1991 Volume 1991 Issue Supplement42 Pages 50-55
Nystagmus towards the upper ear side in both lateral head positions is usually asociated with disturbance in the central nervous system, especially with the lesion in the brain stem or cerebellar posterior vermis.
Fifty patients in whom such positional nystagmus was detected in the ENG test during the last 8 years were investigated. In only 6 cases among them was such positional nystagmus observed under Frenzel spectacles. In these patients, the continual term of the nystagmus and association with positional vertigo were surveyed retrospectively. There were 16 cases of central disturbance,32 cases of peripheral vestibular disturbance, and 2cases of congenital idiopathic nystagmus. The central disturbances included vertebrobasilar insufficiency in 6, acoustic tumor in 2, cerebellar tumor in 2, multiple sclerosis in 2. The peripheral vestibular disturbance cases included 11 of recurrent vertiginous attacks,5 of provocations-vertigo,5 of labyrinthitis induced middle ear inflammation, and 4 of sudden deafness.
Positional nystagmu s towards the upper ear side is consisted to be on important sign of the central disturbance but it may occur in the peripheral vestibular lesion. In the latter case, the positional nystagmus is associated with positional vertigo and disappears for a short time without neurological findings except positional nystagmus.
