The influence of right frontotemporal dysfunction on social behavior in frontotemporal dementia

Background: Frontotemporal dementia (FTD) is associated with a variety of c ognitive and behavioral dysfunctions. Symptoms may be influenced by the rel ative involvement of the right versus the left hemisphere, with left-sided FTD manifesting language changes and right-sided FTD presenting with aggres sive, antisocial, and other socially undesirable behaviors. Objective: To t est the hypothesis that right-sided FTD is associated with socially undesir able behavior. Methods: The authors assessed 41 patients with FTD diagnosed by the new research criteria for FTD1 including behavioral, neuropsycholog ic, and neurologic testing as well as SPECT and MRI. Based on visual inspec tion of SPECT scans, 12 patients were classified as having predominantly ri ght-sided and 19 patients were classified as having predominantly left-side d FTD. A clinician blinded to the imaging data reviewed medical records to tabulate the frequency of the following socially undesirable behaviors: cri minal behavior, aggression, loss of job, alienation from family/friends, fi nancial recklessness, sexually deviant behavior, and abnormal response to s pousal crisis. Results: Eleven of 12 right-sided and 2 of 19 left-sided FTD patients had socially undesirable behavior as an early presenting symptom (chi = 23.3, p < 0.001). Conclusion: The authors conclude that right-sided frontotemporal degeneration is associated with socially undesirable behavio r. The early presence of socially undesirable behavior in FTD differentiate s right-sided from left-sided degeneration. The results highlight the impor tance of the right hemisphere, especially frontotemporal regions, in the me diation of social behavior. The potential mechanism for these social losses with right-sided disease is discussed.