Low-frequency STN-DBS provides acute gait improvements in Parkinson's disease: a double-blinded randomised cross-over feasibility trial.
Zachary J Conway, Peter A Silburn, Thushara Perera and 2 others
PMID 34376190WHAT IT FOUND
In 14 people with Parkinson's, low-frequency subthalamic deep brain stimulation with voltage adjusted made trunk movement while walking more rhythmic side-to-side and up-and-down than usual high-frequency.
Clinical walking tests did not change, and tremor worsened in some.
Key findings
01When electrodes were set to 60 Hz and voltage was increased to keep total electrical energy delivered similar to usual high-frequency stimulation, side-to-side trunk rhythmicity during walking was higher with low-frequency stimulation; the mean difference was 0.42, above the minimal detectable change of 0.32.
02There were no significant differences in walking speed, cadence, step time, step time variability, 6-metre walk time, Timed Up and Go time, MDS-UPDRS III score, or retropulsion score.
0310 of 14 participants had worsening resting tremor with low-frequency stimulation; 6 completed assessments and 4 could not.
STILL TO COME
How it was doneWhat they foundWhat it means for PTs
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What it does not show
Only 14 participants were analysed after 31 expressed interest, 26 were eligible, 19 attended, and 5 were excluded because they took medication or already used low-frequency settings. The study was a feasibility trial with a planned minimum of 12 participants, so it is not a definitive efficacy trial. Participants were tested after at least 12 hours without Parkinson's medication, so the high-frequency condition was not their best medicated state. Both conditions were tested on the same day after a one-hour wash-in period, so the results are acute and may reflect fatigue or carry-over. All participants could stand and walk without assistance, so findings may not apply to people with more severe mobility loss. 10 of 14 had worsening resting tremor with low-frequency stimulation, and 4 could not complete the low-frequency condition, so tolerability is limited. No freezing of gait episodes occurred during testing, so the study does not show effects on freezing. Electrode target and actual location were marked manually, which can introduce bias and inter-operator variability.
The easy way to misread this
Do not conclude that low-frequency subthalamic deep brain stimulation is a proven long-term gait treatment. The study analysed 14 people, tested only acute same-day walking after medication withdrawal, and 4 participants could not complete low-frequency testing because tremor worsened.