What is Alzheimer disease?
Alzheimer disease (AD) is a neurodegenerative disease that causes progressive impairments in memory, language, and thinking, with the eventual loss of the ability to perform social and functional activities in daily life. The Australian Institute of Health and Welfare (AIHW) estimated that in 2023, 411,100 Australians were living with dementia, including AD dementia.
While figures specific to AD were not included, it is generally accepted that AD is the most common cause of dementia, with estimates varying between 60 – 80% of cases.
The principal risk factor for AD is age. After 65 years of age, the incidence of the disease doubles every 5 years. After the age of 85, one in three individuals will have dementia. Genetic forms of AD have been identified. An increased risk of AD is conferred on carriers of the epsilon 4 (ε4) allele of a gene coding for apolipoprotein E (ApoE). Deposition of Aβ is markedly greater in this population, whereas ApoE ε2 appears to confer a small protective effect.
Two microscopic hallmarks of AD are deposits of amyloid and aggregates tau protein in the nerve cells. Accumulation of amyloid in the brain is proposed to be the primary driver of the AD process, and the it precedes the accumulation of tau and subsequent nerve cell death. Treatments atht stop amyloid plaque production or to enhance its clearance are being investigated to see whether they slow or halt the disease process. There is widely held agreement that the accumulation of amyloid is only part of the pathology that contributes to deterioration in AD, and that downstream mechanisms including tau degeneration amongst other things, is also an important contributor.
Cognitive and functional testing in Alzheimer disease
Several clinical outcome measures have been used to assess cognition and function in patients with AD. Some may be used in clinical practice, whereas others are more commonly applied in clinical trials and may have less utility in routine practice. Recently accepted criteria for clinical staging of Alzheimer disease describe stages from 0 (Asymptomatic) to 6 (Dementia with severe functional impairment). The iADRS is a clinical tool that combines scores from two established measures, the ADAS-Cog and the ADCS-iADL, to provide a single, comprehensive assessment of Alzheimer’s disease severity. It captures both cognitive and functional decline to better measure disease progression and treatment effects in clinical trials. A lower iADRS score indicates a greater impairment.
Current treatments available for Alzheimer disease
Current therapeutic options for patients with AD include enhancers of cholinergic function in the central nervous system, for example donepezil, rivastigmine and galantamine, and the N-methyl-D-aspartate receptor antagonist, memantine. These agents provide symptomatic benefit benefits only by addressing neurotransmitter imbalances but do not prevent progression of the disease process. The clinical benefit of these treatments is modest.
Donanemab (Kisunla) and Lacanemb (Leqembi) belong to a class of anti-amyloid (anti-Aβ) monoclonal antibody agents intended to treat AD. It is proposed that by binding to the plaque, the agents aid the removal of amyloid by cellular processing. Treated patients, on avergae had around a 30% reduction in the rate of progression when measured on the iADRS.
For patients who qualify, Donanemab (Kisunla) and Lecanemab (Leqembi) are delivered via an intravenous infusion, that requires nursing oversight and a small needle in a carefully managed program. (From 2026) these infusions can be performed at the Neurology Network rooms at our St Kilda Rd and Box Hill offices. This treatment is not available with PBS subsidy, so the overall costs are very high.
Further information can be found here.
Mild Cognitive Impairment
Mild cognitive impairment (MCI) is a brain condition that involves subtle changes to your memory and thinking.
MCI is not a normal part of ageing. The symptoms of MCI affect you more than normal ageing, but not as severely as dementia.
MCI is only ‘mild’ compared to dementia, which affects a person more severely. It does not mean that, if you have MCI, you only have mild problems. Your MCI symptoms might be very concerning to you and your family.
Mild Alzheimer’s Disease:
Mild Alzheimer’s disease is the earliest stage. Because these changes usually happen gradually, it’s sometimes hard to notice when this stage begins. Many people get their diagnosis of Alzheimer’s disease after this stage.
Moderate Alzheimer’s Disease:
Moderate Alzheimer’s disease is the next stage of the disease. Your symptoms will become stronger. You may experience significant challenges to your independence. You might require daily support.
Donanemab (Kisunla) is not available for patients with moderate AD.
Specialists at NNM.
A/Prof David Williams and Dr Melissa Tang have an interest in neurodegeneration and assessment of cognitive impairment.
All Neurologists practicing at Neurology Network Melbourne are trained in the assessment of cognitive deterioration, including its diagnosis and management.
Our Neuropsychologists work with a range of authorities and clubs to provide expert assessments and management plans..