technetium-tc-99m-exametazime and Alcohol-Amnestic-Disorder

We present a case of acute alcohol-induced Korsakoff amnesia. A severe amnestic-confabulatory syndrome characterized the early clinical status. The initial neuropsychological tests demonstrated severe learning deficits plus impaired performance on many, but not all, tests of frontal lobe function. Single-photon emission CT (SPECT) at this stage showed hypoperfusion in the orbital and medical frontal regions and the medial diencephalic area. Four months later, the patient's amnesia remained but there was no confabulation. Repeat neuropsychological tests confirmed an ongoing severe amnesia, but performance on the frontal lobe tests now was normal. Repeat SPECT showed a return to normal perfusion in the frontal brain areas but little improvement in the medial diencephalic region. These findings along with data from the clinical literature suggest that confabulation results from dysfunction of orbital and a medial frontal cortex.

Topics: Adult; Alcohol Amnestic Disorder; Cerebrovascular Circulation; Cognition Disorders; Diencephalon; Female; Frontal Lobe; Humans; Learning Disabilities; Neuropsychological Tests; Organotechnetium Compounds; Oximes; Regional Blood Flow; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Single photon emission tomography (SPET) with the lipophilic blood flow marker 99mTc-hexamethyl propyleneamine oxime (99mTc-HMPAO) has been used to determine regional uptake of radiolabel into brain regions of patients with presenile Alzheimer's disease and Korsakoff's psychosis, and age-matched controls. Using occipital cortical uptake as reference area, the pattern of relative regional cerebral blood flow (rCBF) was determined in other cortical areas and basal ganglia. In Alzheimer's disease, reduction in rCBF occurred most strikingly in posterior temporal and parietal areas. By contrast, in Korsakoff's psychosis, posterior temporal rCBF was maintained, although there was a trend to reduced tracer uptake in other cortical areas. These impairments of flow were correlated with impairments of neuropsychological function. In Alzheimer's disease, left posterior temporal and left parietal regions in particular showed rCBF to be strongly correlated with most aspects of cognitive function. In Korsakoff's psychosis, however, impaired flow in frontal regions was correlated with impaired performance on tests of memory and orientation. The findings in Alzheimer's disease show quantitative parallels with those from studies using Positron Emission Tomography (PET), and extend our understanding of the relationship between cognition and regional brain function in dementia. The findings in Korsakoff's psychosis offer the first direct evidence linking frontal lobe dysfunction with the cognitive impairment seen in the disorder.

Topics: Adult; Aged; Alcohol Amnestic Disorder; Alzheimer Disease; Basal Ganglia; Cerebral Cortex; Cerebrovascular Circulation; Cognition; Female; Humans; Male; Middle Aged; Organotechnetium Compounds; Oximes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon