Objective: To compare the incidence of head-shaking nystagmus (HSN) with the value of canal paresis (CP) obtained from a caloric test and to propose the optimal value of CP that can be predicted by the presence of HSN.
Material and methods: HSN and caloric tests, together with other vestibular tests, were performed in 132 dizzy patients. HSN was recorded using electronystagmography with Frenzel's glasses.
Results: HSN was observed in 61/132 patients (46%). The sensitivity and specificity of the HSN test regarding the prediction of CP>20% were 66% and 77%, respectively. CP values were significantly higher in patients with than without HSN. Both the sensitivity and specificity of HSN were reasonably high when the limiting value of CP was set between 20% and 30%.
Conclusion: The limiting value of CP that discriminates the presence of HSN may be approximately 20%. At this CP value, HSN shows an appropriately high sensitivity and specificity. The HSN test is not very sensitive but is still acceptable as one of the screening tests for detecting asymmetrical vestibular dysfunction.