Concomitant PET Brain Imaging and Neuropsychological Assessment in Transient Global Amnesia

ABSTRACT

BACKGROUND: Transient global amnesia (TGA) is one of the most striking syndromes in clinical neurology. In recent years, with the development of new types of imaging methods, particularly the clinical application of PET may have helped the medical personnel to understand the nature of this remarkable syndrome. The purpose of this study is to evaluate the common lesion of TGA by 18FDG-PET through Statistical Parametric Mapping (SPM) analysis and compare them with the results of the neuropsychological tests. METHODS: We studied prospectively 10 patients diagnosed clinically as TGA. They received brain MRI and/or CT and PET of the brain with 18FDG as the tracer. The results of the brain PET imaging of patients were analyzed with SPM and were compared with those of 15 normal controls. They also received SNSB and the Korean version of the Rey-Kim memory test. RESULTS: No obvious abnormality was found in the visual analysis of MRI or CT scans of the 10 patients with TGA. However SPM analysis of the brain PET imaging displayed low metabolic areas in the left primary motor and sensory cortex, bilateral anterior cingulate gyrus and right posterior thalamus. SNSB revealed multiple cognitive dysfunctions including visuospatial functions, visual memory, verbal memory, calculation, attention and frontal executive functions. In 5 patients, memory quotients were within the low average range. CONCLUSIONS: SPM analysis of PET imaging displayed multiple low metabolic areas and these lesions were roughly correlated with the results of neuropsychological tests which showed defects of visuospatial functioning and frontal executive functioning.