Approximately 60-70% of people with a dementia diagnosis have Alzheimer’s disease, making this condition the most common form of dementia.
This condition is most frequently seen in individuals over the age of 65 and is more likely to develop with increasing age. Alzheimer’s disease is caused by a specific set of brain changes – the development of protein plaques and tangles – which disrupt the ability of brain cells to process information. Initially, plaques and tangles tend to form in the areas of the brain which are responsible for memory formation, but as the dementia progresses, they start to spread to other brain regions, leading to additional problems with thinking, reasoning and language.
The most common symptom of early-stage Alzheimer’s disease is memory loss; an individual may find it difficult to remember recent events. For example, after a short delay of a couple of minutes, someone may be unable to remember the details of a conversation they have just had. In addition, people with Alzheimer’s disease often have problems planning and organising their activities, processing visual information in their environment and recognising people, particularly in the later stages.
Less commonly, the brain changes associated with Alzheimer’s disease affect areas of the brain responsible for language or vision more than memory.
- Posterior Cortical Atrophy: Typically affects the ability to process visual an spatial information, such as where things are in relation to each other in a room.
- Logopenic Progressive Aphasia: Mostly causes problems with speech and language.
- Frontal variant Alzheimer’s disease: May affect behaviour and/or thinking.
- Corticobasal syndrome: Causes issues with movement and sensation, in addition to thinking and language.