A/Prof Americo Migliaccio responds to the Vestibular-Ocular Reflex

A/Prof Americo Migliaccio’s vestibular research – spanning basic science to clinical trials and biomedical engineering – is helping our understanding of the mechanisms and factors important for recovery of the vestibulo-ocular reflex (VOR) in patients with injuries to their inner ear vestibular (balance) organs.

The VOR is the main vision-stabilising mechanism during rapid head movement. When the VOR is not working normally, the impact on quality-of-life can be devastating: vision for those with a missing VOR is like looking through a camera view-screen with the anti-jitter mode turned off. At present, vestibular rehabilitation can improve quality-of-life through behavioural changes and exercises for these patients, however none of these techniques result in improvement of the VOR response.

Americo and his team have been working towards better understanding of the nerve pathways important for recovery of VOR function, developing training techniques to improve a patient’s VOR. This work has included the development of a take-home device ‘StableEyes‘, currently undergoing clinical trials at the Balance and Vision Laboratory at Neuroscience Research Australia (NeuRA).

Key findings from Americo’s research include:

• Current vestibular prostheses only stimulate the semi-circular canals to restore the angular VOR; however, Americo’s basic science studies have shown that otolith stimulation is also crucial for recovery and should be included in the next generation of prostheses.
• Nearing completion of a 2 year, double-blinded, placebo-controlled, clinical trial using StableEyes. The 6 month intervention phase (using StableEyes) resulted in a 52% increase in VOR response (gain) and 43% earlier onset of compensatory saccades (fast eye movements that help compensate for a poor VOR).
• Development of a video-oculography / StableEyes hybrid device, which allows real-time measures of VOR function to dynamically modify the training task, resulted in VOR response increases after 15 mins training of ~15% (compared to ~10% using the old technique).

Americo’s plans for the future include determining whether stimulating the nerve pathways important for VOR modification could lead to improved VOR recovery; determining more of the factors important for VOR training; and further developing the hybrid device so as to provide easy clinical diagnosis and rehabilitation of vestibular and other eye movement disorders.

Of his research, Americo says “We hope to improve the lives of the 300,000 or so Australians affected by vestibular loss due to organ injury or ageing by addressing each aspect of VOR rehabilitation: from improving the vestibular nerve signals to developing rehabilitation training techniques and devices to help increase VOR function.”

Americo’s work has been completed during his Senior/Principal Research Fellowship (now known as the Senior Fellowship) with the Foundation.