Evaluation of the vertical semicircular canal function by the pendular rotation test: a study on patients with benign paroxysmal positional vertigo

The Video Head Impulse Test in the acute stage of posterior canal benign paroxysmal positional vertigo

OBJECTIVE

Study the high-frequency vestibulo-oculomotor reflex in posterior canal benign paroxysmal positional vertigo (BPPV) through Video Head Impulse Test (vHIT).

METHODS

150 patients suffering for the first time from posterior canal BPPV were studied. Posterior canal vestibulo ocular reflex (VOR) gain was analysed through stimulations in right anterior-left posterior and left anterior-right posterior planes before treatment, immediately after resolution of the acute stage and one month later. Results were compared with a group of 100 healthy individuals.

RESULTS

No significant difference between the study the control groups was observed, except for normalised asymmetry ratio of the posterior canal which was significantly higher in the study group. VOR gains of both affected posterior canals and contralateral healthy posterior canals were not significantly correlated with the VOR gain of ipsilateral and contralateral anterior canals.

CONCLUSIONS

vHIT does not seem to represent an essential tool to study typical posterior canal BPPV in patients affected by this disease for the first time. Different results might be expected in relapsing forms, non-responsive forms, long lasting forms, or atypical variants in which major damage could be provoked by the persistence of otoconia in the canal or by its complete or partial jam.