Journal of Vestibular Research-Equilibrium & Orientation最新文献

Background: Motorist Disorientation Syndrome (MDS) is a term used to describe patients who primarily experience symptoms of dizziness/disorientation whilst in a motor car [21]. There is uncertainty about the relevance of vestibular dysfunction and whether this disorder could instead be a visually induced dizziness (VV) or part of a functional disorder similar to Persistent postural perceptual dizziness (PPPD).

Objective: We present the largest case-series to date of patients whose main complaint is of illusions of movement of self/vehicle when driving, characterising features of this group.

Methods: 18 subjects underwent detailed clinical assessment including validated questionnaires. A subset of patients underwent vestibular function testing.

Results: Mean onset age was 42 years, with no gender preponderance. Mean symptom duration was 6.39 years and was significantly longer in women. 50% reported moderate or severe handicap. Vestibular abnormalities were found in 60% of subjects tested. There was no significant difference in VSS total score between those with MDS and vestibular migraine (p = 0.154) with both having higher scores than healthy controls (p = 0.002, 0.000 respectively).

Conclusions: MDS represents consistent symptoms, with high symptom burden, comparable to vestibular migraine. Vestibular deficits were not a consistent feature and similarities to VV and PPPD exist.

Background: Acceleration and changes in acceleration (jerk) stimulate vestibular otolith afferents. Bone-conducted (BC) vibration applied to the skull accelerates the head and produces short latency reflexes termed vestibular evoked myogenic potentials (VEMPs).

Objective: To determine the magnitude, variability and symmetry in head acceleration/jerk during VEMP recordings and investigate the relationship between head acceleration/jerk and VEMP properties.

Methods: 3D head accelerometery (sagittal, interaural and vertical axes) was recorded bilaterally in thirty-two healthy subjects during cervical (cVEMP) and ocular (oVEMP) recordings. BC 500 Hz sinusoidal tones were applied to the midline forehead using a positive polarity stimulus.

Results: The direction of induced acceleration/jerk was predominately backward, outward and downward on either side of the head during cVEMP and oVEMP recordings.Overall, acceleration/jerk was larger in the sagittal and interaural axes and peaked earlier in the interaural axis bilaterally. Acceleration was more symmetric in the sagittal and interaural axes whereas jerk symmetry did not differ between axes. Regression models did not show a systematic relationship between acceleration/jerk and either VEMP reflex.

Conclusions: The pattern of skull acceleration/jerk was relatively consistent between the two sides of the head and across subjects, but there were differences in magnitude, leading to inter-side and inter-subject variability.

Background: A method for prescribing the difficulty or intensity of standing balance exercises has been validated in a healthy population, but requires additional validation in individuals with vestibular disorders.

Objective: This study validated the use of ratings of perceived difficulty for estimation of balance exercise intensity in individuals with vestibular disorders.

Methods: Eight participants with a confirmed diagnosis of a vestibular disorder and 16 healthy participants performed two sets of 16 randomized static standing exercises across varying levels of difficulty. Root Mean Square (RMS) of trunk angular velocity was recorded using an inertial measurement unit. In addition, participants rated the perceived difficulty of each exercise using a numerical scale ranging from 0 (very easy) to 10 (very difficult). To explore the concurrent validity of rating of perceived difficulty scale, the relationship between ratings of perceived difficulty and sway velocity was assessed using multiple linear regression for each group.

Results: The rating of perceived difficulty scale demonstrated moderate positive correlations RMS of trunk velocity in the pitch (r = 0.51, p < 0.001) and roll (r = 0.73, p < 0.001) directions in participants with vestibular disorders demonstrating acceptable concurrent validity.

Conclusions: Ratings of perceived difficulty can be used to estimate the intensity of standing balance exercises in individuals with vestibular disorders.

Background: Obstructive sleep apnea (OSA) could influence peripheral vestibular function adversely via intermittent hypoxia and its consequences.

Objective: This study aimed to evaluate the risk of peripheral vestibular disorders in OSA using a nationwide population-based retrospective cohort study.

