[Motor negligence in a case of right thalamic hematoma (author's transl)].

In a patient with left motor negligence CT scan showed a right thalamic hematoma of small size, involving the posterior thalamic region. The clinical picture was pure, including neither marked distal or proximal motor deficiency, nor auditory or visual or somesthetic disorders except sensory extinction. Cortical somesthetic evoked potentials were normal. Motor negligence presented 3 basic elements: 1) lack of spontaneous movements of the left side of the body, particularly of the upper limb; 2) absence of nociceptive reactivity; 3) immediate total reversibility of the disorder following verbal commands. Emphasis is placed on this latter sign which indicates the thalamic origin of the disturbance. Of the various explanations proposed for the disorder the most likely one would appear to be a disorder of a relatively specific activation system of motor activities, a system arising from the posterior thalamic nuclei: 1) pulvinar and laterodorsal nuclei projecting over area 23 (posterior cingulum); 2) intralaminar formations, particularly the lateral superior central nucleus, projecting over area 24 (anterior cingulum). The disturbance in this system, at its thalamic origin, might explain the differences between this motor negligence behaviour and lack of spontaneous motility syndromes resulting from frontal cortical lesions. It might also be that the right lateralisation of the lesion plays a relatively minor role.