Temporal Cognitive and Brain Changes in Korsakoff Syndrome.

Abstract

To investigate cognitive and brain changes in patients with Korsakoff syndrome (KS) over months and up to 10 years after the diagnosis. Two groups of 8 patients with KS underwent neuropsychological, motor, and neuroimaging investigations, including structural MRI and ¹⁸F-fluorodeoxyglucose-PET. The KS^C group, recruited at Caen University Hospital, was examined early after the KS diagnosis (KS^C-T1) and 1 year later (KS^C-T2). The KS^R group, recruited at nursing home at Roubaix, was evaluated 10 years after the diagnosis. Longitudinal comparisons in KS^C explored short-term changes, while cross-sectional comparisons between KS^C-T1 and KS^R informed about long-term changes. No cognitive, motor, or brain deterioration occurred over time in patients with KS. There was no clear improvement either, with only modest recovery in the frontocerebellar circuit. Compared to the norms, KS^C-T1 had severe episodic memory impairments, ataxia, and some executive dysfunctions. They also presented widespread atrophy and hypometabolism as well as cerebellar hypermetabolism compared to 44 healthy matched controls. Episodic memory remained significantly impaired in KS^C-T2 and KS^R. Contrary to KS^C at T1 and T2, KS^R had preserved inhibition abilities. Atrophy was similar but less extended in KS^C-T2 and even more limited in KS^R. At all times, the thalamus, hypothalamus, and fornix remained severely atrophied. Hypometabolism was still widespread in KS^C-T2 and KS^R, notably affecting the diencephalon. Cerebellar metabolism decreased over time and normalized in KS^R, whereas motor dysfunction persisted. In KS, structural and metabolic alterations of the Papez circuit persisted over time, in accordance with the irreversible nature of amnesia. There was neither significant recovery as observed in patients with alcohol use disorder nor progressive decline as in neurodegenerative diseases.