Diagnosing Alzheimer's Disease
The most common form of dementia (from the Latin word demens: deprived of mind, confused) is Alzheimer's disease. People over the age of 60 are most often affected by this progressive neurodegenerative disease; which can lead to premature death. According to estimates published in 2006 by the journal "Alzheimer's & Dementia," more than 26 million people suffer from Alzheimer's disease worldwide, and this figure could pass the 100 million mark by 2050.
In the course of this insidiously disease of the brain, the nerve cells slowly – but steadily and inexorably – die. The brain shrinks, and as a result the patients' brain functions steadily degenerate. In the preliminary stage they suffer from impairments of memory and orientation. Experts call these mild cognitive impairments (MCI). Later, sufferers no longer recognize their relatives and friends and lose their power of judgment and personality. In some patients the disease can last for up to two decades.
| PET-MRI overlay in an Alzheimer's patient |
PET-MRI overlay in a healthy control person |
Early diagnosis promises more successful treatments
Although there is currently no cure for the disease, early treatment of the symptoms, combined with the right care and support, could improve the quality of life of people living with Alzheimer's disease. For sufferers, therefore, advanced imaging techniques and the related prospect of early diagnosis could lead to significant improvements.
Although present-day treatments can only alleviate the symptoms, and not the underlying causes, there is growing evidence to suggest that Alzheimer's patients benefit most when treatment begins at an early stage of the disease. Researchers and physicians expect even more progress from the effective use of drugs, and promising candidates are already being clinically investigated. Novel early-detection techniques might give a boost to the development of corresponding anti-Alzheimer's drugs.
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Audio: Positive study with substance to support diagnosis of alzheimers disease |
The disease often goes unrecognized or is misdiagnosed
Even in the early stages of the disease, beta-amyloid already accumulates in the brain and forms what are known as amyloid plaques. However, detection of these protein deposits, and thus a definite diagnosis of Alzheimer's disease, is currently not possible until only after the patient's death.
Today, diagnostic evaluation in vivo involves a time-consuming array of clinical tests, neuropsychological assessment and conventional imaging; it can be especially difficult in patients in the early stages of Alzheimer's disease, in cases of mixed disease (co-morbidity), and in patients with a high IQ.
Post mortem studies also demonstrate that the clinical diagnosis of Alzheimer's disease is incorrect in 10 to 30 percent of cases. Thus, there is a significant unmet medical need for better and earlier ways of differentiating between Alzheimer's and other forms of dementia.
Clinical trials seek an earlier and more accurate diagnosis
Among other things, Bayer Schering Pharma is working on the development of novel tracers for positron emission tomography (PET) to support the diagnosis of Alzheimer's disease. One of the PET tracers undergoing clinical development binds specifically to amyloid plaque in the brain – the pathological hallmark of Alzheimer's disease. The successful development of new substances in this field would represent an important step toward an earlier and more accurate diagnosis of Alzheimer's disease.