Persistent postural-perceptual dizziness: A functional neuro-otologic disorder.

Persistent postural-perceptual dizziness (PPPD) is a functional neuro-otologic disorder that is the most frequent cause of chronic vestibular syndrome. The core vestibular symptoms include dizziness, unsteadiness, and non-spinning vertigo, which are exacerbated by an upright posture or walking, active or passive motion, and exposure to moving or complex visual stimuli. PPPD is mostly precipitated by acute or episodic vestibular diseases; however, its symptoms cannot be accounted for by its precipitants. PPPD is not a diagnosis of exclusion, but may coexist with other structural diseases. Thus, when diagnosing PPPD, the patient's symptoms must be explained by PPPD alone or by PPPD in combination with a structural illness. PPPD is most frequently observed at approximately 50 years of age, with a female predominance. Conventional vestibular tests do not reveal any specific signs of PPPD. However, the head roll-tilt subjective visual vertical test and gaze stability test after exposure to moving visual stimuli may detect the characteristic features of PPPD, that is, somatosensory- and visually-dependent spatial orientation, respectively. Therefore, these tests could be used as diagnostic tools for PPPD. Regarding the pathophysiology of PPPD, neuroimaging studies suggest shifts in interactions among visuo-vestibular, sensorimotor, and emotional networks, where visual inputs dominate over vestibular inputs. Postural control also shifts, leading to the stiffening of the lower body. To treat PPPD, selective serotonin reuptake inhibitors/serotonin noradrenaline reuptake inhibitors, vestibular rehabilitation, and cognitive behavioral therapy are used alone or in combination.

The effect of intratympanic gentamicin as a prehabilitation strategy for objective and subjective vestibular function in patients undergoing microsurgery for a unilateral vestibular schwannoma.

OBJECTIVE: To review the literature on intratympanic gentamicin treatment as prehabilitation for patients undergoing surgery for a unilateral vestibular schwannoma. DATA SOURCES: A systematic literature search was conducted up to March 2023 in Pubmed, Embase, Cochrane, Web of Science, Academic Search Premier, Google Scholar and Emcare databases. REVIEW METHODS: Articles on the effect of intratympanic gentamicin followed by vestibular schwannoma surgery were reviewed. Data on objective vestibular function and subjective outcomes were compiled in tables for analysis. Relevance and methodological quality were assessed with the methodological index for non-randomized tool. RESULTS: A total of 281 articles were identified. After screening and exclusion of duplicates, 13 studies were reviewed for eligibility, of which 4 studies could be included in the review. The posturography test, the subjective visual horizontal test, and the optokinetic nystagmus test showed decreased vestibular function in the group of patients who received intratympanic gentamicin before microsurgery compared to the group of patients without gentamicin. Other objective tests did not show significant differences between patient groups. Subjective vestibular outcomes, as evaluated by questionnaires on quality of life and/or dizziness, did not seem to improve from intratympanic gentamicin pretreatment. CONCLUSION: Vestibular schwannoma patients who received intratympanic gentamicin before surgical resection of the tumor performed better in the posturography test, subjective visual horizontal test, and the optokinetic nystagmus test afterwards. However, studies that also evaluated subjective outcomes such as dizziness, anxiety, depression, and balance self-confidence did not show a positive effect of intratympanic gentamicin on the vestibular complaints and symptoms.

Nationwide Utilization of Computerized Dynamic Posturography in an Era of Deimplementation.

Computerized dynamic posturography (CDP) provides multisensory assessment of balance. Consensus is lacking regarding CDP utility and coverage determinations vary. To inform best practices and policy, this cross-sectional study quantifies provider use of CDP among Medicare beneficiaries over time (2012-2017), by geographic region (hospital referral region [HRR]), and specialty. We observed 195,267 beneficiaries underwent 212,847 CDP tests totaling $15,780,001 in payments. Number of CDPs billed per 100,000 beneficiaries varied 534-fold across HRRs. Over 6 years, CDP use grew by 84% despite stagnant reimbursement. More utilization was attributable to primary care clinicians than specialties focused on care for dizziness and balance disorders. The observed growth and variation illustrate the potential for policy and provider preferences to drive unexpected practice patterns and underscore the need to engage a broad network of providers to develop optimal guidelines for use. CDP may offer a use case for deimplementation of low-value diagnostic services.

Reliability of Monothermal Caloric Test as Screening Test of Vestibular System.

