DIFFERENCE IN ANATOMICAL PATTERN OF CORTICAL THICKNESS BETWEEN LOGOPENIC APHASIA AND PROBABLE ALZHEIMER’S DISEASE PATIENTS IN THAILAND

Abstract

We sought to demonstrate the classical anatomical pattern of cortical atrophy in Thai patients who was clinically diagnosed as logopenic aphasia (LPA) and probable Alzheimer's disease (AD), and to reveal non-classical atrophic areas that may involve in LPA but not in AD. We obtained magnetic resonance images of patients in a cohort consisting of LPA and probable AD patients to determine difference of cortical atrophy pattern between LPA and probable AD. Firstly, cortical surfaces were reconstructed from each patient's brain magnetic resonance image. Cortical thickness measurement was then processed on these surfaces. At last, thickness comparison between the two groups was performed. Our LPA patients had significant atrophy at left parieto-temporal junction [p<.01], while probable AD patients had significant regional cortical atrophy at bilateral entorhino-hippocampal region [p<.01], comparing to another group. These findings were consistent with the classical anatomical pattern of cortical atrophy. Interestingly, we also found significant regional atrophy at left [p=0.0023] and right [p=0.0011] post central gyri, left superior parietal gyrus [p=0.0017], left lingual gyrus [p=0.0071], right precentral gyrus [p=0.0004] and right rostral middle frontal gyrus [p=0.0046] in LPA, comparing to probable AD patients. We demonstrated a different cortical atrophy pattern between LPA and probable AD patients. Particularly, our study showed significant foci of cortical atrophy scattering on bilateral parietal and temporal cortices, and on right frontal cortex in LPA compared to AD. This may support the idea regarding learning disorder-related susceptibility factor for developing LPA.