Video
Mandar Jog, MD
Dr. Jog describes a pilot study that assessed the therapeutic effect of spinal cord stimulation on gait dysfunction in patients with advanced...
VANCOUVER—Spinal cord stimulation improves gait in patients with advanced Parkinson’s disease, according to a pilot study described at the 21st International Congress of Parkinson’s Disease and Movement Disorders. The technique allows neurologists to determine which stimulation parameters provide the greatest benefit for each patient, said Mandar Jog, MD, Professor of Neurology and Engineering and Director of the Movement Disorders Center at Western University in London, Ontario.
Mandar Jog, MD
“Each participant demonstrated unique gait changes due to different spinal cord stimulation combinations,” the investigators said. Many variables affect gait, such as stride width, length, and velocity. “Instead of simply measuring those variables as an outcome, we used those variables to help us program the device,” said Dr. Jog.
Treatment-Resistant Symptoms
Gait dysfunction and freezing of gait are common in advanced Parkinson’s disease, and gait symptoms are largely resistant to dopamine replacement therapy. Studies have suggested that epidural spinal cord stimulation, which is an approved therapy for pain, may help treat levodopa-resistant motor symptoms in Parkinson’s disease.
Dr. Jog and colleagues analyzed objective gait measurements to understand which spinal cord stimulation settings most improved gait. They tested combinations of pulse widths and frequencies that induced paresthesia in patients’ lower limbs.
The six-month study included five men with Parkinson’s disease who had significant gait disturbances on levodopa therapy. The patients were not eligible for deep brain stimulation. Mean age was 71, and mean disease duration was 14 years. The patients underwent mid-thoracic spinal cord stimulation surgery, and a dorsal spinal cord stimulator was implanted in the epidural space (T7–10). The researchers evaluated patients before the operation and at weeks 2, 4, 6, 8, 10, 12, 16, and 24 after surgery.
The investigators conducted randomized testing of different spinal cord stimulation settings at weeks 2, 4, 6, 8, 10, 12, and 16. At week 24, researchers evaluated patients when they had been off stimulation for 48 hours and then with stimulation.
Patients completed walking tasks on a 20-foot walkway with sensors that relayed each footfall to a computer with gait analysis software. The researchers grouped gait variables according to whether they were expected to increase with improvement (eg, step length and stride velocity) or decrease with improvement (eg, stride width and step time).
Determining Optimal Settings
For two of the patients, the most effective spinal cord stimulation setting was a pulse width of 400 µs and a frequency of 60 Hz. The optimal settings for the remaining three patients were 300 µs and 30 Hz, 300 µs and 130 Hz, and 300 or 400 µs and 130 Hz.
Key gait variables improved with spinal cord stimulation. For instance, stride velocity significantly improved by 54% with the optimal settings, compared with baseline. Mean number of freezing of gait episodes significantly decreased. Unified Parkinson’s Disease Rating Scale motor scores and patients’ confidence in performing activities of daily living also significantly improved, compared with baseline.
Patients achieved a greater degree of independence after receiving spinal cord stimulation, Dr. Jog said. For example, one patient no longer had to rely on a wheelchair or scooter to get around, and one patient no longer needed help getting out of a chair. One patient was able to resume working in fields, and one patient was able to walk on a beach. “Everybody improved to different levels. The improvement occurred immediately in the laboratory,” he said.
No adverse events were reported. The researchers plan to conduct further studies. Because spinal cord stimulation already is available for the treatment of pain, it may be feasible to pair a spinal cord stimulation device with a sensor system that allows physicians to optimize the stimulator’s settings for the treatment of gait dysfunction in Parkinson’s disease, Dr. Jog said.
—Jake Remaly
Suggested Reading
de Andrade EM, Ghilardi MG, Cury RG, et al. Spinal cord stimulation for Parkinson’s disease: a systematic review. Neurosurg Rev. 2016;39(1):27-35.
Pinto de Souza C, Hamani C, Oliveira Souza C, et al. Spinal cord stimulation improves gait in patients with Parkinson’s disease previously treated with deep brain stimulation. Mov Disord. 2017;32(2):278-282.