According to the dictionary, tremors are "an unintentional, somewhat rhythmic, muscle movement involving to-and-fro movements (oscillations) of one or more parts of the body. It is the most common of all involuntary movements and can affect the hands, arms, head, face, vocal cords, trunk, and legs."
A Cerebellar tremor or intention tremor is caused by lesions in or damage to the nerves in the cerebellum. It is a "slow, broad movement of the extremities that occurs at the end of a purposeful movement", such as touching your finger to your nose.
This symptom is a pretty common symptom of MS. About 25 to 60% of MSers experience this symptom. They can make it very difficult to walk or hold things, because they can happen at any time with no warning. They can be a disabling and sometimes embarrassing symptom. It's also not very easy to manage.
Where do they come from? This symptom could possibly be due to a mixture of different factors. The damage to cerebellar nerves that cause many of the symptoms of MS is an obvious reason. The nerves that control the muscles leading to the different parts of the body experiencing the them could be another. This symptom could also come from weakness or spasticity in the legs, arms, hands, neck, or whatever body part is affected.
This symptom can affect the throat causing you to have a shaky voice. It can affect the hands making it difficult to write or hold a fork or spoon while eating. Different things like stress or tiredness can cause the action to be more exaggerated. The ones in Cir's leg get worse when he's tired out from walking too long.
It can also come on from exertion. He may be moving around more than usual or just trying to lift his leg - especially the weakest one - when the shaking starts. He has them in both legs, but mostly his right leg which is the weakest.
As far as treatment for this, there really is none. Medications are not that effective. Physical therapy may be able to show you certain techniques that will help until the movement subsides. Here are a few:
As of now, however, there is no treatment that is effective for all cases and types of this symptom. It's one that MSers basically learn to live with. Learn what makes it worse. If it gets worse when you are tired, try to get enough rest. If walking for a long time causes it, then use a wheelchair when you know you will be going a long distance. It's all a part of managing your symptoms.