Disgust and fear recognition in paraneoplastic limbic encephalitis

Paraneoplastic limbic encephalitis (PNLE) affects limbic portions of the brain associated with recognition of social signals of emotions. Yet it is not known whether this perceptual ability is impaired in individuals with PNLE. We therefore conducted a single case study to explore possible impairments in recognising facially, vocally and bodily expressed emotions, using standardised emotion recognition tests. Facial expression recognition was tested with two forced-choice emotion-labelling tasks using static faces with either prototypical or morphed blends of basic emotions. Recognition of vocally and bodily expressed emotions was also tested with forced-choice labelling tasks, one based on prosodic cues, the other on whole-body movement cues. We found a deficit in fear and disgust recognition from both face and voice, while recognition of bodily expressed emotions was unaffected. These findings are consistent with data from previous studies demonstrating critical roles for certain brain regions – particularly the amygdala and insular cortex – in processing facially and vocally displayed basic emotions, and furthermore, suggest that recognition of bodily expressed emotions may not depend on neural structures involved in facial and vocal emotion recognition. Impaired facial and vocal emotion recognition may form a further neuropsychological marker of limbic encephalitis, in addition to the already well-described mnestic deficits.