Differentiating Parkinson Disease Subtypes Using Clinical Balance Measures

Area of Science:

• Neurology
• Movement Disorders
• Clinical Assessment

Background:

• Parkinson disease (PD) presents with distinct phenotypes: tremor-dominant (TD) and postural instability/gait difficulty (PIGD).
• Accurate subtype classification is crucial for predicting disease progression and optimizing treatment strategies.
• Current methods for subtype differentiation may be time-consuming or lack specificity.

Purpose of the Study:

• To evaluate the efficacy of brief mobility and balance assessments in discriminating between PIGD and TD subtypes of Parkinson disease.
• To identify simple clinical tests that can reliably differentiate PD phenotypes.
• To inform clinical practice regarding subtype classification in early-stage Parkinson disease.

Main Methods:

• A cross-sectional study involving 104 individuals with Parkinson disease.
• Assessment using the Unified Parkinson's Disease Rating Scale (UPDRS) or MDS-UPDRS for subtype classification.
• Evaluation of balance measures including the 360° turn test, one-leg stance, reactive postural control, and tandem walk.

Main Results:

• The 360° turn test and one-leg stance were significantly worse in the PIGD subtype compared to the TD subtype.
• Receiver operating characteristic (ROC) curve analysis indicated the 360° turn test demonstrated high specificity (0.84) in discriminating between PIGD and TD.
• Combined analysis of the 360° turn test and tandem walk significantly improved specificity to 0.97.

Conclusions:

• The 360° turn test is a rapid and effective tool for differentiating PIGD from TD subtypes in individuals with mild to moderate Parkinson disease.
• This simple clinical measure can aid clinicians in early diagnosis and personalized treatment planning.
• The findings support the integration of the 360° turn test into routine clinical assessments for Parkinson disease patients.