Delusional misidentification incident in a right hemisphere stroke patient

Area of Science:

• Neuroscience
• Psychiatry
• Cognitive Psychology

Background:

• Delusional misidentification can occur after brain injury.
• Right hemisphere damage is associated with specific cognitive deficits.
• Frégoli delusion is a rare misidentification syndrome.

Purpose of the Study:

• To investigate a case of delusional misidentification following a right hemisphere stroke.
• To analyze the face processing abilities of an individual with right hemisphere damage.
• To explore the relationship between stroke-induced brain injury and delusional misidentification syndromes.

Main Methods:

• Case study of a patient (HW) with a right hemisphere stroke.
• Assessment of face recognition, familiar face recognition, and facial expression matching.
• Evaluation of unfamiliar face matching using standardized tests (Benton test) and novel tasks (disguised vs. undisguised faces).

Main Results:

• The patient experienced a prolonged delusional misidentification, mistaking a student for his daughter.
• Face processing abilities revealed intact familiar face recognition and facial expression matching.
• Severe impairments were observed in matching unfamiliar faces, including on the Benton test and disguised face tasks.

Conclusions:

• Right hemisphere stroke can lead to delusional misidentification syndromes.
• Impaired unfamiliar face matching is a key deficit in this case, potentially underlying the misidentification.
• The findings support the link between right cerebral hemisphere injury and phenomena similar to Frégoli delusion.