Familial, congenital paralysis of horizontal gaze
R. D. Yee, R. M. Duffin, R. W. Baloh and S. J. Isenberg
Eye movements were studied in a sister and brother with familial,
congenital paralysis of horizontal gaze. Horizontal and vertical eye
movements were recorded with DC electro-oculography and analyzed with a
laboratory computer. All horizontal, conjugate eye movements were absent
(saccades, pursuit, optokinetic nystagmus, vestibulo-ocular response, and
visual-vestibular responses). Voluntary vergence eye movements were
preserved and were used to track visual targets. An involuntary,
horizontal, pendular nystagmus was found to represent disconjugate, smooth,
vergence eye movements. Vertical saccades and vestibulo-ocular responses
were normal. However, vertical pursuit, optokinetic nystagmus, and
suppression of the vestibulo-ocular response by fixation were impaired. A
developmental anomaly affecting motor neurons and interneurons in the
abducens nuclei is suggested to be the cause of the absence of conjugate,
horizontal eye movements.
