Alzheimer Disease: Albert MS

McKhann GM, Albert MS, Grossman M, Miller B, Dickson D, Trojanowski JQ, Anonymous00019. · Department of Neurology, Zanvyl Krieger Mind/Brain Institute, Johns Hopkins University School of Medicine, 338 Krieger Hall, 3400 N Charles St, Baltimore, MD 21218-2685, USA. · Arch Neurol. · Pubmed #11708987 links to  free full text

Abstract: An international group of clinical and basic scientists participated in the Frontotemporal Dementia and Pick's Disease Criteria Conference at the National Institutes of Health in Bethesda, Md, on July 7, 2000, to reassess clinical and neuropathological criteria for the diagnosis of frontotemporal dementia (FTD). Previous criteria for FTD have primarily been designed for research purposes. The goal of this meeting was to propose guidelines that would enable clinicians (particularly neurologists, psychiatrists, and neuropsychologists) to recognize patients with FTD and, if appropriate, to expedite their referral to a diagnostic center. In addition, recommendations for the neuropathological criteria of FTD were reviewed, relative to classical neuropathology and modern molecular biology.

Albert MS. · No affiliation provided · Ann Neurol. · Pubmed #11891821 No free full text.

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Albert MS, Drachman DA. · No affiliation provided · Neurology. · Pubmed #10908884 No free full text.

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Albert MS, Blacker D. · Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21212, USA. · Annu Rev Clin Psychol. · Pubmed #17716075 No free full text.

Abstract: Mild cognitive impairment (MCI) is a clinical syndrome thought to represent the transition between normal function and dementia. This review describes data that support the existence of such a transitional phase, outlines the heterogeneity of MCI and how that has influenced the evolving concept of MCI, and discusses the impact of heterogeneity on recent MCI clinical trials.

Atiya M, Hyman BT, Albert MS, Killiany R. · Department of Psychiatry, Massachusetts General Hospital, Harvard Medical School, Boston University, Boston, Massachusetts 02129, USA. · Alzheimer Dis Assoc Disord. · Pubmed #14512832 No free full text.

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Albert MS. · Department of Psychiatry, Harvard Medical School, Massachusetts Geneal Hospital, Charlestown, Massachusetts, USA. · Alzheimer Dis Assoc Disord. · Pubmed #12813213 No free full text.

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Johnson KA, Albert MS. · Departments of Neurology and Radiology, Brigham and Women's Hospital, 75 Francis Street, Boston, MA, USA. · Neurobiol Aging. · Pubmed #10867213 No free full text.

Abstract: Cerebral perfusion abnormalities in patients with established Alzheimer's disease (AD) are most commonly seen in the temporoparietal cortex. As the disease progresses, this perfusion pattern is increasingly prevalent. Recently, investigators have begun to examine the patterns of perfusion among individuals at risk for AD. To date, such studies have been conducted either in individuals who have a progressive memory difficulty but do not yet meet clinical criteria for AD, or in individuals with a genetic risk factor or family history of AD, either with or without a memory problem. These latter studies suggest that a set of brain regions show decreased perfusion during the prodromal phase of AD, and that a brain network or networks with multiple nodes is affected early in the course of AD. These perfusion abnormalities may also shed light on how AD progresses during the prodromal phase of disease and may ultimately lead to improved diagnosis or methods of monitoring response to treatment.

Khachaturian ZS, Snyder PJ, Doody R, Aisen P, Comer M, Dwyer J, Frank RA, Holzapfel A, Khachaturian AS, Korczyn AD, Roses A, Simpkins JW, Schneider LS, Albert MS, Egge R, Deves A, Ferris S, Greenberg BD, Johnson C, Kukull WA, Poirier J, Schenk D, Thies W, Gauthier S, Gilman S, Bernick C, Cummings JL, Fillit H, Grundman M, Kaye J, Mucke L, Reisberg B, Sano M, Pickeral O, Petersen RC, Mohs RC, Carrillo M, Corey-Bloom JP, Foster NL, Jacobsen S, Lee V, Potter WZ, Sabbagh MN, Salmon D, Trojanowski JQ, Wexler N, Bain LJ. · Lou Ruvo Brain Institute, Las Vegas, NV 89106, USA. · Alzheimers Dement. · Pubmed #19328434 No free full text.

