COMT and Stroke: The logic behind this interpretation of the COMT polymorphism seems sound when you consider that the A allele of the COMT gene (Met variant) was associated with improved baseline performance, and worse drug-influenced performance on pre-frontal cortex based tasks, however, in stroke patients not given drugs, better motor performance was seen in patients with the COMT Val/Val or Val/Met genotypes (Mattay et al., 2003; Liepert et al., 2013; Kim et al., 2016).