Cognition and Depression Following Deep Brain Stimulation of the Subthalamic Nucleus and Globus Pallidus Pars Internus in Parkinson’s Disease: A Meta-Analysis

Abstract

Parkinson's disease (PD) is a common, degenerative disorder of the central nervous system. Individuals experience predominantly extrapyramidal symptoms including resting tremor, rigidity, bradykinesia, gait abnormalities, cognitive impairment, depression, and neurobehavioral concerns. Cognitive impairments associated with PD are diverse, including difficulty with attention, processing speed, executive functioning, memory recall, visuospatial functions, word-retrieval, and naming. Deep brain stimulation (DBS) of the subthalamic nucleus (STN) or globus pallidus internus (GPi) is FDA approved and has been shown to be effective in reducing motor symptoms of PD. Studies have found that stimulating STN and GPi are equally effective at improving motor symptoms and dyskinesias; however, there has been discrepancy as to whether the cognitive, behavioral, and mood symptoms are affected differently between the two targets. The present study used random-effects meta-analytic models along with a novel p-curve analytic procedure to compare the potential cognitive and emotional impairments associated with STN-DBS in the current literature to those associated with GPi-DBS. Forty-one articles were reviewed with an aggregated sample size of 1622 patients. Following STN-DBS, small declines were found in psychomotor speed, memory, attention, executive functions, and overall cognition; and moderate declines were found in both semantic and phonemic fluency. However, GPi-DBS resulted in fewer neurocognitive declines than STN-DBS (small declines in attention and small-moderate declines in verbal fluency). With regards to its effect on depression symptomatology, both GPi-DBS and STN-DBS resulted in lower levels of depressive symptoms post-surgery. From a neurocognitive standpoint, both GPi-DBS and STN-DBS produce subtle cognitive declines but appears to be relatively well tolerated.

Awake versus asleep deep brain stimulation for Parkinson’s disease: a critical comparison and meta-analysis

“…One critical area of post-DBS outcomes that was not addressed by our study was cognition. While many have studied the effects on specific DBS targets on cognitive outcomes,36 there have been no studies of anaesthetic technique on short-term or long-term cognitive outcomes after DBS. Finally, meta-analysis results are always limited by the quality of the data reported in the literature.…”

Deep Brain Stimulation of the Subthalamic Nucleus Improves Lexical Switching in Parkinsons Disease Patients

“…According to such a concept, the latter might account for the present findings. In general, DBS of the STN seems to be more susceptible to changes in cognitive scores compared to DBS of the GPi, although it has been stated that the particular influences of stimulation, trajectory, and lead placement still need to be disentangled [63]. …”

No differences in neuropsychological outcomes between constant current and voltage current subthalamic deep brain stimulation for Parkinson’s disease

“…This article expands upon previous finding reporting the outcome of the open-label randomized controlled trial of a constant current DBS device which found improvements in patient reported good quality "on" time compared to a delayed stimulation control group (3). The new study (2) supplements the former limited neuropsychological data presented (3), and examines the cause and impact of verbal fluency declines following surgery, which is the most consistent and persistent cognitive decline reported in DBS patients (4).…”

“…To date, current controlled stimulation has not been evaluated in GPi DBS, which according to a recent meta-analysis 4 may be a safer surgical alternative to STN in terms of its neurocognitive and neurobehavioral profile. The metaanalysis revealed that STN DBS led to cognitive declines in more domains than was found for studies investigating GPi DBS, and a greater reduction in depression symptomatology following GPi versus STN.…”