Essential Tremor Basics
Neal Hermanowicz (Director of the Movement Disorders Program) gives expert video advice on: Who is most at risk for developing essential tremor?; Is essential tremor a normal part of aging? and more...
What is 'essential tremor'?
Essential tremor is the neurological disorder causing shaking, most commonly of the hands, sometimes head, voice, and occasionally the legs. This is a brain generated problem - it's not the limbs themselves or the nerves in the limbs. It's coming from the brain in some fashion.
What causes the symptoms of essential tremor?
The location of the abnormality in the brain that's creating the tremor is not yet well identified. When people have studied a central tremor, one does not find any kind of structural change in the brain. Using functional imaging, things like Positron emission tomography (PET) scans, which don't look at brain structure, but look at how the brain is working. There are certain locations within the brain that seem to be functioning abnormally. These are mostly located in a structure called the cerebellum, and also in the adjacent structure called the brain stem. But exactly how these things or abnormalities create the tremor is not well known. Another structure called the thalamus seems to play a role in essential tremor, because we know that if we injure the thalamus in some way, if we poke an electrode in there and zap it in some fashion, that the tremor will decrease or go away. But its not clear what this process is. There aren't any kind of brain chemistry abnormalities that have been identified with essential tremor as have been in, say, Parkinson's Disease.
What is the age onset of essential tremor?
The typical age of onset of essential tremor would be in the fifties, although it may appear in childhood in certain cases and much later than the fifties in others. Once present, it tends to persist and it can become gradually more troubling as time goes by. But we're talking about years or even decades in terms of the progression of essential tremor. People do find, typically, that it can become more problematic. But, again, only as years go by. Not usually as the course of weeks or months. Like most tremors, or most neurological symptoms, essential tremor does become more pronounced during moments of stress or when people are fatigued.
Who is most at risk for developing essential tremor?
Essential tremor affects both genders approximately equally. Both men and women are affected by essential tremor. It runs in families about half the time, and when it does run in families it may occur at a somewhat younger age. But typically, essential tremor will show up initially in the late 40's or 50's. It can also appear as late as the 80's. But the 50's would probably be a typical age of onset for somebody with essential tremor.
How common is essential tremor?
Essential tremor is one of the most common neurological problems. It's roughly eight times more common than Parkinson's disease. It's more common when people are against forties or fifties or sixties when it usually starts. It may also occur in children. It tends to run in families about half of the time.
Is essential tremor a normal part of aging?
Tremor is often thought to be a consequence of normal aging but, in fact, it is not. It is not normal to shake, especially as one grows older. I think this is one reason that more people don't seek medical attention for essential tremor, because it's just regarded as being a consequence of growing older. It does occur more commonly as we grow older but it's not a normal process of aging. So any tremor that's occurring, I would regard this as an abnormality. Now I'm not saying that it must be treated. It depends on how troubling it is to somebody. But it's not really thought of as a normal consequence of growing older.