Journal of Vestibular Research

Vestibular compensation is the process by which the central nervous system (CNS) attempts to adapt to the loss of vestibular sensory inputs. As such, the compensation process is critically involved in the vestibular rehabilitation programs that are implemented by physical therapists for patients with vestibular disorders. One hypothesis regarding vestibular compensation, which has persisted in some of the published vestibular compensation literature and particularly on some vestibular and physical therapy websites, is the ‘cerebellar shutdown’ or ‘cerebellar clampdown’ hypothesis proposed by McCabe and Ryu in 1969. This hypothesis proposes that the cerebellum inhibits neuronal activity in the bilateral vestibular nuclei (VN) following unilateral vestibular loss (UVL), causing the VN contralateral to the UVL to be electrically silent during the early phases of vestibular compensation. Despite a wealth of evidence against this idea, it has gained traction amongst some physical therapists and has implications for vestibular rehabilitation early in the compensation process.

In this paper it is argued that the ‘cerebellar shutdown’ or ‘clampdown’ hypothesis is inconsistent with well accepted neurophysiological and imaging evidence and that it is also logically flawed.

It has not yet been tested whether averaged gain values and the presence of pathological saccades are significantly altered by manual data selection or if data selection only done by the incorporated software detection algorithms provides a reliable data set following v-HIT testing.

The primary endpoint was to evaluate whether the averaged gain values of all six SCCs are significantly altered by manual data selection with two different v-HIT systems.

120 subjects with previously neither vestibular nor neurological disorders underwent four separate tests of all six SCCs with either EyeSeeCam® or ICS Impulse®. All v-HIT test reports underwent manual data selection by an experienced ENT Specialist with deletion of any noise and/or artifacts. Generalized estimating equations were used to compare averaged gain values based on unsorted data with averaged gain values based on the sorted data.

EyeSeeCam®: Horizontal SCCs: The estimate and the p-value (shown in parenthesis) for the right lateral SCC and the left lateral SCC were 0.00004 (0.95) and 0.00087 (0.70) respectively. Vertical SCCs: The estimate varied from –0.00858 to 0.00634 with p-values ranging from 0.31 to 0.78. ICS Impulse®: Horizontal SCCs: The estimate and the p-value for the right lateral SCC and the left lateral SCC were 0.00159 (0.18) and 0.00071 (0.38) respectively. Vertical SCCs: The estimate varied from 0.00217 to 0.01357 with p-values ranging from 0.00 to 0.17. Based upon the averaged gain value from the individual SCC being tested, 148 tests before and 127 after manual data selection were considered pathological.

None of the two v-HIT systems revealed any clinically important effects of manual data selection. However, 21 fewer tests were considered pathological after manual data selection.

The association between vestibular function and findings of horizontal head-shaking nystagmus (HHSN) and vibration-induced nystagmus (VIN) tests is not well understood.

To investigate the association between function in the five distinct vestibular end organs and findings of these nystagmus tests.

We retrospectively reviewed the medical records of 50 patients with vestibular diseases who underwent HHSN testing, VIN testing, video head impulse testing (vHIT), cervical vestibular evoked myogenic potential testing to air-conducted sound (ACS cVEMP) and ocular VEMP testing to ACS (ACS oVEMP). We performed mixed-effects logistic regression analyses to see whether age, sex or the presence of nystagmus in HHSN or VIN have an association with the presence of peripheral vestibular dysfunction on the opposite side to the direction of nystagmus.

The presence of HHSN had a significant association with abnormal vHIT in the lateral semicircular canal (LSCC) on the opposite side to the direction of nystagmus. The presence of VIN had a significant association with abnormal vHIT in all the SCCs and abnormal ACS oVEMP on the opposite side to the direction of nystagmus.

HHSN had an association with LSCC dysfunction alone. VIN had an association with dysfunction in all the SCCs and the utricle.

To determine if middle-aged and aging men and women with HIV disease (HIV+) should be screened for vestibular and oculomotor dysfunction.

Age- and sociodemographically matched HIV+ and HIV– men and women were tested on vestibular evoked myogenic potential (VEMP), bi-thermic caloric testing, Dix-Hallpike maneuvers and saccades.

HIV+ men had more caloric weakness than HIV– men. HIV+ subjects had more saccade abnormalities than HIV– subjects. A saccade abnormality was positively associated with being HIV+. Among the HIV+ sample, abnormalities were associated with increasing age, being male, ever taking monotherapy, and having an undetectable viral load. Only being male and having an undetectable viral load were statistically significant. Unilateral caloric weakness had a decreased prevalence with age per 10 years, and being HIV+ showed an increased prevalence. In HIV+ subjects only, these abnormalities decreased with age and being male but increased with undetectable viral load and ever taking antiretroviral monotherapy. No statistically significant differences were found.

Women are at greater risk of vestibular and oculomotor abnormalities than men. HIV+ adults are at greater risk than HIV– adults. Physicians who care for HIV+ men and women should monitor the symptoms of vestibular and oculomotor impairment.

Investigations measuring gait tests have rarely been studied in the benign paroxysmal positional vertigo (BPPV) population.

Examine instrumented mobility metrics in people with posterior semicircular canal BPPV. We examined the impact of a canalith repositioning procedure (CRP), prior to and after treatment on instrumented mobility measures, comparing the scores to those of healthy controls.

At baseline, the subject performed a series of instrumented gait and balance tests and then, the CRP was performed. At re-evaluation (1-week later), identical gait and balance tests were assessed. In addition, the Hallpike-Dix test identified patients who had improved or had not improved in their BPPV signs and symptoms.

Thirty-two people with BPPV (25 women) and 15 healthy subjects participated in the study. At baseline (pre-CRP), people with BPPV demonstrated an increased vestibular ratio, and walked more slowly compared with the healthy controls. The CRP resolved the vertigo in 90.6% of the BPPV subjects. Compared with the pre-CRP scores, the BPPV subjects demonstrated a decreased vestibular ratio and faster walking at the post-CRP evaluation. Out of the five parameters that were significantly different from the healthy values pre-CRP, only one remained different post-CRP.

Besides vertigo and balance difficulties, people with BPPV demonstrate walking modifications. Furthermore, the CRP has a high success rate in improving not only vertigo but also in restoring gait and balance in persons with BPPV.