bradyphrenia

noun

bra·​dy·​phre·​nia -ˈfrē-nē-ə 

: slowness of mental processes : slowed cognitive functioning

Finally, her recent imbalance, bradyphrenia, inattention, confusion, depression, and hyperreflexia suggest a … diffuse pattern of dysfunction, which would suggest participation of nearly every component of the CNS.

—Misha L. Pless et al., The New England Journal of Medicine