A Study Of The Feasible Stimulating Frequency And The Clinic Application On Head Shaking Test

ObjectiveThe objective was to explore the feasible stimulating frequency for head shaking test, and to provide the evidence in its clinic practice. What's more, it was to try to determine the characteristics of horizontal head shaking nystagmus of peripheral origin and its relationship to vestibular dysfunction, to make a good understanding of the clinic value of head shaking test.MethodsThe study investigated 73 patients with the complaints of vertigo and 60 control subjects. Each person underwent the head shaking test at the different frequencies of 1Hz, 2Hz and 3Hz. We use the false negative rate and false positive rate as the criterion to choose the feasible frequency. Anyway, we chose the dizzy patients met the inclusion criteria of having peripheral and unilateral disease. All patients were tested with head shaking test and caloric test. We put down the parameters of the nystagmus and analyze the characterization of the HSN.ResultThe false-negative rate and the false-positive rate the patients got at the frequencies of 1Hz,2Hz,3Hz is :0.54.79%; 3.3%;16.43%,16.67%和12.67%. Of the 73 patients, forty-one patients showed a positive head shaking nystagmus. All cases of head shaking nystagmus observed were horizontal. Cross-checking nystagmus was not observed. There were nine biphasic and thirty-two monophasic cases of head shaking nystagmus. The first phases of biphasic head shaking nystagmus beat toward the normal ear. Twenty of the monophasic cases of head shaking nystagmus were contralateral and twelve were ipsilateral. There was a statistically significant correlation between caloric weakness and head shaking nystagmus. Contralateral and biphasic head shaking nystagmus corresponded to greater caloric weakness, and ipsilateral head shaking nystagmus corresponded to weaker caloric weakness. Ipsilateral responses could be distinguished from contralateral responses based on their latency and maximal slow-phase eye velocity. Head shaking nystagmus beat stronger in old patients.ConclusionThe feasible stimulating frequency for the head shaking test is 2Hz, and head shaking nystagmus of peripheral vestibular origin is a response associated both qualitatively and quantitatively with the degree of the vestibular loss.