Cognitive profile as a predictor of the long-term outcome after deep brain stimulation in Parkinson's disease

https://doi.org/10.1016/j.jns.2020.117063Get rights and content

Highlights

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    We studied the outcome of deep brain stimulation in patients with PD with dementia.

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    PD with dementia poses greater risk for deep brain stimulation than those without.

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    Mild cognitive impairment does not impact the outcome of deep brain stimulation.

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    Visuospatial impairment is predictive of poorer outcome of deep brain stimulation.

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    Cognitive profiles can stratify the pre-operative risk for deep brain stimulation.

Abstract

Background

Although dementia is a contraindication for deep brain stimulation (DBS) in patients with Parkinson's disease (PD), the concept is supported by little scientific evidence. Moreover, it is unclear whether PD with mild cognitive impairment (PD-MCI) or domain-specific cognitive impairments affect the outcome of DBS in non-demented PD patients.

Objective

To investigate the influence of baseline cognitive profiles of PD on the outcome of DBS.

Methods

Baseline cognitive levels of patients with PD who underwent DBS were classified into PD with dementia (PDD) (n = 15), PD-MCI (n = 210), and normal cognition (PD-NC) (n = 79). The impact of the cognitive level on key DBS outcome measures [mortality, nursing home admission, progression to Hoehn&Yahr (HY) stage 5 and progression to PDD] were analyzed using Cox regression models. We also investigated whether impairment of a specific cognitive domain could predict these outcomes in non-demented patients.

Results

Patients with PDD showed a substantially higher risk of nursing home admission and progression to HY stage 5 compared with patients with PD-MCI [hazard ratio (HR) 4.20, P = .002; HR = 5.29, P < .001] and PD-NC (HR 7.50, P < .001; HR = 7.93, P < .001). MCI did not alter the prognosis in patients without dementia, but those with visuospatial impairment showed poorer outcomes for nursing home admission (P = .015), progression to HY stage 5 (P = .027) and PDD (P = .006).

Conclusions

Cognitive profiles may stratify the pre-operative risk and predict long-term outcomes of DBS in PD.

Introduction

Patients with Parkinson's disease (PD) develop advanced motor symptoms including motor fluctuation and levodopa-induced dyskinesia as the diseases progresses. Deep brain stimulation (DBS) of the subthalamic nucleus (STN) or globus pallidus interna (GPi) has become a standard treatment for these motor complications [1,2].

Historically, overt dementia has been considered to be a contraindication for DBS in PD [3,4]. However, there is scant scientific evidence to support this contraindication. Moreover, performing DBS procedures in PD patients with mild dementia who are still capable of providing informed consent is being debated because the patient may benefit ‘motorically’ from surgery despite the presence of dementia [5]. For these reasons, some patients with PD with medically intractable motor symptoms and mild dementia were treated with DBS in the real-world, under the circumstance that the patients and caregivers fully understand the disease status [5].

Since the candidates for DBS are mostly in the advanced stage of PD, the severity and pattern of cognitive impairment are highly heterogenous, involving all major cognitive domains to various degrees [6]. Although a substantial number of patients have PD with mild cognitive impairment (PD-MCI) at the time of surgery, which is considered as a transitional stage from PD with normal cognition (PD-NC) to PD with dementia (PDD), little is known about the risk of MCI itself on the outcome of DBS. Moreover, the ability of the characteristics of domain-specific cognitive impairment in non-demented patients predict the outcomes after DBS surgery remains underexplored.

This study aimed to investigate the effect of baseline cognitive profiles, including PDD, PD-MCI, and PD-NC on the long-term outcomes of DBS surgery, while comparing key outcome measures. Moreover, we further estimated whether impairment of a specific cognitive domain could predict the outcome in DBS recipients without dementia.

Section snippets

Participants

We retrospectively reviewed the electronic medical records of patients with PD who underwent STN or GPi DBS surgery at a single tertiary medical center from March 2002 to December 2017. Patients were excluded if: i) the diagnosis changed postoperatively to atypical Parkinsonism, ii) a serious adverse event was caused by the DBS itself, iii) DBS lead revision or removal were performed, and iv) they had not undergone standardized neuropsychological evaluation prior to surgery (Fig. 1). Patients

Results

From March 2002 to December 2017, 304 patients with PD who had undergone DBS for the GPi or STN were included in the final analysis. Fifteen patients underwent DBS surgery during early PDD, 210 during the PD-MCI stage, and 79 patients were PD-NC at the time of surgery (Fig. 1). The median follow-up duration was 4.0 years (interquartile range 3.0–6.0 years). The baseline characteristics are described in Table 1. No differences were observed in the baseline clinical characteristics among the

Discussion

The present study found that patients with PDD at baseline before DBS surgery substantially increased the risk of nursing home admission and progression to a bed-ridden state after DBS surgery compared with patients without dementia. However, patients with PD-MCI at baseline did not have a higher risk compared with those with PD-NC at baseline in any of the outcome variables. Visuospatial impairment was predictive of 3 of 4 key outcome measures (nursing home admission, progression to HY stage

Declarations of Competing Interest

None.

Acknowledgements

This study was supported by a grant from the Korea Healthcare Technology R & D Project, Ministry of Health & Welfare, Republic of Korea (HI19C0256). We appreciate the clinical psychologists who supported the study.

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