DEAR DR. DONOHUE: Can you send me information on sleep apnea? I had testing done in a clinic, and I know I never ever slept a wink during the test. The test results showed I had 45 obstructive episodes and that my oxygen levels dropped. (I don’t understand the oxygen thing.) Wires were all over my head. A thing with a bright-red light was on my finger. White lights were flashing on the ceiling. Two U-shaped plastic items were stuck in my nose. I tried to get comfortable but couldn’t. At 4 a.m. the intercom came on and the nurse asked if I was OK. I said yes, but I was wide awake and had been all night. Just how could they have recorded 45 obstructive episodes? I got a call to return for more testing. I told them no. There is no way I’ll pay for a second night, and no way I’ll use a CPAP. – D.W.

ANSWER: I wish I could have printed your entire four-page letter. It was fascinating and entertaining.

Sleep apnea consists of spells lasting 10 or more seconds during which a person stops breathing (apnea). To qualify as having the condition, a person must experience five to 10 of those spells an hour and, of course, must be sleeping.

People with sleep apnea are usually snorers, and their snoring gets louder and louder until an eerie silence occurs during the no-breathing spell. The problem is an obstruction to the flow of air into the lungs because of lax tissue in the throat and back of the mouth. Sleep apnea leads to daytime sleepiness. It can lead to heart disease and a blood pressure rise. That red thing on your finger tested the oxygen content of your blood. Blood oxygen drops during the no-breathing intervals and often stays low after breathing resumes. The oxygen drop is partly responsible for the health consequences of apnea.

Weight loss is one cure for overweight sleep apnea patients. CPAP (pronounced “sea pap”), continuous positive airway pressure, consists of a mask and machine that delivers pressurized air to the nose. The increased air pressure can get air past the throat obstructions and into the lungs.

I don’t know what to tell you to do next. If you have no signs of sleep apnea — no snoring, no blood pressure problems and no daytime sleepiness, I can see why you’re reluctant to go back for a second time.

DEAR DR. DONOHUE: One doctor said I have Candida of the mouth. I have white spots and lines on my tongue and cheeks. After three months, he put me on Diflucan for four months. Nothing changed. He sent me to an ear, nose and throat doctor, who said the white patches look like lichen planus, and he has me on Kenalog in Orabase. Will you explain these conditions? – E.R.

ANSWER: You probably recognize Candida by its other name: thrush. Candida is a yeast that can cause white patches in the mouth. Proof of Candida infection can be obtained by scraping the white patches and sending the material to a lab for identification. I doubt you had it. Diflucan is an excellent Candida medicine and should have cured you.

Oral lichen planus is patches of lacy, white lines and dots on the tongue, lips, insides of the cheeks and sometimes the gums. It’s believed to be the work of a misfiring immune system, but definite proof is wanting.

Its diagnosis is established with a biopsy. Usual treatment is with a cortisone drug like your Kenalog in Orabase. Don’t eat crispy foods like toast and chips, as they irritate the patches. There’s a small risk of mouth cancer associated with these patches. If your medicine isn’t working and if you haven’t had a biopsy, ask for one.

DEAR DR. DONOHUE: While curling, my wife fell and hit the back of her head. They did scans, but found no damage. Since then, she complains of continuous buzzing in her head. Do you have any idea what this is? – B.P.

ANSWER: The likely diagnosis is tinnitus, noise generated in the ear, which often happens after head trauma. An ear, nose and throat doctor can give her a check. If it is tinnitus, there are ways to dampen the noise. A tinnitus masker is a device that looks like a hearing aid. It delivers a sound that can sometimes block the inner tinnitus noise.

For readers in the South, curling is a popular Canadian sport played on ice.

DEAR DR. DONOHUE: Lord have mercy. This is my third attempt to get you to practice medicine. When someone inquired about pain from arthritis you suggested pain medicine. I am 80 and free from joint pain because I use glucosamine and chondroitin. – M.P.

ANSWER: Keep praying for a miracle. I could change.

Glucosamine is found in joint cartilage, and it promotes repair of damaged cartilage. Chondroitin endows joint cartilage with cushioning property. A large trial, sponsored by the National Institutes of Health, found the benefit of these two supplements to be minimal to nonexistent.

I’m for anything that works for people. Yours is powerful testimony. If people would like to try either or both, no harm will be done, and those people might meet with the same success you have had.

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