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

Starkov, Dmitrii; Vermorken, Bernd; Dooren, T S van; Stiphout, Lisa van; Janssen, Miranda; Pleshkov, Maksim; Guinand, Nils; Fornos, Angelica Pérez; Rompaey, Vincent Van; Kingma, Herman; Berg, Raymond van de

doi:10.3389/fneur.2021.729081

Cited by 8 publications

(11 citation statements)

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“…This demonstrates the need for a standardized approach for evaluating and interpreting head impulse testing outcomes. This should include a universal gain calculation algorithm combined with an assessment of the raw traces [5,8]. Regarding cut-off values, two cut-off values were used for SHIMP in this study (VOR gain <0.6 and <0.5).…”

Section: Himp Versus Shimp: Agreement On the Diagnosis Of Bvmentioning

confidence: 99%

“…Moreover, saccades in SHIMP testing will mainly occur after the head impulse (overt saccades) and not during the head impulse (covert saccades) [2]. However, studies show that predictability during SHIMP could still result in shorter latency of saccades and even covert saccades [8]. Hence, when properly performed, SHIMP testing could enable elimination over covert saccades and might facilitate a more precise VOR gain calculation than in HIMP.…”

Section: Introductionmentioning

confidence: 99%

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

Dooren

Starkov

Lucieer

et al. 2022

JCM

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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.

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Section: Himp Versus Shimp: Agreement On the Diagnosis Of Bvmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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

Dooren

Starkov

Lucieer

et al. 2022

JCM

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“…It emerged that unlike the HIMP, children were able to follow a moving target better than a fixed target that has also been observed in adults ( 13 ). Predictability of the impulses has been previously investigated and proposed to contaminate saccades and VOR gain in SHIMP ( 22 , 23 ). Great care needs to be exercised to eliminate predictability in children that can be mitigated to a certain extent by distractibility between the impulses by an experienced clinician as in this study.…”

Section: Discussionmentioning

confidence: 99%

Suppression head impulse test in children—experiences in a tertiary paediatric vestibular centre

Dasgupta,

Crunkhorn,

Wong

et al. 2024

Front. Neurol.

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The suppression head impulse paradigm (SHIMP) involves suppression of the vestibulo-ocular reflex (VOR) and anticompensatory saccades generated thereof. SHIMP is gaining importance to understand vestibular compensation with its different parameters (VOR gain/peak saccadic velocity PSV/latency of saccades). SHIMP studies are emerging in adults, but pediatric studies have hardly been performed. This study is a retrospective case note audit over a period of 2 months in a tertiary pediatric vestibular center in the United Kingdom to investigate whether SHIMP is safe/robust to be used in children conforming to existing standards/norms in normal children and whether it yields any meaningful inferences in pediatric vestibular hypofunction. This is the largest pediatric SHIMP study to date. A total of 44 referred children (6–18 years, female children>male children) with a range of complaints from dizziness, imbalance, motor incoordination, postural instability, and hearing loss were included, and their SHIMP parameters were measured. All children underwent comprehensive functional/objective audiovestibular assessments. Two groups were defined—Group A with normal vestibular function and Group B with abnormal vestibular function. The normal population showed an average SHIMP VOR gain of 0.98+/−0.08 and latency of overt saccades at 215.68+/–46.16 milliseconds agreeing with published evidence. The PSV of overt saccades was 315.39+/−56.30/s, and there was a gain asymmetry of 7.42+/−4.68 between the sides. Statistically significant differences with moderate/large effect sizes were observed between the groups in terms of VOR gain and PSV but not in saccade latencies. Covert saccades were rare in SHIMP, while overt saccades were observed in 100% of children. VOR gain difference between the head impulse paradigm (HIMP) and the SHIMP was significant as well. We observed statistically significant differences in side asymmetry of VOR gain between the groups. Furthermore, we identified a group of children with cerebellar lesions where overt saccades in SHIMP were rather low in number. Further research is recommended to investigate pediatric PSV, asymmetry, and inability to generate overt saccades that may suggest useful means to assess compensation and central function. We conclude that SHIMP yields valuable information and is a safe, easy to perform, and a reliable test that should be used in children to supplement HIMP.

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“…Note that in this study, which used manual head impulses and therefore with more stimulus variation compared with motorized head impulses, a different testing paradigm had been used (inward versus outward head impulses). A recent study used the SHIMP (suppression head impulse paradigm) paradigm on healthy subjects, in which the subject fixates upon a target that is rotating with the head, and must make corrective saccades to bring the eyes back to the target after being taken away by the intact VOR (35). Using the SHIMP paradigm with predictable and unpredictable cues, there were higher VOR gains for inward, toward the center, head impulses (35).…”

Section: The Influence Of Prediction On the Gain Of The Vormentioning

confidence: 99%

Corrective saccades in acute vestibular neuritis: studying the role of prediction with automated passively induced head impulses

Kerkeni

Zee

Korda

et al. 2023

Journal of Neurophysiology

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When the demands for visual stabilization during head rotations overwhelm the ability of the vestibulo-ocular reflex (VOR) to produce compensatory eye movements, the brain produces corrective saccades that bring gaze towards the fixation target, even without visual cues (covert saccades). What triggers covert saccades and what might be the role of prediction in their generation are unknown. We studied 14 subjects with acute vestibular neuritis. To minimize variability of the stimulus, head impulses were imposed using a motorized torque generator with the subject on a bite-bar. Predictable and unpredictable (timing, amplitude, direction) stimuli were compared. Distributions of covert corrective saccade latencies were analyzed with a 'LATER' (linear approach to threshold with ergodic rate) approach. On the affected side, VOR gain was higher (0.47±0.28 vs. 0.39±0.22, p<<0.001) with predictable than unpredictable head impulses, and gaze error at the end of the head movement was less (5.4±3.3 vs 6.9±3.3 deg p<<0.001). Analyzing trials with covert saccades, gaze error at saccade end was significantly less with predictable than unpredictable head impulses (4.2 ±2.8 vs 5.5 ±3.2 deg, p<<0.001). Furthermore, covert corrective saccades occurred earlier with predictable than unpredictable head impulses (140±37 vs. 153±37 ms p<<0.001). Using a LATER analysis with reciprobit plots, we were able to divide covert corrective saccades into two classes - early and late - with a break point in the range of 88-98ms. We hypothesized two rise-to-threshold decision mechanisms for triggering early and late covert corrective saccades, with the first being most engaged when stimuli are predictable.

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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

Cited by 8 publications

References 51 publications

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

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

Suppression head impulse test in children—experiences in a tertiary paediatric vestibular centre

Corrective saccades in acute vestibular neuritis: studying the role of prediction with automated passively induced head impulses

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