This is the most common cause of dementia, accounting for about two thirds of cases in those aged 65 and above. In truth, we don't really know what causes it but the presence of abnormal forms of two proteins - amyloid and tau - is necessary to make a conclusive diagnosis. Traditionally, these proteins could only be detected post-mortem - by looking at samples of brain tissue. Excitingly though we have now developed brain scans that give a good indication about how much amyloid and tau is in the brain when a person is living. In Australia, these scans are only available to researchers but that will hopefully change with time.
Typical Alzheimer's disease starts with difficulty remembering new things - generally presenting as forgetfulness of recent events and conversations. Memory of things from long ago tends to be more robust and is often not lost until later in the journey. Disorientation can occur early on, especially with regard to knowing days and dates. As the disease spreads, there may be problems with planning and organisation as well as language and calculation. Recognition of familiar objects may falter and familiar people may be forgotten. These are so called cognitive symptoms, but there are often also changes in behaviour and psychological changes such as anxiety, depression and agitation. In the later stages, physical abilities become impacted, leading potentially to problems walking, speaking and swallowing as well as incontinence. It is important to realise, however, that many of these things can be well treated and managed with the right supports.