Abstract: This document proposes an array of recommendations for a National Plan of Action to accelerate the discovery and development of therapies to delay or prevent the onset of disabling symptoms of Alzheimer's disease. A number of key scientific and public-policy needs identified in this document will be incorporated by the Alzheimer Study Group into a broader National Alzheimer's Strategic Plan, which will be presented to the 111th Congress and the Obama administration in March 2009. The Alzheimer's Strategic Plan is expected to include additional recommendations for governance, family support, healthcare, and delivery of social services.

Desikan RS, Cabral HJ, Fischl B, Guttmann CR, Blacker D, Hyman BT, Albert MS, Killiany RJ. · Department of Anatomy and Neurobiology, Boston University School of Medicine, Boston, MA 02118, USA. · AJNR Am J Neuroradiol. · Pubmed #19112067 links to  free full text

Abstract: BACKGROUND AND PURPOSE: Mild cognitive impairment (MCI) represents a transitional state between normal aging and Alzheimer disease (AD). Our goal was to determine if specific temporoparietal regions can predict the time to progress from MCI to AD. MATERIALS AND METHODS: MR images from 129 individuals with MCI were analyzed to identify the volume of 14 neocortical and 2 non-neocortical brain regions, comprising the temporal and parietal lobes. In addition, 3 neuropsychological test scores were included to determine whether they would provide independent information. After a mean follow-up time of 5 years, 44 of these individuals had progressed to a diagnosis of AD. RESULTS: Cox proportional hazards models demonstrated significant effects for 6 MR imaging regions with the greatest differences being the following: the entorhinal cortex (hazard ratio [HR] = 0.54, P < .001), inferior parietal lobule (hazard ratio [HR] = 0.64, P < .005), and middle temporal gyrus (HR = 0.64, P < .004), indicating decreased risk with larger volumes. A multivariable model showed that a combination of the entorhinal cortex (HR = 0.60, P < .001) and the inferior parietal lobule (HR = 0.62, P < .01) was the best predictor of time to progress to AD. A multivariable model reiterated the importance of including both MR imaging and neuropsychological variables in the final model. CONCLUSIONS: These findings reaffirm the importance of the entorhinal cortex and present evidence for the importance of the inferior parietal lobule as a predictor of time to progress from MCI to AD. The inclusion of neuropsychological performance in the final model continues to highlight the importance of using these measures in a complementary fashion.

Scherer RK, Scarmeas N, Brandt J, Blacker D, Albert MS, Stern Y. · Cognitive Neuroscience Division, Taub Institute for Research in Alzheimer's Disease and the Aging Brain, Gertrude H. Sergievsky Center, Department of Neurology, Columbia University Medical Center, 630 West 168th St., P&S Box 16, New York, NY 10032, USA. · J Gerontol A Biol Sci Med Sci. · Pubmed #18840808 No free full text.

Abstract: BACKGROUND: Although there has been much research devoted to understanding the predictors of nursing home placement (NHP) in Alzheimer's disease (AD) patients, there is currently a lack of research concerning the predictors of home health care. The objective of this study was to examine whether the Dependence Scale can predict home health aide (HHA) use. METHODS: The sample is drawn from the Predictors Study, a large, multicenter cohort of patients with probable AD, prospectively followed annually for up to 7 years in three university-based AD centers in the United States. Markov analyses (n=75) were used to calculate annual transition probabilities for the "new onset" of HHA use (instances where an HHA was absent at the previous visit, but present at the next visit) as a function of HHA presence at the preceding year's visit and dependence level at that preceding year's visit. RESULTS: The dependence level at the previous year's visit was a significant predictor of HHA use at the next year's visit. Three specific items of the Dependence Scale (needing household chores done for oneself, needing to be watched or kept company when awake, and needing to be escorted when outside) were significant predictors of the presence of an HHA. CONCLUSION: The Dependence Scale is a valuable tool for predicting HHA use in AD patients. Obtaining a better understanding of home health care in AD patients may help delay NHP and have a positive impact on the health and well-being of both the caregiver and the patient.

Brickman AM, Honig LS, Scarmeas N, Tatarina O, Sanders L, Albert MS, Brandt J, Blacker D, Stern Y. · Taub Institute for Research on Alzheimer's Disease and the Aging Brain, College of Physicians and Surgeons, Columbia University, 630 W 168th St, Campus Box 16, New York, NY 10032, USA. · Arch Neurol. · Pubmed #18779424 No free full text.

