Award Date

Spring 5-14-2021

Degree Type

Doctoral Project

Degree Name

Doctor of Physical Therapy (DPT)


Physical Therapy

Advisor 1

Merrill Landers, PT, DPT, PhD, OCS

First Committee Member

Daniel Young, Ph.D

Second Committee Member

Merrill Landers, Ph.D

Number of Pages



Background: Postural instability (PI) in Parkinson’s disease (PD) is associated with several negative down- stream consequences. Objective: The purpose was to explore the validity of a theoretical model of these downstream consequences arranged in a vicious cycle wherein PI leads to decreased balance con!dence, which in turn leads to increased fear of falling (FOF) avoidance behavior, which in turn leads to decreased physical conditioning, which then feeds back and negatively affects PI. Methods: A path analysis of cross!sectional data from 55 participants with PD was conducted. The four con- structs in the model connected in succession were: 1. PI (principal components analysis (PCA) composite of the Uni!ed Parkinson’s Disease Rating Scale PI and Gait Dif!culty score, Timed Up and Go test, and Berg Balance Scale); 2. balance con!dence (Activities!Speci!c Balance Con!dence Scale); 3. FOF avoidance behav- ior (PCA composite of the FOF Avoidance Behavior Questionnaire and average number of steps per day); and, 4. physical conditioning (2!Minute Step Test). Results: The path model was an excellent !t to the data, !2 (7) = 7.910, p = .341, CFI = 0.985, TLI = 0.968, RMSEA = 0.049 (90% CI: 0.000 to 0.179). The moderate to strong and uniformly signi!cant parameter esti- mates were !0.519, !0.651, !0.653, and !0.570, respectively (ps < 0.01). Conclusions: PI directly and inversely predicted balance con!dence, which in turn directly and inversely pre- dicted FOF avoidance behavior. Furthermore, FOF avoidance behavior directly and inversely predicted phys- ical conditioning, which directly and inversely predicted PI, thereby closing the cycle. These !ndings highlight the downstream consequences of PI in PD and support the notion of a vicious cycle of FOF avoidance behavior.


Postural balance; Gait; Falls; Postural instability; Balance confidence; Fear of falling; Avoidance behavior


Physical Therapy

File Format


File Size

668 KB

Degree Grantor

University of Nevada, Las Vegas