Gaze and attention: mechanisms underlying the therapeutic effect of optokinetic stimulation in spatial neglect by Chan, Mitchell, Sandilands and Balslev, Neuropsychologia, 2024 (in press)

I am delighted to announce that our paper has just been accepted for publication. The contributions from Hilary Chan and Eilidh Sandilands, who were undergraduate students at the University of St Andrews when they completed this research, deserve a special recognition.

In brief, we investigated how left optokinetic stimulation, which is a rehabilitation method in spatial neglect works. Spatial neglect is a common and disabling neuropsychological condition after a right hemisphere lesion characterised by inattention to people and objects in the contralesional space. Optokinetic stimulation is the exposure to large field visual motion, for instance when watching dots that move in the same direction on a computer screen in the lab (or in real life, when looking out of the window from a moving train). Optokinetic stimulation induces a type of eye movements called optokinetic nystagmus.

We found that in healthy participants optokinetic stimulation altered the proprioceptive (stretch) input from the extraocular muscles. The misperception of own gaze direction was associated with a bias in spatial attention. Both changes outlasted the period of optokinetic stimulation.

We are therefore proposing that the change in the eye position signals underlies the therapeutic effect of optokinetic stimulation. If so, then the effect of left optokinetic stimulation in spatial neglect could be improved by combining it with other interventions that affect eye proprioception, such as repetitive transcranial magnetic stimulation over the somatosensory cortex.

I have uploaded our accepted-for-publication manuscript here.