Quantitative estimations of the entorhinal cortex in Alzheimer's disease

OBJECTIVE: To detect and quantify structural parameters in the entorhinal cortex (EC) of potential use in Alzheimer's disease (AD). STUDY DESIGN: We estimated by stereologic tools the total volume of the EC and subfields EI and ER, the number of neurons and the volume-weighted mean soma volume of layer II neurons. EC morphometric parameters were also assessed in both control and AD cases. RESULTS: In AD, EC volume decreased by 35%, while total number of neurons reached 51%. Also, neuron density had a significant decrease mainly due to change in the El subfield (31 % decrease). The EC showed a decrease in size and a morphology more elliptic and irregular. Moreover, layer II neurons soma size (volume, area, and 1 -dimensional parameters) were more rounded. Thus the EC decreases in size and neuron number in AD and minor changes in number per volume were noted. CONCLUSION. These quantitative data can be of value in volumetric MRI studies in AD patients.