Triple test as predictive screen for unilateral weakness on caloric testing in routine practice

Vestibular Physical Therapy Evaluation of Individuals Exposed to Directed Energy

INTRODUCTION

Directed energy has been described as exposure to a unique sound/pressure phenomenon such as infrasonic or ultrasonic acoustic or electromagnetic energy. Following suspected sonic attacks on U.S. Embassies, a subset of individuals presented with a unique cluster of symptoms believed to have resulted from exposure to directed energy. The Joint Force does not have an established protocol to guide the vestibular physical therapy evaluation of individuals exposed to directed energy. Therefore, we sought to provide evidence-based guidance for conducting a comprehensive vestibular physical therapy evaluation in persons exposed to directed energy.

MATERIALS AND METHODS

A comprehensive search of relevant databases was performed from 2018 to the present. Four seminal articles were used to inform suggestions for clinical best practice.

RESULTS

The physical therapist should ask open-ended questions to understand what the individual is experiencing and use key questions to focus attention on the mechanism of injury, symptom report, and symptom timeline. The physical therapist should perform an evaluation to determine if the peripheral vestibular apparatus (semicircular canals and otoliths), vestibular nerve, and/or central pathways have been affected by directed energy exposure. Components of the quantitative examination were selected because they provide information on health condition(s), body structure and function impairments, and activity limitations but require little to no specialized equipment.

CONCLUSIONS

Evidence-based guidance for conducting a comprehensive vestibular physical therapy evaluation in individuals exposed to directed energy may aid in the identification and diagnosis of unconventional brain injury. This standardized approach can help physical therapists to evaluate complaints that do not match any previously known medical conditions but resemble brain injury or vestibular pathology.

Evaluating the Diagnostic Accuracy of the Head-Impulse Test: A Scoping Review

Importance

Vestibular symptoms rank among the most common complaints in medicine worldwide. Underlying disorders manifested by these symptoms are generally associated with an impairment of the vestibular-ocular reflex and can be assessed with different diagnostic procedures. In recent years, an increasing number of diagnostic test accuracy studies comparing various head-impulse test (HIT) methods with other diagnostic procedures have been published but not systematically reviewed.

Objective

To conduct a scoping review and describe key characteristics of the growing number of diagnostic studies in patients presenting with vestibular symptoms.

Evidence Review

In April 2017, published studies were identified through searches of 4 bibliographic databases: Medline, Science Citation Index Expanded, the Cochrane Library, and ScienceDirect. Studies were included if they provided diagnostic accuracy data (sensitivity and specificity) for any HIT method with reference to any other vestibular test or clinical diagnosis in patients with vestibular symptoms. Study key characteristics were extracted, and the current literature was described narratively. All analysis took place between June 2017 and July 2018.

Findings

We identified a total of 27 diagnostic studies (including 3821 participants). There were disagreements between diagnostic test accuracy data both within and between studies when different HIT methods were compared with other diagnostic procedures. The proportion of correctly identified people having the disease (sensitivity) ranged between 0% and 100% (median, 41%), whereas the proportion of correctly identified people without the disease (specificity) was higher and ranged between 56% and 100% (median, 94%).

Conclusions and Relevance

Based on the studies included in this review, sensitivity, specificity, and, more importantly, the risk of misdiagnosis and associated undertreatment or overtreatment cannot be reliably estimated by HIT methods for patients with vestibular symptoms. We recommend that further diagnostic studies consider (1) multiple possible underlying causes of vestibular symptoms and multiple test thresholds, (2) a representative sample of patients with and without the disease, and (3) reporting guidelines for diagnostic test accuracy studies.

The Association Between Vestibular Physical Examination, Vertigo Questionnaires, and the Electronystagmography in Patients With Vestibular Symptoms

OBJECTS

Dizziness makes up a diagnostic and treatment challenge. The diagnostic accuracy of the medical history and vestibular physical examination in cases of vestibular symptoms is not clear. The aim of this study is to determine the association between vestibular physical examination, vestibular questionnaires, and electronystagmography (ENG) test in patients with vestibular symptoms.

METHODS

This is a prospective study of 135 adults with vestibular symptoms. The subjects underwent targeted physical examination and filled vestibular questionnaires, including the Dizziness Handicap Inventory (DHI), before ENG testing. The results of the physical examination and questionnaires were compared with the final ENG findings.