Methods: The National Health Insurance Service-National Sample Cohort represents the entire Korean population from 2002 to 2015. OSA was defined as individuals who had used medical services twice or more under a diagnosis of OSA(G47.33 in ICD-10). A comparison cohort consisted of socio-demographically matched non-OSA subjects in a ratio of 1:4. The incidences of benign paroxysmal positional vertigo(BPPV), Meniere's disease, and vestibular neuritis were evaluated in each cohort.

Results: A total of 2,082 individuals with OSA and 8,328 matched non-OSA subjects were identified. The incidence rates(IRs) of peripheral vertigo in OSA and non-OSA were 149.86 and 23.88 per 10,000 persons, respectively (Ratio of IR, IRR = 6.28, 95%CI 4.89 to 8.08). In multivariable analysis, the risk of peripheral vertigo was significantly higher in OSA(adjusted HR = 6.64, 95%CI 5.20 to 8.47), old age(adjusted HR = 1.03, 95%CI 1.02 to 1.04), female sex(adjusted HR = 1.92, 95%CI 1.48 to 2.50), and comorbidities(adjusted HR = 1.09, 95%CI 1.003 to 1.19). The IRRs of each vestibular disorder in the two groups were 7.32(95%CI 4.80 to 11.33) for BPPV, 3.61(95%CI 2.24 to 5.81) for Meniere's disease, and 9.51(95%CI 3.97 to 25.11) for vestibular neuritis.

Conclusions: Subjects diagnosed with OSA had a higher incidence of peripheral vestibular disorders than those without OSA, according to national administrative claims data. It is recommended to take peripheral vertigo into account when counseling OSA.

Background: Unapparent saccades in video head impulse test (vHIT) are usually present in Meniere's disease (MD) patients but tend to be ignored by the clinician. The result of vHIT is constantly questioned in MD patients due to a lack of uniform metrics. A more effective indicator is needed for indicating MD's pathological progress.

Objectives: To get a comprehensive understanding of the nature and usability of saccades in different MD stages.

Methods: 118 patients diagnosed with unilateral MD were recruited in this study. Patient history, audiological examination, caloric test, vHIT were performed. We proposed 'raw saccades' to represent all showed wave peaks behind the head peak and named saccades by their appearance sequence: 1st saccade, 2nd saccade and 3rd saccade. An exploratory saccade analysis was executed to investigate the effectiveness of saccade attributes in identifying MD stages.

Results: MD patients have greater detectable 1st saccade than PR score as well as 2nd saccade. The time and velocity of the 1st saccade show high interaural variability (p = 0.028, p = 0.000 respectively). No statistical difference concerning the vHIT gain, PR score and 2nd saccade among stages could be recognized on both affected and contralateral sides. Multiple comparisons show the affected 1st saccade velocity and affected 1st saccade absolute velocity have stage-difference. At late stages (3&4), the affected 1st saccade is manifested as a speed increase, and this measure shows a relatively high correlation with MD stages compared to other vestibular indicators.

Conclusion: The 1st saccade velocity on the affected side could indicate the MD disease process and severity.

The percept of vertical, which mainly relies on vestibular and visual cues, is known to be affected after sustained whole-body roll tilt, mostly at roll positions adjacent to the position of adaptation. Here we ask whether the viewing of panoramic visual cues during the adaptation further influences the percept of the visual vertical. Participants were rotated in the frontal plane to a 90° clockwise tilt position, which was maintained for 4-minutes. During this period, the subject was either kept in darkness, or viewed panoramic pictures that were either veridical (aligned with gravity) or oriented along the body longitudinal axis. Errors of the subsequent subjective visual vertical (SVV), measured at various tilt angles, showed that the adaptation effect of panoramic cues is local, i.e. for a narrow range of tilts in the direction of the adaptation angle. This distortion was found irrespective of the orientation of the panoramic cues. We conclude that sustained exposure to panoramic and vestibular cues does not adapt the subsequent percept of vertical to the direction of the panoramic cue. Rather, our results suggest that sustained panoramic cues affect the SVV by an indirect effect on head orientation, with a 90° periodicity, that interacts with a vestibular cue to determine the percept of vertical.