Sniffin' out PD

A recent article describes an MRI study evaluating atrophic changes in olfactory-related brain regions using voxel-based morphometry (VBM).  Early and moderately advanced PD patients and healthy control subjects underwent MR imaging and olfactory testing using the "Sniffin Sticks" test battery. VBM was used to assess  gray matter volumes in olfactory-related regions of the limbic and paralimbic cortex and correlations with  olfactory function. They found correlations between olfactory function and  gray mattern volumes in the right piriform cortex in early PD patients and in the right amygdala in moderatelyadvanced patients. No such relationships were seen in control subjects nor in the PD group as a whole. Although it is not completely clear why correlations were not seen for the PD group as a whole it may have to do with a progressive atrophic process and possible floor effects in the more advanced patients.