Hoarding and obsessive-compulsive behaviours are well documented symptoms in FTD. While contemporary models consider hoarding and obsessive-compulsive disorder distinct, the behaviours have not been separately examined in patients with FTD. The neuroanatomical correlates of hoarding in patients with FTD have not been determined, while findings for OCB have been inconsistent.

To elucidate the neuroanatomical basis of hoarding and obsessive-compulsive behaviours (OCB) in frontotemporal dementia (FTD). 

Patients with FTD who were evaluated between April 2004 and May 2018 at our centre were included. The presence of hoarding or OCB was ascertained through review of all available clinical evaluations and symptom questionnaires. Cortical thickness and subcortical volumetric analyses were completed on available T1 high resolution anatomic scans using FreeSurfer.

We identified 87 patients who met inclusion criteria. 49 had scans available for quantitative MRI volumetric analysis. New or increased hoarding behaviours were present in 28% of patients, while 49% of individuals had new or increased OCB. Hoarding behaviours were more commonly associated with the semantic variant subtype of FTD, while non-fluent primary progressive aphasia was less frequently associated with OCB or hoarding.  Hoarding behaviours were associated with decreased left inferior temporal, superior temporal and temporal pole cortical thickness. The presence of OCB was predicted by greater cortical thickness in the right superior, middle, inferior temporal cortices.