Klingon,1 in 1952, reported the results of caloric vestibular stimulation in a comatose patient. Irrigation of one ear with 20 ml. ice water elicited abduction of the ipsilateral eye, while the contralateral eye remained immobile in the midline. At the end of 1 minute, the abducted eye returned to its initial position. Upon irrigation of the other ear, the same phenomenon was observed: abduction of the ipsilateral eye, while the contralateral eye remained in the midline. No actual nystagmus occurred. Klingon interpreted these reactions as signs of interruption of the median longitudinal fasciculus between the abducens and oculomotor nuclei.
In the conscious subject, lesion at this site results in a characteristic symptom complex called internuclear paralysis,2 anterior internuclear ophthalmoplegia,3,4 or the posterior longitudinal fasciculus syndrome. It is characterized by paralysis of the adduction of the eye at attempted lateral gaze, while the adduction upon convergence is intact.
BLEGVAD B. Caloric Vestibular Reaction in Unconscious Patients. Arch Otolaryngol. 1962;75(6):506–514. doi:10.1001/archotol.1962.00740040521005
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