The N170 and face perception in psychiatric and neurological disorders: A systematic review

Objective: To systematically evaluate evidence for configural and affective face processing abnormalities as measured by the N170 and Vertex Positive Potential (VPP) event-related potential components, and analogous M170 magnetoencephalography (MEG) component, in neurological and psychiatric disorders. Methods: 1251 unique articles were identified using PsychINFO and PubMed databases. Sixty-seven studies were selected for review, which employed various tasks to measure the N170, M170 or VPP; the 13 neurological/psychiatric conditions were Attention-Deficit Hyperactivity Disorder (ADHD), Alcohol Dependence, Alzheimer's Disease, Autism Spectrum Disorders (ASDs), Bipolar Disorder, Bulimia Nervosa, Fibromyalgia, Huntington's Disease, Major Depressive Disorder, Parkinson's Disease, Prosopagnosia, Schizophrenia and Social Phobia. Results: Smaller N170 and VPP amplitudes to faces compared to healthy controls were consistently reported in Schizophrenia but not in ASDs. In Schizophrenia N170 and VPP measures were not correlated with clinical symptoms. Findings from other disorders were highly inconsistent; however, reported group differences were almost always smaller amplitudes or slower latencies to emotional faces in disordered groups regardless of diagnosis. Conclusions: Results suggest that N170/VPP abnormalities index non-specific facial affect processing dysfunction in these neurological and psychiatric conditions, reflecting social impairments being broadly characteristic of these groups. Significance: The N170 and analogous components hold promise as diagnostic and treatment monitoring biomarkers for social dysfunction.