Journal of Vestibular Research-Equilibrium & Orientation最新文献

BackgroundSound stimulation can influence electrophysiological vestibular reflexes. However, the effects of sound stimulation on space perception remain unknown.ObjectiveTo know the effects of monaural sound stimulation on subjective visual vertical (SVV).MethodsWe measured SVV with and without monaural sound stimulation (105 dB, 500 Hz short tone burst presented at 4.7 Hz) in 50 healthy volunteers (aged 20-77 [mean = 42.7] years).ResultsThe mean SVV was deviated 0.139° to the left by right monaural sound stimulation and 0.123° to the right by left monaural sound stimulation. SVV changes due to right and left ear stimulations were significantly different (p = 0.019). Sound stimulation resulted in a significant change in SVV on the left side (p = 0.014) in participants aged 50 or younger (mean = 35.6 years) (n = 37).ConclusionsThis study is the first to show the possibility that the monaural sound input deviates the SVV toward the opposite side and is more pronounced for left-ear input. The vestibular-evoked myogenic potential responses may be involved in the mechanism of the contralateral SVV deviation due to sound input.

BackgroundFlight simulators have an essential role in aircrew training. Occasionally, symptoms of motion sickness, defined as simulator sickness, develop during training sessions. The reported incidence of simulator sickness ranged widely in different studies.ObjectiveThe aims of this study were to calculate the incidence of and to define a threshold value for simulator sickness among rotary-wing pilots using the validated Simulator Sickness Questionnaire (SSQ).MethodsCH-53 and UH-60 helicopter pilots, who trained in helicopter simulators in the Israeli Air Force, were asked to fulfill SSQ. A score of 20 in the SSQ was defined as the threshold for simulator sickness. Simulator sickness incidence and average SSQ were calculated. Correlations between age and simulator training hours to SSQ scores were analyzed.ResultsA total of 207 rotary-wing aircrew participated in the study. Simulator sickness was experienced by 51.7% of trainees. The average SSQ score was 32.7. A significant negative correlation was found between age and SSQ score.ConclusionsSimulator sickness was experienced by more than half of helicopter pilots. A score of 20 in the SSQ was found to be suitable as the threshold for this condition.

BackgroundVestibular migraine (VM) is a common cause of recurrent spontaneous and positional dizziness of varying durations. Short episodes of VM lasting seconds to minutes, triggered by changes in head position can resemble those of benign paroxysmal positioning vertigo (BPPV), while episodes lasting minutes to hours can mimic those of Meniere's disease (MD).ObjectiveWe aimed to compare symptoms and vestibular test results in patients with VM, BPPV and MD, where VM was categorized by episode duration.MethodsWe compared vestibular, aural and migraine symptoms, as well as cervical and ocular vestibular evoked myogenic potentials and 3D video head impulse tests, in 108 patients: 24 with BPPV, 33 with VM episodes of short duration (<10 min), 29 with VM of medium duration (≥10 min) and 22 with MD.ResultsWe found significant overlap in the symptoms of all patient groups, and no significant differences between patients with short and medium VM. Abnormal test results occurred infrequently in all groups.ConclusionsOur results confirm significant symptom overlap between BPPV or MD and VM, and suggest that VM mimics other conditions when the episode duration matches the differential diagnosis, rather than because patients with different durations of vertigo have different symptoms.

BackgroundThe video head impulse test (vHIT) is vital in clinical setting for assessing vestibulo-ocular reflex (VOR) function in patients of all ages. However, how normal aging influence VOR gain and catch-up saccades remains unclear, thus leading to confusion in interpretation of vHIT results.ObjectiveThis study aims to compare VOR gain and saccades parameters (frequency, amplitude, and latency) between younger and older adults, while maintaining head velocity and acceleration within the same range.MethodsA total of 24 younger and 24 older adults performed horizontal vHIT tests (ICS Impulse, Otometrics, Denmark). Gain and saccades were analyzed using a custom MATLAB script. Three VOR gain algorithms were compared: Area under the curve (AUC), instantaneous gain, and regression gain.ResultsIn our sample, no significant differences in the VOR gains were observed between younger and older adults using any of the algorithms. Compared to younger adults, older adults had saccades that were significantly more frequent, of greater amplitude, and of shorter latencies. However, a larger sample size is needed to confirm the lack of aging effect on VOR gains.ConclusionsThe absence of significant effects of aging on VOR gain in vHIT demonstrates that all three gain algorithms should provide similar values for patients across all ages in clinical practice. The results suggest that small saccades in older adults are unrelated to head impulse parameters, and the mechanisms behind this increase in saccades with normal aging remain to be explored.

BackgroundCervical VEMP elicited by air-conducted acoustic stimuli (AC cVEMP) is considered as a valuable test for assessment of saccular function. The dominant component of this response, which is composed of a biphasic positive-negative deflexion, can be recorded from the tensed ipsilateral sternocleidomastoid muscle. It is conveyed by inhibitory connections from the irregular saccular afferents. The contralateral response, which has opposite polarity, is in general not studied in clinical practice. It probably reflects excitatory influences conveyed from irregular afferents of the utricle.ObjectiveThe purpose of this study was to ascertain whether this contralateral response has any clinical value.MethodsAC cVEMPs of 117 control subjects and 353 patients with balance problems and/or BPPV were subjected to retrospective analysis. The contribution of the contralateral excitatory response to the whole response (i.e., amplitudes of the contralateral plus ipsilateral responses) was expressed in percentages calculated according to Jongkee's formula.ResultsThere was statistically significant increase in the contribution of the contralateral excitatory component to the whole response in patients.ConclusionsThis may imply somewhat lower vulnerability of the contralateral utricular response to various disease processes and/or aging.

