DEAR DR. DONOHUE: Will you enlighten me on my husband’s latest diagnosis – progressive supranuclear palsy? Three years ago he was diagnosed with dementia. We recently changed to another neurologist, and he made this present diagnosis. Please address it. – H.S.

ANSWER: Progressive supranuclear palsy – PSP – is being recognized with greater frequency. Dudley Moore, the star of the popular movie “Arthur,” suffered from it, and he helped give it the recognition it deserves.

Frequently, PSP begins with a person losing his or her sense of balance. In addition, the eyes cannot turn downward, so the combination of balance loss and inability to see the ground make falls inevitable. Muscles become rigid, as they do in Parkinson’s disease, for which it is often mistaken. Personality changes are common. Dementia symptoms such as apathy, poor judgment and slow thinking are other parts of the PSP picture. Memory, however, is often unaffected.

The cause has not been ascertained. Its name comes about because the part of the brain that controls eye movement is affected. That section of the brain lies in nuclei that have a direct input into eye-muscle function. Nuclei are nests of nerve cells that have a distinctive job. The area of brain above those nuclei, the “supranuclear” area, greatly affects the eye-movement nuclei, so a disturbance there influences eye movement.

There is no specific medicine for PSP. Drugs used in Parkinson’s disease are often prescribed. If eye movement is majorly impaired, glasses with prisms permit downward vision even if the eyes won’t move in that direction. Upward eye movement also becomes affected in time.

Your husband and all PSP patients should contact The Society for Progressive Supranuclear Palsy for timely information and help. You can reach the society at 1-800-457-4777. Canadians must dial 1-866-457-4777. The Web site is www.psp.org.

DEAR DR. DONOHUE: I took an AIDS test, and it came back positive. I am a heterosexual male, and I don’t have sex with anyone but my wife, to whom I have been married for 10 years. A second test was done, and that test came back negative. Do I or don’t I have AIDS? – R.T.

ANSWER: You don’t have AIDS.

The initial screening test for AIDS is the ELISA test. If that test is negative, testing stops. If it is positive, a confirmatory test, the Western blot test, is done. If that second test is negative, then the first test was a false positive.

Immunizations, like a flu shot, can make the first test transiently positive. So can multiple blood transfusions. A woman who has had many children might have a positive first test. Lupus and similar illnesses can also be responsible for a positive ELISA test. And then there are positive ELISA tests that are inexplicable; they just happen.

The doctor who ordered this test for you should explain it to you in detail and in person.

DEAR DR. DONOHUE: I notice that the prescription drugs for erectile dysfunction carry a warning to seek medical attention if an erection lasts longer than four hours. Why would that condition require medical attention? – J.B.

ANSWER: An erection occurs when blood engorges the cavernous chambers of the penis. Priapism is a prolonged and often painful erection. If blood distends the penis for too long, cells are damaged, and scar tissue forms. Permanent erectile dysfunction can result.

Thirty-six hours practically guarantee such changes will occur. Four hours is a point of warning when action should be taken to drain blood from the penis.

DEAR DR. DONOHUE: In preparation for the hurricane season, everyone stocks a large supply of batteries and stores them in the refrigerator.

Can this practice have an adverse effect on food and one’s health? – B.M.

ANSWER: Not that I know of. I keep batteries in the refrigerator even though I have been told it doesn’t prolong their life. At least I can find them.

DEAR DR. DONOHUE: For more than two years I have been on Diovan for high blood pressure. I have had an MRI of my kidneys, and it shows stenosis in the right renal artery. The write-up on Diovan states that it should not be used in severe renal artery stenosis. Is it safe for me to continue with it? – C.L.

ANSWER: The write-up says it can raise blood urea nitrogen (BUN) and blood creatinine levels. Both are indicators of kidney function. If you have had recent bloodwork, those two substances are almost always checked. If they were elevated, your doctor would have told you. If you’re not sure what they are, then call the office and ask. If they’re normal, ignore the warning.

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