Objective: We aimed at characterizing cognitive changes in patients with Parkinson’s disease (PD) treated with deep brain stimulation (DBS) of the subthalamic nucleus (STN).

Background: A cognitive decline is a serious non-motor sign of PD. There is a rising interest in understanding the deterioration in PD patients treated with STN DBS. Recent meta-analyses suggested that STN DBS can be regarded as generally safe for cognitive functions causing only a mild decline in verbal fluency [1, 2]. The dual-process theory of cognitive deficit in PD postulated two distinct phenotypes with different deterioration time courses, (i) a slowly deteriorating fronto‑striatal phenotype and (ii) a phenotype with visuospatial deficits and rapid conversion to dementia [3]. Here we tested whether PD patients treated with STN DBS exhibited a long-term decline in cognitive performance.

Method: A longitudinal study on a sample of 28 PD patients with motor complications (age 59 ± 7 years, 61 % males) treated with STN DBS bilaterally in combination with oral dopaminergic therapy. Patients’ cognitive functions were assessed using the Dementia Rating Scale (DRS-II) before and 1.97 ± 0.99 years after the DBS surgery. The Wilcoxon test was used to contrast pre- and post-surgery cognitive performance.

Results: A significant decline in (DRS-II Total score) general cognitive performance (Z = -2.92, p = 0.004) was identified together with declines in Attention (Z = -3.22, p = 0.001) and Memory (Z = -2.00, p = 0.045) domains. Decline in the Initiation/Perseveration (Z = -1.51, p = 0.130), Construction (Z = -0.63, p = 0.527), and Conceptualization (Z = -0.35, p = 0.730) domains failed to reach statistical significance.

Conclusion: Our results demonstrated a subtle but significant cognitive decline in PD patients after two years of treatment with bilateral STN DBS. The overall pattern of decline is in line with profiles previously reported in advanced PD patients treated exclusively with oral dopaminergic therapy [4] with primarily fronto-striatal dysfunction and preserved visuospatial functions. Grant support: GAČR 16-13323S and AZV NV19-04-00233 offered by the Czech ministry of health.

References: 1. Combs, H.L., et al., Cognition and Depression Following Deep Brain Stimulation of the Subthalamic Nucleus and Globus Pallidus Pars Internus in Parkinson’s Disease A Meta-Analysis. Neuropsychology review, 2015. 25(4): p. 439-454. 2. Parsons, T.D., et al., Cognitive sequelae of subthalamic nucleus deep brain stimulation in Parkinson’s disease: a meta-analysis. The Lancet Neurology, 2006. 5(7): p. 578-588. 3. Robbins, T.W. and R. Cools, Cognitive deficits in Parkinson’s disease: a cognitive neuroscience perspective. Mov Disord, 2014. 29(5): p. 597-607. 4. Pigott, K., et al., Longitudinal study of normal cognition in Parkinson disease. Neurology, 2015. 85(15): p. 1276-1282.

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MDS Abstracts - https://www.mdsabstracts.org/abstract/cognitive-changes-after-deep-brain-stimulation-of-the-subthalamic-nucleus-in-parkinsons-disease-a-longitudinal-study/