Normal findings
What a normal head impulse, no pathological nystagmus, and absent skew look like — both at the bedside and on quantitative recording.
Normal head impulse
In a healthy subject the VOR generates an equal-and-opposite eye movement for any head rotation, so the eyes remain locked on the target throughout the impulse. There is no overt or covert corrective saccade. On video head impulse testing (vHIT) the VOR gain — peak eye velocity divided by peak head velocity — is approximately 0.9–1.0 for the horizontal canal.
Normal nystagmus pattern
In primary gaze and during fixation there should be no spontaneous nystagmus. With fixation removed, a small amount of physiologic spontaneous nystagmus may be visible. End-point or end-gaze nystagmus — small, exhaustible, symmetric beats in extreme lateral gaze — is a normal variant and should not be confused with pathological gaze-evoked nystagmus.
Absent skew
On alternate cover testing the uncovered eye should not make a vertical refixation movement. Some patients have a small phoria; this is not the same as a vertical skew deviation and is generally well-compensated.
Quantitative norms — vHIT
Published normative ranges for the horizontal canal VOR gain (peak eye velocity ÷ peak head velocity) cluster around 0.9–1.0, with most laboratories using a lower limit of normal around 0.8. Vertical canal gains tend to run slightly lower (~0.7–0.9). Specific cut-offs depend on device and recording protocol; consult the manufacturer's norms8.