Unilateral Vestibular Failure Research Articles

Subjective Assessment of Visual Verticality in follow-up of Patients with Acute Vestibular Disease

We conducted a study of 10 patients with acute unilateral peripheral vestibular failure in order to assess their ability to perceive visual verticality during the acute stage of their disease and during recovery. We also evaluated 31 healthy volunteers to test the reproducibility of our assessment methods. The 10 patients were first evaluated within 4 days of the onset of their vestibular failure, and follow-up tests were conducted 2 and 4 weeks later. The healthy subjects were similarly tested at 2 and 4 weeks following their baseline evaluation. All patients and subjects were tested 10 times during each evaluation session, and results from each as well as from the groups as a whole were calculated as a mean of all responses. The mean visual vertical tilt (the amount of deviation from true verticality) among the 10 patients declined from 8.4 degrees (+/- 2.4 degrees) at the first examination to 3.2 degrees (+/- 1.6 degrees) at week 2 and to 1.4 degrees (+/- 0.7 degree) at week 4. These decreases coincided with the pace of the resolution of their vestibular symptoms. The rates of reproducibility among the 31 healthy volunteers at 2 and 4 weeks following their initial assessment were 95 and 97%, respectively. We concluded that repeated measurements of the static visual vertical can be useful as a follow-up tool for patients with vestibular neuritis.

Autonomic Function Interferes in Cardiovascular Reflexes

Background. Experimental work indicates that the vestibular system participates in autonomic reflexes during body movement and postural changes. However, there are no studies of cardiovascular reflexes during vertigo due to human acute vestibular lesions. Methods. We assessed the response to active change of posture and hand immersion in cold water in seven patients with unilateral peripheral vestibular failure (vestibular neuritis) and seven age/sex-matched healthy subjects in acute phase (72 h from vertigo onset) and at 2 weeks of follow-up. Results. During acute phase, patients showed decreased blood pressure response during cold hand test ( p<0.05). Upright stance induced deficient decrease of the respiratory component of heart rate variability ( p<0.05) with lack of increase in low frequency/high frequency (LF/HF) ratio. At 2 weeks of follow-up, these abnormalities improved. Conclusions. Results suggest that acute vestibular lesions can interfere with cardiovascular autonomic responses in humans. This may reflect disruption of normal vestibulo-autonomic reflexes.

Exercise and Drug Therapy Alter Recovery from Labyrinth Lesion in Humans

Acute unilateral vestibular failure is characterized by rotatory vertigo, horizontal-rotatory nystagmus, and postural imbalance, all of which last from days to weeks. These signs and symptoms are caused by a vestibular tone imbalance between the two labyrinths. Recovery results from a combination of peripheral restoration of labyrinthine function (usually incomplete) and central vestibular compensation (CVC) of the vestibular tone imbalance. Acute unilateral failure is most often caused by vestibular neuritis, which is most likely due to the reactivation of a latent HSV-1 infection. Therefore, therapeutic strategies to improve the outcome of VN are theoretically based on two principles: (a) vestibular exercises and drugs to improve CVC and (b) drug treatment of the assumed viral inflammation. The following conclusions can be drawn from studies in animals and/or humans: (1) There is strong evidence that vestibular exercises may improve vestibulo-spinal compensation. These exercises should begin as early as possible after symptom onset. Moreover, slower exercises are likely to be more effective than faster exercises because slower ones seem to depend more on the vestibular system. (2) Despite extensive data from animal experiments indicating that drugs have a favorable effect on CVC, this has not been clinically proven and thus cannot be recommended yet. (3) Preliminary results of an interim analysis from an ongoing randomized, prospective study showed that methylprednisolone (plus an antiviral agent?) may be useful for improving peripheral vestibular function in vestibular neuritis.