DEAR DR. DONOHUE: For more than a year, my doctor has treated me for Parkinson’s disease with Sinemet. My hands don’t shake, but he insists I have it. The medicine hasn’t done a thing for me. I think I am taking it for no good reason. What would you do? – R.D.

ANSWER: Parkinson’s disease is an illness whose diagnosis rests on the signs and symptoms a person has. It has four chief signs: resting tremor, bradykinesia, rigidity and gait disturbance. Having two of these four signs puts the diagnosis on fairly solid ground. But even then, it takes constant re-evaluation of a patient to be secure in the knowledge that he or she has Parkinson’s disease.

The resting tremor of Parkinson’s is noticeable when the hands are resting in the lap or on a table. One common tremor is the pill-rolling tremor, where the tips of the index finger and the thumb brush over each other almost in constant motion. At first only one hand has the tremor.

Bradykinesia is slow movement. Parkinson’s patients take an eternity to tie their shoes or button their shirt.

Rigidity is tight muscles. Trying to bend the arm of a person with Parkinson’s meets with great resistance and is done with difficulty.

Gait disturbances are things like small, shuffling steps whose rapidity increases as though the person were awkwardly running after someone or something. The body leans forward while walking. Balance is extremely poor.

Other signs include poor handwriting in which the size of the letters shrinks, an expressionless face, infrequent eyelid blinking and a soft, low voice.

You didn’t mention any symptoms in your letter. If you have none, the diagnosis is in doubt. You ought to get the opinion of a neurologist.

DEAR DR. DONOHUE: My boyfriend chews tobacco. It disgusts me. When he spits it out, I could throw up. He says it doesn’t hurt him and he enjoys it. Is that true? I would appreciate any information that I can use to get him to give it up. – P.N.

ANSWER: It’s probably true that he enjoys it. It isn’t true that it doesn’t hurt him.

Chewing tobacco does a great deal of harm. It erodes the teeth and gums. It can induce cancers of the mouth. Nicotine from chewing tobacco gets into the blood through the linings of the mouth. It constricts arteries and brings about artery hardening.

Giving up chewing tobacco can induce the same kinds of symptoms that stopping cigarettes does. Your friend can use nicotine gum to get over those withdrawal symptoms if that’s one of the reasons he hesitates to give up the habit.

DEAR DR. DONOHUE: I have a stomach polyp. I thought polyps were found only in the colon. Mine was discovered when I had a gastroscopy to look for an ulcer, which I didn’t have. The polyp was removed. Any implication to this? – K.R.

ANSWER: Polyps are small growths growing from the lining of many structures – examples of which are the colon, the stomach, the nose, the vocal cords and the uterus. If doctors looked into 1,000 stomachs with a scope, they’d find polyps in four of them. Most of the time, they are benign – they’re not cancer, and they don’t become cancer.

Why they form is hard to say. Irritation might produce them.

Dr. Donohue regrets that he is unable to answer individual letters, but he will incorporate them in his column whenever possible. Readers may write him or request an order form of available health newsletters at P.O. Box 536475, Orlando, FL 32853-6475. Readers may also order health newsletters from www.rbmamall.com.