Tactile restoration of familiarity in Capgras syndrome following right hemorrhagic stroke: Lesion mapping, Disconnectome analysis, and lesion network characterization of multisensory person recognition.

BACKGROUND

Capgras syndrome is characterized by the delusional belief that familiar individuals have been replaced by identical impostors. Current models attribute the syndrome to disrupted affective familiarity despite preserved perceptual recognition, but the underlying network mechanisms and the role of alternative sensory modalities remain unclear.

METHODS

We studied a patient with Capgras syndrome following a right hemispheric hemorrhagic stroke. Neuropsychological assessment, behavioral experiments, and galvanic skin response recordings evaluated multimodal person recognition. Structural lesion mapping, disconnectome analysis, and lesion network mapping identified the neural substrates of the syndrome and the restoration of familiarity through tactile input.

RESULTS

The patient recognized that his wife and son looked identical to themselves but insisted they were impostors. Object, semantic, and structural face recognition were preserved, whereas emotion recognition was impaired. Visual and auditory presentation of his son failed to evoke recognition or autonomic responses. In contrast, tactile interaction restored correct identification and robust GSR responses. Network analyses demonstrated disruption of a right-lateralized network linking face-processing regions with limbic and frontal systems involved in familiarity and belief evaluation.

CONCLUSIONS

These findings support a network-disconnection model of Capgras syndrome and suggest that tactile input can transiently restore familiarity through alternative multisensory pathways.