One patient seeks a return to stability through deep brain stimulation at Keck Medicine of USC.

On a rushed morning one year ago, Mary Shea, stood at a skycap booth at Reagan National Airport and struggled to remove her drivers’ license from her wallet. The skycap and people in line behind her impatiently waited as her hands shook trying to remove the license from the tight wallet pocket — an easy task if your fine motor skills are not compromised.

For 10 years, Shea has lived with the physical effects of Parkinson’s disease (PD) and essential tremor (ET), a secondary movement disorder not related to PD.

“Subliminally, it’s always with you,” she says. “You might be at the happiest occasion, but always thinking about how your meds will work, what symptoms will be noticeable to others, and when your next dosage is due. Even when people know you, it is uncomfortable being on display in this way.”

With the Skycap’s help, she finally retrieved the license, but after the experience, she was more convinced than ever that she needed to take additional steps to improve her daily functioning and her life. It was time to pursue deep brain stimulation (DBS) with her neurologist, Daniel Togasaki, MD, PhD, associate professor of neurology at USC Neurosciences of Keck Medicine of USC.

What Is Deep Brain Stimulation (DBS)?

DBS is a procedure that can decrease the tremors, dyskinesia (tics), and other movement issues that commonly come with Parkinson’s and ET and can often cut the amount of medication required. The majority of patients undergoing DBS have either PD or ET, meaning they will have only one area of the brain stimulated, typically on both sides. In Shea’s case, she had a double diagnosis of PD and ET resulting in two different areas of the brain requiring stimulation on both sides.

DBS is a series of two procedures in which electrodes are implanted in the brain while the patient is awake, though mildly sedated. Once the electrodes are positioned in the correct locations of the brain for the patient, wires are attached and coiled under the scalp for the second part of the operation, which typically occurs within the next one to two weeks. In the second procedure, the wires coiled under the scalp are unwound and channeled internally behind the ears, down the neck to the battery pack(s) implanted in this same operation in the upper chest. The battery pack, somewhat similar to a pacemaker, sends electrical impulses that stimulate specific areas of the brain, blocking abnormal electrical signals from targeted areas.

Shea was diagnosed with essential tremor in 2006, after noticing a tremor in her left index finger when it rested on the steering wheel of her car. Her neurologist at the time told her not to worry about it, but she did worry. Eventually, she sought out a movement disorder specialist. Enter Dr. Togasaki, who diagnosed her with both Parkinson’s disease and essential tremor in 2009.

Shea says with a wry smile, “You don’t want to have your transmission worked on at an oil change place. Dr. Togasaki is my transmission specialist.”

A Coordinated Team Effort

DBS treatment at Keck Medicine of USC is a comprehensive, intensive process. A neuropsychologist, psychologist, a neurosurgeon and a social worker in some cases see patients with a definitive Parkinson’s diagnosis who are currently getting some benefit from the Parkinson’s medications. Patients are also encouraged to attend a DBS support group, held at Keck Medicine of USC and run by Nasrin Esnaashari, NP, MSN, instructor of clinical neurology at Keck Medicine of USC, who programs the DBS for each patient in a series of appointments after their second surgical procedure.

Importantly, all specialists involved in the evaluation process must reach a consensus that the patient is a good candidate for the DBS procedure. The group works closely together, meeting monthly to discuss the treatment of each patient on their roster.

“Treatment for DBS involves many caregivers,” says Esnaashari, “But especially the neurosurgeon, the neurologist, and the nurse practitioner. Proper care can’t occur without all three sides of the triangle.”

In addition to Togasaki and Esnaashari, Shea’s team includes renowned neurosurgeon Mark Liker, MD, assistant clinical professor of neurosurgery at USC Neurosciences of Keck Medicine of USC, who says this collaborative effort between specialists is important to the patient experience.

“We want good outcomes,” says Liker, who has 15 years experience performing DBS surgery at Keck Medicine. “We don’t want a lot of patients who are implanted to not receive benefit from the procedure. I can say almost universally every patient that’s cleared for surgery has a dramatic benefit from the DBS.”

