While memory loss is one of the key indicators of Alzheimer’s disease, if a physician relies on memory loss to diagnose the disease, it may mean that they miss or disregard other forms of Alzheimer’s that don’t affect the memory in the initial stages.
Alzheimer’s disease comes in several forms. Depending on the part of the brain affected, it may cause problems with language, it may disrupt behaviour, alter personality and judgement or it may even affect spatial awareness. Currently, a definitive diagnosis can only be made after a person has died, via an autopsy. However, there is now increasing evidence that by using an imaging test such as an amyloid PET scan, it may be possible to determine the likelihood of Alzheimer’s by tracking the presence of amyloid accumulation within the brain.
For this particular study, the team identified the clinical features of those people who had primary progressive aphasia (PPA). This is a rare form of dementia that causes a progressive decline in the ability to use language. However, unlike some other forms of Alzheimer’s, the memory and other thinking abilities remain relatively intact during the early stages of PPA.
As PPA can be caused by either Alzheimer’s or by another neurodegenerative disease known as frontotemporal lobar degeneration, the presence of Alzheimer’s disease in this particular study was confirmed by either amyloid PET imaging or by an autopsy. The individuals who took part in the study exhibited mild language loss, and were given MRI scans to assess the amount of brain atrophy, together with tests to assess their cognitive skills.
As a result of their research the team believe that simply assessing clinical symptoms isn’t enough to assess whether a person has primary progressive aphasia due to Alzheimer’s or due to another neurodegenerative disease. Therefore, it’s necessary to use extra tools such as amyloid PET imaging to be certain of the cause.
The team have also pointed out that due to lack of an accurate diagnosis, such individuals may be excluded from clinical trials which target Alzheimer’s disease as they don’t exhibit the memory deficits needed to be given an Alzheimer’s diagnosis.
The research was published online in a recent edition of Neurology.