Abstract: OBJECTIVE: To determine if baseline measurements of cerebral atrophy and severity of white matter hyperintensity (WMH) predict the rate of future cognitive decline in patients with Alzheimer disease (AD). DESIGN: Data were drawn from the Predictors Study, a longitudinal study that enrolls patients with mild AD and reassesses them every 6 months with use of the Columbia modified Mini-Mental State (mMMS) examination (score range, 0-57). Magnetic resonance images were analyzed to determine the severity of WMH, using the Scheltens scale, and the degree of atrophy, using the bicaudate ratio. Generalized estimating equations were used to determine whether severity of baseline magnetic resonance image measurements and their interaction predicted the rate of mMMS score decline at subsequent visits. SETTING: Three university-based AD centers in the United States. PARTICIPANTS: At baseline, 84 patients with AD from the Predictors Study received structural magnetic resonance imaging and were selected for analysis. They had a mean of 6 follow-up evaluations. Main Outcome Measure The mMMS score. RESULTS: Generalized estimating equation models demonstrated that the degree of baseline atrophy (beta = -0.316; P = .04), the severity of WMH (beta = -0.173; P = .03), and their interaction (beta = -6.061; P = .02) predicted the rate of decline in mMMS scores. CONCLUSIONS: Both degree of cerebral atrophy and severity of WMH are associated with the rapidity of cognitive decline in AD. Atrophy and WMH may have a synergistic effect on future decline in AD, such that patients with a high degree of both have a particularly precipitous cognitive course. These findings lend further support to the hypothesis that cerebrovascular pathological abnormalities contribute to the clinical syndrome of AD.

Desikan RS, Fischl B, Cabral HJ, Kemper TL, Guttmann CR, Blacker D, Hyman BT, Albert MS, Killiany RJ. · Dept. of Anatomy and Neurobiology, Boston University School of Medicine, Boston, MA 02118, USA. · Neurology. · Pubmed #18672473 links to  free full text

Abstract: BACKGROUND: MRI studies have demonstrated differential rates of atrophy in the entorhinal cortex and hippocampus during the prodromal phase of Alzheimer disease (AD). The current study was designed to determine whether a broader set of temporoparietal regions show differential rates of atrophy during the evolution of AD. METHODS: Sixteen regions of interest (ROIs) were analyzed on MRI scans obtained at baseline and follow-up in 66 subjects comprising three groups: controls = individuals who were cognitively normal at both baseline and follow-up; nonconverters = subjects with mild cognitive impairment (MCI) at both baseline and follow-up; converters had MCI at baseline but had progressed to AD at follow-up. RESULTS: Annualized percent change was analyzed with multivariate analysis of variance (MANOVA), covaried for age. The MANOVA demonstrated an effect of group (p = 0.004). Post hoc comparisons demonstrated greater rates of atrophy for converters vs nonconverters for six ROIs: hippocampus, entorhinal cortex, temporal pole, middle temporal gyrus, fusiform gyrus, and inferior temporal gyrus. Converters showed differentially greater rates of atrophy than controls in five of the same ROIs (and inferior parietal lobule). Rates of change in clinical status were correlated with the atrophy rates in these regions. Comparisons between controls and nonconverters demonstrated no differences. CONCLUSION: These results demonstrate that temporoparietal regions show differential rates of atrophy on MRI during prodromal Alzheimer disease (AD). MRI data correlate with measures of clinical severity and cognitive decline, suggesting the potential of these regions of interest as antemortem markers of prodromal AD.

Holland CM, Smith EE, Csapo I, Gurol ME, Brylka DA, Killiany RJ, Blacker D, Albert MS, Guttmann CR, Greenberg SM. · Center for Neurological Imaging, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA. · Stroke. · Pubmed #18292383 links to  free full text

