An investigation of moral judgement in frontotemporal dementia

To investigate the basis of disturbed moral judgment in patients with frontotemporal dementia (FTD).

FTD is characterized by difficulty in modulating social behavior. Patients lack social propriety and may perform sociopathic acts. In addition, FTD patients often lack empathy for others. These findings suggest alterations in the nature of morality in patients with FTD.

We administered an inventory of moral knowledge and two moral dilemmas to 26 patients with the frontal variant of FTD, 26 patients with Alzheimer disease (AD), and 26 normal control subjects. The FTD patients met Consensus Criteria for FTD and had corroborative frontal abnormalities on functional neuroimaging. The FTD and AD patients were comparably impaired on dementia measures.

All these groups showed the retention of knowledge for moral behavior and the ability to make "impersonal" moral judgments. In contrast, the FTD patients were impaired in their ability to make immediate, emotionally based moral judgments compared with the patients with AD and the normal control subjects.

These findings are consistent with an attenuation of the automatic emotional identification with others that is part of the innate moral sense. Such a disturbance may result from neurodegenerative disease affecting the ventromedial frontal cortex.