Faculty Bibliography

BACKGROUND: Increasingly, postoperative cognitive dysfunction (POCD) is recognized as a complication after surgery in the elderly. We sought to determine whether patients with mild cognitive impairment (MCI) would have an accelerated progression of dementia postoperatively when compared with the patients without MCI. METHODS: The Center for Brain Health at the New York University (NYU) Medical Center maintains records of volunteers who undergo a series of neurological assessments. We reviewed records of 670 patients who received at least 2 evaluations and whose surgery occurred before the second assessment. Longitudinal differences of several cognitive domains were examined. RESULTS: Individuals with MCI and surgery had a greater decline in performance on the Digit Span Forward test compared with those with MCI without surgery on their postoperative evaluation (F(3,158) = 3.12, P = .03). No performance changes were detected in the normal subjects. CONCLUSION: These preliminary findings suggest that surgery negatively impacts attention/concentration in patients with MCI but not in normal individuals. This is the first study that identified a specific subgroup of patients who are predisposed to POCD

Alzheimer's disease (AD) is characterized by specific and progressive reductions in fluorodeoxyglucose positron emission tomography (FDG PET) measurements of the cerebral metabolic rate for glucose (CMRgl), some of which may precede the onset of symptoms. In this report, we describe twelve-month CMRgl declines in 69 probable AD patients, 154 amnestic mild cognitive impairment (MCI) patients, and 79 cognitively normal controls (NCs) from the AD Neuroimaging Initiative (ADNI) using statistical parametric mapping (SPM). We introduce the use of an empirically pre-defined statistical region-of-interest (sROI) to characterize CMRgl declines with optimal power and freedom from multiple comparisons, and we estimate the number of patients needed to characterize AD-slowing treatment effects in multi-center randomized clinical trials (RCTs). The AD and MCI groups each had significant twelve-month CMRgl declines bilaterally in posterior cingulate, medial and lateral parietal, medial and lateral temporal, frontal and occipital cortex, which were significantly greater than those in the NC group and correlated with measures of clinical decline. Using sROIs defined based on training sets of baseline and follow-up images to assess CMRgl declines in independent test sets from each patient group, we estimate the need for 66 AD patients or 217 MCI patients per treatment group to detect a 25% AD-slowing treatment effect in a twelve-month, multi-center RCT with 80% power and two-tailed alpha=0.05, roughly one-tenth the number of the patients needed to study MCI patients using clinical endpoints. Our findings support the use of FDG PET, brain-mapping algorithms and empirically pre-defined sROIs in RCTs of AD-slowing treatments

Autism is characterized by a broad spectrum of clinical manifestations including qualitative impairments in social interactions and communication, and repetitive and stereotyped patterns of behavior. Abnormal acceleration of brain growth in early childhood, signs of slower growth of neurons, and minicolumn developmental abnormalities suggest multiregional alterations. The aim of this study was to detect the patterns of focal qualitative developmental defects and to identify brain regions that are prone to developmental alterations in autism. Formalin-fixed brain hemispheres of 13 autistic (4-60 years of age) and 14 age-matched control subjects were embedded in celloidin and cut into 200-mum-thick coronal sections, which were stained with cresyl violet and used for neuropathological evaluation. Thickening of the subependymal cell layer in two brains and subependymal nodular dysplasia in one brain is indicative of active neurogenesis in two autistic children. Subcortical, periventricular, hippocampal and cerebellar heterotopias detected in the brains of four autistic subjects (31%) reflect abnormal neuronal migration. Multifocal cerebral dysplasia resulted in local distortion of the cytoarchitecture of the neocortex in four brains (31%), of the entorhinal cortex in two brains (15%), of the cornu Ammonis in four brains and of the dentate gyrus in two brains. Cerebellar flocculonodular dysplasia detected in six subjects (46%), focal dysplasia in the vermis in one case, and hypoplasia in one subject indicate local failure of cerebellar development in 62% of autistic subjects. Detection of flocculonodular dysplasia in only one control subject and of a broad spectrum of focal qualitative neuropathological developmental changes in 12 of 13 examined brains of autistic subjects (92%) reflects multiregional dysregulation of neurogenesis, neuronal migration and maturation in autism, which may contribute to the heterogeneity of the clinical phenotype

Having a parent affected with late-onset Alzheimer's disease (LOAD) is a major risk factor among cognitively normal (NL) individuals. This (11)C-Pittsburgh Compound B (PiB)-PET study examines whether NL individuals with LOAD parents show increased fibrillar amyloid-beta (Abeta) deposition, a hallmark of Alzheimer's disease (AD) pathology and whether there are parent-of-origin effects. Forty-two 50- to 80-year-old NL persons were examined with PiB-PET. These individuals included 14 NL subjects with a maternal family history (FH) of LOAD (FHm), 14 NL subjects with a paternal FH (FHp), and 14 NL subjects with a negative family history of any dementia (FH-). Statistical parametric mapping and automated regions-of-interest were used to compare cerebral-to-cerebellar PiB standardized uptake value ratios, reflecting fibrillar Abeta burden, across groups. FH groups did not differ in age, gender, education, and apolipoprotein E (ApoE) status. NL FHm subjects showed higher PiB retention in AD-affected anterior and posterior cingulate cortex (PCC), precuneus, parietal, temporal, occipital, and frontal cortices, right basal ganglia, and thalamus, compared with FH- and FHp subjects. FHp subjects showed increased PiB retention in the PCC and frontal cortex, intermediate between FHm and FH- subjects. Results remained significant after controlling for age, gender, education, and ApoE status. Children of parents with LOAD, particularly those with affected mothers, have increased fibrillar Abeta load in AD-vulnerable regions compared with controls, perhaps accounting for the known increased risk for AD. Present findings may motivate further research on familial transmission and parent-of-origin effects in LOAD