Abstract: BACKGROUND AND PURPOSE: White-matter hyperintensities (WMHs) detected by magnetic resonance imaging are thought to represent the effects of cerebral small-vessel disease and neurodegenerative changes. We sought to determine whether the spatial distribution of WMHs discriminates between different disease groups and healthy aging individuals and whether these distributions are related to local cerebral perfusion patterns. METHODS: We examined the pattern of WMHs by T2/fluid-attenuated inversion recovery-weighted magnetic resonance imaging in 3 groups of subjects: cerebral amyloid angiopathy (n=32), Alzheimer disease or mild cognitive impairment (n=41), and healthy aging (n=29). WMH frequency maps were calculated for each group, and spatial distributions were compared by voxel-wise logistic regression. WMHs were also analyzed as a function of normal cerebral perfusion patterns by overlaying a single photon emission computed tomography atlas. RESULTS: Although WMH volume was greater in cerebral amyloid angiopathy and Alzheimer disease/mild cognitive impairment than in healthy aging, there was no consistent difference in the spatial distributions when controlling for total WMH volume. Hyperintensities were most frequent in the deep periventricular WM in all 3 groups. A strong inverse correlation between hyperintensity frequency and normal perfusion was demonstrated in all groups, demonstrating that WMHs were most common in regions of relatively lower normal cerebral perfusion. CONCLUSIONS: WMHs show a common distribution pattern and predilection for cerebral WM regions with lower atlas-derived perfusion, regardless of the underlying diagnosis. These data suggest that across diverse disease processes, WM injury may occur in a pattern that reflects underlying tissue properties, such as relative perfusion.

Smith EE, Egorova S, Blacker D, Killiany RJ, Muzikansky A, Dickerson BC, Tanzi RE, Albert MS, Greenberg SM, Guttmann CR. · Neurology Clinical Trials Unit, Department of Neurology, Massachusetts General Hospital, Boston, Massachusetts 02114, USA. · Arch Neurol. · Pubmed #18195145 links to  free full text

Abstract: OBJECTIVE: To determine whether magnetic resonance imaging (MRI) white matter hyperintensities (WMH), whole-brain atrophy, and cardiovascular risk factors predict the development of cognitive decline and dementia. DESIGN: Subjects were recruited into this prospective cohort study and followed for incident cognitive decline for mean (SD) 6.0 (4.1) years. Magnetic resonance imaging dual-echo sequences, obtained at baseline, were used to determine the volume of WMH and the brain parenchymal fraction (BPF), the proportion of the intracranial cavity occupied by brain. White matter hyperintensity volume was analyzed as the percentage of intracranial volume (WMHr); "high WMH" was defined as a WMHr more than 1 SD above the mean. SETTING: General community. PATIENTS: Volunteer sample consisting of 67 subjects with normal cognition and 156 subjects with mild cognitive impairment (MCI). MAIN OUTCOME MEASURES: Time to diagnosis of MCI (among those with normal cognition at baseline) or time to diagnosis of dementia, either all-cause or probable Alzheimer disease (AD) (among those with MCI at baseline). Cox proportional hazards models were used for multivariable analysis. RESULTS: High WMH was a predictor of progression from normal to MCI (adjusted hazard ratio [HR], 3.30; 95% confidence interval [CI], 1.33-8.17; P= .01) but not conversion from MCI to all-cause dementia. Conversely, BPF did not predict progression from normal to MCI but did predict conversion to dementia (adjusted HR, 1.10 for each 1% decrease in BPF; 95% CI, 1.02-1.19; P= .02). When conversion to AD dementia was considered as the outcome, BPF was likewise a predictor (adjusted HR, 1.16 for each 1% decrease in BPF; 95% CI, 1.08-1.24; P< .001), but high WMH was not. Past tobacco smoking was associated with both progression from normal to MCI (adjusted HR, 2.71; 95% CI, 1.12-6.55; P= .03) and conversion to all-cause dementia (adjusted HR, 2.08; 95% CI, 1.13-3.82; P= .02), but not AD dementia. CONCLUSIONS: These findings suggest that WMH are associated with the risk of progressing from normal to MCI. In persons whose cognitive abilities are already impaired, BPF predicts the conversion to dementia.

