Alzheimer’s disease has taken on such mythical proportions that many people seem to think it is interchangeable with dementia. It’s not. Alzheimer’s disease is a form of dementia, just as leukaemia is a form of cancer. It’s just that, of dementia, Alzheimer’s disease is arguably the most well-known form, leading to the misconception that any and all dementia is automatically Alzheimer’s. Think of it a bit like this: all elephants are grey, but not all grey things are elephants.
So what makes Alzheimer’s disease “special” in the world of dementia? Symptoms of dementia usually don’t occur before the age of 65, so it makes sense for dementia to be characterized as an “elderly disease”. Alzheimer’s follows this pattern – most people don’t start having weird memory problems until they’re in their 70s – but if what those people have is indeed Alzheimer’s, it actually began about 30 years before they ever started exhibiting symptoms. Think about it: if people in their 60s, right around retirement age, are eventually diagnosed with Alzheimer’s, that means they actually started down this degenerative road in their early 30s. No wonder the genetic risk for Alzheimer’s is a big deal: people’s brains are actively changing for the worse, and they’re having children right around the same time. It’s much different than someone who, long after babymaking years, hit his or her head in a car accident and started forgetting things more often.
The guiltiest party to Alzheimer’s disease is thought to be beta amyloid plaque. For the average person, it may not be worth remembering what beta amyloid is (it’s a particular protein that must be present for the brain to develop and repair itself properly), but it’s worth remembering what those plaques do. Think of it this way: if the plaque on our teeth is allowed to build up (we’re eating the wrong things and not cleaning them out properly), imagine the horrors of dental consequences. Now think about the same thing happening inside the skull.
Other forms of dementia are caused by similar dysfunctions of the brain and how certain proteins become “lost” and end up in places they’re not supposed to be, or perhaps some genetic breakdown has occurred in a way that prevents the brain from communicating with itself the way it did before. Usually these physical deficiencies in the brain will also cause the body to behave in a certain abnormal way (for example, Parkinson’s disease is almost always visible in the “resting tremor” of the hands). Alzheimer’s is set apart by being restricted to memories, and recent ones at that. Someone with Alzheimer’s disease will have almost no trouble remembering the past (often decades into the past), but short-term memory can be almost non-existent. This is why many family members of a person first showing Alzheimer’s symptoms often misinterpret the problem, mistakenly thinking the person is simply neither listening nor paying attention as of late. The irony is, the problem isn’t a recent development – it’s been in the making for decades.