The vestibular rehabilitation of vertiginous patients

By Cristiano Antonino On Sep 26, 2022

Vestibular rehabilitation: In 1940 an English otolaryngologist, Dr. Cawthorne, noticed that vertiginous patients who moved their heads early improved and healed much faster than those who restricted such movements; he therefore asked a physiotherapist, named Cooksey, to develop a series of exercises that would encourage patients to move their heads faster and faster

Since then, vestibular rehabilitation has developed with individual protocols and anecdotal references

Only in recent years has it been systematised with protocols based on anatomo-physiological studies and statistical review of the results.

To understand how this type of Rehabilitation works and what is behind the corrective mechanisms stimulated by the exercises, it is necessary to recall some notions of anatomo-physiology.

Vestibular rehabilitation uses adaptive, substitutive and habitual strategies, in isolation or in a complementary manner, to induce compensation when there has not been spontaneously

Adaptive strategies are the ones to be favoured as they are the only ones that, by acting on the gain of the deficient reflex, allow it to fully resume its functionality.

Some concepts related to vestibular adaptation are particularly important:

First – Adaptation is frequency-specific; experience has shown that adaptation exercises performed at a specific stimulus frequency improve gain only for that frequency used, with little change for the others. It is therefore essential, when planning rehabilitation, to include exercises with a broad frequency spectrum: adaptation of the VOR and VSR should be achieved first with exercises while sitting, then standing and then walking first slowly and then faster.

Secondly – Changes in VOR gain are initially volatile; although these changes occur within a few minutes, it takes a long time for them to become persistent. Consequently, several rehabilitation sessions must be scheduled with intermediate evaluations of the progress made and remote checks to reaffirm their irreversibility.

Third – Not all head movements lead to adaptation. Changes in VOR gain have been demonstrated for horizontal (NO) and vertical (YES) head movements but not for rotational movements that do not alter vestibular responses in the long term.

Replacement strategies cannot completely reintegrate a diminished or lost labyrinthine function because the receptors and vicarious reflexes, however enhanced, still act in a more limited frequency range than the VOR and VSR.

Rapid eye movements, or saccades, cannot be a valid alternative to VOR as they only capture the image at the end but not during eye movement.

Slow tracking or pursuit is also not an effective substitute as it operates at too modest a speed of around 20°-30°/sec.

A more valid, albeit insufficient, replacement can be obtained from the cervico-oculomotor reflex which, in the absence of the labyrinth function, increases its gain and covers a frequency spectrum above its physiological limit of 0.3 Hz and for this use is commonly referred to as the second labyrinth.

The VSR is initially replaced by visual reflexes which, however, are of little value since, in the absence of the stabilising effect of the labyrinth, they are triggered by a visual aim that is in itself unstable; over time, the replacement with proprioceptive reflexes with musculotendinous or muscular departure prevails, which, however, have a sufficient effect in the static aspects but little in the dynamic ones.

The habit then is practically a renunciation of true vestibular rehabilitation since it is aimed at eliminating the discomfort resulting from the functional lesion but not at improving the efficiency of the overall system.

There are numerous studies demonstrating the effectiveness of vestibular rehabilitation with greater success when using therapist-supervised protocols than when self-managed at home.

Instrumental and non-instrumental techniques are used in vestibular rehabilitation

The former are reserved for facilities equipped with therapist supervision, the latter can be used and self-managed directly at home by the patient.

The most correct protocol envisages an initial part of rehabilitation at qualified facilities where instrumental and non-instrumental exercises are performed under the supervision of the therapist and training in home exercises, and then, with protected discharge, moving on to self-management at home of the learned exercises and to regular checks to assess the persistence of the results obtained.

Candidates for vestibular rehabilitation are all those patients suffering from a chronic vertiginous state due to decompensation or absent or partial compensation of mono- or bilateral peripheral labyrinthopathies; good successes, even if more modest, are also had with stabilised outcomes of central pathologies such as Meningitis, vasculopathies and Parkinson’s disease.