Dickerson BC, Sperling RA, Hyman BT, Albert MS, Blacker D. · Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, USA. · Arch Gen Psychiatry. · Pubmed #18056553 links to  free full text

Abstract: OBJECTIVE: To determine whether clinical assessment methods that grade the severity of impairments within the spectrum of mild cognitive impairment (MCI) can predict clinical course, particularly among very mildly impaired individuals who do not meet formal MCI criteria as implemented in clinical trials. DESIGN: Cohort. SETTING: Community volunteers. PARTICIPANTS: From a longitudinal study of normal (Clinical Dementia Rating [CDR] = 0; n = 77) and mildly impaired (CDR = 0.5; n = 167) participants with 5 or more annual clinical assessments, baseline level of cognitive impairment in daily life was graded using CDR sum of boxes (CDR-SB) and level of cognitive performance impairment was graded using neuropsychological test scores. MAIN OUTCOME MEASURES: Five-year outcome measures included (1) probable Alzheimer disease (AD) diagnosis and (2) clinical "decline" (CDR-SB increase > or = 1.0). Logistic regression models were used to assess the ability of baseline measures to predict outcomes in the full sample and separately in the subjects who did not meet formal MCI criteria as implemented in a multicenter clinical trial (n = 125; "very mild cognitive impairment" [vMCI]). RESULTS: The presence of both higher CDR-SB and lower verbal memory and executive function at baseline predicted greater likelihood of probable AD and decline. Five-year rates of probable AD and decline in vMCI (20%, AD; 49%, decline) were intermediate between normal participants (0%, AD; 28%, decline) and participants with MCI (41%, AD; 62%, decline). Within vMCI, likelihood of probable AD was predicted by higher CDR-SB and lower executive function. CONCLUSIONS: Even in very mildly impaired individuals who do not meet strict MCI criteria as implemented in clinical trials, the degree of cognitive impairment in daily life and performance on neuropsychological testing predict likelihood of an AD diagnosis within 5 years. The clinical determination of relative severity of impairment along the spectrum of MCI may be valuable for trials of putative disease-modifying compounds, particularly as target populations are broadened to include less impaired individuals.

Albert MS. · Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, USA. · N Engl J Med. · Pubmed #17671260 No free full text.

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McQueen MB, Bertram L, Lange C, Becker KD, Albert MS, Tanzi RE, Blacker D. · Institute for Behavioral Genetics, University of Colorado at Boulder, Boulder, Colorado 80309-0447, USA. · Am J Med Genet B Neuropsychiatr Genet. · Pubmed #17579348 No free full text.

Abstract: We hypothesize that quantitative phenotypes related to Alzheimer's disease (AD), rather than the dichotomous disease phenotype, will increase the statistical power for identifying genetic risk factors. Neuropsychological test scores, which allow for the measurement of loss of cognitive function over time, are a particularly promising option for this approach. Using data from a cohort study of prodromal AD in 365 community-recruited subjects with and without memory problems with a baseline and often one or more follow-up administrations of a detailed neuropsychological test battery, we performed both cross-sectional and longitudinal analyses using the known AD gene APOE and four other putative AD genes as predictors. APOE and a promoter polymorphism in insulin degrading enzyme (IDE_4U) showed evidence for association with cross-sectional and longitudinal changes in memory (P = 0.016-0.025) and other cognitive functions. APOE and a polymorphism in the alpha-2-macroglobulin gene (A2M18i) also showed evidence for association with cross-sectional and longitudinal changes in executive functioning (P = 0.010-0.042). In some cases, longitudinal analysis offered stronger evidence for association than could be seen cross-sectionally. These preliminary results suggest that this approach has promised the development of a quantitative phenotype related to AD, but more elaborate methods will be required to address multiple comparisons issues in the setting of correlated data.

Moscarillo TJ, Holt H, Perman M, Goldberg S, Cortellini L, Stoler JM, DeJong W, Miles BJ, Albert MS, Go RC, Blacker D. · Department of Psychiatry, Massachusetts General Hospital, Harvard Medical School, Boston, Mass., USA. · Community Genet. · Pubmed #17380059 No free full text.

Abstract: OBJECTIVES: In preparation for the development of an educational intervention on Alzheimer disease (AD) genetics, we undertook a pilot survey of knowledge in this area and attitudes toward genetic testing for AD among individuals with a family history of AD. METHODS: For the pilot study, we administered a 30-min questionnaire to 57 unaffected individuals from a genetic linkage study. For the focus groups, we interviewed two groups of subjects, ages 44-70 years, with a family history of AD, one of 10 Caucasians and the other of 6 African-Americans. RESULTS: The pilot study showed that there was limited knowledge of genetics overall and AD genetics in particular, considerable concern about personal risk, and little knowledge of or interest in genetic testing for the disease. The focus groups reinforced and fleshed out these impressions and highlighted the importance of caregiving experience in the attitudes toward personal risk for AD. CONCLUSIONS: These results underscore the value of genetics education for this and other complex diseases and suggest specific foci for educational interventions.

