A Cross-Sectional Study of Set Shifting Impairments and Falling in Individuals with and without Parkinson's Disease Público

Abstract

BACKGROUND AND OBJECTIVE: Individuals with Parkinson's disease (PD) are at increased risk for falls, and some exhibit characteristic deficits in executive function, including set shifting, which can be measured as the difference between parts B and A of the Trailmaking Test. The objective of this study was to investigate whether impaired set shifting was associated with previous falls in community-dwelling, nondemented individuals with and without PD.

METHODS: We conducted a cross-sectional study using existing baseline data of PD patients with and without freezing of gait (n=69) and community-dwelling neurologically-normal older adults (NON-PD) (n=84) who had previously volunteered to participate in rehabilitative exercise programs. Multivariate logistic regression analyses were performed to determine associations between set shifting, PD, and faller status, as determined by ≥1 self-reported falls in the previous 6 months, after adjusting for demographic and cognitive factors and clinical disease characteristics. Individuals with likely dementia (Montreal Cognitive Assessment<18) were excluded.

RESULTS: The final study sample after applying exclusion criteria (n=73 NON-PD, n=65 PD) included 51 fallers. PD was associated with substantially increased prevalence of previous falls (OR=4.15 [95% CI 1.65-10.44], P<0.01) after controlling for age, sex, and overall cognitive function. Among PD patients the presence of freezing of gait (FOG) was associated with substantially increased prevalence of previous falls (OR=3.63 [1.22-10.80], P=0.02). Impaired set shifting was associated with previous falls after controlling for age, sex, overall cognitive function, PD, FOG, and PD disease duration (OR=1.29 [1.03-1.60]; P=0.02). Although the strongest associations between set shifting and falling were observed among PD without freezing of gait (OR=2.11) compared to HOA (OR=1.14) and PD with FOG (OR=1.46) in a multivariate model that allowed for interaction between set shifting and PD status, there was insufficient evidence of interaction.

CONCLUSIONS: The set shifting component of executive function is associated with previous falls in nondemented older adults with and without PD.

Table of Contents

Introduction 1

Background 3

Parkinson's disease is a common neurological disorder with motor and nonmotor symptoms and unknown causes 3

Freezing of gait (FOG) has been proposed as a "fifth cardinal sign" of PD and is a primary cause of falls 4

Impaired aspects of executive function may increase fall risk in individuals with and without PD 5

Set shifting is a component of executive dysfunction that may be particularly impaired in PD 6

Exercise-based rehabilitation may be the most effective strategy for reducing falls in individuals with and without PD 8

Methods 10

Data sources and setting 10

Study Variables 11

Assessment of primary outcome: Faller Status 11

Estimation of primary exposure: Set Shifting Score 11

Assessment of secondary exposure: PD Status 12

Assessment of overall cognitive function 12

Additional study variables 12

Missing Data 13

Sample size and power considerations 13

Analytic Plan 13

Descriptive statistics and univariate tests of central tendency across groups 13

Associations between Set Shifting Score and Faller Status 13

Tests of primary study hypotheses 14

Sensitivity analyses 15

Associations between PD Status and Faller Status without Set Shifting Score 16

Results 17

Characteristics of the study population 17

Associations between Set Shifting Score and Faller Status 17

Sensitivity analyses 18

Associations between PD Status and Faller Status without Set Shifting Score 19

Discussion 20

Strengths 22

Limitations 23

Future work 25

Conclusions 25

References 26

Tables and Figures 36

About this Master's Thesis

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School	Laney Graduate School
Department	Clinical Research Curriculum Program
Degree	MS
Submission	Master's Thesis
Language	English
Research Field	Health Sciences, General
Palavra-chave	Falls Balance Parkinson's disease Executive function
Committee Chair / Thesis Advisor	Ting, Lena, Emory University
Committee Members	Bruce, Beau Benjamin, Emory University Klein, Mitchel, Emory University

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