J Psychiatry Neurosci 2013; 38(3): 174-182
Karim Virani, MSc; Sarah Jesso, BA; Andrew Kertesz, MD; Derek Mitchell, PhD; Elizabeth Finger, MD
Centre for Addiction and Mental Health, Departments of Pharmacology and Toxicology and Psychiatry, University of Toronto, Toronto, Ont., Canada
Background: Frontotemporal dementia (FTD) is a neurodegenerative disorder resulting in social-cognitive deficits partially attributed to abnormalities processing social cues, such as facial expressions. However, to our knowledge, the functional neuroanatomy of deficient social cue processing in individuals with FTD has not been examined. The objective of this study was to delineate the functional abnormalities under lying altered facial expression processing in individuals with FTD using functional magnetic resonance imaging (fMRI).
Methods: Patients meeting Neary criteria for behavioural variant FTD (bvFTD) with supportive neuroimaging and 18 age-matched healthy controls completed an implicit facial expression task during fMRI. We conducted volumetric brain morphometry to correct functional imaging data for volume differences.
Results: We included 20 patients with bvFTD and 18 controls in our study. The results demonstrate emotion-specific functional abnormalities in frontal and limbic regions in patients with bvFTD. Patients also showed decreased activity in posterior ventral visual regions, specifically the fusiform cortex, possibly reflecting reduced afferent input from limbic regions. Finally, bvFTD was associated with increased activity in posterior regions, including the inferior parietal cortex.
Limitations: Autopsy validation of frontotemporal dementia is not yet available for this cohort.
Conclusion: Together, these findings suggest that fMRI combined with tasks targeting social-cognitive deficits is a powerful technique to objectively measure neural systems involved in emotion processing in individuals with bvFTD. As viewing emotional expressions is known to engage many of the same neural systems that are active when experiencing the emotion itself, fMRI during expression processing provides a novel window into the emotions of patients with FTD.
Submitted Jan. 15, 2012; Revised May 29, July 5, 2012; Accepted July 10, 2012.
Competing interests: None declared for K. Virani, S. Jesso and A. Kertesz. D. Mitchell has received grant funding through his institution from the National Sciences and Engineering Research Council of Canada, Social Sciences and Humanities Research Council and the Ontario Mental Health Foundation, and receives royalties from Blackwell Publishing. E. Finger received funding for this work through her institution from a Lawson Health Research Institute grant.
Contributors: K. Virani, A. Kertesz, D. Mitchell and E. Finger designed the study. K. Virani, S. Jesso and E. Finger acquired the data, which K. Virani, S. Jesso, D. Mitchell and E. Finger analyzed. K. Virani and E. Finger wrote the article, which K. Virani, S. Jesso, A. Kertesz and D. Mitchell reviewed. All authors approved its publication.
Correspondence to: E. Finger, Department of Clinical Neurological Sciences, University of Western Ontario, B10-004, 339 Windermere Rd., London ON N6A 5A5; Elizabeth.Finger@lhsc.on.ca