Background: Persistent postural-perceptual dizziness (PPPD) is a functional vestibular disorder that causes chronic dizziness and limits daily activities. Although pharmacology, vestibular rehabilitation, and cognitive behavioral therapy have been proposed to have some efficacy, they have certain limitations. Some patients with PPPD report that public square dancing can effectively relieve the symptoms of dizziness and instability, and their mood improves.

Objective: To evaluate the effects of combining public square dancing with serotonin reuptake inhibitors (SSRIs/SNRIs) on the subjective sensations of dizziness, balance enhancement, anxiety, and depressive symptom regulation in middle-aged and older women with PPPD.

Materials and methods: In this trial, 124 patients diagnosed with PPPD were enrolled. Among them, 64 patients were randomly assigned to the experimental group (EG), where they received square dance training combined with serotonin reuptake inhibitors. The remaining 60 cases were randomly assigned to the control group (CG), where they received only serotonin reuptake inhibitors and did not participate in organized sports activities, allowing them freedom in their daily lives. Data from the Dizziness Handicap Inventory (DHI), Hospital Anxiety and Depression Scale (HADS), Active-specific Balance Confidence Scale (ABC), and Vestibular Disorder Activities of Daily Living Scale (VADL) were collected and compared at the beginning, 3 months, and 6 months of the trial to evaluate the effect of public square dancing on middle-aged and older women with PPPD.

Results: There were no significant differences between the EG and CG before the trial. Compared with baseline measures, DHI, HADS, ABC, and VADL scores improved as the experiment progressed, and the improvements were more pronounced in the EG.

Conclusion: Public square dancing combined with serotonin reuptake inhibitors has a positive impact on the subjective sensations of dizziness, balance enhancement, anxiety, and depressive symptom regulation in middle-aged and older women with PPPD.

Objective: A normal video Head Impulse Test is the gold standard in the emergency department to rule-in patients with an acute vestibular syndrome and a stroke. We aimed to compare the diagnostic accuracy of vHIT metrics regarding the vestibulo-ocular reflex gain and the corrective saccades in detecting vestibular strokes.

Methods: Prospective cross-sectional study (convenience sample) of patients presenting with acute vestibular syndrome in the emergency department of a tertiary referral centre between February 2015 and May 2020. We screened 1677 patients and enrolled 76 patients fulfilling the inclusion criteria of acute vestibular syndrome. All patients underwent video head impulse test with automated and manual data analysis. A delayed MRI served as a gold standard for vestibular stroke confirmation.

Results: Out of 76 patients, 52 were diagnosed with acute unilateral vestibulopathy and 24 with vestibular strokes. The overall accuracy of detecting stroke with an automated vestibulo-ocular reflex gain was 86.8%, compared to 77.6% for cumulative saccade amplitude and automatic saccade mean peak velocity measured by an expert and 71% for cumulative saccade amplitude and saccade mean peak velocity measured automatically. Gain misclassified 13.1% of the patients as false positive or false negative, manual cumulative saccade amplitude and saccade mean peak velocity 22.3%, and automated cumulative saccade amplitude and saccade mean peak velocity 28.9% respectively.

Conclusions: We found a better accuracy of video head impulse test for the diagnosis of vestibular strokes when using the vestibulo-ocular reflex gain than using saccade metrics. Nevertheless, saccades provide an additional and important information for video head impulse test evaluation. The automated saccade detection algorithm is not yet perfect compared to expert analysis, but it may become a valuable tool for future non-expert video head impulse test evaluations.

Background: Patients with vestibular impairment often suffer from postural instability. This could be compensated by other sensory systems such as the auditory system.

Objective: The aim of this study was to investigate whether auditory input improves postural stability in patients with abnormal subjective haptic vertical (SHV).

Methods: Participants (n = 13) with normal hearing and vision, but abnormal SHV participated. Participants performed standing on firm ground and foam support (eyes open/closed) and Tandem Romberg test (eyes closed) in quiet (reference), noise and with plugged ears. All tasks were conducted in a soundproofed and reverberant room. Postural stability was recorded close to the body's center of gravity. Reference conditions were compared with a control group.

Results: In only two tasks sway increased significantly when noise was presented during challenging tasks in the soundproofed room. Sway of the reference conditions did not differ significantly between control and study group.

Conclusions: This study shows no influence of applied auditory stimulation on posture in participants with abnormal SHV in a reverberant room, but an adverse effect on balance during difficult tasks in the soundproofed room. Noise possibly masked auditory information that was helpful in improving posture in the quiet condition. Futhermore, noise might have distracted participants from maintaining balance.

Background: Dizziness is a common symptom in post-COVID condition (PCC) which may have a large impact on several life domains. However, knowledge on dizziness-severity and disability in PCC is sparse.

Objective: The aim was to describe the severity of dizziness-related disability in individuals with PCC, and how it is manifested in daily life.

Methods: A questionnaire regarding symptoms of PCC, health, and dizziness-related handicap was administered online, and 524 persons with PCC and dizziness were included.

Results: Mean score of the Dizziness Handicap Inventory was 35.2 (24.0) and 51.8%, were classified as having moderate/severe dizziness-related disability. The percentage of maximum value for the subscales were: Physical manifestation, 48%, Emotional Impact, 36% and Catastrophic Impact, 17%. The greatest influence on physical movements was when bending forward, head shaking or doing strenuous physical activities or household chores.

Conclusions: Half had moderate or severe dizziness-related disability and the physical manifestations occurred mostly during specific or strenuous body movements. This indicate a vestibular impairment that may be effectively managed with vestibular rehabilitation. Assessment and treatment of dizziness might be an essential part in PCC rehabilitation and future research should continue to explore the potential causal pathways of dizziness in PCC.