This retrospective study completed at a tertiary care center aimed to assess the monothermal caloric test (MCT) as a screening test, using the bithermal caloric test (BCT) as a reference. Additionally, it attempts to measure the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of a fixed inter-auricular difference (IAD) value for both cold and warm stimuli using water irrigation. Medical records of 259 patients referred for vestibular symptoms who underwent BCT with water irrigation were reviewed. Patients with bilateral vestibular weakness and caloric tests using air irrigation were excluded. BCT showed 40.9% unilateral weakness. Two formulas were used to determine the monothermal caloric asymmetry (MCA-1 and MCA-2). The measurement of agreement Kappa between the two formulas in comparison with BCT revealed moderate agreement at 0.54 and 0.53 for hot and cold stimulation, respectively. The monothermal warm stimulating test (MWST) using MCA-2 showed better results, with a sensitivity of 80%, specificity of 91%, PPV of 83.1%, and NPV of 89.2%. Thirty-four patients had horizontal spontaneous nystagmus (HSN) with a mean velocity of 2.25°/s. These patients showed better sensitivity but lower specificity after adjustment of HSN using the MCA-2 formula at warm temperatures. Therefore, they should complete the caloric test with cold irrigation to perform the BCT. MCT is efficient as a screening test if the warm stimulus is used with the MCA-2 formula fixed at 25%. If present, HSNs should be adjusted. Negative IAD (normal) in the absence or presence of adjusted HSN or slow-phase eye velocity ≤ 6°/s at each right and left warm stimulation should be accomplished by the BCT.

Evaluating children with vestibular migraine through vestibular test battery: A cross-sectional investigation.

Objective: The present study aimed to investigate the status of vestibular function in children with vestibular migraine of childhood (VMC) reflected by vestibular function test battery and explore the pathophysiological implication of these instrument-based findings. Methods: The clinical data of 22 children (mean age 10.7 ± 2.9 years) with VMC who met the diagnostic criteria of the Barany Society were collected from September 2021 to March 2022. A vestibular function test battery on these children included a caloric test, video head impulse test (vHIT), cervical vestibular-evoked myogenic potential (cVEMP), and ocular vestibular-evoked myogenic potential (oVEMP); these parameters were triggered by air-conducted sound (ACS) and galvanic vestibular stimulation (GVS). The subjects were further divided into two groups: <3 months and >3 months according to the disease duration from symptom onset. The functional abnormalities and their characteristics reflected by the vestibular test battery, as well as the outcomes in children with or without aura, were analyzed. Results: (1) The abnormal rate of the caloric test was 15.8% and that of vHIT was 0%. The response rates of ACS-cVEMP and ACS-oVEMP were 100% and 90.5%, respectively. The response rates of GVS-cVEMP and GVS-oVEMP were 100% and 88.9%, respectively. (2) No statistical difference was observed in the abnormal rate of the caloric test (P = 0.55) and the response rate of ACS-oVEMP (P = 0.21) between the two groups, irrespective of the course duration. (3) No statistical difference was detected in the abnormal rate of the caloric test (P = 0.53) and the response rate of ACS-oVEMP (P = 1.00) in children with or without aura. Conclusion: Vestibular function status comprehensively reported by the vestibular test battery did not show an aggravation with the disease duration in children with VMC. Also, it was not affected by the existence of aura in children with VMC. The high abnormal rates of the caloric test and oVEMPs (ACS-oVEMP and GVS-oVEMP) suggested that the lateral semicircular canal (low-frequency function component), the utricle, and the superior vestibular conduction pathway might be involved in VMC.

Comparison of cervical and ocular vestibular-evoked myogenic potential responses between tone burst versus chirp stimulation.

PURPOSE: To compare the effectiveness of chirp and tone burst stimuli in oVEMP and cVEMP testing for healthy adults METHODS: This study was conducted in 56 healthy volunteers (112 ears). Ocular and cervical VEMP (oVEMP, cVEMP) tests were performed for each participant using tone burst and chirp stimuli. VEMP response rates, latency of each peak (p1-n1, n1-p1), peak to peak amplitude (p1-n1 amplitude and n1-p1 amplitude), and rectified amplitudes were measured and compared between these two different stimuli. RESULTS: VEMP response rates with chirp stimuli are higher than the tone burst stimuli for both cVEMP and oVEMP tests (The difference was statistically significant for oVEMP, p = 0.001). Chirp stimuli have higher p1n1 amplitude and rectified amplitude and shorter p1and n1 latency then tone burst stimuli for cVEMP (p = 0.015, p = 0.007, p < 0.001, p < 0.001, respectively). Chirp stimuli also have higher n1p1 amplitude and shorter n1and p1 latency then tone burst stimuli for oVEMP (p = 0.006, p < 0.001, p < 0.001, respectively). CONCLUSION: The present findings show that the chirp stimulus triggers earlier VEMP responses with higher amplitudes than the tone burst stimulus during cVEMP and oVEMP testing. VEMP response rate with chirp stimulus is also higher than the tone burst. Therefore chirp stimulus can be used in VEMP testing as effectively as, if not more than, tone burst stimulus in clinical practice.

