Tracking atrophy progression in familial Alzheimer's disease: A serial MRI study
ABSTRACT Serial MRI scanning of autosomal dominant mutation carriers for Alzheimer's disease provides an opportunity to track changes that could predate symptoms or clinical diagnosis of the disease. We used hierarchical modelling to assess how hippocampal and whole-brain volumes change as familial Alzheimer's disease progresses from the presymptomatic stage through to diagnosis.
Nine mutation carriers had serial clinical assessments and volumetric MRI scans (41 scans: range 3-8 per patient) at different clinical stages (presymptomatic, mild cognitive impairment, or clinical Alzheimer's disease). 25 healthy controls had serial scanning (54 scans: range 2-4 per patient) for comparison. We measured whole brain and total hippocampal volumes using semi-automated techniques, and adjusted for total intracranial volume. Hierarchical models were developed to estimate differences in volume and atrophy rate between mutation carriers and controls in relation to when the disease was clinically diagnosed.
Mutation carriers had significantly increased hippocampal and whole-brain atrophy rates compared with controls and these differences increased with time. Differences in hippocampal and whole-brain atrophy rates between controls and mutation carriers were evident 5.5 and 3.5 years, respectively, before diagnosis of Alzheimer's disease. At a cross-sectional level, differences in mean hippocampal volume between mutation carriers and controls became significant 3 years before clinical diagnosis, whereas differences in mean brain volumes became significant only 1 year before diagnosis.
Structural changes can be seen on MRI scans that predate the clinical onset of familial Alzheimer's disease. Longitudinal measures of atrophy rates can identify differences between mutation carriers and controls 2-3 years earlier than cross-sectional volumetric measures.
- SourceAvailable from: Pieter Jelle Visser
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- "immediately preceding diagnosis). Our results further correspond with the observation that the earliest pathological changes in AD usually occur in the medial temporal lobe regions, which are known to be critical for episodic memory functioning (Ridha et al. 2006; Sluimer et al. 2009). Moreover, our established multi-domain decline in pre-demented subjects also matches findings of spread pathology before AD diagnosis, indicating that multiple brains structures, like the parietal (Jacobs et al. 2011), and frontal cortex (Burgmans et al. 2009) are affected. "
ABSTRACT: We investigated the course of decline in multiple cognitive domains in non-demented subjects from a memory clinic setting, and compared pattern, onset and magnitude of decline between subjects who progressed to Alzheimer's disease (AD) dementia at follow-up and subjects who did not progress. In this retrospective cohort study 819 consecutive non-demented patients who visited the memory clinics in Maastricht or Amsterdam between 1987 and 2010 were followed until they became demented or for a maximum of 10 years (range 0.5-10 years). Differences in trajectories of episodic memory, executive functioning, verbal fluency, and information processing speed/attention between converters to AD dementia and subjects remaining non-demented were compared by means of random effects modelling. The cognitive performance of converters and non-converters could already be differentiated seven (episodic memory) to three (verbal fluency and executive functioning) years prior to dementia diagnosis. Converters declined in these three domains, while non-converters remained stable on episodic memory and executive functioning and showed modest decline in verbal fluency. There was no evidence of decline in information processing speed/attention in either group. Differences in cognitive performance between converters to AD dementia and subjects remaining non-demented could be established 7 years prior to diagnosis for episodic memory, with verbal fluency and executive functioning following several years later. Therefore, in addition to early episodic memory decline, decline in executive functions may also flag incident AD dementia. By contrast, change in information processing speed/attention seems less informative.Psychological Medicine 11/2014; 45(07):1-11. DOI:10.1017/S0033291714002645 · 5.43 Impact Factor
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- "Reiman et al.  reported a different pattern in their study with an increase in CSF A␤ 42 and reduced gray matter volume in the right parietal lobe on MRI 20 years before onset. Finally, a longitudinal study by Ridha et al.  showed differences between mutation carriers and controls in hippocampal and whole brain atrophy rates 5.5 and 3.5 years, respectively, before AD diagnosis. Despite the discrepancies described above, the results from the studies in different FAD populations seem to be more consistent than inconsistent, with abnormalities in CSF biomarkers and on MRI generally being observed in preclinical FAD. "
ABSTRACT: Objective: To compare cerebrospinal fluid (CSF) biomarkers and brain structure in preclinical mutation carriers (MC) and non-carriers (NC) from families with familial Alzheimer disease (FAD). Methods: The study included members from four Swedish families at risk for carrying an APPswe, APParc, PSEN1 H163Y or PSEN1 I143T mutation. Magnetic resonance imaging (MRI) scans were obtained from 13 MC and 20 NC and analyzed using vertex-based analyses of cortical thickness and volume. CSF was collected from 10 MC and 12 NC and analyzed for Aβ42, tau-protein and phospho-tau. Results: The MC had significantly lower levels of CSF Aβ42 and higher levels tau-protein and phospho-tau than the NC. There was a trend showing a decrease in Aβ42 15 – 20 years before expected onset of clinical symptoms, while a trend of increasing tau-protein and phospho-tau was observed closer to expected onset. The MC had decreased volume on MRI in the left precuneus, superior temporal gyrus and fusiform gyrus. Conclusions: Aberrant biomarker levels in CSF as well as regional brain atrophy are present in preclinical FAD, several years before the expected onset of clinical symptoms.Journal of Alzheimer's disease: JAD 08/2014; In-press. · 3.61 Impact Factor
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- "The hippocampus is one of the earliest site of pathological changes (Braak and Braak 1991) and atrophy (Jack et al. 1999; Ridha et al. 2006) in Alzheimer's disease (AD). Magnetic resonance imaging (MRI) based measurement of volume and volume change in the hippocampus may be useful markers for AD diagnosis and tracking progression (Dubois et al. 2010; Henneman et al. 2009; Jack et al. 2005, 2008b; Wang et al. 2009). "
ABSTRACT: Hippocampal volumetric measures may be useful for Alzheimer’s disease (AD) diagnosis and disease tracking; however, manual segmentation of the hippocampus is labour-intensive. Therefore, automated techniques are necessary for large studies and to make hippocampal measures feasible for clinical use. As large studies and clinical centres are moving from using 1.5 Tesla (T) scanners to higher field strengths it is important to assess whether specific image processing techniques can be used at these field strengths. This study investigated whether an automated hippocampal segmentation technique (HMAPS: hippocampal multi-atlas propagation and segmentation) and volume change measures (BSI: boundary shift integral) were as accurate at 3T as at 1.5T. Eighteen Alzheimer’s disease patients and 18 controls with 1.5T and 3T scans at baseline and 12-month follow-up were used from the Alzheimer’s Disease Neuroimaging Initiative cohort. Baseline scans were segmented manually and using HMAPS and their similarity was measured by the Jaccard index. BSIs were calculated for serial image pairs. We calculated pair-wise differences between manual and HMAPS rates at 1.5T and 3T and compared the SD of these differences at each field strength. The difference in mean Jaccards (manual and HMAPS) between 1.5T and 3T was small with narrow confidence intervals (CIs) and did not appear to be segmentor dependent. The SDs of the difference between volumes from manual and automated segmentations were similar at 1.5T and 3T, with a relatively narrow CI for their ratios. The SDs of the difference between BSIs from manual and automated segmentations were also similar at 1.5T and 3T but with a wider CI for their ratios. This study supports the use of our automated hippocampal voluming methods, developed using 1.5T images, with 3T images.Neuroinformatics 07/2014; 12(3). DOI:10.1007/s12021-013-9217-y · 3.10 Impact Factor