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Objective: To investigate the characteristics and clinical utility of vestibular autorotation test (VAT) in patients with vestibular migraine. Methods: This study included two groups, an experimental group (441 patients) and a control group (65 healthy subjects). Both groups undertook VAT; the parameters evaluated were horizontal gain/phase, vertical gain/phase and asymmetry. The differences in VAT results between the two groups were investigated. Results: There were no statistical differences between the VAT data of the control group when compared to the reference value from the manufacturer (p >.05). There were statistically significant differences in VAT results between the experimental and control group, namely elevated horizontal gain at frequency 2, 3, 4 and 5 Hz, horizontal phase delay at frequency 2, 4, 5 and 6 Hz, elevated vertical gain at frequency 2 6Hz and vertical phase delay at frequency 4 6Hz. Conclusion: The results of this study using VAT in VM patients demonstrate elevated horizontal gain, vertical gain and delay in horizontal phase, vertical phase. We suggest the application of VAT as a diagnostic tool which may provide objective evidence that can contribute to the diagnosis of VM and also in differential diagnosis. [ABSTRACT FROM AUTHOR]

Conclusion. Motorized head impulse rotator is an effective technique to assess peripheral vestibular function. Approximately a quarter of patients with vestibular schwannoma (VS) had preserved preoperative responses. Vestibular disability could not be predicted based on vestibulo-ocular reflex (VOR) performance during motion stimuli, or in the caloric test. Objectives. To explore motorized head impulse rotator for evaluation of angular horizontal VOR in patients with VS, and to compare these responses to those of the caloric test and the symptoms. Patients and methods. We prospectively recorded head and eye position during unpredictable motorized head impulses in 38 patients with VS. We calculated gain and asymmetry of VOR (mean±95% CI), and the results were compared to those of the caloric test and a questionnaire regarding dizziness, hearing and quality of life. Results. The VOR during motorized impulses was abnormal in 71% of patients. Asymmetry in gain correlated significantly (p<0.001) with unilateral weakness in the caloric test. Preoperative gain was significantly lowered to 0.83±0.08 on the ipsilateral side compared to 0.98±0.06 on the contralateral side. Postoperative gain on the operated side of 0.53±0.05 was significantly different from preoperative gain (p<0.001). Findings in vestibular tests did not correlate with subjective sensation of dizziness. [ABSTRACT FROM AUTHOR]

Conclusion. Testing of the horizontal vestibulo-ocular reflex (VOR) with head rotations (including head impulses) using the magnetic scleral search coil technique (SCT HHI) provides valuable additional diagnostic information in patients with persistent dizziness, oscillopsia or imbalance. It identifies high and low frequency/acceleration vestibular abnormalities that are frequently missed using other methods. Objectives. To evaluate the diagnostic utility of SCT measurement of the horizontal VOR in the multidisciplinary neurotology clinic of a tertiary referral centre. Patients and methods. The records of 127 consecutive patients referred for persistent dizziness, oscillopsia, imbalance, or with clinical findings suggestive of high frequency/acceleration vestibular dysfunction were reviewed. All had been tested with clinical head impulses, bithermal calorics and vestibular-evoked myogenic potentials. VOR gain (peak eye velocity/peak head velocity) had been measured both in response to sinusoidal oscillations in a rotating chair (0.1-11Hz) and to manually delivered horizontal head rotations (peak head velocities 50-500°/s) using SCT. Results. Agreement between the different test modalities of horizontal semicircular canal function was moderate. Relative to SCT HHI, clinical HHI showed the highest sensitivity and the lowest specificity (both 70%). SCT HHI appeared to have the greatest diagnostic yield, when compared with calorics and SCT ROT (23% of all abnormalities shown were detected only by SCT HHI) and also allowed detection of significant asymmetries in patients with bilateral vestibular dysfunction. [ABSTRACT FROM AUTHOR]

Conclusions. The Dutch (Belgium) translation of the Dizziness Handicap Inventory (DHI) has proven to be as consistent as the original version. In addition to the three original subscales, factor analysis revealed a fourth component scoring self-perceived effects of insufficient functioning of the vestibulo-ocular reflex (VOR). Focus should be on the DHI total score in order to compare future results with the existing literature. Objective. To conduct a factor analysis and to determine its internal consistency. Materials and methods. Charts of 214 outpatients, referred with dizziness or imbalance of vestibular and non-vestibular origin, were reviewed. Results. The Cronbach's alpha coefficients for internal consistency were high for the total scale and good for the subscales. Corrected item-total correlations ranged from 0.71 for 'restricted travelling' to 0.29 for 'difficulties reading', when items were correlated with their respective subtotals, and ranged from 0.69 (restricted participation in social activities) to 0.33 (stressed relationships), when correlated with the total score. A principal component analysis with orthogonal rotation was conducted, suggesting a four-factor solution. Two factors were related to vestibular handicap, referring to the original functional and emotional subcategories. The remaining two factors related to vestibular disability, documenting motion sensitivity (original physical subscale) and insufficient VOR functioning. [ABSTRACT FROM AUTHOR]

