Cognitive Function and Emotional Possessing in Bilateral Facial Palsy

Based on recent findings that botulinum toxin injections in the cranial muscles might reduce emotional processing (Havas 2011), an increasing number of popular newspaper tabloids are suggesting a negative effect on cognition. The underlying research articles address the "facial feedback hypothesis". The hypothesis indicates that expressive behaviour, including facial mimic expressions influences the subject's brain via feedback. (Alam 2008) Other systemic neurological diseases, e.g of inflammatory origin, may lead to temporary bilateral facial nerve palsy (BF). During recovery process, the palsy usually remits completely. The effect of bilateral facial muscle palsy on cognition and emotional possessing has never been evaluated. The results of this pilot study might provide new information about the effect bilateral facial palsy on emotional processing and cognition and the facial feedback hypothesis. The aim of this controlled pilot study is to assess cognitive function and emotional processing in patients with bilateral facial palsy. In addition, differences in cognitive function and emotional processing in patients with different manifestations of dystonia should be evaluated. According to the facial feedback theory, paralysed mimic muscles might alter emotional processing. Therefore, investigators compare patients with bilateral facial muscle palsy and healthy controls. Investigators expect no influence of facial muscle palsy on cognitive functions in any of the tested groups; the investigators expect a mild impairment of emotional processing only in the patients group with bilateral facial muscle palsy (BEB and BF). In addition, the investigators expect no difference in emotional processing in patients with different manifestations of dystonia (BEB and CD) at remission. There might be a slight difference of emotional processing in patients with different manifestations of dystonia (BEB and CD) at time of prominent facial palsy.