Screening for brain fog: Is the montreal cognitive assessment an effective screening tool for neurocognitive complaints post-COVID-19?

BACKGROUND: Cognitive complaints are one of the most frequent symptoms reported in post-acute sequelae of COVID-19 (PASC). The Montreal Cognitive Assessment (MoCA) has been used to estimate prevalence of cognitive impairment in many studies of PASC, and is commonly employed as a screening test in this population, however, its validity has not been established. OBJECTIVE: To determine the utility of the MoCA to screen for cognitive impairment in PASC. METHODS: Sixty participants underwent neuropsychological, psychiatric, and medical assessments, as well as the Montreal Cognitive Assessment, 6–8 months after acute COVID-19 infection. RESULTS: The overall sample had a mean score of 26.1 on the MoCA, with approximately one third screening below the cutoff score of 26, similar to the rate of extremely low NP test performance. MoCA score was inversely correlated with fatigue and depression measures and ethnic minority participants scored on average lower, despite similar education and estimated premorbid function. The MoCA had an accuracy of 63.3% at detecting any degree of diminished NP performance, and an accuracy of 73.3% at detecting extremely low NP performance. DISCUSSION/CONCLUSION: The MoCA may not be accurate for detecting neither mild nor more severe degrees of diminished NP test performance in PASC. Therefore, patients with persistent cognitive complaints in the setting of PASC who score in the normal range on the MoCA should be referred for formal NP assessment.