HiNTs examination

The HiNTs examination is a clinical test to differentiate between central and peripheral causes, in patients with vertigo. In some studies it has shown a greater sensitivity than MRI to exclude posterior circulation stroke in these patients.(4)

The HiNTs exam comprises three elements, head impulse, nystagmus, and test-of-skew. It is only valid in patients who have continuous, ongoing vertigo at the time of assessment.

Head impulse

The patient stands in front of the examiner, with their head held between the examiner’s hands. The patient is asked to fixate on the tip of the examiner’s nose, and their head is rotated 20 to 40 degrees in each direction, before being rapidly brought back to neutral.

The normal response, which is preserved in posterior stroke, is to maintain a continuous direction of gaze. In peripheral causes of vertigo, the vestibulo-ocular reflex is disrupted, so they lose eye contact and correct with a saccade.

Nystagmus

The patient is asked to look straight ahead, to the left, and to the right, while the direction of nystagmus is observed.

Nystagmus due to a peripheral cause is always horizontal, and will always have the fast phase in the same direction, and is often accentuated when the patient looks in the direction of the fast phase. Any vertical or rotational element, or if the direction changes with direction of gaze, is suggestive of a central cause of vertigo.

Test-of-skew

The patient stands in front of the examiner and is asked to fixate on the tip of their nose. The eyes are alternately covered.

In a central cause of vertigo, the vertical alignment of the eyes may be different, and a vertical corrective movement will be seen as the eye is covered and uncovered. In peripheral causes, this finding is absent.

A video demonstration of the examination can be viewed here. (6)