[Unusual pathological ocular movement caused by dysfunction of the saccade generation mechanism].
We describe a patient with abnormal ocular movement, probably due to dysfunction of saccade generation mechanism in the lower pons involving the omnipause neuron and a feed-back circuit. A 26-year-old man had fever, mild headache and sore throat for a few days and also noted unstable gait and diplopia. These symptoms subsided, but he noticed oscillopsia about 2 months later. On admission in our hospital, the neurological examination revealed no abnormalities except for abnormal eye movements, which were induced by voluntary or involuntary ocular movement and lasted for a few minutes. The abnormal ocular movement was irregular in direction, amplitude and rhythmicity, and the voluntary and involuntary ocular movements could not be elicited during the period of this abnormal ocular movement. The abnormal ocular movement completely disappeared for about 1 hour by intravenous injection of TRH. At this time bilateral mild abducens palsy was demonstrated by EOG examination. The abnormal ocular movement in this patient, which has nerve been reported in the literature, was considered to be due to a disinhibition of excitatory burst neuron (EBN) caused by the dysfunction of omnipause neuron, and possibly due to a delay of feed-back information of saccade to the EBN.
Maeda
T
T
Department of Neurology, Faculty of Medicine, Kyushu University.
Kobayashi
T
T
Goto
I
I
Kato
M
M
Mukuno
K
K
D000010:Abducens Nerve; D000328:Adult; D003389:Cranial Nerve Diseases / Q000503:physiopathology; D004585:Electrooculography; D006801:Humans; D008297:Male; D009474:Neurons / Q000502:physiology; D011149:Pons / Q000503:physiopathology*; D012438:Saccades