RESULTS

Of patients who had normal ENG results, 32.1% (17/52) showed abnormal physical examination, and 48.8% (40/82) of the patient who had normal physical examination showed abnormal ENG results ( P = .46). Among patients with severe disability by DHI, 46.4% (13/28) had an abnormal ENG, and 42.9% (12/28) had a normal ENG ( P = .39).

CONCLUSIONS

This study did not demonstrate association between vestibular physical examination, vestibular questionnaires, and ENG results. Although history (augmented by questionnaires) and physical examination are the initial steps in the evaluation of vertigo, the current study suggests that they should be complemented by objective testing for evaluation of inner ear origin of vertigo.

Role of video-head impulse test in lateralization of vestibulopathy: Comparative study with caloric test

OBJECTIVE

To evaluate the lateralization value of video head-impulse test (vHIT) for the diagnosis of vestibulopathy and to analyze cases showing dissociated results with caloric test.

METHODS

In total, 19 healthy volunteers and 92 dizzy patients who underwent both a caloric test and a vHIT were enrolled. Patients were divided into two groups depending on their fluctuating pattern of vertigo. The vestibulo-ocular reflex (VOR) gain and gain asymmetry (GA) of a vHIT as well as unilateral weakness (UW) and the sum of the slow-phase velocities (SPVs) of warm and cold irrigation of the same side were compared. A cutoff value of VOR gain of a vHIT was also calculated using a receiver-operating characteristic curve.

RESULTS

A VOR gain in an affected ear and GA of a vHIT showed a statistically significant correlation with UW in a caloric test. The cutoff value of a vHIT was determined to be 0.875, derived under the assumption that UW of a caloric test ≤25% is normal. However, the parameters of the two tests were dissociated in 18%.

CONCLUSION

A VOR gain of vHIT is a valuable objective parameter with a lateralization value determining vestibular hypofunction. However, considering substantial dissociation between a vHIT and a caloric test, these tests can be complementary tools for the lateralization of vestibular impairment for the comprehensive evaluation of patients' VOR.

Polarity-Dependent Misperception of Subjective Visual Vertical during and after Transcranial Direct Current Stimulation (tDCS)

Pathologic tilt of subjective visual vertical (SVV) frequently has adverse functional consequences for patients with stroke and vestibular disorders. Repetitive transcranial magnetic stimulation (rTMS) of the supramarginal gyrus can produce a transitory tilt on SVV in healthy subjects. However, the effect of transcranial direct current stimulation (tDCS) on SVV has never been systematically studied. We investigated whether bilateral tDCS over the temporal-parietal region could result in both online and offline SVV misperception in healthy subjects. In a randomized, sham-controlled, single-blind crossover pilot study, thirteen healthy subjects performed tests of SVV before, during and after the tDCS applied over the temporal-parietal region in three conditions used on different days: right anode/left cathode; right cathode/left anode; and sham. Subjects were blind to the tDCS conditions. Montage-specific current flow patterns were investigated using computational models. SVV was significantly displaced towards the anode during both active stimulation conditions when compared to sham condition. Immediately after both active conditions, there were rebound effects. Longer lasting after-effects towards the anode occurred only in the right cathode/left anode condition. Current flow models predicted the stimulation of temporal-parietal regions under the electrodes and deep clusters in the posterior limb of the internal capsule. The present findings indicate that tDCS over the temporal-parietal region can significantly alter human SVV perception. This tDCS approach may be a potential clinical tool for the treatment of SVV misperception in neurological patients.

Head position and increased head velocity to optimize video head impulse test sensitivity

