RESUMEN
Although reports on EEG in dementia with Lewy bodies (DLB) are conflicting, the recent diagnostic guidelines define EEG abnormalities as being supportive for the diagnosis. We examined EEG abnormalities in 18 patients with DLB, 34 patients with Alzheimer's disease (AD) and 36 patients with subjective memory complaints (SMC) using the Grand Total EEG (GTE) score. There was a difference in median GTE score of DLB (11.0), AD (4.8) and SMC (2.5) (p<0.001). Patients with DLB had higher scores than patients with AD. ROC analyses revealed that patients with DLB could be distinguished from those with AD with a sensitivity of 72% and a specificity of 85% at a GTE cut-off of 9.5. The association between GTE and DLB was independent of age, gender, Mini Mental State Examination and medication use. Frontal intermittent rhythmic delta activity (FIRDA) was found in 2.9% of the patients with AD and in 33.3% of the patients with DLB. The GTE is a simple EEG scoring method that can be helpful in the differential diagnosis between DLB and AD with good sensitivity and specificity.
Asunto(s)
Electroencefalografía , Enfermedad por Cuerpos de Lewy/diagnóstico , Procesamiento de Señales Asistido por Computador , Anciano , Anciano de 80 o más Años , Enfermedad de Alzheimer/diagnóstico , Enfermedad de Alzheimer/fisiopatología , Estudios de Casos y Controles , Diagnóstico Diferencial , Dominancia Cerebral/fisiología , Epilepsia del Lóbulo Frontal/diagnóstico , Epilepsia del Lóbulo Frontal/fisiopatología , Femenino , Lóbulo Frontal/fisiopatología , Humanos , Enfermedad por Cuerpos de Lewy/fisiopatología , Masculino , Trastornos de la Memoria/diagnóstico , Trastornos de la Memoria/fisiopatología , Escala del Estado Mental , Persona de Mediana Edad , Grupo de Atención al Paciente , Sensibilidad y EspecificidadRESUMEN
OBJECTIVE: A large cohort of subjects with mild cognitive impairment (MCI) was categorized into tertiles based on hippocampal atrophy rates, as a proxy for Alzheimer-type pathology. We compared baseline clinical, neuropsychological, and MRI measures to characterize these MCI subgroups. METHODS: Serial MRI data of 323 subjects with MCI (49% men; mean +/- SD age: 69 +/- 9 years), followed for 2 years in a clinical trial, were available. Baseline hippocampal and whole brain volumes (WBV) were measured, and hippocampal volume change was assessed. Baseline medial temporal lobe atrophy (MTA), white matter hyperintensities (WMH), and lacunes were rated visually. The cohort was categorized into tertiles based on hippocampal atrophy rates (absent, moderate, and severe). RESULTS: Rates of hippocampal atrophy (%/year) were 0.0 +/- 0.8 in the absent, 1.7 +/- 0.4 in the moderate, and 3.6 +/- 1.0 in the severe (mean +/- SD) tertile. Older age and the APOE epsilon 4 allele were associated with higher hippocampal atrophy rates (p < 0.0001 and p = 0.015). General cognition deteriorated over the MCI groups (p < 0.0001), whereas, after adjustment for age and sex, episodic memory and executive function did not. Baseline hippocampal atrophy was associated with increasing atrophy rates (hippocampal volume: p = 0.025; MTA score: p = 0.008); in contrast, WBV, WMH, and lacunes, adjusted for age and sex, were not significantly associated with hippocampal atrophy rates. CONCLUSIONS: In mild cognitive impairment (MCI), older age, poorer general cognition, hippocampal atrophy, and APOE epsilon 4 predict subsequent accelerated rates of hippocampal atrophy, suggestive of the accumulation of Alzheimer-type pathology, which may become clinically manifest in the future. These markers may improve identification of subjects with MCI at risk for Alzheimer disease.
