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BACKGROUND: Hyperventilation-induced nystagmus test (HINT) is capable of generating a response in 77.2% of cases of acute unilateral vestibulopathy (AUVP); both nystagmus toward the affected side (excitatory pattern) and toward the healthy side (inhibitory pattern) have been described. The aim of the study is to investigate the clinical and prognostic role of the test by evaluating its correlation with vestibulo-ocular reflex (VOR) gain. METHODS: We evaluated 33 AUVP patients by performing the HINT and video head impulse test (V-HIT) during the acute phase and then at 15 and 90 days after the onset of the symptoms. The correlation between the VOR gain of the affected side and test responses was evaluated first, phase by phase, and then considering the pattern shown during the first assessments. RESULTS: Patients with a negative HINT had a higher mean VOR gain than patients with a positive test at both 15 and 90 days. Patients who showed an inhibitory pattern at the first assessment had a continuous improvement in V-HIT performance, while patients with an initial excitatory response had a transient decrease in gain at the subsequent evaluation (P=.001). No difference between these 2 groups emerged at 90 days (P=.09). CONCLUSION: The finding of a negative HINT during the follow-up correlates with good V-HIT performance and could be an indicator of good recovery. The inhibitory pattern is associated with a subsequent improvement; and it would be indicative of compensation. but, despite this, the prognostic value of the test is limited [ABSTRACT FROM AUTHOR]

BACKGROUND: The aim of this study is to compare the possible functional involvement of the vestibulo-ocular reflex in the follicular and luteal phases. METHODS: The research was carried out at a university located in eastern Turkey. The study included 37 healthy female volunteering students aged 18-25 years. The functional head impulse test was applied twice in the follicular phase and in the luteal phase, and the results in both phases were compared. RESULTS: In the functional head impulse test, statistically significant differences were obtained between the follicular phase and the luteal phase at the stimulus to the lateral semicircular canal direction total and 6000°/s² acceleration percentage of correct answers values, the posterior semicircular canal direction stimulations at 3000°/s² and 5000°/s² acceleration percentage of correct answers values, and the anterior semicircular canal direction stimulations at 5000°/s² acceleration percentage of correct answers values. CONCLUSION: In the luteal phase, which corresponds to the period before menstruation, the vestibulo-ocular reflex is functionally negatively affected. [ABSTRACT FROM AUTHOR]

BACKGROUND: Cerebellar ataxia, neuropathy, and vestibular areflexia syndrome (CANVAS) presents an unpredictable and uneven clinical development of cerebellar ataxia, neuropathy, and vestibular areflexia. The aim of this study is to report the variability of vestibular test results in genetically confirmed patients with cerebellar ataxia, neuropathy, and vestibular areflexia syndrome. METHODS: Caloric testing, video head impulse test (vHIT), and rotatory chair testing were performed in 7 patients who presented pathogenic repeat expansions in the replication factor complex unit 1 gene related to cerebellar ataxia, neuropathy, and vestibular areflexia syndrome. RESULTS: Reduced vestibulo-ocular reflex (VOR) gain was observed in 100% of the patients in rotatory chair testing. Three of them had bilateral areflexia in caloric testing while 2 showed unilateral hypofunction and 2 had no alterations in the test. Only 1 patient had bilateral abnormal vHIT with gains under 0.6 in both ears. CONCLUSION: Genetic testing allows an early diagnosis of cerebellar ataxia, neuropathy, and vestibular areflexia syndrome, whereby the vestibular system may be affected to different degrees. Rotatory chair testing has a higher sensitivity for the detection of vestibular hypofunction in these patients. Caloric testing can provide additional information. vHIT might underdiagnose patients with mild-to-moderate vestibulopathy. [ABSTRACT FROM AUTHOR]

