Detected with automated surface mesh modeling, regionally clustered reductions in hippocampal thickness may be a biological substrate of multiple sclerosis (MS) depression in female patients, according to a study published in the January issue of Human Brain Mapping.
Depression is frequently associated with MS, yet its neuroanatomical correlates are not well understood.
“Patients with MS often suffer from disease-related fatigue, which may resemble vegetative symptoms of depression. Fatigue itself has been linked to lower regional volumes in basal ganglia and frontal or parietal cortical regions in MS. Thus, the overlap of vegetative symptoms of depression and MS-related fatigue may potentially impede the identification of anatomical substrates,” wrote the study’s lead author, Stefan M. Gold, PhD, of University Hospital Hamburg-Eppendorf in Germany, and colleagues.
Gold and colleagues designed a cross-sectional study to characterize the role of hippocampal substructures in MS-associated depression using automated volumetric and shape analysis in a large sample of patients with MS. The researchers also strove to examine the affective, vegetative, and psychosocial components of MS depression and their relative association with hippocampal subregions.
The study evaluated 109 female patients with MS by segmenting bilateral hippocampi from MRI scans with automated tools, performing shape analysis with surface mesh modeling, and assessing depression with the Center for Epidemiologic Studies-Depression (CES-D) scale.
Eighty-three patients were classified with low depression, while 26 subjects were classified with high depression. Importantly, the right hippocampal volumes were smaller in the high depression groups than in the low depression groups. No significant differences were seen in the left hippocampal volumes.
Surface rendering analysis indicated that hippocampal shape changes in depressed patients with MS were clustered in the right hippocampus. Significant associations were seen between right hippocampal shape and affective symptoms, but not vegetative symptoms of depression.
“Our studies are designed to help us better understand how MS-related depression differs from other types, improve diagnostic imaging systems to make them more widely available and efficient, and create better, more individualized treatments for our patients,” said senior author Nancy L. Sicotte, MD, of the Cedars-Sinai Medical Center in Los Angeles, in a press release.
Future studies regarding the pathogenesis of depression in MS should include additional mechanistic markers, according to the study’s authors.