are given with respect to primary generalized epilepsy at the onset of the disease and later on with respect to dyssynergia cerebellaris myoclonica and to the progressive myoclonic epilepsy without Lafora bodies.