BACKGROUND: The suppression head impulse test is a new paradigm of the head impulse test, recently introduced for clinical use. The aim of this study was to assess the importance of the suppression head impulse paradigm in evaluating vestibular function. METHODS: This comparative study was conducted from June 2020 to June 2022. The ears of the participants were divided into 2 groups: (i) ears with vestibular weakness and (ii) healthy controls. All participants underwent video head impulse tests at the time of presentation with both conventional head impulse paradigm and suppression head impulse paradigm, performed by the same examiner. The results of the 2 tests were compared, and the correlation between the corresponding parameters obtained (vestibulo-ocular reflex gain and saccades) was examined. RESULTS: Ninety-five participants were included in the study (190 ears) with a mean age of 42.2 ± 12.6 years. Forty-six ears had vestibular weakness, and 144 were healthy controls. The suppression head impulse paradigm test showed a significantly lower vestibulo-ocular reflex gain than the head impulse paradigm in both groups. A positive correlation emerged between the vestibulo-ocular reflex gain measured with both paradigms. Regarding the saccades, a negative correlation was observed between the overt saccades latency and amplitude measured with both paradigms. CONCLUSION: The new suppression head impulse paradigm complements the head impulse paradigm for a better evaluation of the vestibular function. The inconsistency of covert saccades in suppression head impulse paradigm makes it superior to head impulse paradigm in measuring vestibulo-ocular reflex gain, especially in patients with vestibular loss. [ABSTRACT FROM AUTHOR]

BACKGROUND: This study investigates the test-retest reliability, aging effects, and differences in horizontal semicircular canals gain values between the head impulse paradigm and suppression head impulse paradigm. METHODS: Sixty healthy adult subjects aged 22-76-year-old (mean ± standard deviation = 47.27 ± 18.29) participated in the head impulse paradigm and suppression head impulse paradigm using the video head impulse test. The Head impulse paradigm was used to assess all 6 semicircular canals, while suppression head impulse paradigm measured only the horizontal canals. Twenty subjects aged 22-40-year-old (25.25 ± 4.9) underwent a second session for the test-retest reliability. RESULTS: There were good test-retest reliability for both measures (right horizontal head impulse paradigm, intraclass correlation coefficient = 0.80; left horizontal head impulse paradigm, intraclass correlation coefficient = 0.77; right anterior head impulse paradigm, intraclass correlation coefficient = 0.86; left anterior head impulse paradigm, intraclass correlation coefficient = 0.78; right posterior head impulse paradigm, intraclass correlation coefficient = 0.78; left posterior head impulse paradigm, intraclass correlation coefficient = 0.75; right horizontal suppression head impulse paradigm, intraclass correlation coefficient = 0.76; left horizontal suppression head impulse paradigm, intraclass correlation coefficient = 0.79). The test-retest reliability for suppression head impulse paradigmanti-compensatory saccade latency and amplitude were moderate (right latency, intraclass correlation coefficient = 0.61; left latency, intraclass correlation coefficient = 0.69; right amplitude, intraclass correlation coefficient = 0.69; left amplitude, intraclass correlation coefficient = 0.58). There were no significant effects of age on head impulse paradigm and suppression head impulse paradigm vestibulo-ocular reflex gain values and suppression head impulse paradigmsaccade latency. However, the saccade amplitude became smaller with increasing age, P < .001. The horizontal suppression head impulse paradigm vestibuloocular reflex gain values were significantly lower than the head impulse paradigm for both sides (right, P = .004; left, P = .004). CONCLUSION: There was good test-retest reliability for both measures, and the gain values stabilized with age. However, suppression head impulse paradigm anti-compensatory saccade latency and amplitude had lower test-retest reliability than the gain. The suppression head impulse paradigm vestibulo-ocular reflex gain was lower than the head impulse paradigm and its anti-compensatory saccade amplitude reduced with increasing age. [ABSTRACT FROM AUTHOR]

The central vestibular compensation reduces vestibular symptoms and helps individuals improve balance affected by vestibular dysfunction. The video head impulse test provides an opportunity to study central vestibular compensation objectively. This study aims to methodically present existing information about the video head impulse test as a measure to evaluate central vestibular compensation in patients with unilateral vestibular dysfunction. Literature review comprised 12 research articles selected based on pre-set criteria and timeline (January 2010 to June 2020). The findings indicate that the appropriate video head impulse test measures to evaluate central vestibular compensation after the occurrence of temporary unilateral vestibular dysfunction are the improvement in vestibulo-ocular reflex gain. And, for permanent unilateral vestibular dysfunction are reduction in catch-up saccades percentage, velocity, amplitude, latency, and Perez and Rey score. [ABSTRACT FROM AUTHOR]

