Year: 2010
Type: article
Study designs: Systematic Review, Meta-Analysis
Abstract: The identification of biological markers at early stages of Alzheimer's disease (AD) contributes to diagnostic accuracy and adds prognostic value. Early diagnosis is very important as treatment and preventive interventions will be more efficacious if started at pre-dementia stages. Structural magnetic resonance imaging (MRI) is a safe and widely available method and is a promising tool to improve accuracy of early diagnosis. However, in spite of recent developments, results of neurostructural imaging studies on predicting conversion to AD are not uniform. We aimed to conduct a systematic review and meta-analysis of voxel-based morphometry (VBM) studies about the neurostructural predictors of conversion to AD. We carried out a systematic and comprehensive search in September 18, 2009 using Medline, ISI Web of Science, PsycInfo, Embase and Scopus databases for longitudinal VBM studies investigating conversion to AD. We selected studies that used whole brain VBM methods to compare converters and non-converters according to baseline brain MRI. Meta-analysis was based on the activation likelihood estimation method using the revised algorithm in Ginger Ale 2.0 program. This method aims to indicate the anatomical convergence between results from different studies and requires the input of the reported coordinates and the sample sizes of each study. The meta-analytical statistical threshold was set at a false discovery rate p < 0.01 and a minimum cluster extent of 100mm. Ten studies met the inclusion criteria. Nine reported baseline regional gray matter (GM) atrophy in mild cognitive impairment (MCI) or healthy subjects who progressed to AD. Out of the ten studies, six included subjects with amnestic MCI (aMCI) at baseline. These studies comprised a total of 429 aMCI subjects, of which 142 converted to AD. Meta-analysis of the 31 coordinates from these six studies yielded one significant cluster of GM volumetric reduction in aMCI patients who converted to AD, located in the left hippocampus and parahippocampal gyrus (see figure). Atrophy in aMCI patients who convert to AD is a consistent finding across studies. Meta-analysis showed that left medial temporal lobe atrophy is the most consistent neurostructural biomarker to predict conversion from aMCI to AD.
Source: Alzheimer s & Dementia
Institution: Universidade de São Paulo
Language: English
Subfield: Psychiatry and Mental health
Field: Medicine
Domain: Health Sciences
Open Access status: bronze
OpenAlex ID: W2022854061