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

Normalization of the Suppression Head Impulse Test (SHIMP) and its correlation with the Head Impulse Test (HIMP) in healthy adults

OBJECTIVE

In our study, it was aimed to compare vestibulo-ocular reflex (VOR) gain and saccade parameters in HIMP and SHIMP tests between gender, right and left ears, and age groups in healthy adults and to examine the correlation between the tests regarding these parameters.

METHODS

The study included a total of 100 healthy participants aged 18-65 and without complaints of hearing loss, dizziness, lightheadedness, and/or imbalance. Participants underwent HIMP and SHIMP tests, respectively.

RESULTS

No significant difference was found in HIMP and SHIMP VOR gain values according to gender and age groups. SHIMP duration was significantly longer in women. VOR gain values were lower in the right ear. HIMP amplitude values were higher and SHIMP amplitude values were lower with increasing age. In older age groups, SHIMP peak velocity and duration values were significantly decreased, while HIMP duration value increased and latency value was longer. In the 1st saccade, a significant difference was obtained between HIMP and SHIMP tests for all saccade parameters. There was a statistically significant positive correlation between the VOR gain values of HIMP and SHIMP tests.

CONCLUSIONS

The present study showed that VOR gain and saccade parameters obtained in different age groups will be important in determining clinical outcomes in vestibular pathologies.

Suppression Head Impulse Test (SHIMP) versus Head Impulse Test (HIMP) When Diagnosing Bilateral Vestibulopathy

The Suppression Head Impulse (SHIMP) test was introduced as an alternative to the Head Impulse Paradigm (HIMP) to overcome challenges in VOR gain calculation due to the interference of covert saccades. The objectives of this study were (1) to determine if SHIMP, compared to HIMP, reduces covert saccades in BV patients and (2) to define the agreement on diagnosing BV between SHIMP and HIMP. First, the number of covert saccades was compared between SHIMP and HIMP. Secondly, VOR gain was compared between SHIMP and HIMP. Lastly, the agreement between SHIMP and HIMP on identifying BV (horizontal VOR gain <0.6) was evaluated. A total of 98 BV patients were included. To our knowledge, this is the largest study population on SHIMP testing in BV patients. Covert saccades were significantly reduced, and a lower VOR gain was found during SHIMP compared to HIMP (p < 0.001). However, the clinical relevance of these statistically significant differences is small. In 93% of the patients, an agreement was found between the two paradigms regarding the diagnosis of BV, and both paradigms detect BV in the vast majority of patients.

Association Analysis of HIMP and SHIMP Quantitative Parameters in Patients With Vestibular Neuritis and Healthy Participants

Background: The Head Impulse Paradigm (HIMP) and Suppression Head Impulse Paradigm (SHIMP) are objective, quantitative methods that directly test the vestibulo-ocular reflex (VOR) and are increasingly becoming a standard in evaluating patients with vestibular disorders. Objective: The main objective was to assess the correlations between HIMP and SHIMP parameters in patients with superior vestibular neuritis (VN) and healthy participants. Additionally, the correlations between the parameters of each method were analyzed. Methods: A retrospective cohort, non-randomized study was designed. HIMP and SHIMP were performed on 40 patients with VN and 20 healthy participants (40 ears). HIMP and SHIMP parameters were measured and calculated. Pearson's or Spearson's correlations were used to establish the associations among them. Results: A strong positive correlation was found between HIMP and SHIMP gain (Pearson's r = 0.957, p = 0.000), while strong negative correlations were detected between HIMP and SHIMP saccade amplitudes (r = -0.637, p = 0.000) and percentages of overt saccades (r = -0.631, p = 0.000). In HIMP, strong and moderate positive correlations were identified between gain and saccade amplitude (R ² = 0.726, p = 0.000) and gain and saccade percentage (R ² = 0.558, p = 0.000), respectively. By contrast, an extremely weak positive correlation was observed between gain and latency (R ² = 0.053, p = 0.040). In SHIMP, strong and moderate positive correlations were found between gain and saccade percentage (R ² = 0.723, p = 0.000) and gain and saccade amplitude (R ² = 0.525, p = 0.000), respectively, but no correlation was detected between gain and latency (R ² = 0.006, p = 0.490). Conclusions: HIMP and SHIMP-related parameters were highly correlated (inter-method). Within each method (intra-method), moderate to strong correlations in VOR assessment were observed. These results further contribute to our understanding of the relationship between HIMP and SHIMP as well as to the diagnosis.

