Medical Center participates in clinical studies of two neurological disorders
Loma Linda University Medical Center neurosurgeon Frank Hsu, MD (left), and neurologist David Swope, MD, are collaborating on clinical studies of two neurological disorders, Parkinson disease and essential tremor. The studies, which are sponsored by Advanced Neuromodulation Systems (ANS), will determine whether a deep brain stimulation device is effective against symptoms of the disorders.
Loma Linda University Medical Center has been selected as one of 12 hospitals nationwide to participate in clinical studies of Parkinson disease and essential tremor, according to Maureen Murphy of Advanced Neuromodulation Systems (ANS), the sponsor of the studies. The tests will determine whether an implant device ANS manufactures—known as the Libra DBS (deep brain stimulation) system—is effective against key symptoms of the two disorders.
Essential tremor and Parkinson disease are degenerative neurological disorders, which often impair motor skills and speech and cause involuntary movements known.
Neurologist David Swope, MD, and neurosurgeon Frank Hsu, MD, are the principal investigators on the Parkinson and essential tremor studies, respectively. Dr. Swope will evaluate potential study participants for compatibility with the investigational criteria established for the studies, and Dr. Hsu will surgically implant the devices in patients who qualify. Dr. Swope explains that the Libra DBS system is very effective when used on the right patients.
“There are three good indications for the surgery for patients with Parkinson,” he notes. “The most common is for patients with severe dyskinesia who develop involuntary movements like Michael J. Fox. The second is for patients with motor fluctuations. They take their meds and get better, but when the medication wears off, the symptoms keep coming back throughout the day. Surgery can smooth-out their symptoms and reduce the severity of dyskinesia. The third are patients with disabling tremor. Tremors can be hard to control with medications, but often respond well to surgery.”
Dr. Swope goes on to distinguish between tremors associated with Parkinson disease and those in patients with essential tremor. “The Parkinson tremor occurs when the patient is at rest,” he says. “Essential tremor gets started with action.”
According to Dr. Hsu, the study is going very well, but one problem is hindering progress. “Recruitment is slow,” he explains. “We need to recruit more people for the studies. Anybody with a debilitating essential tremor should consider it.” He points out that LLUMC needs a total of 12 participants to complete the studies, but so far, only six have volunteered.
In describing the process, Dr. Hsu notes that the surgery does not involve a lot of pain. “They see Dr. Swope first,” he reiterates, “and talk about possible surgical intervention. After they go though the screening process with him, they come see me. I discuss the risks and benefits of surgery and prepare a timetable with them.”
Dr. Hsu goes on to note that the surgery takes three to four hours. “The first step is to put a frame around the patient’s head to localize precisely our target,” he reports. “Then we send them out for a CT scan, then take them back into the operating room. The procedure involves inserting the DBS implant electrodes into the thalamus or STN. The patient stays awake the whole time. We do some talking with them and need them to be awake to cooperate. It’s not very painful.”
Dr. Swope is similarly optimistic about the results. “So far, people who have had the surgery have improved quite a bit,” he notes. “That’s really the key. If you do the procedure on patients you know will benefit, the results will be good.”
While Dr. Swope acknowledges that both studies utilize the same procedure, the procedure is performed on different targets in the brain depending on the diagnosis.
“Dr. Hsu does the surgery,” he notes, “and I do the programming. They are really two different studies because there are two different conditions that we’re treating. The protocols are very similar with minor differences.”
The studies have been underway at LLUMC for about a year. “They will continue until enough patients have participated,” Dr. Swope says.
By James Ponder