Brain Atrophy in Alzheimer's Disease (AD)


Alzheimer's Disease (also Alzheimer's or Alzheimer's Dementia) is the leading cause of dementia and is characterised by memory loss, impairment of activites of daily living and behavioural changes that are slowly progressive.


30% of people aged >80


Increased risk with age


About 1.2 times more common in females

Risk Factors

[4] [5]

Signs and Symptoms

  • Memory Loss
  • Confusion
  • Abnormal Speech
  • Depression
  • Abnormal behaviour and personality change
    • Repetition
    • Social withdrawal
    • Irritability
    • Poor Adherence to treatment
  • Primitive reflexes may return


[7] [8]
Alzheimer's disease is associated with significant brain atrophy which can result in a loss of more than 10% of the brain's total weight. The majority of the atrophy occurs in cortical areas of the temporal, frontal and parietal lobes. Alzheimer's disease is preceded by a period of Mild Cognitive Impairment (MCI). Histologically, Alzheimer's disease is characterised by extracellular amyloid plaques and intacellular neurofibrillary tangles. This is the gold standard for diagnosis which can only be done post-mortem. Changes in Cerebrospinal Fluid beta-amyloid can be seen as early as 25 years before the onset of symptoms. The exact machanism behind the deposition of plaques and neurofibrillary tangles is still not fully understood. The basis for current treatment is based on damage to cholinergic neurons of the basal forebrain.






Alzheimer's diseases is diagnosed clinically; however, the most accurate test is a post-mortem biopsy showing histological changes of amyloid plaques and neurofibrillary tangles.

Differential Diagnosis


  • Supportive care and environmental control changes



Patients should be followed up every 6 months for evaluation of changes in cognition and functional capacity. It is also important to assess burden to carers, who may develop depression, and home risk. Many patients with Alzheimer's Disease eventually find themselves in nursing homes or high level care.




[14] [15]
There is no cure for Alzheimer's Disease. Patients progressively deteriorate becoming less interactive and less mobile. Immobility is associated with a number of different complications. The time from onset of symptoms varies from as little as three years to more than 10.

See Also

Oxford Handbook of Clinical Medicine - 9th edition p492-93
BMJ Best Practice - Alzheimer's Disease


Alzheimer's Disease brain atrophy image: "Alzheimers brain" by National Institutes of Health - Licensed under Public Domain via Commons -
  1. ^ Oxford Handbook of Clinical Medicine - 9th edition p492-93
  2. ^ Oxford Handbook of Clinical Medicine - 9th edition p492-93
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