Autopsy consent, brain collection, and standardized neuropathologic assessment of ADNI participants: The essential role of the Neuropathology Core

Alzheimer's Disease Research Center, Washington University School of Medicine, St. Louis, MO 63110, USA.
Alzheimer's & dementia: the journal of the Alzheimer's Association (Impact Factor: 12.41). 05/2010; 6(3):274-9. DOI: 10.1016/j.jalz.2010.03.012
Source: PubMed


Our objectives are to facilitate autopsy consent, brain collection, and perform standardized neuropathologic assessments of all Alzheimer's Disease Neuroimaging Initiative (ADNI) participants who come to autopsy at the 58 ADNI sites in the USA and Canada.
Building on the expertise and resources of the existing Alzheimer's Disease Research Center (ADRC) at Washington University School of Medicine, St. Louis, MO, a Neuropathology Core (NPC) to serve ADNI was established with one new highly motivated research coordinator. The ADNI-NPC coordinator provides training materials and protocols to assist clinicians at ADNI sites in obtaining voluntary consent for brain autopsy in ADNI participants. Secondly, the ADNI-NPC maintains a central laboratory to provide uniform neuropathologic assessments using the operational criteria for the classification of AD and other pathologies defined by the National Alzheimer Coordinating Center (NACC). Thirdly, the ADNI-NPC maintains a state-of-the-art brain bank of ADNI-derived brain tissue to promote biomarker and multi-disciplinary clinicopathologic studies.
During the initial year of funding of the ADNI Neuropathology Core, there was notable improvement in the autopsy rate to 44.4%. In the most recent year of funding (September 1(st), 2008 to August 31(st) 2009), our autopsy rate improved to 71.5%. Although the overall numbers to date are small, these data demonstrate that the Neuropathology Core has established the administrative organization with the participating sites to harvest brains from ADNI participants who come to autopsy.
Within two years of operation, the Neuropathology Core has: (1) implemented a protocol to solicit permission for brain autopsy in ADNI participants at all 58 sites who die and (2) to send appropriate brain tissue from the decedents to the Neuropathology Core for a standardized, uniform, and state-of-the-art neuropathologic assessment. The benefit to ADNI of the implementation of the NPC is very clear. Prior to the establishment of the NPC in September 2007, there were 6 deaths but no autopsies in ADNI participants. Subsequent to the establishment of the Core there have been 17 deaths of ADNI participants and 10 autopsies. Hence, the autopsy rate has gone from 0% to 59%. The third major accomplishment is the detection of co-existent pathologies with AD in the autopsied cases. It is possible that these co-morbidities may contribute to any variance in ADNI data.

