Abstract Details

Title Comparison of a Standardized Treadmill Perturbation to the Pull Test to Assess Postural Instability in Parkinson's Disease

Topic Movement Disorders

Presentation(s) P3 - Poster Session 3 (5:30 PM-6:30 PM)

Poster/Presentation
Number 10-050

Objective The primary objective was to create a variant of the clinical pull test which would not suffer from examiner bias in strength of the pull. In our variant we used a standard anterior perturbation of the treadmill belt.

Background Postural instability is a common and disabling feature of Parkinson's disease (PD). The “pull test” is performed by posterior displacement of the patient’s center of mass at the shoulders. Currently regarded as the gold standard for evaluating postural instability, it is included in the Unified Parkinson’s Disease Rating Scale (UPDRS). However, problems with the pull test include variability in performance and inconsistent pull strength.

Design/Methods We compared the pull test and treadmill perturbation across multiple conditions including on medications and off medications for PD participants, 0% weight support, and partial 20% weight support via safety harness. Steps were logged by a blinded trained rater who reviewed videos of the experiments.

Results Controls required fewer steps than PD subjects to regain their balance (ns). Linear regression analysis demonstrated a positive relationship between the treadmill perturbation and pull test for both the PD off medication + controls and PD on medication conditions (F test: p<0.001 and p<0.05 respectively). Postural instability of PD subjects did not differ on or off medication, although a subset of participants appeared to fare better on medication. Participants took significantly fewer steps with 20% weight support (t test: pull test PD off medication + controls, p<0.05; treadmill PD off medication + controls, p<0.01; pull test PD on medication, p<0.01, treadmill PD on medication, p<0.001).

Conclusions The treadmill perturbation predicts postural instability similar to the pull test and has the advantage of providing a standard anterior displacement without bias. We also found that postural instability was less severe during partial weight support, which may have implications for gait training.

Authors/Disclosures
Amber Stutz, MD PRESENTER	No disclosure on file
	No disclosure on file
	No disclosure on file
Scott E. Cooper, MD, PhD	The institution of Dr. Cooper has received research support from NIH.

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