A voxel-based morphometry study of anosmic patients

Abstract

This study examines the atrophy pattern in and between GM and WM-a subject that has not been widely researched previously.

Brain volume changes in hyposmic patients before and after olfactory training

“…Voxel‐based morphometry (VBM) is a mass‐univariate technique to detect differences in the volume of gray (GM) and white matter (WM) . Studies have reported hyposmia is correlated with a decreased volume in olfactory‐related brain regions . Whereas Bitter and colleagues were the first to describe the GM alteration in anosmic and hyposmic patients, Peng and colleagues showed an association between the duration of smell loss and amount and size of atrophies .…”

“…Whenever appropriate nonparametric tests were used, VBM analysis was done, using age, sex, and TIV as covariates in a multiple regression. An uncorrected threshold with P < .001 and a cluster size of 100 voxels was applied to investigate changes in the olfactory‐related brain areas (piriform, entorhinal, orbitofrontal, insular cortex, anterior cingulate, hippocampus, and thalamus) . To label areas of volume changes, the automated anatomic labelling atlas was used .…”

“…They assumed VBM analysis was not the right method to display changes in the relatively small structures of the primary olfactory‐related regions. As in the present study, they reported changes in the cerebellum and parahippocampal structures, and discussed especially the role of the cerebellum in olfactory perception . Yao and colleagues reported a case of a boy with congenital anosmia and performed a study with 20 healthy controls comparing GM volume.…”

“…The anterior and medial OFC, which showed a small area of significantly increased GM volume in the 16 patients with a clinically significant improvement, are part of the processing of olfactory information . Although former VBM studies showed a decrease of GM in the OFC, we were able to detect a recovery of this structure after OT. A study about the connectivity after OT also reports an increasing connectivity of the integrative network to which the OFC belongs …”

Burning odor-elicited anxiety in OEF/OIF combat veterans: Inverse relationship to gray matter volume in olfactory cortex

“…Gray matter volume in piriform cortex is related to general olfactory function, with smaller volumes indicative of odor-detection deficits (Bitter et al, 2010, Peng et al, 2013, Wattendorf et al, 2009). While odor-detection deficits in PTSD would require additional study to confirm, preliminary work in our laboratory (Cortese, Leslie, 2014) revealed mild hyposmia in combat trauma-exposed veterans with and without PTSD.…”