Download full-text


Available from: Nigel J. Cairns, Nov 03, 2014
  • Source
    • "The ADNI Neuropathology Core (ADNI-NPC) was funded and established at Washington University in St. Louis in September 2007; therefore no autopsies were performed on deceased ADNI subjects prior to this time. Established procedures for obtaining informed consent for autopsy and the autopsy procedures has been previously described [41]. Briefly, participating centers undertake their own brain assessment and provide standard sets of fixed tissue blocks/sections and frozen sections to the ADNI-NPC or send the brain to the ADNI-NPC if the center does not routinely perform neuropathological assessments. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Autopsy series commonly report a high percentage of coincident pathologies in demented patients, including patients with a clinical diagnosis of dementia of the Alzheimer type (DAT). However many clinical and biomarker studies report cases with a single neurodegenerative disease. We examined multimodal biomarker correlates of the consecutive series of the first 22 Alzheimer's Disease Neuroimaging Initiative autopsies. Clinical data, neuropsychological measures, cerebrospinal fluid Aβ, total and phosphorylated tau and α-synuclein and MRI and FDG-PET scans. Clinical diagnosis was either probable DAT or Alzheimer's disease (AD)-type mild cognitive impairment (MCI) at last evaluation prior to death. All patients had a pathological diagnosis of AD, but only four had pure AD. A coincident pathological diagnosis of dementia with Lewy bodies (DLB), medial temporal lobe pathology (TDP-43 proteinopathy, argyrophilic grain disease and hippocampal sclerosis), referred to collectively here as MTL, and vascular pathology were present in 45.5%, 40.0% and 22.7% of these patients, respectively. Hallucinations were a strong predictor of coincident DLB (100% specificity) and a more severe dysexecutive profile was also a useful predictor of coincident DLB (80.0% sensitivity and 83.3% specificity). Occipital FDG-PET hypometabolism accurately classified coincident DLB (80% sensitivity and 100% specificity). Subjects with coincident MTL showed lower hippocampal volume. Biomarkers can be used to independently predict coincident AD and DLB pathology, a common finding in amnestic MCI and DAT patients. Cohorts with comprehensive neuropathological assessments and multimodal biomarkers are needed to characterize independent predictors for the different neuropathological substrates of cognitive impairment.
    Full-text · Article · Oct 2013
  • Source
    • "While the autopsy numbers at this point are small, to date 10 of our subjects have come to autopsy bearing the clinical diagnosis of either mild cognitive impairment (n = 2) or Alzheimer's dementia (n = 8) at the time of death. Of these, four (40%) had autopsy findings of Alzheimer's pathology without any other significant co-morbidity and six (60%) had autopsy findings of mixed Alzheimer's pathology (Cairns et al., 2010). While subjects with mixed pathology are not addressed by the 'biomarker Figure 3 Hypothetical effects of pure Alzheimer's pathology versus mixed pathology on time-to-progression from mild cognitive impairment to dementia. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Biomarkers of brain Aβ amyloid deposition can be measured either by cerebrospinal fluid Aβ42 or Pittsburgh compound B positron emission tomography imaging. Our objective was to evaluate the ability of Aβ load and neurodegenerative atrophy on magnetic resonance imaging to predict shorter time-to-progression from mild cognitive impairment to Alzheimer's dementia and to characterize the effect of these biomarkers on the risk of progression as they become increasingly abnormal. A total of 218 subjects with mild cognitive impairment were identified from the Alzheimer's Disease Neuroimaging Initiative. The primary outcome was time-to-progression to Alzheimer's dementia. Hippocampal volumes were measured and adjusted for intracranial volume. We used a new method of pooling cerebrospinal fluid Aβ42 and Pittsburgh compound B positron emission tomography measures to produce equivalent measures of brain Aβ load from either source and analysed the results using multiple imputation methods. We performed our analyses in two phases. First, we grouped our subjects into those who were 'amyloid positive' (n = 165, with the assumption that Alzheimer's pathology is dominant in this group) and those who were 'amyloid negative' (n = 53). In the second phase, we included all 218 subjects with mild cognitive impairment to evaluate the biomarkers in a sample that we assumed to contain a full spectrum of expected pathologies. In a Kaplan-Meier analysis, amyloid positive subjects with mild cognitive impairment were much more likely to progress to dementia within 2 years than amyloid negative subjects with mild cognitive impairment (50 versus 19%). Among amyloid positive subjects with mild cognitive impairment only, hippocampal atrophy predicted shorter time-to-progression (P < 0.001) while Aβ load did not (P = 0.44). In contrast, when all 218 subjects with mild cognitive impairment were combined (amyloid positive and negative), hippocampal atrophy and Aβ load predicted shorter time-to-progression with comparable power (hazard ratio for an inter-quartile difference of 2.6 for both); however, the risk profile was linear throughout the range of hippocampal atrophy values but reached a ceiling at higher values of brain Aβ load. Our results are consistent with a model of Alzheimer's disease in which Aβ deposition initiates the pathological cascade but is not the direct cause of cognitive impairment as evidenced by the fact that Aβ load severity is decoupled from risk of progression at high levels. In contrast, hippocampal atrophy indicates how far along the neurodegenerative path one is, and hence how close to progressing to dementia. Possible explanations for our finding that many subjects with mild cognitive impairment have intermediate levels of Aβ load include: (i) individual subjects may reach an Aβ load plateau at varying absolute levels; (ii) some subjects may be more biologically susceptible to Aβ than others; and (iii) subjects with mild cognitive impairment with intermediate levels of Aβ may represent individuals with Alzheimer's disease co-existent with other pathologies.
    Full-text · Article · Oct 2010 · Brain
  • [Show abstract] [Hide abstract]
    ABSTRACT: Vocoders compress speech by estimating model parameters at a given transmission rate over an analysis window, assuming that speech is stationary within this window. In this paper, the limits of this assumption are explored with regard to the spectral envelope parameters in the form of line spectral frequency (LSF) parameters. It is shown that all LSF parameters have considerable variations over time, regardless of LSF vector extraction and transmission rates. LSF track variations are investigated through oversampling and are shown to contain high frequency variations above the frequency corresponding to the LSF vector transmission rate. An anti-aliasing filter with cut-off frequency adequate for the chosen LSF vector transmission rate is proposed to alleviate possible spectral overlapping of the LSF parameter spectra. It is confirmed, through experiments, that the proposed method offers an advantage over the classic LSF extraction method with respect to quantisation shown by bit savings of typically 10 to 15%.
    No preview · Conference Paper · Nov 2002
Show more