Emotional processing in behavioral variant frontotemporal dementia.

摘要

Behavioral variant frontotemporal dementia (bvFTD) is the second most prevalent form of dementia and may be the primary cause of dementia in individuals under age 65. It is characterized by early changes in behavior, which can include apathy, disinhibition, obsessive and compulsive acts, emotional blunting, and a loss of sympathy and empathy. A number of studies have found that bvFTD patients show significant impairment in recognizing emotion through facial expression. However, it is unclear at this time whether this deficit represents an underlying impairment in all emotional processing or if some emotional processing remains preserved but cannot be incorporated into a behavioral response. The purpose of the present study was to examine the ability of bvFTD patients to implicitly process emotional information and compare this with their ability to explicitly process emotional information. Experimental tasks that measure both implicit and explicit processing of emotional material in faces and words were administered. Implicit emotional processing was measured with two tasks, a gender discrimination task that incorporated both emotional or neutral facial expressions and a lexical decision task, which contained both emotional and neutral words. Explicit emotional processing was assessed with two tasks. In the first, patients had to recognize facial expressions of the six basic emotions, as well as neutral facial expressions. In the second, patients were required to determine if single English words were emotional or neutral. It was hypothesized that patients with bvFTD, in comparison to cognitively normal age- and education-matched control subjects, would have difficulty explicitly processing emotional information but would show preserved implicit processing of emotional information. Results of the study indicate that bvFTD patients show some preserved implicit processing of emotional information, specifically in the domain of single word processing. Additionally, bvFTD patients displayed a dissociation in their explicit processing of emotions across all domains, showing marked impairment in their processing of negative emotional information despite preserved processing of positive emotional information. These results suggest that deficits in emotional processing are not as pervasive in this population as originally thought and that preserved implicit emotional processing can, in fact, influence the behavioral responding of these patients.