Johnson KA, Moran EK, Becker JA, Blacker D, Fischman AJ, Albert MS. · Department of Radiology, Massachusetts General Hospital, Fruit Street, Boston, MA 02114, USA. · J Neurol Neurosurg Psychiatry. · Pubmed #17056633 No free full text.

Abstract: OBJECTIVE: To relate cerebral perfusion abnormalities to subsequent changes in clinical status among patients with mild cognitive impairment (MCI). METHODS: Perfusion single photon emission computed tomography (SPECT) images were acquired in 105 elderly patients without dementia with MCI, using 99mTc-HMPAO. Clinical outcome after a 5-year follow-up period was heterogeneous. RESULTS: Baseline SPECT data differed in those patients with MCI who were later diagnosed with Alzheimer's disease (the converter group) from those patients with MCI who experienced clinically evident decline but did not progress to a diagnosis of Alzheimer's disease within the follow-up period (the decliner group), from patients with MCI who had no clinical evidence of progression (the stable group), and from a group of 19 normal subjects (the control group). The most consistent decreases in relative perfusion in converters compared with the normal, stable and decliner groups were observed in the caudal anterior cingulate, and in the posterior cingulate. In addition, converters showed increased relative perfusion in the rostral anterior cingulate in comparison to the stable and decliner groups. A group of patients with Alzheimer's disease were also included for purposes of comparison. The group of patients with Alzheimer's disease at baseline differed from each of the other groups, with temporoparietal regions showing the most significant reductions in perfusion. CONCLUSIONS: These results suggest that clinical heterogeneity in MCI is reflected in SPECT perfusion differences, and that the pattern of perfusion abnormalities evolves with increasing clinical severity.

Celone KA, Calhoun VD, Dickerson BC, Atri A, Chua EF, Miller SL, DePeau K, Rentz DM, Selkoe DJ, Blacker D, Albert MS, Sperling RA. · Memory Disorders Unit, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA. · J Neurosci. · Pubmed #17021177 links to  free full text

Abstract: Memory function is likely subserved by multiple distributed neural networks, which are disrupted by the pathophysiological process of Alzheimer's disease (AD). In this study, we used multivariate analytic techniques to investigate memory-related functional magnetic resonance imaging (fMRI) activity in 52 individuals across the continuum of normal aging, mild cognitive impairment (MCI), and mild AD. Independent component analyses revealed specific memory-related networks that activated or deactivated during an associative memory paradigm. Across all subjects, hippocampal activation and parietal deactivation demonstrated a strong reciprocal relationship. Furthermore, we found evidence of a nonlinear trajectory of fMRI activation across the continuum of impairment. Less impaired MCI subjects showed paradoxical hyperactivation in the hippocampus compared with controls, whereas more impaired MCI subjects demonstrated significant hypoactivation, similar to the levels observed in the mild AD subjects. We found a remarkably parallel curve in the pattern of memory-related deactivation in medial and lateral parietal regions with greater deactivation in less-impaired MCI and loss of deactivation in more impaired MCI and mild AD subjects. Interestingly, the failure of deactivation in these regions was also associated with increased positive activity in a neocortical attentional network in MCI and AD. Our findings suggest that loss of functional integrity of the hippocampal-based memory systems is directly related to alterations of neural activity in parietal regions seen over the course of MCI and AD. These data may also provide functional evidence of the interaction between neocortical and medial temporal lobe pathology in early AD.

Desikan RS, Ségonne F, Fischl B, Quinn BT, Dickerson BC, Blacker D, Buckner RL, Dale AM, Maguire RP, Hyman BT, Albert MS, Killiany RJ. · Department of Anatomy and Neurobiology, Boston University School of Medicine, 715 Albany Street, W701, Boston, MA 02118, USA. · Neuroimage. · Pubmed #16530430 No free full text.

