Background: An effective treatment is needed for long-COVID patients which suffer from symptoms of vision and/or cognition impairment such as impaired attention, memory, language comprehension, or fatigue. Objective: Because COVID-19infection causes reduced blood flow which may cause neuronal inactivation, we explored if neuromodulation with non-invasive brain stimulation with microcurrent (NIBS), known to enhance blood flow and neuronal synchronization, can reduce these symptoms. Methods: Two female long-COVID patients were treated for 10–13 days with alternating current stimulation of the eyes and brain. While one patient (age 40) was infected with the SARS CoV-2 virus, the other (age 72) developed symptoms following AstraZeneca vaccination. Before and after therapy, cognition was assessed subjectively by interview and visual field using perimetry. One patient was also tested with a cognitive test battery and with a retinal dynamic vascular analyser (DVA), a surrogate marker of vascular dysregulation in the brain. Results: In both patients NIBS markedly improved cognition and partially reversed visual field loss within 3–4 days. Cognitive tests in one patient confirmed recovery of up to 40–60% in cognitive subfunctions with perimetry results showing stable and visual field recovery even during follow-up. DVA showed that NIBS reduced vascular dysregulation by normalizing vessel dynamics (dilation/constriction), with particularly noticeable changes in the peripheral veins and arteries. Conclusions: NIBS was effective in improving visual and cognitive deficits in two confirmed SARS-COV-2 patients. Because recovery of function was associated with restoration of vascular autoregulation, we propose that (i) hypometabolic, “silent” neurons are the likely biological cause of long-COVID associated visual and cognitive deficits, and (ii) reoxygenation of these “silent” neurons provides the basis of neurological recovery. Controlled trials are now needed to confirm these observations.
