knee-jerk reaction. Fig. an automatic or reflex reaction; an immediate reaction made without examining causes or facts. With one of his typical knee-jerk reactions, he said no immediately, citing some moral argument that no one understood. See also: reaction.
What did you see when the patients head was rolled to the opposite side? In horizontal canal BPPV, you should have seen a direction change. When the horizontal nystagmus is geotropic, the BPPV is suspected to be canalithiasis, occurring on the side with the more intense nystagmus.
Unilateral third cranial nerve palsy. 1  Horizontal deviation is divergent or temporal (exotropia) because of weakness of the medial rectus muscle of the involved side. 2  Vertical deviation results from weakness of the superior rectus, inferior oblique (both elevators), and inferior rectus (depressor) muscles.