Liberal bias mediates emotion recognition deficits in frontal traumatic brain injury

It is well-known that patients having sustained frontal-lobe traumatic brain injury (TBI) are severely impaired on tests of emotion recognition. Indeed, these patients have significant difficulty recognizing facial expressions of emotion, and such deficits are often associated with decreased social functioning and poor quality of life. As of yet, no studies have examined the response patterns which underlie facial emotion recognition impairment in TBI and which may lend clarity to the interpretation of deficits. Therefore, the present study aimed to characterize response patterns in facial emotion recognition in 14 patients with frontal TBI compared to 22 matched control subjects, using a task which required participants to rate the intensity of each emotion (happiness, sadness, anger, disgust, surprise and fear) of a series of photographs of emotional and neutral faces. Results first confirmed the presence of facial emotion recognition impairment in TBI, and further revealed that patients displayed a liberal bias when rating facial expressions, leading them to associate intense ratings of incorrect emotional labels to sad, disgusted, surprised and fearful facial expressions. These findings are generally in line with prior studies which also report important facial affect recognition deficits in TBI patients, particularly for negative emotions.