Washington DC: Alzheimer's steals not only the memory but also the ability to recognise your loved ones and now, a recent study has revealed why it is so.
The study by the team of Dr. Sven Joubert of the Universite de Montreal has demonstrated that, beyond causing memory problems, Alzheimer's disease also impairs visual face perception. This finding may help families better understand their loved one's inevitable difficulties and lead to new avenues to postpone this painful aspect of the disease.
Also known as "holistic perception," face perception is in contrast to the local and detailed analysis required to perceive individual facial features, such as the eyes, nose or mouth. Dr. Joubert's study has demonstrated that the holistic ability to perceive faces is impaired by Alzheimer's disease.
For the study, the Montreal team recruited people with Alzheimer's along with healthy seniors to study their ability to perceive faces and cars in photos that were either upright or upside down.
Dr. Joubert explained that the results for people with Alzheimer's were similar to those in the control group in terms of answer accuracy and the time to process the upside-down faces and cars. To perform these tasks, the brain must perform a local analysis of the various image components perceived by the eye. However, with the upright faces, people with Alzheimer's were much slower and made more mistakes than the healthy individuals.
He added that this led them to believe that holistic face recognition in particular becomes impaired. Subjects with Alzheimer's disease also demonstrated normal recognition of the upright cars, a task that in theory does not require holistic processing. This suggests that Alzheimer's leads to visual perception problems specifically with faces.
The fact that impaired facial recognition might stem from a holistic perception problem and not just a general memory problem opens the door to different strategies (such as the recognition of particular facial traits or voice recognition) to help patients recognize their loved ones for longer.
The study is published in the Journal of Alzheimer's Disease.