Spinal stimulation found safe, shows mixed benefits in small study
Patients maintained movement, but didn't see posture, balance, or gait improve
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- Spinal cord stimulation for Parkinson's was found safe but showed mixed benefits.
- It improved leg movement, muscle stiffness, and bradykinesia, but not posture or balance.
- Larger studies are needed to confirm its long-term effectiveness for gait impairment.
Spinal cord stimulation appears to be safe and may help people with Parkinson’s disease maintain movement, although it did not improve posture, balance, or gait compared with sham treatment in a small study from Denmark.
The STEP-PD study (NCT05110053) involved 12 patients with gait impairments who were randomly assigned to receive either active stimulation with a MicroBurst device or a sham treatment for six months. After six months, all received active stimulation for another six months.
The study, “Spinal cord stimulation therapy for gait impairment in Parkinson’s disease: a double-blinded, randomised feasibility trial with an open extension,” was published in Nature Communications.
Motor symptoms of Parkinson’s include slowness of movement (bradykinesia), muscle stiffness (rigidity), and problems with posture and balance. As a result, patients may experience changes in gait, increasing the risk of falls.
In spinal cord stimulation, small electrical pulses are delivered via thin wires implanted surgically near the spinal cord at the level of the chest (thorax). Researchers believe this may improve the way motor signals travel through the nervous system, easing problems with posture and balance.
Testing safety, gait problems
The main goals of the STEP-PD study were to determine whether spinal cord stimulation could be performed safely and whether it improved a score called the Postural Instability and Gait Disorder (PIGD), which measures balance and gait problems. Secondary measures included the Lower Body and Gait (LBG) score, which focuses on how well the legs move.
Serious surgery-related side effects occurred in four of the 12 study participants. These included accidental puncture of the membrane around the spinal cord, pain, and misplaced leads, which required additional surgery. Five patients had swelling at the implant site.
After surgery, nine patients — three in the MicroBurst group and six in the sham group — saw their symptoms worsen temporarily, but improved without changing medication. Three patients had falls, but all had a history of falls before the study. None of the patients reported uncomfortable stimulation sensations such as tingling or numbness.
At six months, MicroBurst did not significantly improve the PIGD score compared with sham treatment. However, muscle stiffness in the legs and bradykinesia lessened in the MicroBurst group. After 12 months, the LBG score improved significantly, especially among those who received active stimulation for the full year. Muscle stiffness and bradykinesia also lessened.
When the researchers compared these patients with a similar group from a large Parkinson’s database who did not receive spinal cord stimulation, the untreated group’s walking worsened over a year, while those who received spinal cord stimulation tended to improve slightly.
After six months of active stimulation, PIGD and LBG scores improved significantly for all patients, regardless of original group assignment. About 30% had a meaningful improvement in PIGD. Still, quality-of-life scores worsened in some areas, possibly reflecting expectations or other Parkinson’s symptoms.
On brain scans, patients with gait impairments showed increased activity in the right anterior insula, a region linked to attention and motor control. After MicroBurst, there was decreased activity in the right anterior insula and the thalamus, a relay center for motor signals. After a year, additional changes appeared in motor and limbic regions.
Spinal cord stimulation “applied over thoracic spinal levels is feasible, safe, and well-tolerated by patients with [Parkinson’s], and may, especially over time, provide improvement of bradykinesia and rigidity in the legs,” the researchers wrote. However, they noted, larger studies are needed to confirm whether it can meaningfully improve gait over time.
