In this article the authors performed an extensive neurophysiological and neuropsychological assessment of such patients focusing on motor cortex physiology and executive cognitive functions. 67 patients were enrolled complaining of fatigue and/or cognitive difficulties after resolution of mild SARS-CoV-2 infection and 22 healthy controls (HC). Persistent clinical symptoms were investigated by means of a 16-item questionnaire. Fatigue, exertion, cognitive difficulties, mood and “well-being” were evaluated through self-administered tools. Utilizing transcranial magnetic stimulation of the primary motor cortex (M1) the authors evaluated resting motor threshold (RMT), motor evoked potential (MEP) amplitude, cortical silent period (SP) duration, short-interval intracortical inhibition (SICI), intracortical facilitation (ICF), long-interval intracortical inhibition (LICI), and short-latency afferent inhibition (SAI). Global cognition and executive functions were assessed with screening tests. Attention was measured with computerized tasks. Post COVID-19 patients reported a mean of 4.9 persistent symptoms, high levels of fatigue, exertion, cognitive difficulties, low levels of well-being and depressive symptoms. Compared to HC, patients presented higher RMTs, lower MEP amplitudes and longer SPs, concurring with reduced M1 excitability. LICI and SAI were also impaired, indicating altered GABAB- and cholinergic neurotransmission. SICI and ICF were not affected. Patients also showed poorer global cognition and executive functions as compared to HC and a clear impairment in sustained and executive attention. The authors concluded that patients with fatigue and cognitive difficulties following mild COVID-19 present altered excitability and neurotransmission within M1 and deficits in executive functions and attention.
Ortelli P, Ferrazzoli D, Sebastianelli L, Maestri R, Dezi S, Spampinato D, Saltuari L, Alibardi A, Engl M, Kofler M, Quartarone A, Koch G, Oliviero A, Versace V. Altered motor cortex physiology and dysexecutive syndrome in patients with fatigue and cognitive difficulties after mild COVID-19. Eur J Neurol. 2022 Feb 9.
doi: 10.1111/ene.15278.