This study investigated the effects of head position on gain values during video head impulse tests (vHITs). Different head positions were used for vHIT of the horizontal semicircular canals of 20 healthy controls and 18 patients with unilateral vestibular loss (UVL), with head velocities ranging from 150°/s to 200°/s. Differences in vestibulo-ocular reflex gain in the control and patient groups according to head position (0° and 30° downward pitch) were analyzed. In the unaffected control group, the 30° pitched-down position resulted in a mean gain increase of up to 1.0 in both ears (right ear: 0.85 ± 0.26 for head-up and 1.05 ± 0.12 for head-down, p = 0.004; left ear: 0.75 ± 0.18 for head-up and 0.98 ± 0.16 for head-down, p < 0.001). In patients with UVL, the mean gains on the diseased side were 0.92 ± 0.16 in the head-up position and 0.82 ± 0.2 in the head-down position, at similar head velocities (p = 0.046). The pitched-down position also increased the asymmetry between ears in patients with UVL, at the same head velocity. A 30° head-down position can increase vHIT sensitivity, which resulted in increased mean gain in unaffected people and decreased mean gain in most of the patients with UVL in this study. This method may more effectively stimulate the horizontal semicircular canal. This vHIT modification may be helpful for more precisely evaluating vestibular function, thus reducing false-negative findings.

Verticality Perceptions Associate with Postural Control and Functionality in Stroke Patients

Deficits of postural control and perceptions of verticality are disabling problems observed in stroke patients that have been recently correlated to each other. However, there is no evidence in the literature confirming this relationship with quantitative posturography analysis. Therefore, the objectives of the present study were to analyze the relationship between Subjective Postural Vertical (SPV) and Haptic Vertical (HV) with posturography and functionality in stroke patients. We included 45 stroke patients. The study protocol was composed by clinical interview, evaluation of SPV and HV in roll and pitch planes and posturography. Posturography was measured in the sitting and standing positions under the conditions: eyes open, stable surface (EOSS); eyes closed, stable surface (ECSS); eyes open, unstable surface (EOUS); and eyes closed, unstable surface (ECUS). The median PV in roll plane was 0.34° (-1.44° to 2.54°) and in pitch plane 0.36° (-2.72° to 2.45°). The median of HV in roll and pitch planes were -0.94° (-5.86° to 3.84°) and 3.56° (-0.68° to 8.36°), respectively. SPV in the roll plane was correlated with all posturagraphy parameters in sitting position in all conditions (r = 0.35 to 0.47; p < 0.006). There were moderate correlations with the verticality perceptions and all the functional scales. Linear regression model showed association between speed and SPV in the roll plane in the condition EOSS (R2 of 0.37; p = 0.005), in the condition ECSS (R2 of 0.13; p = 0.04) and in the condition EOUS (R2 of 0.22; p = 0.03). These results suggest that verticality perception is a relevant component of postural control and should be systematically evaluated, particularly in patients with abnormal postural control.

Vestibular results after intratympanic gentamicin therapy in disabling Menière's disease

Intratympanic injection of gentamicin is increasingly used in the treatment of unilateral disabling Menière's disease (MD). Several objective functional and subjective tests have been developed to assess the control of vertigo after gentamicin treatment. The aim of this study was to show that subjective results require a vestibular deafferentation as profound as possible, evidenced with multifrequency vestibular assessment. Sixty four patients with intractable MD in situation of medical treatment failure longer than 6 months were included between 1998 and 2013 in this case control study. A 2-year follow-up was performed after the last intratympanic gentamicin performed with the titration technique. A vestibular assessment was applied before and after 2 years of treatment with a functional level score using the AAOHNS vertigo scale and multifrequency vestibular assessment: skull vibration-induced nystagmus test (SVINT), head-shaking test (HST) and caloric test (CaTe). The correlation between the results of the questionnaire and the level of the deafferentation as evaluated by the tests was analyzed with the Spearman test. Among the 64 included patients, 56 (87.5 %) described vertigo control. There was a correlation (=-0.33 [-0.53; -0.09], p = 0.008) between subjective improvement (AAO -HNS 1 or 2) and the degree of vestibular deafferentation as evidenced by a destructive nystagmus (beating toward the safe side) with the HST and the SVINT, as well as a caloric hypofunction >90 % with the CaTe. The present study demonstrates that a profound vestibular deafferentation confirmed with multifrequency test evaluation is needed to have a subjective improvement in the treatment of unilateral disabling MD with intratympanic gentamicin.

Unidentified Bright Objects on Brain Magnetic Resonance Imaging Affect Vestibular Neuritis

Objectives

The aim of this study was to investigate the differences in clinical manifestations of in two groups of vestibular neuritis (VN) patients with or without unidentified bright objects (UBOs).

