Psychometric Properties of the Clinical Dementia Rating Scale Sum of Boxes in Parkinson's Disease.

Julia Gallagher,Nabila Dahodwala,John E Duda,Daniel Weintraub,James Morley,Pablo Martinez-Martin,Jacqueline Rick,Alice Chen-Plotkin,Sharon X Xie,Andrew Siderowf,Eugenia Mamikonyan,John Q Trojanowski

doi:10.3233/jpd-202390

Abstract

Background:A composite measure that assesses both cognitive and functional abilities in Parkinson’s disease (PD) would be useful for diagnosing mild cognitive impairment (MCI) and PD dementia (PDD) and as an outcome measure in randomized controlled trials. The Clinical Dementia Rating Scale Sum of Boxes (CDR-SOB) was designed to assess both cognition and basic-instrumental activities of daily living in Alzheimer’s disease but has not yet been validated in PD.Objective:To validate the CDR-SOB as a composite cognitive-functional measure for PD patients, as well as to assess its sensitivity to change.Methods:The CDR-SOB and a comprehensive cognitive and functional battery was administered to 101 PD patients at baseline (39 normal cognition [NC], 41 MCI and 21 PDD by expert consensus panel), and re-administered to 64 patients after 1-2 years follow-up (32 NC and 32 cognitive impairment [CI] at baseline).Results:Cross-sectionally, CDR-SOB and domain scores were correlated with corresponding neuropsychological or functional measures and were significantly different between cognitive subgroups both at baseline and at follow-up. In addition, CDR-SOB ROC curves distinguished between normal cognition and dementia with high sensitivity, but did not distinguish well between NC and MCI. Longitudinal changes in the CDR-SOB and domain scores were not significant and were inconsistent in predicting change in commonly-used cognitive and functional tests.Conclusion:The CDR-SOB detects dementia-level cognitive impairment in PD but may not be appropriate for predicting longitudinal combined cognitive-functional changes in patients without significant cognitive impairment at baseline.

Highlights

Cognitive impairment, including mild cognitive impairment (MCI) and dementia, are increasingly recognized as common and sometimes debilitating symptoms in Parkinson’s disease (PD)
Up to 80% of PD patients will become demented during the course of their disease [1, 2], and patients with established PD and normal cognition who develop MCI subsequently progress to dementia frequently [3]
Due to small sample sizes, participants diagnosed with MCI (N = 27) or PD dementia (PDD) (N = 5) at baseline were combined into a “cognitive impairment” (CI) group, for comparison with the NC group (N = 32)

Summary

Introduction

Cognitive impairment, including mild cognitive impairment (MCI) and dementia, are increasingly recognized as common and sometimes debilitating symptoms in Parkinson’s disease (PD). In 2007 a Movement Disorder Society (MDS) Task Force published clinical diagnostic criteria for PD dementia (PDD), which include impairment in multiple cognitive domains plus clinically significant functional impairment independent of motor symptoms [4]. In 2012 another MDS Task Force published criteria for PD-MCI, which include cognitive deficits that are not sufficient to interfere significantly with functional independence [5]. While both definitions require or recommend assessment of cognitive abilities across multiple domains and an evaluation of functional abilities, there is no agreed upon gold standard for either, and no single instrument validated to assess both in PD. Longitudinal changes in the CDR-SOB and domain scores were not significant and were inconsistent in predicting change in commonly-used cognitive and functional tests

Objectives

Methods

Findings

Conclusion