[Selective paralysis of downward gaze with permanent conjugated upwards deviation : report of a new case (author's transl)].

Permanent upward conjugated ocular deviations are exceptional in conscious subjects : 8 cases only have been reported. They are always associated with a more or less selective paralysis of downward gaze. A further case is reported, with results of oculographic and computed tomography examinations. The latter showed a median or bilateral lesion at the diencephalo-mesencephalic junction. The mechanism provoking the deviation was clarified by studying vestibular movements which appeared abnormally ample and rapid. The authors suggest that the deviation of the eyes could result from this release of movements of vestibular origin, which can only be expressed as upwards movements because of complete paralysis of all lowering movements.