Differences in video head impulse test gains from right versus left or outward versus inward head impulses

Park, Jun Woo; Kim, Tae Su; Hye, Eun; Kang, Byung Chul; Park, Hong Ju

doi:10.1002/lary.27607

Cited by 11 publications

(11 citation statements)

References 23 publications

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“…The more predictable inward passive head movements demonstrated lower VOR gains than did the less predictable outward passive head impulses. This is congruent with the hypothesis and with previous literature ( 7 , 9 ). Possible contributing factors are decreased alertness, less contraction of cervical muscles, and better VOR suppression due to the predictability during inward head impulses, leading to lower VOR gains ( 5 – 7 , 9 , 27 – 30 ).…”

Section: Discussionsupporting

confidence: 94%

“…VOR gain was found to be decreased in inward, more predictable head movements in HIMP. This could involve impulses to both directions, or only to the contralesional side in patients with unilateral vestibulopathy ( 7 , 9 , 10 ). However, another study did not find any difference between passive inward and outward head impulses in healthy subjects ( 11 ).…”

Section: Introductionmentioning

confidence: 99%

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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

et al. 2021

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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.

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Section: Discussionsupporting

confidence: 94%

Section: Introductionmentioning

confidence: 99%

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

et al. 2021

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“…Note that there are differences in gaze gains from the left and right side [main effect side : F (1,17) = 43.4, p < 0.001, and partial η 2 = 0.72], which are known from vHIT testing ( Park et al, 2019 ) and attributed to the asymmetric camera position in the EyeSeeCam system. Although there was a significant interaction of gaze shift side with group in the rmANOVA [ side ∗ group interaction: F (1,17) = 9.96, p = 0.006, and partial η 2 = 0.37], in post hoc testing, those group differences did not reach statistical significance for neither the left ( p = 0.055) nor the right side ( p = 0.44).…”

Section: Methodsmentioning

confidence: 99%

Unstable Gaze in Functional Dizziness: A Contribution to Understanding the Pathophysiology of Functional Disorders

et al. 2021

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Objective: We are still lacking a pathophysiological mechanism for functional disorders explaining the emergence and manifestation of characteristic, severely impairing bodily symptoms like chest pain or dizziness. A recent hypothesis based on the predictive coding theory of brain function suggests that in functional disorders, internal expectations do not match the actual sensory body states, leading to perceptual dysregulation and symptom perception. To test this hypothesis, we investigated the account of internal expectations and sensory input on gaze stabilization, a physiologically relevant parameter of gaze shifts, in functional dizziness.Methods: We assessed gaze stabilization in eight functional dizziness patients and 11 healthy controls during two distinct epochs of large gaze shifts: during a counter-rotation epoch (CR epoch), where the brain can use internal models, motor planning, and resulting internal expectations to achieve internally driven gaze stabilization; and during an oscillation epoch (OSC epoch), where, due to terminated motor planning, no movement expectations are present, and gaze is stabilized by sensory input alone.Results: Gaze stabilization differed between functional patients and healthy controls only when internal movement expectations were involved [F(1,17) = 14.63, p = 0.001, and partial η2 = 0.463]: functional dizziness patients showed reduced gaze stabilization during the CR (p = 0.036) but not OSC epoch (p = 0.26).Conclusion: While sensory-driven gaze stabilization is intact, there are marked, well-measurable deficits in internally-driven gaze stabilization in functional dizziness pointing at internal expectations that do not match actual body states. This experimental evidence supports the perceptual dysregulation hypothesis of functional disorders and is an important step toward understanding the underlying pathophysiology.

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“…41 Gain asymmetry is usually calculated as the absolute or relative 19,43 difference, and normalization is not required, unlike for the caloric test. Gains for left LC are higher than those for right LC, by approximately 0.09, when recording using a monocular right eye vHIT system, 44 that is, gain from the adducting eye (during left SCC impulse) is higher than the gain from the abducting eye (during right SCC impulse). This difference is thought to be because of firing characteristic of the abducens interneurons and higher active force of the medial rectus, 45 but the ascending tract of Deiters (ATD), which transmits excitatory signals to the ipsilateral medial rectus through a disynaptic pathway, 46 is like to be equally important.…”

Section: Performing Vhitmentioning

confidence: 89%

Video Head Impulse Testing: From Bench to Bedside

Chen

Hálmagyi

2020

Semin Neurol

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Over 30 years ago, the head impulse test (HIT) was measured with search coil recordings and it provided robust evidence for a new test of vestibular function that could detect impairment of a single semicircular canal, that is, the lateral canal. Over the next two decades, the diagnostic spectrum of HIT was expanded to the testing of vertical canals, differentiation of central from peripheral vestibulopathy, and incorporation of visual interaction—the suppressed head impulse. However, HIT measurement was limited to very few specialized laboratories that were able to maintain the time-consuming and expensive operation of the scleral search coil system, which is the gold standard in eye movement recording. The video HIT (vHIT) was validated for the first time over 10 years ago, against the search coils, and its introduction into dizzy clinics worldwide has revolutionized the practice of neuro-otology. Here we review the basic physiology, practical aspects, and clinical application of the vHIT.

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Differences in video head impulse test gains from right versus left or outward versus inward head impulses

Cited by 11 publications

References 23 publications

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

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

Unstable Gaze in Functional Dizziness: A Contribution to Understanding the Pathophysiology of Functional Disorders

Video Head Impulse Testing: From Bench to Bedside

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