The Effect of Different Head Movement Paradigms on Vestibulo-Ocular Reflex Gain and Saccadic Eye Responses in the Suppression Head Impulse Test in Healthy Adult Volunteers

Objective: This study aimed to identify differences in vestibulo-ocular reflex gain (VOR gain) and saccadic response in the suppression head impulse paradigm (SHIMP) between predictable and less predictable head movements, in a group of healthy subjects. It was hypothesized that higher prediction could lead to a lower VOR gain, a shorter saccadic latency, and higher grouping of saccades. Methods: Sixty-two healthy subjects were tested using the video head impulse test and SHIMPs in four conditions: active and passive head movements for both inward and outward directions. VOR gain, latency of the first saccade, and the level of saccade grouping (PR-score) were compared among conditions. Inward and active head movements were considered to be more predictable than outward and passive head movements. Results: After validation, results of 57 tested subjects were analyzed. Mean VOR gain was significantly lower for inward passive compared with outward passive head impulses (p < 0.001), and it was higher for active compared with passive head impulses (both inward and outward) (p ≤ 0.024). Mean latency of the first saccade was significantly shorter for inward active compared with inward passive (p ≤ 0.001) and for inward passive compared with outward passive head impulses (p = 0.012). Mean PR-score was only significantly higher in active outward than in active inward head impulses (p = 0.004). Conclusion: For SHIMP, a higher predictability in head movements lowered gain only in passive impulses and shortened latencies of compensatory saccades overall. For active impulses, gain calculation was affected by short-latency compensatory saccades, hindering reliable comparison with gains of passive impulses. Predictability did not substantially influence grouping of compensatory saccades.

Effect of Aging and Direction of Impulse in Suppression Head Impulse Test

OBJECTIVE

To identify differences in the vestibulo-ocular reflex (VOR) gain value and the peak saccade velocity in the suppression video head impulse test paradigms according to the age of the subject and the direction of the impulse.

STUDY DESIGN

Retrospective chart analysis.

SETTING

Tertiary referral hospital.

PATIENTS/INTERVENTIONS

Between October 2017 and May 2019, we enrolled subjects who had previous histories of dizziness but no dizziness over the last 1 month.

MAIN OUTCOME MEASURE

We conducted cervical vestibular-evoked myogenic potential and caloric tests, as well as video head impulse tests. We excluded the subjects who had abnormal cervical vestibular-evoked myogenic potential results (asymmetry ratio of greater than 30%) and abnormal caloric test results (caloric paresis of greater than 25%).

RESULTS

We included 647 subjects aged 10 to 87 years. The mean VOR gain and peak saccade velocity were maintained in subjects less than 70 years old (VOR gain, 0.991 ± 0.08, peak saccade velocity, 348.47 ± 142.32). However, the decreases in VOR gain and peak saccade velocity were significant in subjects over 70 years old (VOR gain, 0.928 ± 0.09, peak saccade velocity, 315.51 ± 0.09; p < 0.001). The mean VOR gain of the rightward impulse (1.00 ± 0.09) was higher than the leftward impulse (0.96 ± 0.08, p < 0.001).

CONCLUSIONS

Both the VOR gain and peak saccade velocity of suppression video head impulse test paradigms declined with increasing age over 70 years. In addition, the VOR gain of the rightward impulse was higher than the leftward impulse in the right-eye recordings.

Audiovestibular clinician experiences and opinions about cisplatin vestibulotoxicity

Purpose

Vestibulotoxicity associated with cisplatin chemotherapy is known to exist, but the extent, severity, and impact is unclear from the literature. This study explored knowledge, experiences, and opinions of audiovestibular professionals about cisplatin vestibulotoxicity.

Methods

An online survey was disseminated to clinicians working in the audiovestibular field.

Results

Ninety-three respondents participated in the survey. Most professionals were aware of potential vestibulotoxicity associated with cisplatin chemotherapy. Thirty-three percent of the respondents reported that they had seen patients with cisplatin vestibulotoxicity. Forty percent of them were confident in making the diagnosis and in managing the patient in this situation. The prevalence and impact of vestibulotoxicity including practicality of the assessment should be considered when designing an effective vestibulotoxicity screening protocol.

Conclusion

This study provides a better understanding of cisplatin vestibulotoxicity from the perspectives of audiovestibular clinicians, which will underpin appropriate detection and management of the condition.