Donepezil increases regional cerebral blood flow in a case of Korsakoff syndrome

Cholinesterase inhibitors improve cognitive functions and regional cerebral blood flow (rCBF) in mild to moderate Alzheimer's disease (AD). Recently, the possibility has been suggested that in patients with dementia other than AD cholinesterase inhibitors are useful for the treatment of their cognitive impairment and behavioral symptoms. In the present study we report the effectiveness of donepezil for a patient with Korsakoff syndrome. The patient was a 65-year-old man who gradually showed disturbances in memory, attention and concentration. The etiology was considered to be alcoholism. He would indulge in drinking and repeatedly asked the same questions over and over. He also developed emotional fluttering and would not settle down. On admission, he showed a severe memory deficit, disorientation and momentary confabulation. It was obvious that the patient was inactive and not spontaneous. He also manifested disinhibited behaviors. The patient's confabulation gradually diminished in hospital. He had no focal neurological deficit. Cranial magnetic resonance imaging (MRI) did not reveal any abnormality. Single photon emission computed tomography (SPECT) with 99 m-TC- hexamethyl propylamenamine oxide (HMPAO) indicated hypoperfusion in the left thalamus, left basal ganglia and bilateral medial temporal lobes. In order to improve his cognitive function, the patient was treated donepezil. An evaluation of the effects of donepezil on rCBF was performed with the images showing a remarkable improvement in cerebral perfusion in the right medial temporal, the left thalamus and basal ganglia. However, the patient's memory impairment, disorientation, disinhibition, and stereotypical behavior and utterance were not improved. As an explanation, it was speculated that his neural network might be damaged so severely that there was no room for improvement by the acetylcholinesterase inhibitors.