Alzheimer’s disease remains a diagnosis of exclusion. It is important to rule out other conditions that may cause similar symptoms such as stroke, hypothyroidism, depression, nutritional deficiency, brain tumor, Parkinson’s disease and inappropriate medications. Conclusive diagnosis is still only possible at autopsy. However, science has made tremendous progress using more accurate diagnostic tests and techniques ranging from psychological testing to state of the art imaging. Symptoms of memory impairment are usually classified as:
MCI (mild cognitive impairment): A person exhibits some signs of disease but is still able to manage on their own quite well. If diagnosed and treated early, these individuals are sometimes treated with an acetycholinesterase inhibitor in an effort to delay the onset of Alzheimer’s disease.
Possible Alzheimer’s disease (AD): There is clinical evidence that AD is responsible for dementia but there are either other complicating disorders present that could impair cognition (e.g., stroke) or there are some atypical presentations (e.g., language dysfunction is more severe than would be expected).
Probable AD: The clinical syndrome is recognized and there are no other evident causes of dementia.
Since dementia is a clinical syndrome and not a disease, full investigation is required for each person identified with the bundle of symptoms. Much information is obtained from a careful history of the patient and from their partner and/or family members. An assessment of the pattern of the cognitive impairment, both by bedside and on-site testing, and a more detailed assessment of neuropsychological function, will provide the likely diagnosis in the majority of cases. Neuroimaging or brain scan, of which magnetic resonance imaging (MRI) is the most useful, will exclude many of the secondary causes of dementia such as tumors or strokes. A variety of blood tests and occasionally an electroencephalogram (EEG) will complete the investigation. Some patients will require more intensive investigation such as examination of the cerebrospinal fluid. Read more.