Abstract: In this study, we have assessed the validity and reliability of an automated labeling system that we have developed for subdividing the human cerebral cortex on magnetic resonance images into gyral based regions of interest (ROIs). Using a dataset of 40 MRI scans we manually identified 34 cortical ROIs in each of the individual hemispheres. This information was then encoded in the form of an atlas that was utilized to automatically label ROIs. To examine the validity, as well as the intra- and inter-rater reliability of the automated system, we used both intraclass correlation coefficients (ICC), and a new method known as mean distance maps, to assess the degree of mismatch between the manual and the automated sets of ROIs. When compared with the manual ROIs, the automated ROIs were highly accurate, with an average ICC of 0.835 across all of the ROIs, and a mean distance error of less than 1 mm. Intra- and inter-rater comparisons yielded little to no difference between the sets of ROIs. These findings suggest that the automated method we have developed for subdividing the human cerebral cortex into standard gyral-based neuroanatomical regions is both anatomically valid and reliable. This method may be useful for both morphometric and functional studies of the cerebral cortex as well as for clinical investigations aimed at tracking the evolution of disease-induced changes over time, including clinical trials in which MRI-based measures are used to examine response to treatment.

Dickerson BC, Salat DH, Greve DN, Chua EF, Rand-Giovannetti E, Rentz DM, Bertram L, Mullin K, Tanzi RE, Blacker D, Albert MS, Sperling RA. · Department of Neurology, The Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA. · Neurology. · Pubmed #16087905 No free full text.

Abstract: OBJECTIVE: To use fMRI to investigate whether hippocampal and entorhinal activation during learning is altered in the earliest phase of mild cognitive impairment (MCI). METHODS: Three groups of older individuals were studied: 10 cognitively intact controls, 9 individuals at the mild end of the spectrum of MCI, and 10 patients with probable Alzheimer disease (AD). Subjects performed a face-name associative encoding task during fMRI scanning, and were tested for recognition of stimuli afterward. Data were analyzed using a functional-anatomic method in which medial temporal lobe (MTL) regions of interest were identified from each individual's structural MRI, and fMRI activation was quantified within each region. RESULTS: Significantly greater hippocampal activation was present in the MCI group compared to controls; there were no differences between these two groups in hippocampal or entorhinal volumes. In contrast, the AD group showed hippocampal and entorhinal hypoactivation and atrophy in comparison to controls. The subjects with MCI performed similarly to controls on the fMRI recognition memory task; patients with AD exhibited poorer performance. Across all 29 subjects, greater mean entorhinal activation was found in the subgroup of 13 carriers of the APOE epsilon4 allele than in the 16 noncarriers. CONCLUSIONS: The authors hypothesize that there is a phase of increased medial temporal lobe activation early in the course of prodromal Alzheimer disease followed by a subsequent decrease as the disease progresses.

El Fakhri G, Kijewski MF, Albert MS, Johnson KA, Moore SC. · Department of Radiology, Harvard Medical School, Boston, Massachusetts 02115, USA. · J Nucl Med. · Pubmed #15585477 links to  free full text

Abstract: We investigated the impact of the quantitation and reconstruction protocol on clinical tasks. The performance of standard clinical reconstruction procedures in discrimination tasks related to the diagnosis of prodromal Alzheimer's disease (AD) was compared with the performance of a quantitative approach incorporating improved corrections for scatter, attenuation, intrinsic spatial resolution, and distance-dependent spatial resolution. METHODS: Seventeen normal controls (normal group), 56 subjects who did not have dementia, who did have memory problems, but who did not develop AD within 5 y of follow-up (questionable group), and 27 subjects who did not have dementia, who did have memory problems, and who did develop AD over the follow-up period (converter group) were considered in this study. (99m)Tc-hexamethylpropyleneamine oxime SPECT and MRI studies were performed for each subject at baseline. The standard quantitation protocol (STD), routinely used in our clinic, consisted of Compton window scatter correction followed by filtered backprojection with attenuation correction using a uniform attenuation map. In the improved quantitative approach (QUAN), projections were corrected for scatter by use of a general spectral method and reconstructed by use of ordered-subset(s) expectation maximization, incorporating corrections for collimator response and attenuation using both a uniform attenuation map (QUANunif) and a nonuniform attenuation map (QUANnonunif). Mean SPECT activity concentration and MRI volume were estimated for 7 structures: rostral anterior cingulate gyrus, caudal anterior cingulate gyrus, posterior cingulate gyrus, hippocampus, basal forebrain, amygdala, and the banks of the superior temporal sulcus. Data were analyzed by pairwise discriminant analysis, and performance in binary group discrimination was measured by correlated receiver-operating-characteristic analysis. RESULTS: The use of QUANnonunif yielded a small but systematic improvement in discrimination accuracy for normal versus converter groups (accuracy or area under the receiver-operating-characteristic curve [Az], 0.965), normal versus questionable groups (Az, 0.973), and questionable versus converter groups (Az, 0.881) compared with the results obtained with QUANunif (Az, 0.955, 0.962, and 0.866, respectively). Discrimination performance was significantly lower (P < 0.05) with STD than with QUAN in all 3 tasks (Az with STD, 0.906, 0.878, and 0.768, respectively). MRI volume estimation led to a lower overall performance in all 3 tasks than did QUANnonunif (Az with MRI, 0.947, 0.917, and 0.872, respectively). CONCLUSION: Improved quantitative image reconstruction with accurate compensation for scatter, attenuation, and variable collimator response led to significantly better performance in discrimination tasks related to the diagnosis of prodromal AD than did standard clinical reconstruction procedures. The use of a nonuniform brain attenuation map yields a small improvement in discrimination accuracy.

