Decreased sensitivity to negative facial emotions and limbic lesions in patients with myotonic dystrophy type 1

Abstract

It has been noted that patients with myotonic dystrophy type I (DM 1) exhibit social cognitive impairment. However, the mechanisms of social cognitive functions in DM I have not been well examined. We investigated the recognition of facial expressions in patients with DM 1. Four DM I patients participated in the experiment. The sensitivity of basic emotions in patients with DM I was measured and compared with MRI and SPECT findings. DM I patients showed lower sensitivity to fearful, disgusted, and angry faces. DM I patients showed lesions in the anterior temporal white matter, the amygdala, the insular, and the orbitofrontal cortex. The sensitivity to facial expressions was decreased in the patients with marked lesions in the anterior temporal area. Patients with relatively mild anterior temporal lesions did not show a significant decrease in sensitivity to facial emotions. The present results indicate subcortical lesions in anterior temporal areas, including the amygdala, the insular, and the orbitofrontal cortex, in some DM 1 patients. Given that the limbic system, including the amygdala, plays an important role in emotional processing, social cognitive impairment in patients with DM I could be associated with decreased sensitivity to facial expressions caused by limbic lesions.