Cosmetic appreciation and emotional processing in patients with a peripheral facial palsy: A systematic review.

Background; The goal of this review is 1) to summarize the studies assessing PFP by casual observers, patients themselves and the cosmetic appreciation of the PFP and 2) to summarize the studies assessing whether there is a difference in emotional recognition/processing of facial emotions and/or cognitive tasks in patients with a PFP. Materials and Methods; A multi-database systematic literature search was performed using the following databases: Pubmed, Embase, Medline, and The Cochrane Library from the earliest date of each database up to December 2019. Population of interest consisted of patients with a PFP and studies that investigated cosmetic appreciation and/or emotional recognition and/or emotional processing in these patients. Two authors rated the methodological quality of the included studies independently using the 'Newcastle - Ottawa Quality Assessment Scale' for nonrandomised studies' (NOS). Two authors extracted the outcome data regarding cosmetic appreciation and/or emotional recognition/processing from the included studies. Results; Twelve hundred and thirty-two studies were found of which eleven studies met the inclusion criteria. Most studies were assessed to be of 'fair' to 'good' methodological quality. The Cohen's kappa (between author RL and SP) was 0.68. Two studies investigated emotional processing and/or emotional recognition. Nine studies investigated cosmetic appreciation in both patients and casual observers. Important findings of this systematic review are that there is a correlation between the perceived severity of the PFP of the patients and the ratings by casual observers. Secondly there seems to be a laterality difference in cosmetic appreciation and thirdly there might to be a decreased emotional recognition and processing in patients with a PFP. Conclusion; Emotional recognition and cosmetic appreciation in patients with a PFP is an under investigated area, in which further studies are needed to substantiate the findings in current literature.