This morning, millions of people around the world will wake up not knowing where they are. They will be greeted by a seemingly friendly face, perhaps calling them ‘mom’ or ‘dad’, but they will not know who this person is.
The brain is an unfathomably complex maze of nerve cells connected to form circuits and pathways that somehow give rise to consciousness, cognition, thoughts and the memories that make us what we are.
Sometimes, that maze can become a trap. In November 1901, Dr Alois Alzheimer was puzzled by a patient who seemed to be suffering from an unusually severe and progressive form of dementia that was stripping her of her personality and memories. She died within five years of their first meeting.
Frustrated by his inability to help his patient, Dr Alzheimer asked to examine her brain after she died, to literally look into her head and untangle the mystery of her condition. What he found was a dense mess of knotty plaques and nerve cells that had slowly replaced the neural networks that once allowed her to interact with the world.
What we know now, from post-mortem observations in Alzheimer’s patients but also by using PET imaging, is that abnormal proteins build up in the brain and form the plaques first observed by Dr Alzheimer. The most widely studied of these proteins is called beta amyloid, which gathers in certain areas of the brain and either scrambles or cuts off communication signals between the cells, explaining the symptoms of memory loss and changing behavior.
“We think that when those signals are interrupted, brain cells start to die. Over time, the death of brain cells can be detected as a shrinkage in the brain,” said Dr Ben Newton, Director of PET (Positron Emission Tomography) Neurology for GE Healthcare. “Death of brain cells, loss of nerve tissue, and shrinkage of the brain results in cognitive dysfunction, thinking difficulties, memory loss and so on.”
Alzheimer’s disease’s reputation as an insidious condition comes from the fact that it is only diagnosed once it has firmly taken hold of the brain. Amyloid plaques can in fact start to accumulate in brain tissue about ten years before any symptoms occur. PET imaging, using tracers called beta amyloid imaging agents, can show the presence of amyloid in a patient’s brain well before symptoms appear.
“A lot of the damage to the brain may have already occurred well before the patient experiences the memory loss and behavioral problems which are typical of dementia,” said Dr Newton.
Results released from a survey have shown that, globally, an average of three out of four people would want to know if they were going to develop an incurable neurological disorder. More people, 81%, would want to know if a loved one was going to develop such an illness. This desire to know is understandable considering the course of the disease but not always fit with published “Appropriate Use Criteria.” Amyloid imaging, however, has not been approved to diagnose or predict the occurrence of AD or other cognitive disorder.
This April, the Alzheimer’s Association received protocol approval from the Centers for Medicare & Medicaid Services of a $100 million study to examine whether getting a scan with beta amyloid tracers can affect the diagnosis, management, and future healthcare of patients suspected of dementia.
These days, it seems that Alzheimer’s disease and dementia are never far from the news. The urgent need for early diagnosis, the lack of effective treatments or concern that better dementia care is needed, are often in sharp focus. But with the help of new studies and renewed investment in research, we may be close to a day when Alzheimer’s is all but forgotten.