Skull vibration-induced nystagmus in vestibular neuritis

Background As described by Dumas, an 80-100 Hz vibration applied to the mastoid produces a horizontal nystagmus, with quick phases beating away from the affected side in patients with unilateral vestibular loss (UVL). Aim/objectives To elucidate the characteristics of skull vibration-induced nystagmus (SVIN) in patients suffering from vestibular neuritis and how these characteristics are related to information provided by the video head impulse test (vHIT). Material and methods Sixty-three patients were enrolled to perform a vHIT to measure the gain in both ears. SVIN was induced with stimulation at 30 Hz, 60 Hz, and 100 Hz. The slow phase velocity (SPV) of the SVIN was measured. Results The SVIN test was positive in 25/63 patients at 30 Hz, 36/63 at 60 Hz and 46/63 at 100 Hz. Mean gain difference between both ears to obtain a positive SVIN at 30 Hz was observed to be 0.38 +/- 0.25, decreasing to 0.35 +/- 0.23 at 60 Hz, and 0.31 +/- 0.24 at 100 Hz (p = .025). We found a significant positive linear correlation between the gain asymmetry measured using horizontal vHIT and SPV in SVIN at 100 Hz. Conclusions and significance There is a close relationship between the difference in the gains of both ears as measured using VHIT and the SPV of the nystagmus induced by SVIN at 100 Hz.