29th April 2024

Clinical features

Mild cognitive impairment, often in the form of mild memory impairment, will often precede the onset of AD.  The most common clinical feature is memory impairment. Classically episodic memory is affected in a temporal gradient. Distant memories are preserved for longer, with the loss of more recent events more prevalent. Working memory tends to be preserved but there is a progressive loss in the ability to learn, process, and retain new information.

As the AD advances, deterioration in other cognitive domains becomes more apparent. Language impairment is reflective of a decline in semantic and pragmatic language processing. Semantic language involves language content and fluency whilst pragmatic language involves language adaptation in social interactions.

Other common deficits include an inability to carry out skilled tasks (apraxia) and failure to recognise objects, people and places (agnosia). AD affects the ability to organise and plan. These cognitive deficits become more pronounced and progress as the AD advances.

Besides the decline across cognitive domains, AD can present with psychiatric symptoms including delusions, hallucinations and mood disorders including depression. Behavioural symptoms can also manifest, including personality changes, aggression, wandering and searching.

End stage AD can leave a person fully dependent on professionals for their care needs with marked global physical decline.