It is well known that regions of the brain exhibit functional synchrony. A well established method is the average cross correlation termed the COSLOF index which has proved useful as a noninvasive quantitative marker of hippocampal synchrony for the preclinical stage of Alzheimer's disease. This paper presents the COMDET, an alternative index of functional synchrony, and compares it to the COSLOF with their statistical underpinnings. Logarithmic functions of these two statistics are presented with their asymptotic chi squared distributions. These two statistics are empirically compared under five correlation structures. It is found that the COMDET performs better than the COSLOF except under very specific cases. Critical values of the COMDET and COSLOF as well as their logarithmic functions are presented which are determined via Monte Carlo simulation.
Copyright 2003, Walter de Gruyter
