March 10, 2016
Primary Progressive Aphasia (PPA) is a rare neurological syndrome in which language capabilities become slowly and progressively impaired, while other mental functions remain relatively preserved. Unlike other forms of aphasia resulting from stroke or traumatic brain injury, PPA is a degenerative brain condition. It results from deterioration of brain tissue affecting areas of the brain that are important for speech and language. A recent study was able to shed some light on a type of PPA where deterioration of brain tissue is caused by similar biological processes as in Alzheimer’s – the accumulation of toxic build-up called amyloid protein plaques.
Using a special imaging technique, scientists at Northwestern Medicine have discovered that the left side of the brain of PPA patients, which is essential for language processing, has higher levels of these toxic plaques than the right side of the brain. This is the same build-up that has been associated with memory deterioration in Alzheimer’s disease.
PPA is not the same as Alzheimer’s, which affects memory function and also results from deterioration of brain tissue. Most people with PPA maintain ability to take care of themselves, pursue hobbies, and, in some instances, remain employed. Also, not all PPA is caused by amyloid protein build-up. In this study, scientists specifically compared PPA patients with amyloid build-up to Alzheimer’s patients.
Researchers showed that the toxic amyloid protein was distributed differently in people that had the PPA language dementia versus the Alzheimer’s memory dementia – there was more amyloid in the left hemisphere parietal region of individuals with PPA compared to those with Alzheimer’s.
The new imaging technique used in this study is called Amyloid PET Imaging. Northwestern news post explained:
Previously, amyloid accumulation in the brain could only be studied after an individual with Alzheimer’s disease had died. This snapshot in time was after the disease had run its full course, and amyloid had spread throughout the entire brain. Now, [Amyloid PET Imaging] allows researchers to study the build-up of the toxic amyloid during life.
With the ability to visualize the amyloid protein build-up over the course of the disease, scientists have a better chance to understand its progression and guide targeted treatments.