OBJECTIVE: To explore the usefulness of the responses of video head impulse testing (vHIT) in assessing symptomatic patients with superior semicircular canal dehiscence (SSCD). METHODS: This was a prospective case-control study performed in a tertiary skull base referral Centre in the UK. It included all patients diagnosed with SSCD from January 2015 to January 2019 and compared to a control group of age and gender-matched unaffected individuals. The main outcome of the study was semicircular canal vestibule-ocular reflex (VOR) gains during vHIT assessment and link to patients' symptoms. RESULTS: A total of 28 patients were diagnosed with SSCD during the study period and completed the vHIT assessment. Reduced VOR gains (<0.8) were noted in 57% of patients (n = 16). Half of these (n = 8) were in canals other than the superior semicircular (posterior only: n = 5; lateral and posterior: n = 3). Three patients (10.7%) had abnormal responses in 2 canals. The canals in the contralateral side were affected in 56.5% of the cases. There was no correlation with the patients' symptoms. Results were directly comparable with the control group vHIT results with no identifiable statistically significant differences on comparison of the ipsilateral SSCD side with a randomly selected side from the control group (all comparisons: P > .05). CONCLUSION: SSCD can affect the vestibular responses from all 3 semicircular canals; not necessarily the superior one. Similar responses were found in a control group of normal subjects. Although the use of vHIT in the assessment of SSCD is not diagnosis-specific, it can still help with identifying the impact of surgery on all canals prior to any intervention in order to avoid bilateral vestibular failure. [ABSTRACT FROM AUTHOR]

OBJECTIVES: This study aimed to evaluate the correlation between tinnitus parameters (duration, severity, reaction, handicap levels) and vestibulo-ocular reflex (VOR) gain values in patients with tinnitus with normal hearing without vertigo or any other complaints and to compare the VOR gains with a healthy group. MATERIALS and METHODS: The study group consisted of 30 individuals aged between 18 and 65 years who suffered from tinnitus but not from hearing loss and vertigo. The control group also consisted of 30 individuals who were categorized as healthy adults. The tinnitus handicap inventory, tinnitus reaction questionnaire, and tinnitus handicap questionnaire were applied to each individual in the tinnitus group, and the video head impulse test (VHIT) was conducted in 2 groups. RESULTS: Statistically, a significant difference was found between the 2 groups in terms of VOR gain values in horizontal and vertical semicircular canal planes (p<0.05). However, there was no statistically significant correlation between tinnitus parameters, age, and VOR gain values in the study group (p>0.05). CONCLUSION: Considering the lower VOR gain values of the study group than the control group, these patients may need to be followed up for vestibular dysfunction associated with tinnitus, which can be a symptom of peripheral vestibular disorder. Moreover, this study will contribute to the literature because we determined a high-frequency component of VOR by VHIT, which was used to evaluate the relationship between tinnitus parameters and peripheral vestibular function. [ABSTRACT FROM AUTHOR]

OBJECTIVES: The objective of this study was two-fold: (1) To evaluate the impact of the physiological aging process on somatosensory, vestibular, and balance functions, and (2) To examine the extent to which age and somatosensory and vestibular functions can predict balance performance. MATERIALS and METHODS: In this cross-sectional study, 141 asymptomatic subjects were assessed for touch pressure thresholds (TPT) with Semmes- Weinstein monofilaments (SWF), vibration thresholds (VT) with a neurothesiometer (NT) and a Rydel-Seiffer tuning fork 128Hz (RSTF). Horizontal vestibulo-ocular reflexes (HVOR gain and asymmetry) were assessed using the video Head Impulse Test (vHIT). A modified version of the Romberg test was used to assess standing balance and the Timed Up and Go test (TUG) and tandem gait (TG) to evaluate dynamic balance. RESULTS: Significant age effects were found for TPT, VT, and balance but not for HVOR gain or asymmetry. Standing balance was explained for 47.2% by age, metatarsal 1 (MT1) (NT), and heel (SWF). The variance in TUG performance was explained for 47.0% by age, metatarsal 5 (MT5) (SWF), and medial malleolus (MM) (NT). Finally, the variance in TG performance was predicted for 43.1% by age, MT1 (NT), HVOR gain, and heel (SWF). CONCLUSION: Among asymptomatic adult population, both somatosensation and balance performance deteriorate with aging. In contrast, HVOR remains rather constant with age, which is possibly explained by the process of vestibular adaptation. Furthermore, this study provides evidence that the VT, TPT, HVOR gain, and age partly predict balance performance. Still, further research is needed, especially with bigger samples in decades 8 and 9. [ABSTRACT FROM AUTHOR]

