Vestibulo-Ocular Compensation following Unilateral Vestibular Deafferentation

Abstract

Vestibulo-ocular compensation following vestibular deafferentation was investigated in 26 acoustic neuroma patients following tumor removal and in 5 Menière's disease patients following vestibular nerve section by using sinusoidal harmonic acceleration testing. All three test parameters (phase lead, gain, and asymmetry), when averaged, shifted significantly on the first postoperative test (average 0.4 months after operation). A marked progression in central compensation with gain returning to the range of normal control values was seen in the tests performed 1 to 6 months (average 2.6 months) postoperatively. However, phase lead and asymmetry (especially at 0.01, 0.02, 0.04, and 0.08 Hz) remained outside the range of normal control values, and all three parameters failed to return to their preoperative level even when tested at more than 12 months (average 20.2 months) after operation. This finding indicates that the deficits of the vestibulo-ocular reflex to head acceleration are of long duration if not permanent.

Improvement After Vestibular Rehabilitation Not Explained by Improved Passive VOR Gain

“…Given the high range of velocity and frequency of head motion encountered during such typical life, healthy vestibular function is essential to ensure gaze stability (3). When lesioned, the vestibulo-ocular reflex (VOR) is unable to stabilize the eyes during head motion and visual acuity degrades (4)(5)(6).…”

Translabyrinthine surgery for disabling vertigo in vestibular schwannoma patients

“…In vestibular schwannoma literature, most studies focus on vestibular symptoms in general and not specifically on the concommitant vertigo 3,5,6 . Several authors have reported on the quality of life after microsurgery 7–11 or at the degree of vestibular compensation after surgery 12,13 . Vertigo, however, has not been quantified before in vestibular schwannoma patients and using validated quality of life measures.…”

“…3,5,6 Several authors have reported on the quality of life after microsurgery [7][8][9][10][11] or at the degree of vestibular compensation after surgery. 12,13 Vertigo, however, has not been quantified before in vestibular schwannoma patients and using validated quality of life measures. Furthermore, there are few studies in which vertigo has been discussed as an indication for (surgical) treatment in vestibular schwannoma.…”

Association of the Video Head Impulse Test With Improvement of Dynamic Balance and Fall Risk in Patients With Dizziness

“…In patients with surgical vestibular deafferentation, VOR gain and asymmetry during lower-velocity rotary chair testing usually improve over time. 26,27 Whether the highfrequency VOR can be similarly improved is a matter for debate. 21,22 However, more recent studies using a specific VOR adaptation protocol (incremental velocity error signal) 28 have shown that the high-frequency VOR gain (measured using head impulses) can improve after training.…”