Head-only rotational testing in the elderly.

Head-only rotational testing (HORT) is a noninvasive technique to assess the vestibuloocular reflex (VOR) that can be performed in a nonlaboratory environment with inexpensive, portable equipment. Little data are available regarding the applicability of this technique to the elderly in whom limitations of cervical range of motion might reduce the usefulness of the technique. This study was designed to apply HORT to a small group of normal elderly subjects to determine whether the technique could be used successfully in this population. Also, the VOR parameters derived from HORT were compared with the results obtained from a group of healthy young control subjects. HORT was performed both with and without visual fixation of an earth-fixed target, using both active head movement and passive head movement. Results indicated that the responses of the elderly were indistinguishable from those of the young except for a slightly higher gain at 1 Hz in the young subjects. Other findings, consistent across young and elderly, were that visual fixation increased gain and decreased phase lead at lower frequencies and that VOR parameters were unaffected by volition, that is, active and passive head rotation produced similar responses. These findings suggest that HORT can be applied to the elderly without difficulty. Future studies will assess the usefulness of HORT in elderly patients with VOR disorders.