Recharging After Long COVID

The variable presentation of long COVID symptoms might just be the biggest mystery of the pandemic. Initial infection with SARS-CoV-2 is already a mixed bag of symptoms – especially with variants changing the picture – but long COVID also appears to result in a scattered array of cognitive issues, likely caused by infiltration of the central nervous system (CNS). Along with changes in attention, tiredness, memory, and basic comprehension of language, a manifestation of particular note for ophthalmologists is vision impairment.

Symptoms can last for weeks or months, with no treatment currently available. But recent research has uncovered that alternating non-invasive brain stimulation (NIBS) significantly improved the vision and cognition of two patients in just three days (1). The effective “recharging” of the vasculature and neurons affected by long COVID partially reversed visual field loss and increased cognition – and the two patients were even able to return to work.

The probable cause of both visual and cognitive long COVID symptoms is through vascular dysfunction – the retina being an obvious source of damage from disruption at the blood-retinal barrier. NIBS was considered as a potential treatment for visual impairment because of a previous study in glaucoma patients, in which most participants gained vision improvement after the treatment (2). 

The authors believe the neurological deficits in cognition and sight that arise from long COVID are due to hypometabolism in neurons – which are rejuvenated by the NIBS treatment. Perhaps just as importantly, this strong indication of a vascular and neuronal pathology to long COVID could be further investigated to develop other effective treatments. Of course, the positive findings need to be assessed in much larger cohorts and, ultimately, a clinical trial setting before more concrete conclusions can be made about NIBS effectiveness. Nevertheless, given the serious dearth of long COVID treatments available, NIBS at least represents an interesting and non-invasive potential option.