Caudate Volume Change in Transient Global Amnesia Patients; Voxel-Based Morphometric Study

BACKGROUND: Transient global amnesia (TGA) is characterized by a severe disturbance of memory, lasting less than a day, and complete resolution. However, some authors have suggested the occurrence of permanent memory impairment in such cases. In this study, we investigated whether the gray-matter structure suffers degeneration in TGA, based on the assumption that TGA attacks appear to be related to underlying permanent pathology. METHODS: T1-weighted magnetic resonance imaging data for 20 TGA and 55 normal subjects were analyzed. The gray-matter volume was measured using voxel-based morphometry. The subjects also completed the Seoul Neuropsychological Screening Battery (SNSB). RESULTS: The gray-matter volume was reduced in the left superior frontal gyrus, right precentral gyrus, right superior frontal gyrus, left caudate nucleus, left precentral gyrus, left post central gyrus, and both putamens. The SNSB revealed the presence of selective neuropsychological dysfunctions after clinical recovery. Most of the cases exhibited attention deficit, and difficulties in copying of the Rey-Osterrieth Complex Figure, and in the Seoul verbal learning test. CONCLUSIONS: Left caudate nucleus atrophy could explain the attention deficit and memory impairment experienced in these TGA patients. Many patients with TGA have neuropsychological dysfunctions even after they appear to be clinically improved.

Concomitant PET Brain Imaging and Neuropsychological Assessment in Transient Global Amnesia

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.

Differences of Tc-99m HMPAO SPECT Imaging in the Early Stage of Subcortical Vascular Dementia Compared with Alzheimer's Disease / 핵의학분자영상

PURPOSE: The aim of this study is to assess the specific patterns of regional cerebral blood flow (rCBF) in patients with the early stage of subcortical vascular dementia (SVaD) and Alzheimer's disease (AD) using Tc-99m HMPAO SPECT, and to compare the differences between the two conditions. MATERIALS AND METHODS: Sixteen SVaD, 46 AD and 12 control subjects participated in this study. We included the patients with SVaD and AD according to NINCDS-ADRDA and NINDS-AIREN criteria. They were all matched for age, education and clinical dementia rating scores. Three groups were evaluated by Tc-99m HMPAO SPECT using statistical parametric mapping (SPM) for measuring rCBF. The SPECT data of patients with SVaD and AD were compared with those of normal control subjects and then compared with each other. RESULTS: SPM analysis of the SPECT image showed significant perfusion deficits on the right temporal region and thalamus, left insula and superior temporal gyrus, both cingulate gyri and frontal subgyri in patients with SVaD and on the left supramarginal gyrus, superior temporal gyrus, postcentral gyrus and inferior parietal lobule, right fugiform gyrus and both cingulate gyri in AD compared with control subjects (uncorrected p<0.01). SVaD patients revealed significant hypoperfusion in the right parahippocampal gyrus with cingulated gyrus, left insula and both frontal subgyral regions compared with AD (uncorrected p<0.01). CONCLUSION: Our study shows characteristic and different pattern of perfusion deficits in patients with SVaD and AD, and these results may be helpful to discriminate the two conditions in the early stage of illness.