Globus Pallidus Pars Interna: A Preferred Target of DBS in Parkinson Disease

When considering cognitive outcomes in patients with Parkinson disease, globus pallidus pars interna (GPi) may be a preferred target for deep brain stimulation (DBS), according to a study published in the Journal of Neuropsychiatry and Clinical Neurosciences.

The study included 2 groups of patients with Parkinson disease — 12 who underwent bilateral GPi DBS and 17 who underwent bilateral subthalamic nucleus (STN) DBS — at the DBS Center of Mayo Clinic in Scottsdale, Arizona, between 2002 and 2015.

At baseline and 6 months after DBS, investigators assessed differences in neuropsychological test scores on the Boston Naming Test and the Wechsler Adult Intelligence Scale Verbal Comprehension, Working Memory, and Processing Speed Indexes.

There were no significant differences between baseline and follow-up scores on any of the neuropsychological tests among patients in the GPi DBS group. Patients in the STN DBS group had significantly worse Processing Speed Index scores at follow-up compared with baseline (mean [standard deviation (SD)], 91.47 [10.42] vs 81.65 [12.03]; P =.03).

When investigators compared the 2 groups, they found a significant difference between baseline and follow-up scores on the Wechsler Adult Intelligence Scale Verbal Comprehension Index. Patients in the STN DBS group scored lower (mean delta, –3.41 [SD=5.91]), whereas patients in the GPi DBS scored higher (mean delta, 4.83 [SD=10.15]; P =.008) at baseline vs follow-up.

Despite this study’s small sample size, researchers stated, “Our findings add to the growing body of evidence showing that the preferred target for DBS in patients with Parkinson disease might be GPi rather than STN, as this approach may be more likely to minimize potential negative effects on cognition.”

Reference

Hansen AL, Krell-Roesch J, Kirlin KA, et al. Deep brain stimulation and cognitive outcomes among patients with Parkinson’s disease: a historical cohort study [published online February 22, 2019]. J Neuropsychiatry Clin Neurosci. doi: 10.1176/appi.neuropsych.18050118