The impact of COVID-19 on eye movements in persons with Severe Speech and Physical Impairment

Whilst there have been significant follow up studies on the effects of COVID-19, the impact of the disease on the neurological functioning in persons with Severe Speech and Physical Impairment (SSPI) has seen limited reporting. Quantitative assessment of video-based eye tracking is a simple, non-invasive means to map cognitive functions to specific brain circuits. Eyegaze is a robust alternative response modality for cognitive-linguistic assessment by persons with SSPI which traditionally rely on verbal responses or that require physical responses such as pointing.

A cued attention prosaccade task, using a VT3 Mini Eye Tracker and analysed using MangoldVision software, was carried out with an SSPI group and a neurotypical (NT) control group. Participants were grouped according to historical SARS-CoV-2 infection. We hypothesized that individuals who previously had COVID-19 would perform significantly worse than those who had not.

The mean time to first fixation (TTF) to the location of an abrupt onset peripheral target was significantly faster in the NT group than the SSPI group (p<0.05), as could be expected when comparing a neurotypical group to persons with neurological disorders. Unexpectedly, however, we found that the TTF was faster in both the NT Group (P<0.001) and SSPI Group (P<0.01) in persons who previously had COVID-19.

Using eye tracking it appears that COVID-19 (a) influences brain circuits that drive eye movements in reaction to visual stimuli, supporting reports that SARS-CoV-2 can disrupt neurotransmitter balance and amplify signals between neurons; and (b) does not differentiate between a pre-existing neurological movement impairment or lack thereof.