Alzheimer’s progression

A new method for clinical trials for patients with Alzheimer’s disease, developed in an original investigation, published in the Journal of the American Medical Association: Neurology, has opened up the possibility for clinical trials using a smaller number of participants and may also better predict Alzheimer’s progression. Better predictions of the rate of progression of Alzheimer’s disease can help in end-of-life planning and improved use of medical resources.


Alzheimer’s disease is a neurodegenerative disease with a pathophysiology for individuals that is hard to determine because of its heterogeneity; the damage done is spread throughout the brain and does not manifest in specific areas. This disease also varies between individuals in where the damage occurs and at what rate the disease progresses. Alzheimer’s disease only progresses. Being such a variable disease, Alzheimer’s disease requires very large sample sizes in clinical trials and, frustratingly, makes counseling patients difficult. Alzheimer’s disease manifests itself, most widely known, in memory, but also affects linguistic ability. As such, many tests have employed word association tasks.

An original investigation published in the Journal of the American Medical Association: Neurology employed a word association task (specifically, vegetable naming) among many other tasks and tests to quantify a participant’s progression of Alzheimer’s disease. Most importantly, the study utilized positron-emission topography (PET) in diagnosis and to determine the stage of the disease. There were nearly one thousand participants in the study; again, studies of Alzheimer’s disease require large sample sizes, all with the disease and no other primary neurological diseases, among many other factors. Data collection started at the autopsy and the longitudinal stage was done, nominally, backward, with death being zero. The length between initial clinic visit to death—the length of the longitudinal study for each individual—was, on average, just under three years. The study found that observation of neurofibrillary tangles—signifiers of the stage of Alzheimer’s disease—with PET can better predict Alzheimer’s progression.

All of this means that future clinical trials of people with Alzheimer’s disease should not require as large of a sample size. Smaller sample sizes, in turn, should empower researchers to perform more studies which, with lengthening life-spans, is and will continue to be of vast import. On the personal level, the improved ability to predict the rate of change of the disease for individuals should greatly help the individual and the individual’s family in dealing with the disease. This will also improve access to more informed clinical support and treatment while also improving the use of medical resources for the individual. Back to the universal impact, improved use of medical resources may possibly help in delegating funding to the corresponding infrastructure.


Written By: Brian Jones

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