Is Skull Vibration-Induced Nystagmus Useful in Vestibular Neuritis Follow Up?

The aim of this study was to evaluate the vestibulo-ocular reflex (VOR) gain and the saccade regrouping pattern PR score of the Video Head Impulse Test (vHIT) and its relationship with the slow-phase velocity (SPV) of skull vibration-induced nystagmus (SVIN) in recovery after a unilateral vestibular loss (UVL). A total of 36 patients suffering from vestibular neuritis (VN) were recruited and followed up for twelve months. In every visit, horizontal vHIT and an SVIN were performed, as well as VOR gain; PR score and the SPV of SVIN were measured. We observed a positive association between the VOR gain difference and the SPV of SVIN over time (probability greater than 0.86). Additionally, we obtained a positive association between the SPV of SVIN and the PR score in successive visits (odds ratio (OR) = -0.048; CI [0.898, 1.01]), with a probability of 0.95. Our results confirm that SPV of SVIN; VOR gain difference; and PR score decrease over time after a UVL. Both tests are useful in the follow-up of VN, as they could reflect its clinical compensation or partial recovery.

Can Benign Paroxysmal Positional Vertigo Be Treated in a One Session?

OBJECTIVE: To determine the reliability and safety of posterior canal BPPV (pc-BPPV) treatment with subsequent assessment of the effectiveness of the maneuver in a single session, compared to the classic weekly procedure. METHOD: A prospective study of two randomized groups of unilateral pc-BPPV was performed: a weekly management group (27 patients) and single-session treatment group (26 patients). The number of maneuvers required to clear pc-BPPV, incidence of side effects (re-entries and canal conversions), and recurrence rates were compared. RESULTS: There were no statistically significant differences in the number of maneuvers needed to resolve pc-BPPV, the incidence of side effects, or the recurrence rate between the two groups. Two re-entries were diagnosed in the single-session group, and both were easily and successfully treated. Three early recurrences were found in the single-session group and one spontaneous recovery was encountered in the weekly group. Time required to discharge patients to follow-up was significantly reduced in the single-session group. CONCLUSION: Managing pc-BPPV in one session is safe and reliable, resulting in fewer visits to outpatient clinics and optimization of treatment strategies.

Parameters of skull vibration-induced nystagmus in normal subjects.

HYPOTHESIS: The knowledge of vibration-induced nystagmus test (SVINT) values in the normal population is highly relevant to provide a rapid orientation on the diagnosis attitude in a patient with vertigo. BACKGROUND: Although mastoid bone vibration should only induce nystagmus in the presence of vestibular asymmetry, it has also been reported in normal individuals raising doubts as to how to interpret the SVINT. To date, no population studies involving the use of the SVINT and that establish normative values have been published. METHODS: This study was carried out at two tertiary healthcare centres on a total of 122 subjects. We stimulated at three frequencies (30, 60 and 100 Hz), in increasing order, first stimulating the right mastoid and then the left mastoid, and waiting for 30 s between each stimulus. The response was recorded with a videonystagmography system. The following variables were evaluated in each subject: the mean and maximum speed of the slow phase of nystagmus, the frequency of the nystagmatic response (NR) and the component and direction of the rapid phase of nystagmus. RESULTS: Only 26 subjects (20.5%) of the subjects studied here (122 subjects) developed any kind of nystagmatic response and 96 subjects (79.5%) did not display any response. Stimulation at 100 Hz provoked the largest number of responses (p = 0.04), while there was no difference in the number of responses induced by 30 and 60 Hz stimulations (p = 0.85). The frequency of nystagmus was ≤ 0.7 n/s in 80.8% of the positive responses. The mean velocity of the horizontal component of the NR was 2.2°/s (SD 1.6) and that of the vertical component was 1.3°/s (SD 1.2). CONCLUSIONS: Healthy subjects do not generally develop to NR upon vibratory stimulation and only 20% of the subjects studied here developed any kind of NR, this being a slow and inconsistent response of low frequency. The establishment of normal values contributes to improve the orientation in clinical practice in the pathological population and this opens possibilities for tackling more reliable studies in this population.