I was very much one of the many individuals in the public that thought it was the deterioration in memory that had robbed people of their identity in the case of dementia. When I read this study, I felt like I was hit on the head by a bolt from the blue.
The study published in June 2015, in the Journal of the Association for Psychological Science on neurodegeneration and identity. In this study, researchers, Nina Strohminger from Yale University and Shaun Nichols from the University of Arizona made a breathtaking discovery.
Nina and Shaun had measured perceived identity changes in 248 patients with Frontotemporal Dementia, Alzheimer’s Disease (AD) and Amyotrophic Lateral Sclerosis (ALS).
They found that moral behavior, not memory loss, causes loved ones to say that the patient wasn’t “the same person” anymore. That people with Frontotemporal Dementia was observed to have the greatest change in perceived change in the identity of the person with dementia by the caregiver. Next in line was AD and lastly ALS.
You can read more about the study here http://www.psychologicalscience.org/index.php/news/releases/how-others-see-our-identity-depends-on-moral-traits-not-memory.html
Strohminger N, Nichols S. Neurodegeneration and Identity. Psychol Sci. 2015