Undifferentiation of somatic responses to emotions in a case of functional amnesia

The term functional amnesia (FA) has been proposed for cases of memory impairment presenting with severe retrograde amnesia in the absence of cerebral injury or history of psychiatric disturbance. Emotional flattening has often been reported alongside FA, however the mechanism of such a modification is unknown. This study aimed to explore the emotional processing in a rare case of a patient with FA complaining of severe emotional flattening. We presented ecological dynamic video stimuli conveying strong peaceful and fearful emotions to the patient and 13 controls. We then explored their emotional responses considering both conscious emotional judgements and automatic psychophysiological responses (skin conductance) and facial muscular activity (corrugator supercilii). Both patient P.P. and controls perfectly recognized the emotions conveyed by the films. However, P.P. failed to show an increased skin conductance and corrugator activity as found in controls during fearful film extracts compared with peaceful extracts. Taken together, these finding demonstrate the presence of an emotional deficit, characterized by a failure to generate appropriate somatic responses to positive and negative stimuli. Although this altered somatic processing did not interfere with PP's explicit recognition of emotion, it modified his emotional experience, thereby constituting a possible explanation for his emotional flattening. This study therefore suggests that FA is not limited to a mnemonic impairment, but is a more complex disorder, involving also the processing of emotionally loaded experiences.