Spinal Cord Stimulation Found to Reduce Pain, Motor Symptoms in Parkinson Disease

The current gold standard of treatment for Parkinson disease (PD) includes dopamine and deep brain stimulation (DBS) therapy, but researchers of a study published this week in Bioelectronic Medicine note that both approaches have their limitations and reported adverse effects. Moreover, they also have been shown to lose efficacy over time.

Along with dopamine and DBS, spinal cord stimulation (SCS) has emerged as an alternate therapy linked with alleviating both motor and nonmotor symptoms, such as pain, in PD.

“Whether to use SCS as a singular bioelectric therapy option or as a salvage therapy after dopamine and DBS treatments have begun to lose efficacy continues to be a question of interest,” said the study authors.

The researchers examined the use of SCS for the treatment of pain and motor symptoms in 15 patients with PD, as both a singular bioelectric therapy and as a salvage therapy after DBS. The study cohort had experienced pain not alleviated by prior treatment, with 8 having undergone DBS pain therapy and 7 having received only drug treatments.

In the study, the researchers implanted percutaneous electrodes through the skin of participants at the level of the thoracic or cervical spine. Each participant was set to 1 of 3 stimulation modes:

• Continuous tonic stimulation
• Continuous burst stimulation (40 Hz, 500 Hz, 1000 μs)
• On-off cycle mode bursts (on time of 10 to 15 seconds, off time of 15 to 30 seconds) with burst (40 Hz, 500 Hz, 1000 μs).

The mean age of the participants was 74, with an average disease duration of 17 years. Participants additionally completed the Visual Analogue Scale (VAS), Unified Parkinson’s Disease Rating Scale, Self-Rating Depression Scale, Hamilton Depression Rating Scale, Profile of Mood State, 10-meter walking test, and the Timed Up and Go (TUG).

After continuous programmed treatment post implantation, significant improvement based on the VAS, a measurement of pain intensity, was reported among all patients and stimulation modes, with a mean reduction of 59% reported. When comparing the stimulation modes, those who chose the cycling burst stimulation parameter had an average 67% reduction in VAS scores compared with the continuous burst parameter group who had an average 48% reduction in VAS scores.

Further improvements were shown in the 10-meter walk, a test measuring walking speed to assess functional mobility and gait, as 73% of patients exhibited an average improvement of 12%. The TUG test, which assesses physical balance and stability, both standing and in motion, was also improved among 64% of patients, with an average TUG improvement of 21%.

"We are seeing growing data on novel uses of spinal cord stimulation and specific waveforms on applications outside of chronic pain management, specifically PD," said lead study author Krishnan Chakravarthy, MD, PhD, assistant professor of anesthesiology at the University of California San Diego School of Medicine, in a statement. "The potential ease of access and implantation of stimulators in the spinal cord compared to the brain suggests that this is a very exciting area for future exploration."

While promising, SCS has its own reported risks, including undesirable feelings such as a jolt or shock, hematoma, infection, seroma, and,in extreme cases, epidural hemorrhage. The researchers say that further studies are warranted to determine whether improved motor function is due to neurological changes caused by SCS or simply decreased pain.

Reference

Chakravarthy KV, Chaturvedi R, Agari T, Iwamuro H, Reddy R, Matsui A. Single arm prospective multicenter case series on the use of burst stimulation to improve pain and motor symptoms in Parkinson’s disease. Bioelectron Med. Published online September 28, 2020. doi:10.1186/s42234-020-00055-3