Methods

A prospective, observational study with 46 patients diagnosed with VN between May 2013 and November 2013 was executed. A caloric test, a cervical vestibular-evoked myogenic potentials (cVEMPs) test, brain magnetic resonance imaging (MRI), spontaneous nystagmus test, head impulse test, and head-shaking nystagmus test were performed.

Results

Of the patients, 56.5% (n=26) were classified as UBO-positive by MRI. These showed lower caloric weakness and more prominent cVEMP asymmetry compared with the UBO-negative group (P<0.05). Total VN (TVN) was the most common in the UBO-positive group (45.0%), followed by superior VN (SVN, 30.0%), and inferior VN (IVN, 25.0%). However, in the UBO-negative group, SVN (75.0%) was the most common, followed by TVN and IVN (P<0.05). The recovery rate was not influenced by UBOs (P>0.05).

Conclusion

UBOs on T2-weighted or fluid attenuated inversion recovery MRI may affect the patterns of the vestibular nerve in patients with VN.

The Effect of Intravenous Dexamethasone on the Nausea Accompanying Vestibular Neuritis: A Preliminary Study

PURPOSE

We undertook a preliminary assessment of the efficacy of administering intravenous dexamethasone (DEX) for relieving the nausea and dizziness accompanying vestibular neuritis (VN).

METHODS

Between November 2013 and October 2014, 26 patients with VN were prospectively enrolled in this study. The patients were randomly assigned to treatment with a combination of 20 mg/d of intravenous metoclopramide, 100 mg of oral dimenhydrinate, and 5 mg/d of intravenous DEX or 20 mg/d of intravenous metoclopramide, 100 mg of oral dimenhydrinate, and intravenous normal saline as a placebo therapy. Patients' subjective assessments of the severity of their nausea and dizziness were recorded using a visual analog scale on the day of admission and 2 days, 3 days, 1 month, and 3 months thereafter. Bedside examinations consisted of spontaneous nystagmus (SPN) assessment, the head shaking nystagmus test, and the head impulse test, which were performed at every follow-up visit.

FINDINGS

The severity of nausea and dizziness was significantly reduced over time (both P < 0.05). However, there was no significant effect of DEX injection on the severity of nausea or dizziness (P > 0.05). The presence of SPN was solely associated with nausea (hazard ratio = 3.34; 95% CI, 1.85-6.02).

IMPLICATIONS

The administration of intravenous DEX did not relieve nausea or dizziness any better than a placebo treatment. However, further research is required to confirm whether there is a dose-dependent effect of DEX on the control of nausea or dizziness in VN.

Economic management of vertigo/dizziness disease in a county hospital: video-head-impulse test vs. caloric irrigation

The video-head-impulse test (vHIT) is an important test for examining unilateral vestibular hypofunction. Alternatively, one can test for vestibular hypofunction with the caloric irrigation test. Various studies have shown that both tests may not always identify vestibular hypofunction; instead, the results of the tests might be contradictory. This retrospective study reproduces those finding in a much larger group of patients at a county hospital. 1063 patients were examined with the vHIT and bithermal caloric irrigation on the same day and analyzed with respect to side differences. Of those patients 13.3% had pathological vHIT and a caloric irrigation test, 4.6% a pathological vHIT only and 24.1% a pathologic caloric test only. As both tests might be necessary, we calculated the optimal sequence of the two examinations based on savings in time for the different disease groups. Especially in vestibular failure using the vHIT first and only applying the caloric irrigation in case of an unremarkable vHIT saves time and optimizes the diagnostic work up. In contrast, in Menière's disease and vestibular migraine testing caloric irrigation first might be more efficient.

Partial Recovery of Audiological, Vestibular, and Radiological Findings following Spontaneous Intralabyrinthine Haemorrhage

The diagnosis, work-up, and treatment of sudden sensorineural hearing loss and sudden vestibular loss vary widely between units. With the increasing access to both magnetic resonance imaging and objective vestibular testing, our understanding of the various aetiologies at hand is increasing. Despite this, the therapeutic options are limited and without a particularly strong evidence base. We present a rare, yet increasingly diagnosed, case of intralabyrinthine haemorrhage (ILH) together with radiological, audiological, and vestibular test results. Of note, this occurred spontaneously and has shown partial recovery in all the mentioned modalities.