Video-Oculography-Assisted Head Impulse Test and Caloric Testing for Detecting Stroke in Acute Vertigo Patients via Modified HINTS Plus

Background: We assessed whether detection of stroke underlying acute vertigo using HINTS plus (head-impulse test, nystagmus type, test of skew, hearing loss) can be improved by video-oculography for automated head-impulse test (V-HIT) analysis. Methods: We evaluated patients with acute vestibular syndrome (AVS) presenting to the emergency room using HINTS plus and V-HIT-assisted HINTS plus in a randomized sequence followed by cranial MRI and caloric testing. Image-confirmed posterior circulation stroke or vertebrobasilar TIA were the reference standards to calculate diagnostic accuracy. We repeated statistical analysis for a third protocol that was composed post hoc by replacing the head-impulse test with caloric testing in the HINTS plus protocol. Results: We included 30 AVS patients (ages 55.4 ± 17.2 years, 14 females). Of these, 11 (36.7%) had posterior circulation stroke (n = 4) or TIA (n = 7). Acute V-HIT-assisted HINTS plus was feasible and displayed tendentially higher accuracy than conventional HINTS plus (sensitivity: 81.8%, 95% CI 48.2–97.7%; specificity 31.6%, 95% CI 12.6–56.6% vs. sensitivity 72.7%, 95% CI 39.0–94.0%; specificity 36.8%, 95% CI 16.3–61.6%). The new caloric-supported algorithm showed high accuracy (sensitivity 100%, 95% CI 66.4–100%; specificity 66.7%, 95% CI 41–86.7%). Conclusions: Our study provides pilot data on V-HIT-assisted HINTS plus for acute AVS assessment and indicates the diagnostic value of integrated acute caloric testing.

Influence of Tasking During Vestibular Testing

Purpose The purpose of this study was to investigate the effectiveness of different types of tasking on the measurement of peak slow phase velocity (SPV) for caloric testing and rotary chair testing. Method This study evaluated the peak SPV response for caloric testing and rotary chair across five conditions. Three verbal, one tactile, and one condition without tasking were used for both caloric testing and rotary chair. The subjects consisted of 20 young adults (age range: 22–33 years, M = 26.65, SD = 3.72; seven male, 13 female) with normal vestibular function and no history of ear surgery or vestibular disorder. Study participation consisted of two visits with 24 hr minimum between each, one for caloric testing and one for rotary chair testing. The test completed at each visit was counterbalanced. Caloric Testing : The caloric irrigations were performed 5 times, with the ears randomized and tasking conditions randomized. Rotary Chair Testing : Rotary chair sinusoidal harmonic acceleration testing was performed 5 times at 0.08 Hz with the tasking conditions randomized. Results Tasking of any kind resulted in significantly larger peak SPV responses when compared to the no tasking condition for rotary chair testing. When comparing each type of tasking, no significant differences were noted. No significant difference was noted when comparing the conditions with tasking to the no tasking condition for caloric testing. Conclusions Clinically, either mental or tactile tasking can be utilized as a method to reduce VOR suppression during rotary chair testing. As no difference was found when comparing different verbal tasks to each other, the type of tasking can be catered to the patient. If verbal tasking cannot be completed, the braiding tactile task is a valid substitution. Caloric results varied widely across subjects and did not reach statistical significance, so conclusions on the need for tasking cannot be drawn.

Therapeutic Effect of Steroids on Vestibular Neuritis: Systematic Review and Meta-analysis

Objectives: The present meta-analysis sought to assess further evidence for the efficacy of steroids in vestibular neuritis (VN). Methods: The PubMed, EMBASE and Cochrane Library databases were searched through August 30, 2019. The main outcome measures were 1) complete caloric recovery, 2) improvement of canal paresis (CP) in caloric testing, and 3) dizziness handicap inventory. The follow-up times were divided into short, mid, and long-term. The main outcome measures were 1) complete caloric recovery, 2) improvement of canal paresis (CP) in caloric testing, and 3) dizziness handicap inventory. Results: Among 276 records identified, 5 studies (n = 253) were included in the analysis. The therapeutic effect of steroid on VN was confirmed (Hedges’g = 0.172, 95% CI 0.048 to 0.295, p = .006). This effect was statistically significant on long-term follow-up (Hedges’g = 0.496, 95% CI 0.285 to 0.708, p < .0001). The therapeutic effect of steroids on VN was better than that of non-steroid treatment (Hedges’g = 0.299, 95% CI 0.107 to 0.490, p = .002). However, this effect was obscured by combination of other treatments. The therapeutic effect of steroids on VN was statistically significant regarding complete caloric recovery and improvement in CP (Hedges’g = 0.364, 95% CI 0.181 to 0.547, p < 0.0001; Hedges’g = 0.592, 95% CI 0.315 to 0.5869, p < .0001) Conclusions: The results suggest that corticosteroids are effective at VN recovery, especially in long-term follow-up. More data are required before recommendations can be made regarding management in patients on corticosteroids.