Test-retest reliability of subjective visual vertical measurements with lateral head tilt in virtual reality goggles.

OBJECTIVE: The objective is to investigate the test-retest reliability of subjective visual vertical (SVV) in the upright position and with lateral head tilts through a computerized SVV measuring system using virtual reality (VR) goggles. MATERIALS AND METHODS: Thirty healthy controls underwent SVV test in upright position, with the head tilted to the right 30°, and with the head tilted to the left 30°. Subjects wore SVV VR goggles, which contained a gyroscope for monitoring the angle of head tilt. Each subject completed 10 adjustments in each head position. The mean value of SVV deviations and SVV imprecision (the intra-individual variability of SVV deviations from the 10 adjustments) were recorded and compared across different head positions. The participants then repeated the same SVV protocol at least 1 week later. The test-retest reliability of SVV deviation and SVV imprecision were analyzed. RESULTS: The SVV deviation (mean ± standard deviation) was 0.22° ± 1.56° in upright position, -9.64° ± 5.91° in right head tilt, and 7.20° ± 6.36° in left head tilt. The test-retest reliability of SVV deviation was excellent in upright position (intra-class correlation coefficient [ICC] = 0.77, P < 0.001), right head tilt (ICC = 0.83, P < 0.001) and left head tilt (ICC = 0.84, P < 0.001). The SVV values from the 10 adjustments made during right and left head tilts were less precise than when measured at upright (P < 0.001). The test-retest reliability of SVV imprecision was poor at upright (ICC = 0.21, P = 0.26) but fair-to-good in right head tilt (ICC = 0.72, P < 0.001) and left head tilt (ICC = 0.44, P = 0.04). CONCLUSION: The test-retest reliability of SVV deviation during lateral head tilts via VR goggles is excellent, which supports further research into the diagnostic value of head-tilt SVV in various vestibular disorders. In addition, the degree of SVV imprecision during head tilt has fair-to-good test-retest reliability, which suggests SVV imprecision may have clinical applicability.

Video head impulse test (vHIT) in migraine dizziness.

BACKGROUND AND OBJECTIVE: Migraine is an extremely prevalent primary headache disorder that frequently associates parallel symptoms such as dizziness, tinnitus and hearing loss. Our aim is to investigate differences in video head impulse (vHIT) results with patients suffering from vestibular migraine (VM) and healthy people, taking into consideration mean values of vestibule ocular reflex (VOR) gain, occurrence of the compensatory saccades latency and amplitude. According to the results, determine the usefulness of vHIT in vestibular migraine diagnostics. METHODS: A total number of 120 subjects were enrolled in the study, 80 of them were vestibular migraine patients (VM), while the other 40 were a control group of age matched healthy subjects. History was taking during the evaluation; videonystagmography and the video head impulse test were done. RESULTS: The rate of saccades is much more higher in the VM group compared to the healthy subjects group, only 7.5% of the VM group showed a low VOR gain with compensatory saccades denoting a vestibular deficit. CONCLUSION: The refixation saccades are an important sign that could underlie different vestibular problems. vHIT result can contribute to the completion of full mosaic of vestibular migraine diagnostics.

Suppression head impulse paradigm in healthy adolescents - A novel variant of the head impulse test.

BACKGROUND: Suppression Head Impulse Paradigm (SHIMP), a novel variant of the Head Impulse Test has been introduced. At the same time, the Head Impulse Test was renamed to the Head Impulse Paradigm (HIMP). Contrary to HIMP saccades, SHIMP saccades are a sign of vestibular function. OBJECTIVE: 1) To compare SHIMP and HIMP feasibility, vestibular-ocular reflex (VOR) gain value and the saccadic pattern in healthy adolescents. 2) To compare SHIMP and HIMP feasibility in the hands of an experienced and an inexperienced HIMP examiner. METHOD: A total of 29 adolescents from Skåde Municipal School, Denmark were tested with HIMP and then with SHIMP. RESULTS: Neither covert nor overt saccades were observed in the HIMP, whereas SHIMP saccades were observed in all SHIMP reports. SHIMP gain values were statistically lower than HIMP gain values. A statistically significant difference was observed between the two examiners' right SHIMP gain values, but not for the left SHIMP gain values or the HIMP gain values. CONCLUSIONS: We found that HIMP and SHIMP tests are feasible in healthy adolescents for experienced as well as inexperienced examiners. However, one must be aware of potential pitfalls in the execution and interpretation of both tests. This is a well-known fact for the HIMP test, but additional considerations are needed to obtain reliable results from the SHIMP test.

