Gaze stability training is a type of exercise utilised in vestibular therapy. Its main aim is to improve the functioning of the vestibular ocular reflex (VOR). It may be of benefit to those who experience the following symptoms:
- Blurred vision when moving, or when turning their head
- Dizziness with head movement
- Nausea associated with movement
- Poor coordination in activities that require movement of the head.
Let’s briefly consider the function of this reflex.
Vestibular Ocular Reflex
The VOR allows for gaze stability by stabilising vision during head movement. This works for both rotation and linear movements of the head. For vision to remain clear during these movements, the eyes must move in an equal and opposite direction simultaneously with the head. If the VOR is not functioning optimally, the eyes will move after the head movement, known as a ‘corrective saccade. If this eye reflex is correctly functioning, information regarding the movement of the head is sent to an area of the brain known as the vestibular nuclear complex. This information follows a pathway in the brain, resulting in a message sent to the muscles around the eyes, instructing them to move in the opposite direction to the head turn. The result is opposite movements of the eyes in the same plane as the head motion, and stable vision is maintained.
In an ideal VOR, the speed of the eye movement is the same as that of the head movement. . Gaze-stability training has the primary aim of improving the speed of the eye movements to correspond with head movement. This can translate into not only improved visual acuity, but also reduction of symptoms such as dizziness and nausea.
What does gaze-stability training involve?
Gaze stability training works primarily on the principle known as adaptation. Adaptation training aims to induce long-term changes in the neural response of the vestibular system to a specific stimulus. In the case of gaze-stability training, adaptation exercises aim to increase the speed and accuracy of the eye movements in relation to the head.
The exercises utilised as part of this training vary from person to person, and adaptation is context specific. However, they usually follow a structure that involves movement of the head in the appropriate plane, while focusing on a stationary target, or a target moving in the opposite direction to the head.
Substitution strategies can also be used to complement these exercises. Substitution strategies are developed by the therapist in collaboration with the client and are unique to their circumstances and abilities. They usually involve the client making pre-emptive movements in their gaze immediately prior to head movements, to compensate for the inadequately functioning eye reflex. In other words, the eye movements precede the head movements where the eye movements cannot keep up the head movements.
Customised Rehabilitation Plans:
Physiotherapy is a vital element of rehabilitation for those experiencing symptoms due to deficits in their VOR. Optimum Health Solutions’ physiotherapists work with our clients to tailor their rehabilitation plan to the individual, recognising their unique abilities, circumstances, and goals. This personalised approach improves the likelihood of a successful recovery and safe return to daily life activities.
If you need a physiotherapist, you can book an appointment here or by calling (02) 8599 6584.
REFERENCES:
Anson, E. R., Bigelow, R. T., Carey, J. P., Xue, Q.-L., Studenski, S., Schubert, M. C., & Agrawal, Y. (2016). VOR gain is related to compensatory saccades in healthy older adults. Frontiers in Aging Neuroscience, 08. https://doi.org/10.3389/fnagi.2016.00150
Clendaniel, R. A. (2010). The effects of habituation and gaze stability exercises in the treatment of unilateral vestibular hypofunction: A preliminary results. Journal of Neurologic Physical Therapy, 34(2), 111–116. https://doi.org/10.1097/npt.0b013e3181deca01
Herdman, S. J. (2013). Vestibular rehabilitation. Current Opinion in Neurology, 26(1), 96–101. https://doi.org/10.1097/wco.0b013e32835c5ec4
Tian, J., Crane, B. T., & Demer, J. L. (2000). Vestibular catch-up saccades in labyrinthine deficiency. Experimental Brain Research, 131(4), 448–457. https://doi.org/10.1007/s002219900320