Conclusions. When considering benign recurrent vertigo and a similar peripheral vestibular deficiency, the asymmetry of the vestibulo-ocular reflex (VOR) time constant (Tc) is lower in those patients with paretic head-shaking nystagmus (HSN) than in those with reversed HSN or without HSN. Objective: To determine whether the existence of HSN is related to the time constant of the VOR in patients with benign recurrent vertigo (BRV). Patients and methods. This was a prospective study conducted at a tertiary care center in which patients were subjected to the head-shaking test, the caloric test and rotatory chair impulsive test on the same day. The clinical features of the disease analyzed were the disease duration, frequency of vertigo spells, time since the last vertigo spell and the existence of migraine. The results of the head-shaking test were considered positive when nystagmus appeared after head-shaking had ended. Two groups of patients were established on the basis of these results and the group that displayed HSN was divided according to the direction of nystagmus. In the impulsive test, the time constant of the VOR after ipsilesional and contralesional acceleration was analyzed, as was the symmetry of the response. The differences in the means were calculated. Results: BRV was diagnosed in 25% of patients suffering recurrent spells of vertigo, of which 33 patients were HSN- and 29 were HSN+. In the latter group, vestibular migraine was frequently observed (83% of the patients), the spells of vertigo were more frequent and the patients were seen closer to the previous spell of vertigo. No differences were observed in the Tc of the VOR between HSN+ and HSN- patients, although the asymmetry of this Tc was higher in HSN- patients than in HSN+ patients. Nevertheless, the differences observed were only significant between paretic and reversed HSN patients and paretic HSN patients and HSN- patients. [ABSTRACT FROM AUTHOR]

Conclusions. Our findings suggest that canal function is substantially preserved in subjects with active vertigo attacks as a result of Ménière's disease (MD). In these subjects, the head-thrust test (HTT) may not be as sensitive to canal dysfunction as traditional caloric testing. MD may differentially affect the low-frequency sensitivity of the canals. Objective. Caloric tests have traditionally been used to characterize semicircular canal function in vestibular disorders, including MD. The quantitative HTT provides an objective measurement of semicircular canal function in the frequency and velocity ranges of normal head movements. The aim of this study was to compare the findings of caloric and HTTs in subjects with unilateral MD. Material and methods. The study population consisted of 38 candidates for gentamicin treatment due to a high frequency of vertiginous attacks (25 males, 13 females; mean age 52.9 years; range 30–70 years). The duration of symptoms was 1–30 years (mean 5.3 years). Horizontal canal function was characterized with bithermal aqueous caloric tests and recordings of the angular vestibulo-ocular reflexes (aVORs) using the scleral search-coil technique during HTTs. The main outcomes were unilateral weakness (UW) on caloric testing and aVOR gain asymmetry (GA) during HTTs. A caloric response asymmetry of >20% was considered to be indicative of pathologic UW. A difference in GA during HTTs of >5.8% was considered significant. Results. Twenty subjects (52.6%) showed abnormal results on one or both tests. Pathologic UW was present in 16 subjects (42.1%). During HTTs, 11 subjects (28.9%) showed pathologic GA. Seven subjects (18.4%) showed abnormal results on both tests. A significant correlation was found between UW and GA. However, pathologic GA during HTTs in subjects with unilateral MD was less frequent and the values smaller than those published for vestibular neuritis patients. Two subjects with unilateral MD had 100% UW, but none had >30% asymmetry on HTTs. [ABSTRACT FROM AUTHOR]

Objective To compare the incidence of head-shaking nystagmus (HSN) with the value of canal paresis (CP) obtained from a caloric test and to propose the optimal value of CP that can be predicted by the presence of HSN. Material and Methods HSN and caloric tests, together with other vestibular tests, were performed in 132 dizzy patients. HSN was recorded using electronystagmography with Frenzel's glasses. Results HSN was observed in 61/132 patients (46%). The sensitivity and specificity of the HSN test regarding the prediction of CP>20% were 66% and 77%, respectively. CP values were significantly higher in patients with than without HSN. Both the sensitivity and specificity of HSN were reasonably high when the limiting value of CP was set between 20% and 30%. Conclusion The limiting value of CP that discriminates the presence of HSN may be ≈20%. At this CP value, HSN shows an appropriately high sensitivity and specificity. The HSN test is not very sensitive but is still acceptable as one of the screening tests for detecting asymmetrical vestibular dysfunction. [ABSTRACT FROM AUTHOR]