OBJECTIVES: To assess and monitor lateral semicircular canal (LSC) function over time in patients affected by chronic otitis media with cholesteatoma (CHO) complicated by fistula of LSC (LSC-F) before and after surgery using video Head Impulse Test (vHIT). MATERIALS and METHODS: Eight patients aged 18-67 years affected by CHO with imaging-ascertained LSC-F were included in this preliminary prospective study. The following protocol has been applied: oto-microscopic diagnosis with patient's history; computed tomography scan of the temporal bone; surgery with concomitant resurfacing of LSF-F; audiological and vestibular evaluation before surgery (T0) and at 30 days (T1), 6 months (T2), and 1 year after surgery (T3). vHIT was used to assess vestibulo-ocular reflex (VOR) in LSC. RESULTS: None of the patients showed deterioration of bone conduction hearing levels during the different time of evaluation. Three patients showed a reduced VOR gain and catch-up saccades at T0, with VOR gain normalization at T2. This finding remained stable at the 1-year follow-up. The VOR gain in the nonaffected side generally experienced an increase, paralleled by the normalization on the affected side, with statistically significant correlation. The subjects with normal vHIT before surgery did not show any variation following surgery. CONCLUSION: vHIT allows the assessment of LSC function in case of fistula. The adopted surgical fistula repair did not induce deterioration of the auditory or LSC function, but indeed, it could prevent worsening and help promoting recovery to the normal function. [ABSTRACT FROM AUTHOR]

We present an unusual case of a patient with a positive Tullio phenomenon, brief Valsalva-induced transient horizontal nystagmus, reduced left caloric response, and bilateral vestibulo-ocular reflex loss. This study discusses the pathophysiology and differential diagnosis concerning the suspected pathology for the phenomenon of utricular hydrops or vestibular atelectasis and presents a literature review. [ABSTRACT FROM AUTHOR]

We present an unusual case of a patient with a positive Tullio phenomenon, brief Valsalva-induced transient horizontal nystagmus, reduced left caloric response, and bilateral vestibulo-ocular reflex loss. This study discusses the pathophysiology and differential diagnosis concerning the suspected pathology for the phenomenon of utricular hydrops or vestibular atelectasis and presents a literature review. [ABSTRACT FROM AUTHOR]

OBJECTIVE: The aim of this study is to compare nystagmus characteristics after caloric irrigation in patients with lateral canal (LC) and posterior canal (PC) benign paroxysmal positional vertigo (BPPV) and to analyze the role of symptom duration. MATERIALS and METHODS: A prospective study was conducted in 65 patients with BPPV (20 LC and 45 PC) who were subjected to caloric testing. Average slow-phase velocity and nystagmus duration were analyzed. RESULTS: Caloric hypo-excitability was 20.4%. It was more evident in patients with apogeotropic-type LC-BPPV. The comparison of average slowphase velocity of the nystagmus and nystagmus duration between selected types of BPPV for pathologic, non-pathologic, and the control ears after warm and cold stimulation was not statistically significant (p>0.05). No correlation was found between caloric results and symptom duration (p>0.05). CONCLUSION: Some patients presented caloric hypo-excitability. Reliability of caloric testing to differentiate the ear with normal and abnormal vestibular function in different types of BPPV was low. No difference was found in the analysis of the impact of symptom duration. Caloric testing is not an ideal tool to study BPPV [ABSTRACT FROM AUTHOR]

