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. 2016 Jul 26;87(4):410–418. doi: 10.1212/WNL.0000000000002827

Figure 4. Cumulative saccade amplitude as a function of latency after head impulse onset.

Figure 4

(A) In healthy controls, HIMP elicits only a few saccades (upward histogram bars), while SHIMP elicits a multitude of saccades (downward histogram bars) with a peak latency of about 176 milliseconds (ms). (C) Patients with BVL show a reversed saccadic pattern with large saccades in HIMP but only a few saccades in SHIMP. Patients with UVL often produce covert HIMP saccades with head impulses to the affected side (B) and overt SHIMP saccades to the healthy side (D). Note that in the same patients with UVL, overt SHIMP saccades to the healthy side (D) have a longer peak latency (176 ms) compared to the covert HIMP saccades to the affected side (104 ms, B). Histogram bars represent summated amplitudes of HIMP saccades (positive) and SHIMP saccades (negative) in 8-ms bins after head impulse onset. Saccade amplitude was normalized relative to the number of head impulses and participants and kept in proportion between participant groups (A, n = 6 controls × 2 sides), patients with UVL (B, affected side; D, healthy side, n = 5), and patients with BVL (C, n = 5 × 2). BVL = bilateral vestibular loss; HIMP = conventional head impulse paradigm; SHIMP = suppression head impulse paradigm; UVL = unilateral vestibular loss.