Brianna Harris

Summer Research Description: The neurodegenerative changes in Alzheimer’s disease (AD) begin in the hippocampus early in the disease and later spread to the neocortex.  This study focused on individuals with mild cognitive impairment (MCI; a prodromal stage of AD) and compared four methods used to measure hippocampal volume: manual tracing, FreeSurfer, FSL, and Mutli-Atlas.  My hypotheses were 1) the four methods would be highly correlated and 2) manual tracing would be the most sensitive method.  20 participants were included in the study (10 MCI, 10 cognitively normal age-matched controls).  Pearson correlations were run to compare measures, and independent sample t-tests were run to evaluate group differences.  Cohen’s d and the area under the curve were used to measure sensitivity and specificity.  There was a positive correlation between the four methods (r≥0.81, p≤7.936×10-4).  In t-test analyses we observed significant group differences (p<0.05) for manual tracing left and right hippocampus, multi-atlas left and right hippocampus, and FreeSurfer right hippocampus.  Manual tracing was most sensitive and specific (AUC=0.73, d=1.04).  As predicted, all methods of measuring hippocampal volume were highly correlated.  Manual tracing, the current gold standard, was the most sensitive and specific.  Future work will expand the sample and evaluate the proprietary software package NeuroQuant.