Emotional modulation of touch in alexithymia

Alexithymia refers to difficulties in recognizing one's own emotions, but difficulties have also been found in the recognition of others' emotions, particularly when the task is not easy. Previous research has demonstrated that, in order to understand other peoples' feelings, observers remap the observed emotion onto their own sensory systems. The aim of the present study was to investigate the ability of high and low alexithymic subjects to remap the emotional expressions of others onto their own somatosensory systems using an indirect task. We used the emotional Visual Remapping of Touch (eVRT) paradigm, in which seeing a face being touched improves detection of near-threshold tactile stimulation concurrently delivered to one's own face. In eVRT, subjects performance is influenced by the emotional content of the stimuli, while they were required to distinguish between unilateral or bilateral tactile stimulation on their own cheeks. The results show that tactile perception was enhanced when viewing touch on a fearful face compared with viewing touch on other expressions in low but not in high alexithymic participants. A negative correlation between TAS-20 alexithymia subscale ("difficulty in identify feelings") and the magnitude of the eVRT effect was also found. Conversely, arousal and valence ratings of emotional faces did not vary as a function of the degree of alexithymia. The results provide evidence that alexithymia is associated with difficulties in remapping seen emotions, particularly fear, onto one's own sensory system. This impairment could be due to an inability to modulate somatosensory system activity according to the observed emotional expression.