Paradigm shift in acute dizziness: is caloric testing obsolete?

Objective Cold and warm water ear irrigation, also known as bithermal caloric testing, has been considered for over 100 years the ‘Gold Standard’ for the detection of peripheral vestibular hypofunction. Its discovery was awarded a Nobel Prize. We aimed to investigate the diagnostic accuracy of Caloric Testing when compared to the video head impulse test (vHIT) in differentiating between vestibular neuritis and vestibular strokes in acute dizziness. Design Prospective cross-sectional study (convenience sample). Setting All patients presenting with signs of an acute vestibular syndrome at the emergency department of a tertiary referral center. Participants One thousand, six hundred seventy-seven patients were screened between February 2015 and May 2020 for Acute Vestibular Syndrome (AVS), of which 152 met the inclusion criteria and were enrolled. Inclusion criteria consisted of a state of continuous dizziness, associated with nausea or vomiting, head-motion intolerance, new gait or balance disturbance and nystagmus. Patients were excluded if they were younger than 18 years, if symptoms lasted < 24 h or if the index ED visit was > 72 h after symptom onset. Of the 152 included patients 85 completed testing. We assessed 58 vestibular neuritis and 27 stroke patients. Main outcome measures All patients underwent calorics and vHIT followed by a delayed MRI which served as a gold standard for vestibular stroke confirmation. Results The overall sensitivity and specificity for detecting stroke with a caloric asymmetry cut-off of 30.9% was 75% and 86.8%, respectively [negative likelihood ratio (NLR) 0.29] compared to 91.7% and 88.7% for vHIT (NLR 0.094). Best VOR gain cut-off was 0.685. Twenty-five percent of vestibular strokes were misclassified by calorics, 8% by vHIT. Conclusions Caloric testing proved to be less accurate than vHIT in discriminating stroke from vestibular neuritis in acute dizziness. Contrary to classic teaching, asymmetric caloric responses can also occur with vestibular strokes and might put the patient at risk for misdiagnosis. We, therefore, recommend to abandon caloric testing in current practice and to replace it with vHIT in the acute setting. Caloric testing has still its place as a diagnostic tool in an outpatient setting.

Saccades Matter: Reduced Need for Caloric Testing of Cochlear Implant Candidates by Joint Analysis of v-HIT Gain and Corrective Saccades

Objectives: Video head impulse test (v-HIT) is a quick, non-invasive and relatively cheap test to evaluate vestibular function compared to the caloric test. The latter is, however, needed to decide on the optimal side to perform cochlear implantation to avoid the risk on inducing a bilateral vestibular areflexia. This study evaluates the effectiveness of using the v-HIT to select cochlear implant (CI) candidates who require subsequent caloric testing before implantation, in that way reducing costs and patient burden at the same time.Study Design: Retrospective study using clinical data from 83 adult CI-candidates, between 2015 and 2020 at the Leiden University Medical Center.Materials and Methods: We used the v-HIT mean gain, MinGain_LR, the gain asymmetry (GA) and a newly defined parameter, MGS (Minimal Gain &amp; Saccades) as different models to detect the group of patients that would need the caloric test to decide on the ear of implantation. The continuous model MGS was defined as the MinGain_LR, except for the cases with normal gain (both sides ≥0.8) where no corrective saccades were present. In the latter case MGS was defined to be 1.0 (the ideal gain value).Results: The receiver operating characteristics curve showed a very good diagnostic accuracy with and area under the curve (AUC) of 0.81 for the model MGS. The v-HIT mean gain, the minimal gain and GA had a lower diagnostic capacity with an AUC of 0.70, 0.72, and 0.73, respectively. Using MGS, caloric testing could be avoided in 38 cases (a reduction of 46%), with a test sensitivity of 0.9 (i.e., missing 3 of 28 cases).Conclusions: The newly developed model MGS balances the sensitivity and specificity of the v-HIT better than the more commonly evaluated parameters such as mean gain, MinGain_LR and GA. Therefore, taking the presence of corrective saccades into account in the evaluation of the v-HIT gain can considerably reduce the proportion of CI-candidates requiring additional caloric testing.

