ABSTRACT
BACKGROUND AND OBJECTIVES: Although Alzheimer's disease (AD) and dementia with Lewy bodies (DLB) represent two different pathologies, they have clinical overlap, and there is a significant degree of co-occurrence of their neuropathological findings. Many studies have examined imaging characteristics in clinically diagnosed patients; however, there is a relative lack of longitudinal studies that have studied patients with pathological confirmation. We examined whether there were differences in longitudinal patterns of cortical atrophy between patients with both AD and DLB (AD/DLB) vs. those with AD alone. METHODS: We collected and analyzed clinical and neuroimaging data from the Alzheimer's Disease Neuroimaging Initiative (ADNI) database for patients who underwent autopsy. The rates of change in various neuropsychological assessments were not significantly different between AD/DLB and AD patients, and each group had neuropsychological outcomes consistent with disease progression. For our neuroimaging analysis, we used a linear mixed effects model to examine if there were longitudinal differences in cortical rates of atrophy between AD/DLB and AD patients. RESULTS: Autopsies and serial neuroimaging was available on 48 patients (24 AD, 24 AD/DLB). Patients with AD alone had significantly higher atrophy rates in the left cuneus, lateral occipital, and parahippocampal regions over time when compared to patients with concomitant DLB, after covarying for interval from imaging to autopsy, gender, and total estimated intracranial volume (eTIV). Site ID was included as a random effect to account for site differences. For these regions, the rate of decline over time in the AD/DLB group were less steep by a difference of 0.1887, 0.395, and 0.0989, respectively (p =.022, .006, and .006). The lattermost left cuneus volume measurement also positively correlated to Braak Lewy score (Pearson's product-moment correlation 0.37, p=.009), while the lattermost left parahippocampal volume measurement negatively correlated to Braak NFT score (Pearson's product-moment correlation -0.327, p=.02). DISCUSSION: AD patients had more significant atrophy in the left cuneus, lateral occipital, and parahippocampal regions when compared to AD/DLB patients. These regions are known to distinguish DLB and AD pathology cross-sectionally, but here are shown to distinguish longitudinal disease progression.
ABSTRACT
PURPOSE: The participation in concussive susceptible sports such as boxing may cause chronic traumatic brain injury. The objective of this study was to determine whether there are unique patterns of reduced brain glucose metabolism in professional and amateur boxers. METHOD: We compared the fluorine-18 fluorodeoxyglucose (F-18 FDG) PET brain scans of boxers (group) (N=19) with those of controls (group) (N=7) using both statistical parametric mapping and region of interest analysis. RESULTS: Boxers showed decreased F-18 FDG uptake by 8-15% in the following brain areas: posterior cingulate cortex, parieto-occipito, frontal lobes (Broca's area) bilaterally, and the cerebellum (P<0.005) as compared with controls. CONCLUSION: Our results suggest that F-18 FDG PET scans of boxers suspected of chronic traumatic brain injury show unique patterns of hypometabolism, and that these patterns may reflect the mechanisms of repeated traumatic brain injury unique to boxers.
