A new study from Western University provides researchers and clinicians with insight into a particularly debilitating memory problem that is present in some patients suffering from neurodegeneration caused by Lewy body dementia or Alzheimer's disease.
This disorder, known as Capgras Syndrome (or sometimes Misidentification Syndrome), is characterized by the delusional belief that a person with whom the patient shares a close emotional bond, typically the spouse, has been replaced by an imposter or look-alike.
In their study, Western researchers demonstrated that person recognition difficulties experienced by patients with Capgras Syndrome are not restricted to the person who is the target of their delusion, and can affect recognition of other well-known individuals, such as famous TV and sports personalities. For faces, such difficulties even extended to recognizing the intensity of emotional facial expressions. Interestingly, name recognition was spared, however.
The study, which was funded by the London and Middlesex Alzheimer Society, was led by Chris Fiacconi, a postdoctoral fellow at Western's Brain and Mind Institute, and his collaborators Stefan Köhler and Elizabeth Finger. The findings were published in the journal Frontiers in Human Neuroscience.
The disorder places an enormous burden on patient care in dementia, given that the imposter is usually also the primary caregiver.
"Very little is known about Capgras Syndrome," says Fiacconi. "Our results suggest that it arises as a consequence of a missing emotional response that normally accompanies recognition of close family members and other well-known individuals, when we see their faces or hear their voices," adds Fiacconi.
"This missing emotional response is likely the result of abnormal functioning in the autonomic nervous system. We are now examining this theory with psychophysiological recordings in the Köhler Memory Lab."
Read the full-length study for no charge at:
Nature and extent of person recognition impairments associated with Capgras syndrome in Lewy body dementia, Chris M. Fiacconi, Victoria Barkley, Elizabeth C. Finger, Nicole Carson, Devin Duke, R. Shayna Rosenbaum, Asaf Gilboa and Stefan Köhler, Frontiers in Human Neuroscience, doi: 10.3389/fnhum.2014.00726, published online 24 September 2014.
- Wetern University