Vestibuloocular Reflex (VOR) Test and Dynamic Illegible ‘E’ Test

Timothy C. Hain, MD

Last updated 6/2002
The vestibuloocular reflex (VOR) test is most helpful for diagnosing ototoxicity and other bilateral vestibulopathies.

The dynamic illegible ‘E’ (DIE) test is a very helpful procedure (Longridge, 1987). The physician has a patient view an eye chart with the head still and records visual acuity. Then the physician moves the patient’s head slowly (about 2 Hz), 30 degrees to either side, and again records visual acuity. Normal patients have no loss in visual acuity with this procedure. Patients with bilateral loss, especially acutely, often lose six to eight lines of visual acuity.

As patients recover from bilateral loss, they perform better on this test. This is probably related to a combination of adaptive changes in the vestibuloocular reflex, as well as predictive preprogramming of eye movements (Herdman et al, 2001).


  • Herdman SJ et al. Role of central preprogramming in dynamic visual acuity with vestibular loss. Arch Oto HNS 2001:127:1205-1210
  • Longridge NS, Mallinson AI. The dynamic illegible E (DIE) test: a simple technique for assessing the ability of the vestibulo-ocular reflex to overcome vestibular pathology. J Otolaryngol 1987;16:97-103, Acta Otol (Stockh) 103: 273-279, 1987; Otolarygol HNS 1984:92:671-7