Barry J. Goldlist, MD, FRCPC, FACP
Diseases that affect the brain have a special horror for people of any age. A person who has suffered a heart attack might be very ill, might even die, but the disease does not alter the 'essence' of the individual. They are recognizably the same people they were before their illness. The same is not true of diseases that affect the brain. Our intellect, our communication skills, our emotions, define us as human beings and differentiate us from other creatures and also from each other.
The two great scourges of old age are stroke and Alzheimer's Disease (AD): they rob individuals not only of their health but also of that very 'essence' of individual humanity. Over the last four decades, enormous strides have been made in our ability to prevent stroke. The pillars of this advance have been aspirin and carotid endarterectomy for TIA's and strokes, control of hypertension, and anticoagulation for atrial fibrillation. Further progress is likely when the correct place for lipid lowering medication and homocysteine lowering maneuvers are better understood in the elderly.
Unfortunately, the story for the prevention and treatment of AD has so far not been as favorable. For many years the very term 'senile dementia' itself has been an impediment to research. Many physicians, and much of the general public, assumed it was an inevitable part of aging, and therefore not amenable to any therapy. This despite the fact that the majority of elderly do not develop cognitive impairment that impairs function, even at very advanced ages. Only a few scientists devoted themselves to research in AD (one notable example being Donald McLachlan at the University of Toronto, who was awarded the Order of Canada for his contributions).
This lack of interest has changed dramatically over the past few years. Part of the 'push' towards research has been the changing demography of developed nations. A larger proportion of the population is over 65, and the segment of the population over 80 is the fastest growing segment of society. The Canadian Study on Health and Aging has suggested that up to a third of this group over 80 will develop cognitive impairment severe enough to warrant the diagnosis of dementia. Dementia is the most common reason for long term institutionalization of the elderly, so the human tragedy of this disease is now compounded by economic pressures.
As is the case in most medical advances, the key to any successes in understanding AD - that lead to treatment or prevention - lies in basic research. The original wave of scientific discoveries in AD highlighted some of the biochemical deficiencies, and has led to the current therapeutic strategy of cholinesterase inhibition in patients with the disease. An even more fundamental understanding of the disorder is likely to come from understanding the molecular biology of the disease. Already, several genes linked to Alzheimer's Disease have been identified. It is hoped that this represents the first step in unraveling the actual pathogenesis of the disease, and thus identifying possible preventive and therapeutic options.
As the disease becomes a more popular one for scientific research, more and more information is becoming available. The present wave of correlations discovered by epidemiological research have to be viewed cautiously. Certainly, the preventive possibilities of estrogen and non-steroidal anti inflammatory drugs are very exciting, but not yet at the stage where they can be prescribed for that indication. Similarly the literature on anti-oxidants, ginkgo biloba, and other substances is not yet solid enough to warrant routine therapy.
It is also important to remember that meticulous attention to concurrent illnesses (medical and psychiatric) can result in dramatic and sustained functional improvements in demented individuals, even though the underlying dementing process is not altered. As well, attention to caregiver support can be as effective in maintaining demented individuals at home as any of the current medications in our growing armamentarium.
Alzheimer's Disease, the scourge of old age, is not yet truly amenable to medical intervention. However, for the first time since its description, a reasonable expectation of progress is finally here. It is certainly an exciting time to be involved in the research surrounding this challenging illness.