Discrepancy in freezing of gait measurements: self-report, clinical, and physical therapy assessments

Brent Bluett¹, Ece Bayram¹, Jason Longhurst¹, Sarah J. Banks¹, Irene Litvan²

¹Cleveland Clinic Lou Ruvo Center for Brain Health, Las Vegas, NV, USA.

²University of California San Diego Department of Neurosciences, Parkinson and Other Movement Disorders Center, La Jolla, CA, USA

Background and Objective: Previous studies evaluating freezing of gait (FOG) in Parkinson’s disease (PD) have identified participants using self-report assessments or the Movement Disorders Society- Unified Parkinson’s Disease Rating Scale (MDS-UPDRS). However, brief observations in the clinic as well as the patient’s self-assessment may not be sufficient to identify an episodic phenomenon. This study investigated the most accurate method to identify FOG in PD.

Methods: 22 PD patients were assessed for FOG. FOG Questionnaire-Item 3 was used for self-report, MDS-UPDRS Part III for clinical evaluation, and FOG assessment score for PT assessment. FOG assessment score includes several triggering conditions for FOG and dual-tasking. MDS-UPDRS and FOG assessment score were evaluated while levodopa off. Generalized kappa was used to measure agreement between the three measures.

Results: 15 patients self-reported FOG, 3 patients had FOG according to MDS-UPDRS, and 9 patients had FOG according to FOG assessment score. All subjects who had FOG according to MDS-UPDRS also had self-reported FOG and FOG during physical therapy assessment. All patients with FOG based on the FOG assessment score also self-reported FOG. Kappa value for the agreement between measures was 0.248.

Discussion and Conclusions: There is a significant discrepancy between the three FOG measures. Patients tend to over-report, and brief clinical assessments may lead to under assuming the occurrence of FOG. Self report measures are overly sensitive but not specific, and brief clinical evaluation is specific but not sensitive. Future studies would benefit from identifying FOG by physical therapy assessment for more reliable classification.

Acknowledgement: Research reported in this publication was supported by an Institutional Development Award (IDeA) from the National Institute of General Medical Sciences of the National Institutes of Health under grant number 5P20GM109025.