Twenty-two years ago, Perry Conrad played in the band at Donald Whiting's wedding.

Two months ago, the bridegroom more than returned the favor.

That is when Dr. Donald Whiting, who today is a neurosurgeon at Allegheny General Hospital, gave Mr. Conrad a new lease on life by inserting two thin electrodes into his brain.

Mr. Conrad, 49, of Tyrone, Blair County, arrived at his old friend's office earlier this year with severe muscle tremors and rigidity from the Parkinson's disease he has struggled with since 2000. A video done before his Oct. 8 surgery shows him struggling to play the banjo with his clenched and shaking left hand.

Three months later, his tremors not only have disappeared, but his muscular control has actually improved. He can play guitar runs with his left hand that he could never achieve before. "I am the bionic man," he said with a laugh. "That's what it feels like."

The electrodes on either side of Mr. Conrad's brain are controlled with two pacemaker-like devices that sit under the skin below his collarbones. Wires from the devices run up the neck and beneath the scalp to connect to leads from the electrodes.

The two-stage operation is known as deep brain stimulation, and it has been approved by the Food and Drug Administration as a treatment for Parkinson's and two other movement disorders for the past five years.

But Mr. Conrad and another local patient, 49-year-old Darlene Dunning of Monroeville, represent a new trend in the surgery -- using it on younger patients who are in much earlier stages of their disease.

Parkinson's is caused by the loss of brain cells that produce the neurotransmitter dopamine. The lack of dopamine causes two paradoxical results -- muscles become rigid, but they also develop a severe tremor.

The standard treatment for many years has been a synthetic form of dopamine, Sinemet, along with other drugs that mimic the action of dopamine.

Over time, though, the drugs lose their effectiveness, and for patients who are becoming increasingly disabled, the relief created by deep brain stimulation can seem like a miracle.

No one is sure exactly why the surgery works, Dr. Whiting said, but after guiding the electrodes carefully into a tiny part of the brain known as the subthalamic nucleus, the low-voltage stimulation seems to counteract the disruptive signals that cause the tremors and muscle stiffness.

Dr. Whiting, who now does one or two of these surgeries a week, said one affirmation for the push toward younger patients came from a major new German study published in August in the New England Journal of Medicine. The study looked at 156 Parkinson's patients under 75 who had severe symptoms, and found the surgery was much more effective than medication alone in improving muscular control and quality of life.

By putting the electrodes in two nearby areas of the brain, neurosurgeons also can treat two other movement disorders.

One is a fairly rare condition called dystonia, in which patients' bodies are contorted because their muscles cannot unclench.

The other condition, essential tremor, is even more common than Parkinson's, but is less well known. It causes major tremors whenever someone tries to move, making it impossible, for instance, to drink a cup of coffee without spilling it.

Because the human brain can be viewed as a highly complex electrical device, it's not surprising to learn that the electrode stimulation technique is now being tried for several other conditions.

One local trial is now being set up to use deep brain stimulation for obesity in people who have had gastric bypass surgery but are still severely overweight, Dr. Whiting said. The electrodes would be inserted in the hypothalamus, which helps control appetite, testing the theory that the signals might "reset the dietary thermostat and get rid of the urge to eat."

Deep brain stimulation is also being used experimentally for treating Tourette syndrome, epilepsy, obsessive-compulsive disorder and clinical depression, according to Medtronic Inc., the major manufacturer of the devices.

To do the surgery, doctors attach a metal halo to the patient's skull after injecting local anesthetic in the scalp, and then do a CT scan of the head with the halo attached, all of which helps them guide the electrodes to the right place through two holes that are drilled in the top of the head.

But the only surefire way to know the surgery is working is to keep the patient awake so doctors can see whether applying a voltage stops the tremors.

Mr. Conrad's surgery, captured on video by Allegheny General, shows that effect dramatically.

As surgeons get ready to apply the voltage, Mr. Conrad's left hand shakes violently. And then, suddenly, it stops.

"It was just -- I'm going to break up thinking about it -- [a physician's assistant] was working my wrist and hand and said how does that feel, and I looked at my hand and for the first time in seven years, it wasn't shaking -- I thought, how can that be?"

For Darlene Dunning, the most dramatic results came after the second surgery, which takes place about a week after the electrodes are implanted. In that operation, the patient is put under general anesthesia so the electrodes can be attached to cables that run down to the twin stimulator packs that are placed below the collarbones.

Once patients at Allegheny General wake up from that surgery, they are sent to HealthSouth Rehabilitation Hospital in Harmarville, where a doctor adjusts the settings on the stimulators to get the best results.

As with Mr. Conrad, Mrs. Dunning's Parkinson's had affected her left side, causing her hand to shake so much she could only use her right hand while working as an assembler at the Mine Safety Appliances plant in Murrysville. Her left foot also had started to curl inward.

But as soon as the Harmarville doctor adjusted her electrode settings, she said, her foot straightened out, and "I was walking and exercising and doing whatever they told me to do."

Mrs. Dunning and Mr. Conrad both noticed one other thing after the surgery -- their moods lifted.

Mrs. Dunning said she cried frequently in the days before her surgery, and not because of fear. Since then, the weeping has stopped.

Mr. Conrad, a registered nurse who now works for a computer company that makes software for emergency room management, said "the thing I never expected to get back with this was personality."

His mood "has been flat over the past couple years," he said, "I often had to force myself to be sociable. Now people will tell me, 'I can't believe it; you're like you were 10 years ago.' It's great to feel so good again. What a payoff."

Dr. Susan Baser, a North Side neurologist who treats 3,000 Parkinson's patients in the region, said this emotional rebound isn't just appreciation for successful surgery.

The same dopamine shortage that causes muscle problems also contributes to depression in Parkinson's patients, she said.

In fact, a Mayo Clinic study published this month in the Archives of General Psychiatry showed that immediate relatives of Parkinson's patients have an abnormal risk of depression or anxiety disorders, which suggests that Parkinson's has a strong genetic component.

Dr. Baser prescribes more Sinemet, the main Parkinson's drug, than any other physician in the nation.

That's not just because she has developed a large practice, but because Western Pennsylvania has one of the highest rates of Parkinson's in the country.

Part of the reason is that the population here is older, and Parkinson's is particularly prevalent among whites of European descent. Another reason may be the area's industrial heritage, she suggested.

Some studies have shown an association between certain kinds of air pollution and Parkinson's rates, especially the presence of manganese, which is used in steelmaking and welding.

Despite the early success of deep brain stimulation, both she and Dr. Whiting believe patients should try medication for several years before undergoing the surgery.

"But if they get to the point where they're looking at disability," Dr. Baser said, "they should consider the surgery."

There is one unusual downside to the surgery, she added.

Because the constant tremors are a form of energy-burning activity, she said, Parkinson's patients are often thin, despite eating anything they want. Once the tremors stop, though, they have to watch their diets and exercise, she said, or they can quickly gain 20 to 30 pounds.

Dr. Whiting said that because of its success rate, deep brain stimulation "is the most rewarding thing that I do as a neurosurgeon. The patients are a most appreciative group."

Mr. Conrad said it has given him a deep sense of gratitude. "I feel like I've been given a chance to live a miracle," he said, "and if I don't give something back, it will all be for naught."

He is setting up a Web site to help other Parkinson's patients considering the surgery, and tries to give talks to nursing students and other health care professionals whenever he can.

"It's like I've washed those seven years away," he said.