Asunto(s)
Enfermedad de Alzheimer/patología , Atrofia/patología , Trastornos del Conocimiento/patología , Hipocampo/patología , Factores de Edad , Anciano , Enfermedad de Alzheimer/tratamiento farmacológico , Enfermedad de Alzheimer/fisiopatología , Apolipoproteína E4/genética , Atrofia/etiología , Atrofia/prevención & control , Biomarcadores/análisis , Inhibidores de la Colinesterasa/farmacología , Trastornos del Conocimiento/tratamiento farmacológico , Trastornos del Conocimiento/fisiopatología , Estudios de Cohortes , Progresión de la Enfermedad , Método Doble Ciego , Femenino , Estudios de Seguimiento , Galantamina/farmacología , Predisposición Genética a la Enfermedad/genética , Hipocampo/efectos de los fármacos , Hipocampo/fisiopatología , Humanos , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Fibras Nerviosas Mielínicas/patología , Pruebas Neuropsicológicas , Valor Predictivo de las Pruebas , PronósticoRESUMEN
BACKGROUND: Hippocampal atrophy--particularly of the CA1 region--may be useful as a biomarker for Alzheimer's disease (AD) or the risk for AD. The extent to which the AD hippocampus can be distinguished in vivo from changes due to normal aging or other processes that affect the hippocampus is of clinical importance and is an area of active research. In this study, we use structural imaging techniques to model hippocampal size and regional shape differences between elderly men with incident AD and a non-demented comparison group of elderly men. METHODS: Participants are Japanese-American men from the Honolulu Asia Aging Study (HAAS). The HAAS cohort has been followed since 1965. The following analysis is based on a sub-group of men who underwent MRI examination in 1994-1996. Participants were diagnosed with incident AD (n=24: age=82.5+/-4.6) or were not demented (n=102: age=83.0+/-5.9). One reader, blinded to dementia diagnosis, manually outlined the left and right hippocampal formation using published criteria. We used 3D structural shape analysis methods developed at the Laboratory of Neuro Imaging (LONI) to compare regional variation in hippocampal diameter between the AD cases and the non-demented comparison group. RESULTS: Mean total hippocampal volume was 11.5% smaller in the AD cases than the non-demented controls (4903+/-857 mm(3) vs. 5540+/-805 mm(3)), with a similar size difference for the median left (12.0%) and median right (11.6%) hippocampus. Shape analysis showed a regional pattern of shape difference between the AD and non-demented hippocampus, more evident for the hippocampal body than the head, and the appearance of more consistent differences in the left hippocampus than the right. While assignment to a specific sub-region is not possible with this method, the surface changes primarily intersect the area of the hippocampus body containing the CA1 region (and adjacent CA2 and distal CA3), subiculum, and the dentate gyrus-hilar region.
Asunto(s)
Enfermedad de Alzheimer/diagnóstico , Hipocampo/patología , Aumento de la Imagen , Procesamiento de Imagen Asistido por Computador , Imagenología Tridimensional , Imagen por Resonancia Magnética , Factores de Edad , Anciano , Anciano de 80 o más Años , Enfermedad de Alzheimer/patología , Atrofia , Encéfalo/patología , Estudios de Cohortes , Dominancia Cerebral/fisiología , Humanos , Masculino , Valores de Referencia , Factores de RiesgoRESUMEN
HYPOTHESIS: Based on recent findings on the association between vascular risk factors and hippocampal atrophy, we hypothesized that hypertension and diabetes mellitus (DM) are associated with medial temporal lobe atrophy (MTA) in subjects without disability, independent of the severity of white matter hyperintensities. METHODS: In the Leukoaraiosis And DISability in the elderly (LADIS) study, we investigated the relationships between DM, hypertension, blood pressure and MTA in 582 subjects, stratified by white matter hyperintensity severity, using multinomial logistic regression. MTA was visually scored for the left and right medial temporal lobe (score 0-4), and meaned. RESULTS: Mean age was 73.5 years (sd 5.1), 54% was female. Of the subjects, 15% had DM, and 70% had a history of hypertension. The likelihood of having MTA score 3 was significantly higher in subjects with DM (OR 2.9; 95% CI: 1.1-7.8) compared with an MTA score of 0 (no atrophy). The odds ratio for MTA score 2 was not significantly increased (OR 1.8; CI: 0.9-4). Systolic and diastolic blood pressure and a history of hypertension were not associated with MTA. There was no interaction between DM and hypertension. Stratification on white matter hyperintensities (WMH) did not alter the associations. CONCLUSION: Our study strengthens the observation that MTA is associated with DM, independently of the amount of small vessel disease as reflected by WMH.
Asunto(s)
Angiopatías Diabéticas/patología , Hipertensión/patología , Lóbulo Temporal/patología , Anciano , Anciano de 80 o más Años , Atrofia/patología , Femenino , Humanos , Imagen por Resonancia Magnética , Masculino , Factores de RiesgoRESUMEN
As population-based epidemiologic studies may acquire images from thousands of subjects, automated image post-processing is needed. However, error in these methods may be biased and related to subject characteristics relevant to the research question. Here, we compare two automated methods of brain extraction against manually segmented images and evaluate whether method accuracy is associated with subject demographic and health characteristics. MRI data (n = 296) are from the Honolulu Asia Aging Study, a population-based study of elderly Japanese-American men. The intracranial space was manually outlined on the axial proton density sequence by a single operator. The brain was extracted automatically using BET (Brain Extraction Tool) and BSE (Brain Surface Extractor) on axial proton density images. Total intracranial volume was calculated for the manually segmented images (ticvM), the BET segmented images (ticvBET) and the BSE segmented images (ticvBSE). Mean ticvBSE was closer to that of ticvM, but ticvBET was more highly correlated with ticvM than ticvBSE. BSE had significant over (positive error) and underestimated (negative error) ticv, but net error was relatively low. BET had large positive and very low negative error. Method accuracy, measured in percent positive and negative error, varied slightly with age, head circumference, presence of the apolipoprotein eepsilon4 polymorphism, subcortical and cortical infracts and enlarged ventricles. This epidemiologic approach to the assessment of potential bias in image post-processing tasks shows both skull-stripping programs performed well in this large image dataset when compared to manually segmented images. Although method accuracy was statistically associated with some subject characteristics, the extent of the misclassification (in terms of percent of brain volume) was small.