The video head impulse (now called the head impulse paradigm – HIMP) is now a routine test battery in neuro-otological practice. Few will be familiar with the new suppression head impulse paradigm (SHIMP) test. The key difference is that, in HIMP, catch up saccades are abnormal but the opposite is the case in SHIMP i.e. saccades are normal. In SHIMP, the visual laser target moves with head movement. A head impulse moves the eyes in the opposite direction and a SHIMP saccade is required to refocus on the target. This is normal VOR. Because SHIMP is a new test, the authors designed this study in a group of healthy adolescents to a) compare SHIMP and HIMP feasibility, VOR gain value and the saccadic pattern and b) to compare the feasibility of the SHIMP and HIMP testing using a commercially available system in the hands of an experienced and an inexperienced HIMP examiner. Thirty-three 13-16-year-olds were recruited but four excluded due to incomplete data. The study showed that SHIMP was feasible in the children and adolescents. The inexperienced performed as well as the experienced examiner. Statistically, there were no differences in gain in HIMP and SHIMP between the examiners although the confidence interval was larger for the inexperienced. The mean gain in both test paradigms was significantly lower on the left than the right but that applied to both examiners. The left-right difference could be physiological. Limitations of SHIMP were discussed. This is a promising test but with any new development, more work is needed on software algorithms to sharpen its clinical utility. 

Suppression head impulse paradigm in healthy adolescents – A novel variant of the head impulse test.
Devantier L, Hoskison E, Ovesen T, Mølby Henriksen J-J.
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Victor Osei-Lah

Bournemouth, UK.

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