Background: It is well established that chronic alcoholism is associated with a deficit in the decoding of emotional facial expression (EFE). Nevertheless, it is still unclear whether this deficit is specifically for emotions or due to a more general impairment in visual or facial processing. This study was designed to clarify this issue using multiple control tasks and the subtraction method.
Methods: Eighteen patients suffering from chronic alcoholism and 18 matched healthy control subjects were asked to perform several tasks evaluating (1) Basic visuo-spatial and facial identity processing; (2) Simple reaction times; (3) Complex facial features identification (namely age, emotion, gender, and race). Accuracy and reaction times were recorded.
Results: Alcoholic patients had a preserved performance for visuo-spatial and facial identity processing, but their performance was impaired for visuo-motor abilities and for the detection of complex facial aspects. More importantly, the subtraction method showed that alcoholism is associated with a specific EFE decoding deficit, still present when visuo-motor slowing down is controlled for.
Conclusion: These results offer a post hoc confirmation of earlier data showing an EFE decoding deficit in alcoholism by strongly suggesting a specificity of this deficit for emotions. This may have implications for clinical situations, where emotional impairments are frequently observed among alcoholic subjects.