Emotion recognition in people with Huntington's disease: A comprehensive systematic review

Background Deficits of emotion recognition have received increasing attention in people with Huntington's disease (HD) in the three decades since the discovery of the HD gene. However, the characterisation of such deficits across different disease stages, types of stimuli, and sensory modalities is currently unclear. Objective This study aimed to provide a comprehensive review of the evidence on emotion recognition deficits in HD gene carriers (both manifest and premanifest) over the three decades since definitive gene testing. Method A systematic review was carried out from January 1993 to January 2025 across MEDLINE, PsycINFO, Academic Search Complete, and CINAHL (PROSPERO registration: CRD42023398649). Results From 9735 initial citations, 59 studies were eventually included. In manifest HD, facial recognition of negative emotions such as anger, fear, disgust, and sadness was consistently impaired, whereas happiness and neutral expressions were generally spared. A few auditory studies showed consistent deficits for disgust, fear, and anger, while happiness and sadness appeared less affected. Only preliminary evidence is currently available for deficits involving body language, visual and written vignettes, videos, and olfactory and gustatory tasks. Although sparser, the evidence for premanifest HD suggests that some individuals may develop significant recognition difficulties prior to motor onset, particularly due to early frontostriatal deterioration and white matter disruption. Conclusions Impairments of facial recognition of negative emotions are reported consistently in manifest HD, while only preliminary results are available for other modalities. The evidence involving premanifest HD is much sparser. Key implications for clinical practice and future research are outlined and discussed.