Video Head Heave Test: A Practical Tool for Utricular Testing

Background/Objectives: The Head Heave Test (HHT) was proposed approximately 25 years ago for the study of the linear translational vestibulo-ocular reflex (TVOR) of utricular origin. The exam consists of delivering a series of sudden, unpredictable movements along the interaural axis of the patient's head, with the patient asked to focus on the examiner's nose in front of them. It is considered abnormal if a clear corrective saccade is observed, visible only on one side, or significantly greater on one side compared to the other. The use of HHT has not become widespread due to the difficulties in assessing corrective saccades with the naked eye. The aim of this study is to propose a simple-to-use instrumental method that clearly documents corrective saccades following translational head impulses. To exclude the possibility that compensatory saccades could be due to simultaneous stimulation of the ipsilateral Lateral Semicircular Canal (LSC), we also recorded Video Head Impulse Test (VHIT). Methods: For this purpose, 110 consecutive outpatients evaluated for balance disorders underwent HHT, which was recorded using a VHIT device. The Video Head Heave Test (VHHT), performed in this manner, enabled the easy identification of compensatory saccades. Results: The patients were divided in three groups: A) without compensatory saccades (50,9%), B) with TVOR compensatory saccades on both sides (23,6%), C) with a prevalence of saccades on one side (25,5%). We found that VHHT compensatory saccades were present in patients without LSC deficit on VHIT, and conversely, we found patients with marked LSC impairment on VHIT without compensatory saccades at VHHT. Conclusions: The detected TVOR compensatory saccades are independent of any concomitant dysfunction of the ipsilateral LSC. We propose a simple method for evaluating utricular function that does not require dedicated equipment and instead uses the VHIT instruments commonly used in vestibular diagnostics.