Application of ABR in pathogenic neurovascular compression of the 8th cranial nerve in vestibular paroxysmia.

PURPOSE

To investigate the clinical value of electrophysiological tests in indicating pathogenic vascular contact of the 8th nerve in definite vestibular paroxysmia (VP) cases to provide a reference for decompression surgery.

METHODS

We retrospectively analyzed patients who had vertigo, unilateral tinnitus, or hearing loss and exhibited vascular contact of the 8th cranial nerve by MRI. Participants were classified into the VP or non-VP group according to the criteria of the Bárány Society in 2016. The demographic characteristics and audiological and electrophysiological test results of the two groups were compared. Receiver operating characteristic (ROC) curves were calculated for ABR to determine the best parameters and cutoff values to predict the existence of pathological neurovascular contact in VP.

RESULTS

Thirteen patients in the VP group and 66 patients in the non-VP group were included. VP patients had longer interpeak latency (IPL) I-III and wave III latency compared to non-VP patients (p < 0.001; p < 0.001). According to the ROC analyses, IPL I-III and wave III latency were the best indicators for the diagnosis of VP. The optimal cutoff for IPL I-III was 2.3 ms (sensitivity 84.6%, specificity 95.5%), and that for wave III latency was 4.0 ms (sensitivity 92.3%, specificity 77.3%). There were no differences in the PTA, caloric test, o-VEMP, or c-VEMP results between the two groups.

CONCLUSION

Prolonged IPL I-III and the wave III latency of ABR strongly suggested that vascular contact of the 8th cranial nerve was pathological, which may provide some references for microvascular decompression surgery of VP.