Head Thrust
- Head thrust test is also referred to as the 'Head Impulse Test.'
- This test examines the vestibulo-ocular reflex (VOR).
- Sensitivity and specificity for diagnosing unilateral vestibular hypofunction (UVH) in patients following vestibular ablation is 100%. Sensitivity for patient is non-surgically induced UVH is 35-39%.
- The patient is asked to focus his or her eyes on a fixed target (i.e. the nose of the therapist).
- The head of the patient should be positioned into 30 degrees of cervical neck flexion to isolate the lateral semicircular canals.
- The therapist is positioned in front of the patient.
- The head of the patient is then grasped on both sides by the therapist.
- The therapist then manually induces a small amplitude (5-10 degrees) and high acceleration rotational thrust.
- The thrusts can be applied multiple times in alternating directions to evaluate both sides. Each thrust is a separate test that should be evaluated.
- The thrust should be applied at random intervals, so that the patient can not anticipate when the thrust will occur.
- Immediately after the thrust is completed, the head position is maintained by the therapist and the eyes are observed for a corrective saccade. A saccade is a rapid eye motion that returns the eyes toward their original target (nose of therapist).
- Observation of a saccade is indicative of a positive test.
- Patients with vestibular hypofunction may use a corrective saccade after the head is thrust toward the affected side.
- A saccade will not be noted in individuals with normal vestibular function.
(Schubert, 2004)