A Question of Health: Dr Fred Kavalier

What is the difference between Parkinson's disease and other forms of tremor of the hands? I have started getting very shaky and find it more difficult to write, but typing seems unaffected. I am in my late 40s and I think my father and grandfather had exactly the same problem.

Parkinson's is a complex neurological condition caused by a deterioration in one specific part of the brain. A tremor is one symptom, but there can be many others, such as difficulty walking and problems with muscle stiffness and speech. Parkinson's seems at times to run in families, but most sufferers don't have other family members with the disease. It sounds more likely that you have "essential tremor", which is not related to Parkinson's. This neurological condition runs in families, usually coming on in middle age and getting worse. It can cause shaking of the head as well. The tremor is worse when the muscles are tired. Many people with essential tremor notice it improves when they have some alcohol, but this hasn't proved an effective long-term treatment. Beta-blockers sometimes help.

Is it any use to take zinc at the first sign of a cold?

Researchers in Detroittested zinc lozenges on 50 people. Half were told to suck a lozenge every two to three waking hours for as long as they had cold symptoms. The rest took a placebo. Among zinc suckers the average duration of cold symptoms fell from 8.1 to 4.5 days. Cough symptoms lasted half as long. But previous studies yielded inconclusive results, and some volunteers said zinc irritated their mouths and affected their taste.

E-mail your questions to health@independent.co.uk. Dr Kavalier regrets that he is unable to respond personally to questions