OBJECTIVE: The objective of this study was to establish which factor leads to a higher vestibulo-ocular reflex (VOR) gain: the timing of the movement or the direction of the movement. For this purpose, healthy volunteers were examined under three conditions: (1) when they were informed about the timing of the head movement; (2) when they were informed about the direction of the head movement; and (3) when they knew both the timing and the direction of the head movement. MATERIALS and METHODS: This study included data from 19 participants between the ages of 20 and 23 years with no neurological or vestibular ailments. The gains of the video head impulse test (vHIT) were measured under four different conditions and the final control tests. Five subgroups were defined, and the differences in the subgroups were assessed with using several statistical procedures. RESULTS: We found that there were significant differences between all subgroups gains on the right and left head rotations. Nevertheless, nonsignificant differences were found by performing independent samples t-tests and Mann-Whitney U tests between left and right head rotations for the pairwise comparisons of subgroups. Also, analysis of variance (ANOVA) results indicated that vHIT gains for the right and left, respectively). Thus, knowing the timing or direction or both does not affect vHIT gains. CONCLUSION: The results of these experiments revealed that there is no association whatsoever between VOR gain and awareness of the timing or direction of the movement or both. [ABSTRACT FROM AUTHOR]

OBJECTIVE: To explore clinical features of patients with bilateral vestibular hypofunction (BVH) verified in motorized head impulse test (MHIT). MATERIALS and METHODS: We examined clinical records of 23 adult patients (10 males and 13 females), whose gain of the vestibulo-ocular reflex in the MHIT was bilaterally lowered. Fifteen of 62 unilateral cochlear implant (CI) recipients routinely tested both pre- and postoperatively with the MHIT had BVH. Eight of 198 vestibular outpatients selected to the MHIT due to clinical causes had BVH. Clinical characteristics and a questionnaire regarding current sensations were analyzed. RESULTS: The mean gain±SD in the MHIT was 0.26±0.17 on the right and 0.26±0.14 on the left side. The mean gain in the CI recipients did not differ from that of vestibular outpatients (p>0.05). All outpatients with BVH suffered from oscillopsia, whereas only 46% of CI recipients experienced oscillopsia (p=0.048). Instability was more prominent (p=0.004) and quality of life further decreased (p=0.012) among vestibular outpatients compared with CI patients. Most common etiology for the BVH was meningitis. Other causes were either sudden or progressive loss of labyrinthine function, bilateral Meniére's disease, and ototoxicity. CONCLUSION: BVH is rare even in a specialized clinic. Vestibular outpatients were more disabled than CI recipients with the BVH. [ABSTRACT FROM AUTHOR]

OBJECTIVE: Velocity storage mechanism is a multisensory rotation estimator; it compensates for errors in the information provided by the peripheral vestibular organs by means of an adjustment in the duration of the vestibular signal. The aim of this study was to determine the activity of the velocity storage mechanism in the presence of a labyrinthine disorder, using galvanic vestibular stimulation to cause direct activation of the vestibular afferent neurons. MATERIALS and METHODS: Forty-one subjects with definite Meniere's disease (MD) and 36 healthy volunteers were evaluated using a 20-s galvanic vestibular stimulation. RESULTS: We found a post-stimulus nystagmus overshoot exclusively in subjects with MD (47% in subjects with unilateral disease and 82% in subjects with bilateral disease), but no overshoot in healthy subjects. CONCLUSION: Because post-stimulus nystagmus overshoot is caused by the velocity storage mechanism, this finding suggests an increase in the velocity storage in subjects with a labyrinthine disease. [ABSTRACT FROM AUTHOR]

OBJECTIVE: To characterize the response in the video head-impulse test for the assessment of the vestibulo-ocular reflex (VOR) in patients because of vertigo and dizziness. MATERIALS and METHODS: After rightward and leftward head impulses, the following results evaluated were: gain of the reflex and appearance of refixation saccades. A particular type of response (normal gain VOR and refixation saccades) was evaluated in a group of patients. RESULTS: In patients with a unilateral abnormality consisting of normal gain and refixation saccades, there was a close concordance with the diseased side and the side to which head impulses elicited the abnormal result. CONCLUSION: In the assessment of patients with dizziness, finding a normal gain VOR with refixation saccades indicates the existence of a peripheral vestibulopathy and localizes to the side of the lesion. [ABSTRACT FROM AUTHOR]

