Value of head-shaking nystagmus in examination of the dizzy patient

ABSTRACT

The value of head-shaking nystagmus in vestibular examination was studied in 30 patients who complained of dizziness, this was done by comparing the head-shaking test results with the results of the saccade test, spontaneous nystagmus test and the caloric test, we found that head-shaking nystagmus is a highly sensitive method indicating unilateral peripheral vestibular hypofunction and its direction is always toward the intact side. In bilateral peripheral vestibular lesions or in central lesions the direction of the head-shaking nystagmus is not significant. The origin of head-shaking nystagmus was also discussed and we concluded that head-shaking nystagmus is not an amplification of a spontaneous nystagmus, hidden by suppressive mechanisms but it is due to a combination of directional asymmetry of vestibular responses and central velocity storage