The clinical utility of vestibular autorotation test in patients with vestibular migraine.

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.

[The analysis of the value of　spontaneous nystagmus in peripheral vestibular hypofunction].

Objective:To study the characteristics and clinical value of spontaneous nystagmus in patients with peripheral vestibular dysfunction.Method:Sixty cases with acute unilateral peripheral vestibular dysfunction were studied.All were diagnozed as vestibular neuritis(VN) . The relationship between SN and disease duration,DP and UW were analyzed.Result:SN was present in49 patients(81.7%)and absent in the remaining 11(18.3%).The intensity of SN ranged from 0.5°/s-20.4°/s and had negative correlation with the disease duration(r=-0.478，P<0.01). The patients were divided into 3 groups (mild,medium and severe) according to SN intensity,with median duration of disease being 6.5 d，5 d and 3 d respectively. The difference between groups was statistically significant(χ²=9.071，P<0.01).The result of the caloric test were as following：caloric test revealed DP in 44 cases（89.8%） of SN ;DP values were normal in 8 cases（10.2%）;SN intensity was positively correlated with DP value（r=0.513,P<0.01） ;unilateral weakness was found in 35 cases（71.4%）,with the direction of SN towards the weakness side in 4 cases and towards the opposite direction in the remaining 31 cases; 7 cases（14.3%）had bilateral weakness and 7 cases（14.3%）normal. There were no relationship between the intensity of SN and UW value（r=-0.321,P>0.05）.The UW value of patients with SN (40.9±26.3）% was compared to the group without SN（29.9±18.2）% . The difference was statistically significant (F=4.497,P<0.05).Conclusion:The intensity of SN in patients with acute unilateral peripheral vestibular dysfunction was often moderate and severe. The intensity of SN waned as the disease progressed or the direction reversed,The vestibular injury in patient with SN was more severe than those without. SN is useful in clinical assessment of vestibular injury and compensatory status.

Monothermal Caloric Screening Test Accuracy: A Systematic Review.

OBJECTIVE: To minimize discomfort, time, and costs, vestibular laboratories may perform monothermal caloric irrigations and discontinue testing if responses are symmetric. This systematic review aimed to determine the diagnostic accuracy of the monothermal caloric screening test (MCST) for unilateral vestibular dysfunction compared with bithermal caloric testing (BCT). DATA SOURCES: Ovid-MEDLINE, EMBASE, Scopus, Cochrane CENTRAL, and manual bibliographic searches. REVIEW METHODS: Inclusion criteria specified concurrent MCST and BCT performance and reporting of test measures (monothermal caloric asymmetry, unilateral weakness). The primary outcomes were between-measure correlation, sensitivity, and specificity. Meta-analysis was performed with hierarchical bivariate and univariate random-effects models. Heterogeneity was assessed with the I(2) statistic. RESULTS: Fifteen studies (n = 5572 participants) met inclusion criteria. Thresholds varied between studies. Asymmetries calculated by MCST and BCT were strongly correlated, but a subgroup analysis showed no correlation for those with mild unilateral weakness. The sensitivity and specificity of the MCST ranged from 0.54 to 1.00 and 0.25 to 0.96, respectively. Predictably, higher sensitivity resulted from lower cutoff points for the MCST, higher thresholds for the BCT, and additional test positivity criteria. Warm irrigations yielded higher sensitivity than cool. Studies excluding participants with severe unilateral weakness yielded lower sensitivity estimates. After pooling by threshold, temperature, and risk of bias, most performance estimates remained substantially heterogeneous (I(2) > 60%). CONCLUSION: Accuracy of the MCST is lacking precisely where it is needed most-at the border of normal and abnormal vestibular function. To guide clinical practice, research should include analysis of subgroups with varying levels of function and employ standardized testing parameters.

Normative Scores for the NIH Toolbox Dynamic Visual Acuity Test from 3 to 85 Years.

As part of the National Institutes of Health Toolbox initiative, a computerized test of dynamic visual acuity (cDVA) was developed and validated as an easy-to-administer, cost- and time-efficient test of vestibular and visual function. To establish normative reference values, 3,992 individuals, aged 3-85 years, without vestibular pathology underwent cDVA testing at multiple clinical research testing facilities across the United States. Test scores were stratified by sociodemographic characteristics. cDVA was worse in males (p < 0.001) and those subjects 50 years or older, while there was no difference in dynamic visual acuity across age groups binned from 3 to 49 years. Furthermore, we used these normative cDVA data as a criterion reference to compare both the long (validated) and short versions of the test. Both versions can distinguish between those with and without vestibular pathology (p = 0.0002 long; p = 0.0025 short). The intraclass correlation coefficient between long- and short-cDVA tests was 0.86.