Early Diagnosis of Alzheimer’s Disease

When we think about someone suffering from Alzheimer’s Disease (AD), most of us imagine an old person who can do nothing for themselves and who has lost so much cognitive function that they can do little more than sit and stare vacantly all day long until eventually the disease reaches its inevitable and tragic conclusion.

Whilst it’s true that the effects of AD are devastating, incurable and ultimately fatal, medical advancements now mean that many people are being diagnosed with the disease at a much earlier stage than ever before and certainly before many of the more debilitating symptoms have become apparent.

Even a few years ago, accurate early diagnosis of AD was hard to achieve but nowadays people can be diagnosed early enough so that they are still articulate and still have the ability to demand better care and better research. They are able to speak up for those sufferers who can no longer talk for themselves and give a voice to a disease whose victims have until recently remained largely silent, and powerless.

This will inevitably bring about changes, especially if you factor in the actual number of people affected by Alzheimer’s. It is the most common form of dementia in old age. It is estimated that in the US alone, there are more than 5 million AD sufferers. Although no-one knows exactly how many of these people have been formally diagnosed, research indicates that as many as half of Alzheimer's sufferers may be in the disease's early stages; And if these early stage AD sufferers begin to make their voices heard, their presence will be felt and this will have ramifications in terms of the amount of funding used in a bid to find new treatments.

Diagnosis Challenges

That is not to say that early diagnosis is straight forward. Diagnosis can be difficult particularly as there is no single definitive test for AD. At the moment diagnosis is about 90% accurate. Post mortem is the only way to establish beyond doubt the presence of AD. It’s also important to rule out other conditions that can mimic the symptoms of AD such as brain tumours and depression.

Diagnosis is hindered even further by the fact that memory problems may not be the first symptom to develop. Indeed as AD is a progressive disease, early symptoms may be too subtle to notice and symptoms differ from one person to the next. How the disease manifests itself depends on various factors including the areas of the brain affected.

Common early stage symptoms may include:

Sometimes early diagnosis in itself can be a problem. A lack of education about AD particularly in its early stages can leave AD sufferers feeling stigmatized and without a voice any more. Many people go from seeing the person who has been diagnosed as the person they knew before diagnosis to simply seeing an AD patient. Invariably that means they focus on the later more devastating symptoms of the disease even though they haven’t yet developed, forgetting that the person diagnosed may still be very high functioning, completely articulate and still have years of independent living ahead of them.

In a way, this is understandable. Even the Alzheimer’s Association in the US, until very recently, concentrated its education programs and even its legislative efforts for such things as respite care on the carers rather than the patients themselves. But now there are a growing number of early stage sufferers who are demanding that they should be heard and given the same level of support and assistance in managing their disease themselves while they still can.

The Value of Early Diagnosis

Some may argue that there is little point knowing that you have AD as soon as possible because it is incurable and you cannot change the final outcome. However, for many people there are real benefits in learning their diagnosis as early as possible. It gives people a chance to contribute in the decision making processes about their medication and care both now while they still have the mental capacity to do so and also to enable them to give directions for their future care when they may no longer be able to express their wishes. This can help give a person some sense of control over what may otherwise seem a hopeless situation.

Early diagnosis may also be of benefit in terms of treatment. Early detection allows for early intervention and many of the drug treatments that are currently available are known to be most effective in the early stages of the disease. If they could be prescribed earlier then they could be used to greater effect. Furthermore, as medications are developed early detection in the future could well be the key to preventing the irreversible damage to the brain that occurs as Alzheimer's progresses.

Traditional Treatment Choice

The majority of drugs currently used to treat the symptoms of AD seek to inhibit the action of an enzyme called acetylcholinesterase.

Acetylcholinesterase breaks down the neurotransmitter, acetylcholine which is necessary for cognitive function. Research has shown that the level of this important neurotransmitter is greatly reduced in the cerebral cortex of the brain of an AD sufferer. The cerebral cortex is associated with the "higher" functions of the mind—thought, reasoning, sensation, and motion.

By preventing acetylcholinesterase from breaking down acetylcholine, the amount of acetylcholine available and the duration of its action, are increased, thus supporting these “higher” functions and treating AD.

A New Choice of Treatment - Memantine

Memantine, on the other hand, works very differently and is the first drug to have some impact on the symptoms of late AD.

It appears to protect the brain’s nerve cells against glutamate. Glutamate is the most common neurotransmitter in the brain. In AD, neurons (brain cells) are damaged and destroyed by amyloid deposits. These damaged neurons release excessive amounts of glutamate in a process known as overexcitation. The released glutamate binds to N-methyl-D-aspartate (NMDA) receptors and this in turn allows calcium to flow freely into cells. Over a period of time increased glutamate levels results in chronic overexposure to calcium. This overexposure leads to cell degeneration. Memantine appears to stop this destructive process by inhibiting the action of glutamate. It fills the NMDA receptor sites, which halts the sequence.

Recent research has highlighted the unique properties of Memantine and there can be little doubt that it can be extremely useful in improving quality of life for those with moderate or severe AD. However, that is not to say that it should be held in reserve until such a time. By adding Memantine to the therapy mix, the time period during which patients can function with minimized AD symptoms may be prolonged and that has to be of benefit to all.