Prediction of Alzheimer's disease pathophysiology based on cortical thickness patterns

Abstract

IntroductionRecent studies have shown that pathologically defined subtypes of Alzheimer's disease (AD) represent distinctive atrophy patterns and clinical characteristics. We investigated whether a cortical thickness–based clustering method can reflect such findings.MethodsA total of 77 AD subjects from the Alzheimer's Disease Neuroimaging Initiative 2 data set who underwent 3-T magnetic resonance imaging, [18F]-fluorodeoxyglucose-positron emission tomography (PET), [18F]-Florbetapir PET, and cerebrospinal fluid (CSF) tests were enrolled. After clustering based on cortical thickness, diverse imaging and biofluid biomarkers were compared between these groups.ResultsThree cortical thinning patterns were noted: medial temporal (MT; 19.5%), diffuse (55.8%), and parietal dominant (P; 24.7%) atrophy subtypes. The P subtype was the youngest and represented more glucose hypometabolism in the parietal and occipital cortices and marked amyloid-beta accumulation in most brain regions. The MT subtype revealed more glucose hypometabolism in the left hippocampus and bilateral frontal cortices and less performance in memory tests. CSF test results did not differ between the groups.DiscussionCortical thickness patterns can reflect pathophysiological and clinical changes in AD.

Distinct subtypes of Alzheimer’s disease based on patterns of brain atrophy: longitudinal trajectories and clinical applications

“…Despite this, when comparing our results with other studies, the characteristics of our AD subtypes are largely comparable with what has previously been reported. The typical AD subtype has previously been found to be among the oldest12491115, have later onset1491115, include a higher frequency of males211, and have similar disease duration to limbic-predominant and hippocampal-sparing1911. Contrary to our finding, hippocampal-predominant AD has been found to be among the oldest groups14915 and to have shorter disease duration14.…”

“…The typical AD subtype has previously been found to be among the oldest12491115, have later onset1491115, include a higher frequency of males211, and have similar disease duration to limbic-predominant and hippocampal-sparing1911. Contrary to our finding, hippocampal-predominant AD has been found to be among the oldest groups14915 and to have shorter disease duration14. An explanation could be that atrophy in the medial temporal lobe is frequent in normal aging, hence clinical cut-offs for the medial temporal atrophy (MTA) scale are age-corrected19.…”

“…Limbic-predominant AD and the group with no atrophy showed slower progression than typical AD and hippocampal-sparing AD11. Data-driven approaches using MRI data have largely confirmed these pathologically defined subtypes121415. Other authors have also applied data-driven approaches to cognitive data but the resulting subtypes differ noticeably from study to study351617.…”

Neuroimaging markers of global cognition in early Alzheimer's disease: A magnetic resonance imaging–electroencephalography study

“…Especially, atrophy patterns in the left temporal, frontal, and parietal lobe are in accord with previous studies (Du et al, 2007;Hwang et al, 2016). Especially, atrophy patterns in the left temporal, frontal, and parietal lobe are in accord with previous studies (Du et al, 2007;Hwang et al, 2016).…”

Thinner temporal and parietal cortex is related to incident clinical progression to dementia in patients with subjective cognitive decline

“…The predictive values of hippocampal volumes and medial temporal cortex were quite comparable, although the predictive value of the medial temporal lobe was slightly stronger. Moreover, hippocampal volume did not add any predictive value over the effect of cortical thickness of the medial temporal lobe [39,47]. Of note, hippocampus volume was the only brain region associated with clinical progression to MCI, thus likely an early marker for AD.…”