Pam Hillock, 61, settles onto the seat of her shiny white Harley-Davidson Fat Boy with a smile on her face. It’s time for a quick ride with her husband, Steve. She pushes a button on the handlebar, and the motorcycle roars to life.

That’s the sound of celebration.

Not so long ago, Hillock, who lives in Hollis, rarely left her house. She was too self-conscious about the constant shaking of her head and arms. Hillock has essential tremor, a neurological disorder that often runs in families. Both of her parents had it.

The shaking began in her early 20s, starting with her head, and it eventually affected her hands and arms. By last year, she couldn’t hold a glass of water without spilling it.

“I stopped going to restaurants,” Hillock says, “stopped going to people’s homes.”

It broke her heart when she could no longer pick up her 2-year-old grandson for fear she’d drop him.

“Basically, everything I had ever done – ride my motorcycle, write, eat soup, put on makeup – everything stopped.”

Then in March, her neurologist made a suggestion.

“He said, ‘I’ve got something to discuss with you,’ ” says Hillock. “He said, ‘DBS.’ And I said, ‘What the heck is DBS?’ ”

Good question.

DBS stands for deep brain stimulation, a surgical procedure now available in Maine for the first time. It helps control the involuntary muscle movements associated with such conditions as essential tremor and Parkinson’s disease. Patients with Parkinson’s are good candidates for the surgery if they’re still fairly high-functioning, don’t have advanced dementia and have responded well to medication.

The Food and Drug Administration approved the surgery for essential tremor in 1997 and for tremors associated with Parkinson’s disease in 2002. According to the National Parkinson Foundation, more than 100,000 patients have had the surgery worldwide.

DBS isn’t a cure, but it has proven to be an effective tool to manage the symptoms of movement disorders.

Maine Medical Center’s Movement Disorders Program began offering DBS 10 months ago.

It’s not for the faint of heart. It’s brain surgery – with your eyes wide open.

Electrodes are implanted in specific areas of the brain, targeted by an MRI scan, and then attached to a battery-operated device placed under the skin of the patient’s chest. That device emits pulses of electricity that help restore normal function by interrupting the abnormal brain activity that’s causing the involuntary muscle movement.

“It’s technology that was adopted from cardiac pacemaker technology 20 to 30 years ago,” says Dr. Anand Rughani, a neurosurgeon at Maine Med who specializes in DBS therapy.

The patient remains awake in order to give the surgeon feedback.

“There aren’t any pain receptors in the brain,” Rughani says, “so there’s no pain associated with the actual electrodes in the brain. The only discomfort is being stuck on an operating table for the time it takes (usually two to five hours) to do the surgery.”

Once the DBS system is in place, it can be programmed to make sure the patient gets the maximum benefit with no side effects, such as double vision or speech problems.

“The battery is a simple little battery that’s programmable through the skin,” Rughani says. “We have a little wand that can communicate with it.”

On April 14, Pam Hillock was wheeled into an operating room at Maine Med to undergo DBS. She remembers the moment when the tremors – which had ruled her life for so long –stopped.

“I didn’t know whether to laugh or cry,” she says. “But all of a sudden my whole body was just as relaxed. It was phenomenal. Phenomenal.”

Four months later, it’s still phenomenal.

“I’m doing beautiful,” Hillock says. “All my family and friends who haven’t seen me for a while, the first thing out of their mouths is, ‘Pam, you’re not shaking!’ ”

What’s new to Maine is old hat to the doctors at the University of Florida College of Medicine’s Center for Movement Disorders and Neurorestoration.

Dr. Michael Okun, co-director of the center, and his team have done more than 1,000 DBS surgeries since 2002. Okun says the most important lesson they’ve learned is to make sure they understand the patient’s expectations going in – and that the patient understands potential risks and benefits.

“We ask the patient what is it that’s going to make it worth it to you to have this operation,” Okun says. “Once we understand what the patient wants and expects, we can … counsel them as to whether or not the technology can even come close to their expectations.”

For Inge Valentine, who lives in Kennebunk, the goal was to stop the uncontrolled flailing of her arms and legs – something she called “dancing.”

Valentine, 73, was diagnosed with Parkinson’s disease 13 years ago.

“I lost a lot of weight,” says Valentine, a former physical therapist and onetime avid cross country skier, “because I was always in motion. I couldn’t sit still, ever, and that got on my nerves big time.”

Valentine had DBS surgery at Maine Med with Rughani this spring. She was happy to be able to have it close to home – happy that her “dancing” days are over.

“People say now, ‘Hey, you’re not dancing anymore,’ ” Valentine says. “Definitely a success.”