Vestibular Preservation After Cochlear Implantation Using the Round Window Approach

Background: The development of less traumatic surgical techniques, such as the round window approach (RWA), as well as the use of flexible electrodes and post-operative steroid administration have enabled the preservation of residual hearing after cochlear implantation (CI) surgery. However, consideration must still be given to the complications that can accompany CI. One such potential complication is the impairment of vestibular function with resulting vertigo symptoms. The aim of our current study was to examine the changes in vestibular function after implantation in patients who received CI using less traumatic surgery, particularly the RWA technique.Methods: Sixty-six patients who received CI in our center were examined by caloric testing, cervical vestibular evoked myogenic potential (cVEMP) and ocular VEMP (oVEMP) before or after implantation, or both, to obtain data on semicircular canal, saccular and utricular function, respectively. Less traumatic CI surgery was performed by the use of the RWA and insertion of flexible electrodes such as MED-EL FLEX soft, FLEX 28, and FLEX 24 (Innsbruck, Austria).Results: Caloric response and the asymmetry ratio of cVEMP and oVEMP were examined before and after implantation using less traumatic surgical techniques. Compared with before implantation, 93.9, 82.4, and 92.5% of the patients showed preserved vestibular function after implantation based on caloric testing, cVEMP and oVEMP results, respectively. We also examined the results for vestibular function by a comparison of the 66 patients using the RWA and flexible electrodes, and 17 patients who underwent cochleostomy and insertion of conventional or hard electrodes. We measured responses using caloric testing, cVEMP and oVEMP in patients after CI. There were no differences in the frequencies of abnormal caloric and oVEMP results in the implanted ears between the RWA and cochleostomy. On the other hand, the frequency of abnormal cVEMP responses in the implanted ears in the patients who received implantation by cochleostomy was significantly higher than that in the patients undergoing surgery using the RWA.Conclusion: Patients receiving CI using less traumatic surgical techniques such as RWA and flexible electrodes have reduced risk of damage to vestibular function.

Paradigm shift in acute dizziness: is caloric testing obsolete?

Objectives: We aimed to investigate the diagnostic accuracy of Caloric Testing and video Head Impulse Testing (vHIT) in differentiating between vestibular neuritis and strokes in acute dizziness. Design: Prospective cross-sectional study. Setting: Emergency department of a tertiary referral center. Participants: 1677 adult patients were screened between 2015 and 2020 for AVS, of which 152 met the inclusion criteria. Inclusion criteria consisted of a state of continuous dizziness, associated with nausea or vomiting, head-motion intolerance, new gait or balance disturbance and nystagmus. Patients were excluded if symptoms lasted <24 hours or if the index ED visit was >72 hours after symptom onset. Eighty-five patients completed testing of which 58 were vestibular neuritis and 27 strokes. Main outcome measures: All patients underwent calorics and vHIT followed by a delayed MRI (gold standard for vestibular stroke confirmation). Results: The sensitivity/specificity for detecting stroke (caloric asymmetry cut-off of 30.9%) was 75% and 86.8% respectively (Negative likelihood ratio (NLR) 0.29) compared to 91.7% and 88.7% for vHIT (NLR 0.094). Best VOR gain cut-off was 0.685. Twenty-five percent of vestibular strokes were misclassified by calorics, 8% by vHIT. Conclusions: Caloric testing demonstrated lower accuracy than vHIT in discriminating stroke from vestibular neuritis in acute dizziness. Asymmetric caloric responses can also occur with vestibular strokes and might put the patient at risk for misdiagnosis. We therefore recommend replacing calorics with vHIT in the acute setting. Caloric testing has still its place as a diagnostic tool in an outpatient setting.

Impact of caloric test asymmetry on response to treatment in vestibular migraine

Objective This study aimed to examine the association between caloric asymmetry and response to treatment in patients with vestibular migraine. Method Dizziness Handicap Inventory scores were compared between patients with less than and more than 25 per cent asymmetry (using Cohen effect size) in a cohort of definite vestibular migraine patients who underwent caloric testing between August 2016 and March 2019. Results A total of 31 patients (mean age: 48.7 ± 20.0 years; mean follow up: 9.1 ± 8.1 months) were included. Mean caloric asymmetry was 15.1 ± 15.6 per cent, with 6 (19.4 per cent) patients having asymmetry more than 25 per cent. Overall, patients experienced significant improvement in Dizziness Handicap Inventory total (d = 0.623 (95 per cent confidence interval, 0.007, 1.216)), emotional domain (d = 0.635 (95 per cent confidence interval, 0.019, 1.229)) and functional domain (d = 0.769 (95 per cent confidence interval, 0.143, 1.367)) but not physical domain (d = 0.227 (95 per cent confidence interval, −0.370, 0.815)) scores. Patients with more than 25 per cent asymmetry had no significant improvement in Dizziness Handicap Inventory scores, whereas those with less than 25 per cent asymmetry had significant improvement in Dizziness Handicap Inventory functional domain scores only (d = 0.636 (95 per cent confidence interval, 0.004, 1.244)). Conclusion Vestibular migraine patients with peripheral vestibular weakness on caloric testing may be less likely to improve after treatment compared with those without.