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Texas Health Dallas Researcher Studies How 'Brain Pacemaker' Can Control Little-Known Parkinson's Symptom|
DALLAS — A researcher at Texas Health Presbyterian Hospital Dallas has discovered that electrical impulses sent by a “brain pacemaker” to control tremors in Parkinson’s disease patients can help control more rare symptoms of the condition.
The paper, “Alleviation of drenching sweat following subthalamic deep brain stimulation in a patient with Parkinson’s disease,” appears in the Journal of the Neurological Sciences. The case study describes how the full-body, drenching sweats of one Parkinson’s patient stopped after deep brain stimulation (DBS).
The procedure, which can treat a variety of disabling neurological conditions, involves delicate brain surgery in which neurosurgeons place a battery-operated neurostimulator — similar to a heart pacemaker — in the region of the brain where an “electrical storm” is causing motor-function problems.
The device delivers pulses of electricity to targeted areas in the brain to block abnormal electrical signals that cause Parkinson’s symptoms, which can include hyperhidrosis (excessive sweating).
“For some Parkinson’s patients, medications aren’t effective and deep brain stimulation is an option,” said co-author Dr. Malcolm Stewart, a neurologist on the medical staff at Texas Health Dallas and medical director of the hospital’s Human Performance Lab. “DBS can help the motor-function for many of these patients — and we’ve also found that their drenching sweats are often brought under control.”
Parkinson’s disease is a progressive brain disorder that affects more than a million Americans. Many patients become profoundly disabled, while some continue to function relatively well for many years.
The condition occurs when nerve cells in the substantia nigra area of the brain die or become impaired. Normally, these neurons produce a vital chemical known as dopamine, which allows smooth, coordinated function of muscles. The loss of dopamine production in the brain causes the primary symptoms of Parkinson’s disease: tremor (shaking), stiffness and difficulty with balance.
“It’s a devastating disease that profoundly impacts the lives of patients and their loved ones,” Stewart said. “The disease is as seemingly complex as the brain itself, thus the need for better ways to diagnose and treat the condition and the need for ongoing research into the origins of the disorder.”
Stewart’s paper describes a Parkinson’s patient who, among other debilitating symptoms, suffered from periodic episodes of full-body drenching sweat. About half of patients suffer from hyperhidrosis, though exactly why is not known. Neurologists have theorized that excessive sweating is connected to damage to peripheral and central sympathetic mechanisms in the brain.
The patient first exhibited signs of Parkinson’s disease at age 39. By age 50, he had developed severe motor-function problems that could not be controlled by medications. Periodic episodes of tremor and loss of muscle control confined him to a wheelchair.
Medications did little to help with his muscle control and did not control the body-drenching sweats. According to the researchers, though, the sweating problems stopped completely after DBS surgery, which stimulated the brain’s subthalamic nucleus and adjacent structures.
“DBS has been a great option for patients whose Parkinson’s disease can’t be adequately controlled with medication,” said Dr. Michael Desaloms, chair of neurosurgery at Texas Health Dallas. “This research is fascinating because it sheds more light on the potential value of DBS to control multiple Parkinson’s symptoms. It helps us better understand what’s going on in different regions of the brain.”
In addition to hyperhidrosis, other secondary symptoms of Parkinson’s disease include depression, difficulty swallowing, excessive salivation, dementia, scaling and dry skin on the face and scalp, and a loss of voice volume.
Other authors of the paper include C. Ward, a neurologist at the Michael E. Debakey VA Medical Center in Houston, M.K. Sanghera, a neurophysiologist at Scott & White Hospital in Temple, Texas, K. Mewes, a neurologist at Emory University in Atlanta, Dr. R.K. Simpson, a neurosurgeon at the Neurological Institute at Methodist Hospital in Houston, and E.C. Lai, a neurologist at the Houston VA Hospital and Baylor College of Medicine in Houston.
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