29th April 2024

Diagnosis

AD, like other subtypes of dementia, should be formally diagnosed by a specialist dementia diagnostic service. However, prior to a referral, investigations should be sought to establish whether a reversible cause is present for the patient’s symptoms.

Initial assessment should include a clinical history, a collateral history, a physical examination, a drug history review and appropriate blood and urine investigations to exclude reversible pathology. Cognitive testing tools should also be utilised to aid assessment. Specialist dementia diagnostic services will carry out neuropsychological testing and pursue other appropriate investigations as per validated diagnostic criteria.

Imaging modalities such as CT scanning can be used to rule out structural pathology, and MRI imaging can be used to identify patterns of cerebral atrophy to further confirm the diagnosis.

If, despite these investigations, a diagnosis of AD is still uncertain, Fluorodeoxyglucose-positron emission tomography- CT (FDG-PET) or Perfusion single photon emission CT (SPECT) can be considered, as can CSF examination. Apolipoprotein E genotyping or EEG should not be used to diagnose AD.