Consistency and Stability of Motor Subtype Classifications in Patients With de novo Parkinson's Disease

Jingru Ren; Chenxi Pan; Yuqian Li; Lanting Li; Ping Hua; Ligang Xu; Li Zhang; Wenbin Zhang; Pingyi Xu; Weiguo Liu

doi:10.3389/fnins.2021.637896

Consistency and Stability of Motor Subtype Classifications in Patients With de novo Parkinson's Disease

Front Neurosci. 2021 Mar 1:15:637896. doi: 10.3389/fnins.2021.637896. eCollection 2021.

Authors

Jingru Ren¹, Chenxi Pan¹, Yuqian Li¹, Lanting Li¹, Ping Hua¹, Ligang Xu¹, Li Zhang², Wenbin Zhang³, Pingyi Xu⁴, Weiguo Liu¹

Affiliations

¹ Department of Neurology, The Affiliated Brain Hospital of Nanjing Medical University, Nanjing, China.
² Department of Geriatrics, The Affiliated Brain Hospital of Nanjing Medical University, Nanjing, China.
³ Department of Neurosurgery, The Affiliated Brain Hospital of Nanjing Medical University, Nanjing, China.
⁴ Department of Neurology, First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China.

Abstract

Objective: Patients with Parkinson's disease (PD) are commonly classified into subtypes based on motor symptoms. The aims of the present study were to determine the consistency between PD motor subtypes, to assess the stability of PD motor subtypes over time, and to explore the variables influencing PD motor subtype stability.

Methods: This study was part of a longitudinal study of de novo PD patients at a single center. Based on three different motor subtype classification systems proposed by Jankovic, Schiess, and Kang, patients were respectively categorized as tremor-dominant/indeterminate/postural instability and gait difficulty (TD/indeterminate/PIGD), TD _S /mixed _S /akinetic-rigid _S (ARS), or TD _K /mixed _K /AR _K at baseline evaluation and then re-assessed 1 month later. Demographic and clinical characteristics were recorded at each evaluation. The consistency between subtypes at baseline evaluation was assessed using Cohen's kappa coefficient (κ). Additional variables were compared between PD subtype groups using the two-sample t-test, Mann-Whitney U-test or Chi-squared test.

Results: Of 283 newly diagnosed, untreated PD patients, 79 were followed up at 1 month. There was fair agreement between the Jankovic, Schiess, and Kang classification systems (κ _S = 0.383 ± 0.044, κ _K = 0.360 ± 0.042, κ _SK = 0.368 ± 0.038). Among the three classification systems, the Schiess classification was the most stable and the Jankovic classification was the most unstable. The non-motor symptoms questionnaire (NMSQuest) scores differed significantly between PD patients with stable and unstable subtypes based on the Jankovic classification (p = 0.008), and patients with a consistent subtype had more severe NMSQuest scores than patients with an inconsistent subtype.

Conclusion: Fair consistency was observed between the Jankovic, Schiess, and Kang classification systems. For the first time, non-motor symptoms (NMSs) scores were found to influence the stability of the TD/indeterminate/PIGD classification. Our findings support combining NMSs with motor symptoms to increase the effectiveness of PD subtypes.

Keywords: akinetic-rigid; de novo Parkinson’s disease; motor subtypes; non-motor symptoms; postural instability and gait difficulty; tremor-dominant.