Alterations of the sense of "humanness" in right hemisphere predominant frontotemporal dementia patients.
OBJECTIVE
To evaluate the sense of "humanness" in frontotemporal dementia (FTD) patients with right hemispheric involvement.


BACKGROUND
Early in the course, FTD is often asymmetric, and those with predominant right frontotemporal disease have disproportionate disturbances in social behavior and empathy. A disruption in a sense of humanness may underlie these behavioral disturbances.


METHODS
Sixteen patients with asymmetric FTD on functional neuroimaging underwent recognition tests of facial masking, human-animal morphing, and facial distortion. Additional tests evaluated facial discrimination and the recognition of famous faces, facial emotions, and animate-inanimate differences.


RESULTS
On the distorted and morphed face tasks, 8 FTD patients with predominant right hemisphere involvement were significantly more likely to call morphed and distorted faces "human" as compared with both 8 FTD patients with predominant left hemisphere involvement and normal controls. The FTD groups did not differ on thresholds for recognizing masked faces or on other face recognition measures.


CONCLUSIONS
In FTD, right hemispheric involvement may alter the threshold for judging someone as human independent of the recognition of faces or facial affect. These results suggest that a specific sense of humanness facilitates a person recognition network in the right frontotemporal region of the brain.
Mendez
Mario F
MF
David Geffen School of Medicine at UCLA, The University of California at Los Angeles, Los Angeles, California, USA. Mmendez@UCLA.edu
Lim
Gerald T H
GT
D000368:Aged; D003704:Dementia / Q000473:pathology / Q000523:psychology*; D004645:Empathy; D005145:Face; D005260:Female; D005625:Frontal Lobe / Q000000981:diagnostic imaging / Q000473:pathology*; D007839:Functional Laterality; D006808:Humanism; D006801:Humans; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography; D021641:Recognition, Psychology; D012649:Self Concept; D012919:Social Behavior; D013702:Temporal Lobe / Q000000981:diagnostic imaging / Q000473:pathology*