Association between visual rating of posterior cortical atrophy and the rate of cognitive decline in Alzheimer's disease

Abstract

Rate of disease progression in Alzheimers disease (AD) is associated with prognosis in terms of mortality and caregiver dependency. Rapid progressive AD patients have different characteristics compared with slow progressive patients. Some researchers have found that brain morphological changes correlate with rate of AD progression. Recent Voxel-based morphometric (VBM) analysis demonstrated that AD patients with rapid cognitive decline had a more extensive cortical atrophy than slow decliners, especially in the medial occipito-parietal areas. Nonetheless, there is a limit to apply VBM analysis in individual patients. Recently, easily applicable posterior visual rating scale is developed which can evaluate the posterior cortical atrophy. In this study we investigated the relation between visual rating scale of posterior cortical atrophy and the progression rate of disease in early stage of AD patients. This was a retrospective cohort study from newly diagnosed AD patients who visited Seoul National University Bundang Hospital. 106 AD patients with initial MMSE score 21 to 26 were followed up for 1 year. We measured posterior atrophy scale and one-year follow-up MMSE score to see whether brain atrophy according to posterior atrophy scale is associated with rapid cognitive decline after one year. Rapid cognitive decline (≥3 score drop in MMSE test) at one year follow-up occurred in 27 subjects (25.5%). In logistic regression analysis, posterior atrophy in brain MRI was associated with rapid cognitive decline in one-year follow-up (regression coefficient 2.79, 95% CI 1.16 to 6.97, p=0.028). While, medial temporal lobe atrophy or frontal atrophy showed no significant association with rapid cognitive decline. This study showed that an easily measurable posterior visual rating scale can predict the rate of disease progression in early AD patients.