Progressive Supranuclear Palsy: Pedunculopontine Nucleus DBS May Not Improve Symptoms

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There was a significant improvement in axial motor activities, step length, stride length, and walking speed with 8 Hz of pedunculopontine nucleus deep brain stimulation.
There was a significant improvement in axial motor activities, step length, stride length, and walking speed with 8 Hz of pedunculopontine nucleus deep brain stimulation.

For patients with progressive supranuclear palsy, bilateral pedunculopontine nucleus deep brain stimulation can improve cyclic gait and hypokinesia, but the effects are not clinically significant, according to results published in Parkinsonism and Related Disorders.

The study included 7 participants with progressive supranuclear palsy with a clinical diagnosis of progressive supranuclear palsy, a levodopa-resistant gait and balance disorder, age <75 years, and absence of dementia or major psychiatric comorbidities.

Each participant received bilateral pedunculopontine nucleus deep brain stimulation. The researchers assessed the effects of stimulation frequencies at 8, 20, 60, and 130 Hz on motor scores and gait. Motor scores were followed up for 2 years postoperatively. The researchers also compared activities of daily living, frequency of falls, health-related quality of life, cognition, and mood at 12 months with baseline parameters.

Treating participants with 8 Hz stimulation resulted in significant reduction of axial motor scores [t(5)=2.91; P =.034] and improvement of step length [t(5)=−5.0; P =.004], stride length [t(5)=−3.14; P =.026], and walking speed [t(5)=−2.99; P =.030].

Treating participants with 130 Hz stimulation improved bradykinesia [t(5)=2.6; P =.048], but it did not improve gait or balance.

Despite improvements, the researchers found that they did not translate into clinically important benefits. Participants' frequency of falls did not change, and participants saw declines in activities of daily living, quality of life, and frontal cognitive functions at 12 months compared with baseline. Their mood at 12 months of follow-up remained unchanged.

"Taken together with previous results of unilateral [pedunculopontine nucleus deep brain stimulation] in [progressive supranuclear palsy]-patients with either an only mild or no effect on motor symptoms, the lack of symptom improvement that translate[s] into a clinical benefit [makes us] question the role of bilateral [pedunculopontine nucleus deep brain stimulation] as a routine intervention and treatment option in [progressive supranuclear palsy]," the researchers wrote.

Reference

Galazky I, Kaufmann J, Lorenzi S, et al. Deep brain stimulation of the pedunculopontine nucleus for treatment gait and balance disorder in progressive supranuclear palsy: effects of frequency modulations and clinical outcome [published online February 19, 2018]. Parkinsonism Relat Disord. doi: 10.1016/j.parkreldis.2018.02.027.

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