Varied Symptoms And Consequences

Part of the reason for this collaborative effort is the nature of Parkinson’s.

“It’s a boutique disease,” Shea says. “Everyone is affected differently.”

Many patients experience “freezing,” where their lower body refuses to move from a tile floor to a carpeted floor, for example. Some patients experience rigidity and/or slowness. Some experience dystonia, painful muscle contractions in various body parts, such as the foot and ankle. Others experience tremors, fatigue, decline in fine motor skills, more general gait issues, balance problems and falls, a loss of sense of smell, trouble sleeping, difficulty speaking, or loss of the ability to use facial expressions. The symptoms and consequences are so varied, the disease can be difficult to diagnose. Even with a proper diagnosis, some patients are not aware that they may be eligible for the DBS procedure.

“Fifty percent of the people who can benefit from DBS never consider the opportunity,” says Esnaashari.

Lack of access or fear of brain surgery could contribute to this low number. However, the doctors that perform this surgery consider it minimally invasive, and most patients who undergo the procedures recover quickly afterwards.

Before surgery, patients are cautioned that DBS is not a cure, and it should not be expected to relieve all physical symptoms. However, many patients who receive this treatment report improvement in so many areas that they may feel as though they have a new lease on life.

The benefits of this thoughtful and dedicated process are not lost on patients like Shea.

“I can’t speak highly enough of Dr. Togasaki, Nasrin and the specialists of Keck Medicine of USC,” she says. “As far as being cutting-edge, taking time with patients, explaining things to you, giving you hope for the future, they really take the time to prepare you for the procedure in every way.”

Continued Comprehensive Care

The process continues to be comprehensive after the surgery. Some institutions program the DBS implants while the patient is under anesthesia for implantation of the battery pack, but this leaves the patient unable to respond to stimulus. At Keck Medicine, each DBS patient’s implants are programmed post-surgery, enabling the patient to be active and reactive to the changes. The programming is based on the patient’s clinical symptoms and its therapeutic effects occur when the contacts located in the brain are stimulated. There are patients still receiving benefit from their DBS device twelve years after their initial surgery, with only an occasional office visit for a check up and to do minor adjustments to the programming.

Even before her DBS surgeries, Shea was very active in the Parkinson’s community.

She spends some of her time lobbying for research funding and educational outreach. Now that her initial programming sessions are complete, she plans to continue to champion the advancement of research, patient education, and public awareness of Parkinson’s. With the progress she’s made thanks to DBS, her ability to do advocate and perform the normal tasks of everyday life are greatly enhanced.

With a steady hand and a smile on her face, Shea says, “It’s such a terrible disease, and to have this procedure available is like magic.”

About Parkinson’s Disease*

  • PD is the second most common neurodegenerative disease after Alzheimer’s disease.
  • Approximately 1 million Americans have PD. There are as many as 60,000 new cases diagnosed every year.
  • Incidence of PD increases with age. Only 4% of people with Parkinson’s are diagnosed before the age of 50.
  • Men are one and a half times more likely to have PD than women.

* Statistics from the Parkinson’s Disease Foundation

Advancing Parkinson’s Disease Research

Researchers at Keck Medicine of USC are looking for volunteers with Parkinson’s disease and memory or thinking issues to discover if exercise and socializing can improve mild cognitive impairment (MCI) and executive function (EF).

Recent studies in healthy aging show that skill-based exercise has an impact on MCI and EF. This important finding could mean that exercise will be able to arrest or reverse the effects of MCI and EF impairment in Parkinson’s patients.

Principle investigator Giselle M. Petzinger, MD, assistant professor of neurology, is a movement disorders specialist at USC Neurosciences at Keck Medicine of USC. Her research focuses on clinical trials that examine the potential effects of lifestyle in modifying disease in order to find novel therapeutic targets for Parkinson’s disease. The study involves memory and cognitive evaluations, fitness evaluations, and a Parkinson’s disease assessment.

For more information, please call (800) USC-CARE or visit

by Amanda Busick