Home > About Alzheimer’s disease > Diagnosing Alzheimer’s

Currently a definite diagnosis is only able to be made when the brain is examined after death (post mortem). However, based upon clinical observations and testing of cognitive capacity and memory loss a working diagnosis can be made. There are as yet no identified biological markers for Alzheimer’s disease that have been proved to be reliable and accurate indicators.

During diagnosis additional testing and clinical assessment is required to rule out other conditions that have similar symptoms, such as depression. As the diagnosis has to be based upon observable characteristics, unfortunately it can only be diagnosed once the condition has progressed and considerable neurological damage has already occurred.

While a confirmed diagnosis of Alzheimer’s disease (AD) can only be achieved through post mortem identification of the neurofibrillary tangles and / or abnormal plaque deposits on the brain known to be associated with AD, recent research is indicating that new brain scanning techniques and genetic testing can also be used to identify the likelihood of Alzheimer’s disease.

  • Scanning technology such as magnetic resonance imaging (MRI), computed tomography (CT) and positron emission tomography (PET) can reveal atrophy of the brain and are being studied as to their efficacy in identifying evidence of amyloid plaque build-up and the relationship of this build up to the progression of Alzheimer’s disease.
  • Genetic testing is another area being developed. Though this is unlikely to become a means of diagnosis on its own, current evidence indicates it has potential as an early indicator of risk and can improve the accuracy of a diagnosis using other bio-markers such as beta amyloid.
  • Differential diagnosis and assessment by a specialist is important, in particular for distinguishing Alzheimer’s disease from “normal” memory and cognitive impairment of ageing, from other types of dementia and other disorders such as major depression.

There is some community concern that informing a person that they have Alzheimer’s disease may be detrimental to their well-being. While the wishes of each individual must be respected, information may in fact assist future planning and the development of strategies for managing the illness and associated disability. It also facilitates access to services including medical treatments and community support services, and assists families, carers and others to understand what is happening.