OBJECTIVE: The caloric test and the video head-impulse test are diagnostic tools that examine the function of the horizontal semicircular canal. There are major differences between the two tests. These are stimulus characteristics, methodology, and function examined. MATERIALS and METHODS: This is a prospective work in 123 patients with different types of vestibular disease seen because of dizziness in which both procedures were performed the same day. First, the spontaneous nystagmus and head-shake nystagmus were measured. The video head-impulse test was carried out, and finally, the caloric test was performed with water at two different temperatures. Both ears were irrigated alternately. Main outcome measures were the canal paresis in the caloric test and gain of vestibulo-ocular reflex, gain asymmetry, and refixation saccades in the vHIT. RESULTS: The caloric test and the vHIT results were fully coincident in 60 patients (48.7%), and the results for both were normal in 36 patients. Discrepancies were found in 3 patients regarding the deficient side, and in 14 patients, an added contralateral (according to the caloric test) abnormal result was obtained. In 46 patients, one of the tests was normal while the other was not, but both were in accordance with the diseased side. The correlation coefficient for canal paresis and gain asymmetry was 0.67, and the agreement was low: κ=0.252. CONCLUSION: The assessment of horizontal semicircular canal function with the vHIT needs to take into consideration not only the gain in VOR but also the existence of refixation saccades. The information from both methods is redundant in some cases but complementary in most, and the existence of discrepancies is very low. [ABSTRACT FROM AUTHOR]

Objectives: The aim of this study is to record the VEMP changes that occur in patients with vestibular schwannoma to assess vestibulospinal reflexes. Material and Methods: This study was carried on fifteen patients with vestibular schwannoma. Fifteen persons not suffering from any vestibulo-cochlear problem were subjected to VEMP recordings as controls. Results: In this study, 3 patients (20%) had no VEMP waves on the affected side (but the waves were preserved on the other side), 11 patients (73.4%) had no VEMP waves bilaterally, and 1 patient (6.6%) had VEMP waves preserved on both sides As for the latencies of p1, n1 waves and peak to peak amplitude variation, VEMP could be elicited only in 4 patients (26.8%). There was a significant difference between the patients and controls in regard to mean p1 and n1 latencies but there was no significant difference between the peak amplitudes of patients and controls. Conclusion: VEMP can be a good indicator for the function of the vestibulospinal reflexes than other physiological examinations in cases of vestibular schwannoma. [ABSTRACT FROM AUTHOR]

Objective: To compare VEMP response characteristics between binaural and monaural stimulation and to determine normative data for logon stimulus in adults. Subjects and Methods: Twenty-two healthy adults were involved in the study. Two set types of VEMP recordings were performed for each subject. One is simultaneous binaural logon stimulation with bilateral recordings (B-VEMP) and the other one is monaural logon stimulation of each ear separately with two sequential ipsilateral recording (M-VEMP). Subjects were divided into two groups involving 11 participants in each group. In the first group all participants underwent initial B-VEMP test and subsequent M-VEMP test; while in the second group all participants underwent initial M-VEMP test and subsequent BVEMP test. Logon type stimulus with 120 dB HL intensity was used to trigger VEMPs in both methods. Results: There was no statistical difference between B-VEMP and M-VEMP recordings in respect to P1 and N1 latencies, P1- N1 interval and P1-N1 amplitude in any of the groups. When the VEMP responses of 2 groups were combined (42 ears), we have found that the mean P1 latency was 14.9 ± 1.5 msec, the mean N1 latency was 22.3 ± 2.3 msec, the mean P1-N1 interval was 7.6 ± 2.4 msec, and the mean P1-N1 amplitude was 14.1 ± 6.1 μV for B-VEMP recordings. These values were 15.1 ± 1.6 msec, 22.2 ± 1.6 msec, 7.0 ± 1.9 msec, and 14.8 ± 6.0 μV respectively for M-VEMP recordings. Conclusion: Binaural stimulation with simultaneous bilateral recording gives similar results with monaural stimulation with a separate recording for each site. B-VEMP recording can be a more convenient way of VEMP testing especially in those subjects who have difficulty to maintain a constant muscular effort during test procedure. [ABSTRACT FROM AUTHOR]