Dickerson BC, Salat DH, Bates JF, Atiya M, Killiany RJ, Greve DN, Dale AM, Stern CE, Blacker D, Albert MS, Sperling RA. · Department of Neurology, Gerontology Research Unit, Massachusetts General Hospital, MGH-East (149-2691), 149 13th Street, Charlestown, MA 02129, USA. · Ann Neurol. · Pubmed #15236399 No free full text.

Abstract: Functional magnetic resonance imaging (fMRI) was used to study memory-associated activation of medial temporal lobe (MTL) regions in 32 nondemented elderly individuals with mild cognitive impairment (MCI). Subjects performed a visual encoding task during fMRI scanning and were tested for recognition of stimuli afterward. MTL regions of interest were identified from each individual's structural MRI, and activation was quantified within each region. Greater extent of activation within the hippocampal formation and parahippocampal gyrus (PHG) was correlated with better memory performance. There was, however, a paradoxical relationship between extent of activation and clinical status at both baseline and follow-up evaluations. Subjects with greater clinical impairment, based on the Clinical Dementia Rating Sum of Boxes, recruited a larger extent of the right PHG during encoding, even after accounting for atrophy. Moreover, those who subsequently declined over the 2.5 years of clinical follow-up (44% of the subjects) activated a significantly greater extent of the right PHG during encoding, despite equivalent memory performance. We hypothesize that increased activation in MTL regions reflects a compensatory response to accumulating AD pathology and may serve as a marker for impending clinical decline.

Ingelsson M, Fukumoto H, Newell KL, Growdon JH, Hedley-Whyte ET, Frosch MP, Albert MS, Hyman BT, Irizarry MC. · Harvard Medical School, Massachusetts General Hospital, Boston. · Neurology. · Pubmed #15037694 No free full text.

Abstract: BACKGROUND: Pathologic changes in the Alzheimer disease (AD) brain occur in a hierarchical neuroanatomical pattern affecting cortical, subcortical, and limbic regions. OBJECTIVE: To define the time course of pathologic and biochemical changes-amyloid deposition, amyloid beta-peptide (Abeta) accumulation, neurofibrillary tangle (NFT) formation, synaptic loss, and gliosis-within the temporal association cortex of AD cases of varying disease duration, relative to control brains. METHODS: Stereologic assessments of amyloid burden and tangle density as well as ELISA-based measurements of Abeta, synaptophysin, and glial fibrillary acidic protein (GFAP) were performed in the superior temporal sulcus from a cohort of 83 AD and 26 nondemented control brains. RESULTS: Relative to control cases, AD brains were characterized by accumulation of NFT and amyloid plaques, increase of tris- and formic acid-extractable Abeta species, reduced levels of synaptophysin, and elevated levels of GFAP. In AD cases, the duration of dementia correlated with the degree of tangle formation, gliosis, and synaptic loss but not with any Abeta measures. Accumulation of Abeta, measured both neuropathologically and biochemically, was markedly increased in AD brains independent of disease duration, even in cases of short duration. CONCLUSIONS: These data support distinct processes in the initiation and progression of AD pathology within the temporal cortex: Deposition of Abeta reaches a "ceiling" early in the disease process, whereas NFT formation, synaptic loss, and gliosis continue throughout the course of the illness.