After advanced age, having a parent affected with Alzheimer's disease (AD) is the most significant risk factor for developing AD among cognitively normal (NL) individuals. Although rare genetic mutations have been identified among the early-onset forms of familial AD (EOFAD), the genetics of the more common forms of late-onset AD (LOAD) remain elusive. While some LOAD cases appear to be sporadic in nature, genetically mediated risk is evident from the familial aggregation of many LOAD cases. The patterns of transmission and biological mechanisms through which a family history of LOAD confers risk to the offspring are not known. Brain imaging studies using 2-[ (18) F]fluoro-2-deoxy-D-glucose positron emission tomography ((18)F-FDG PET) have shown that NL individuals with a maternal history of LOAD, but not with a paternal family history, express a phenotype characterised by a pattern of progressive reductions of brain glucose metabolism, similar to that in AD patients. As maternally inherited AD may be associated with as many as 20 per cent of the total LOAD population, understanding the causes and mechanisms of expression of this form of AD is of great relevance. This paper reviews known genetic mutations implicated in EOFAD and their effects on brain chemistry, structure and function; epidemiology and clinical research findings in LOAD, including in vivo imaging findings showing selective patterns of hypometabolism in maternally inherited AD; possible genetic mechanisms involved in maternal transmission of AD, including chromosome X mutations, mitochondrial DNA and imprinting; and genetic mechanisms involved in other neurological disorders with known or suspected maternal inheritance. The review concludes with a discussion of the potential role of brain imaging for identifying endophenotypes in NL individuals at risk for AD, and for directing investigation of potential susceptibility genes for AD

Early diagnosis of Alzheimer disease (AD) is one of the major challenges for the prevention of this dementia. The pathologic lesions associated with AD develop many years before the clinical manifestations of the disease become evident, during a likely transitional period between normal aging and the appearance of first cognitive symptoms. AD biomarkers are needed not only to reveal these early pathologic changes but also to monitor progression in cognitive and behavioral decline and brain lesions. PET neuroimaging can reliably assess indirect and direct aspects of the molecular biology and neuropathology of AD. This article reviews the use of [18F] 2-fluoro-2-deoxy-D-glucose-PET and amyloid PET imaging in the early detection of AD.

The development of prevention therapies for Alzheimer's disease (AD) would greatly benefit from biomarkers that are sensitive to subtle brain changes occurring in the preclinical stage of the disease. Early diagnostics is necessary to identify and treat at risk individuals before irreversible neuronal loss occurs. In vivo imaging has long been used to evaluate brain structural and functional abnormalities as predictors of future AD in non-demented persons. Prior to development of amyloid-beta (Abeta) tracers for positron emission tomography (PET), the most widely utilized PET tracer in AD was 2-[18F]fluoro-2-Deoxy-D-glucose (FDG) PET. For over 20 years, FDG-PET has been used to measure cerebral metabolic rates of glucose (CMRglc), a proxy for neuronal activity, in AD. Many studies have shown that CMRglc reductions occur early in AD, correlate with disease progression, and predict histopathological diagnosis. This paper reviews reports of clinical and preclinical CMRglc reductions observed in association with genetic and non-genetic risk factors for AD. We then briefly review brain Abeta PET imaging studies in AD and discuss the potential of combining symptoms-sensitive FDG-PET measures with pathology-specific Abeta-PET to improve the early detection of AD

Preclinical diagnosis of Alzheimer's disease (AD) is one of the major challenges for the prevention of AD. AD biomarkers are needed not only to reveal preclinical pathologic changes, but also to monitor progression and therapeutics. PET neuroimaging can reliably assess aspects of the molecular biology and neuropathology of AD. The aim of this article is to review the use of FDG-PET and amyloid PET imaging in the early detection of AD.

The development of prevention therapies for Alzheimer's disease (AD) would greatly benefit from biomarkers that are sensitive to the subtle brain changes that occur in the preclinical stage of the disease. Reductions in the cerebral metabolic rate of glucose (CMRglc), a measure of neuronal function, have proven to be a promising tool in the early diagnosis of AD. In vivo brain 2-[(18)F]fluoro-2-Deoxy-D-glucose-positron emission tomography (FDG-PET) imaging demonstrates consistent and progressive CMRglc reductions in AD patients, the extent and topography of which correlate with symptom severity. There is increasing evidence that hypometabolism appears during the preclinical stages of AD and can predict decline years before the onset of symptoms. This review will give an overview of FDG-PET results in individuals at risk for developing dementia, including: presymptomatic individuals carrying mutations responsible for early-onset familial AD; patients with Mild Cognitive Impairment (MCI), often a prodrome to late-onset sporadic AD; non-demented carriers of the Apolipoprotein E (ApoE) epsilon4 allele, a strong genetic risk factor for late-onset AD; cognitively normal subjects with a family history of AD; subjects with subjective memory complaints; and normal elderly followed longitudinally until they expressed the clinical symptoms and received post-mortem confirmation of AD. Finally, we will discuss the potential to combine different PET tracers and CSF markers of pathology to improve the early detection of AD

The associations of inflammation/immune responses with clinical presentations of Alzheimer's disease (AD) remain unclear. We hypothesized that TNF-alpha and elevated antibodies to periodontal bacteria would be greater in AD compared to normal controls (NL) and their combination would aid clinical diagnosis of AD. Plasma TNF-alpha and antibodies against periodontal bacteria were elevated in AD patients compared with NL and independently associated with AD. The number of positive IgG to periodontal bacteria incremented the TNF-alpha classification of clinical AD and NL. This study shows that TNF-alpha and elevated numbers of antibodies against periodontal bacteria associate with AD and contribute to the AD diagnosis.