The single-leg-stance test in Parkinson's disease

Area of Science:

• Neurology
• Gerontology
• Movement Disorders

Background:

• The timed single-leg-stance test (SLST) is a common measure of postural control in older adults.
• In Parkinson's disease (PD), an SLST of approximately 10 seconds or less may predict future falls.
• The clinical significance of this 10-second threshold in PD progression remains under-investigated.

Purpose of the Study:

• To investigate whether SLST times around 10 seconds signify a clinically important stage of disease progression in Parkinson's disease.
• To explore the relationship between SLST performance and motor impairment in individuals with PD.

Main Methods:

• A cross-sectional study involving 27 participants with Parkinson's disease.
• Participants performed timed single-leg-stance tests (SLST) for both legs.
• Motor impairment was assessed using the Unified Parkinson's Disease Rating Scale Part 3 (UPDRS-III).

Main Results:

• The SLST demonstrated good test-retest reliability in people with PD.
• Two distinct SLST clusters emerged: a low group (10.4 ± 6.3 seconds) and a high group (47.6 ± 11.7 seconds).
• Only the low SLST group showed abnormal results compared to age-matched norms, and was associated with lower UPDRS-III scores, particularly bradykinesia.

Conclusions:

• A low SLST time, around 10 seconds, signifies a clinically important stage in Parkinson's disease progression.
• This stage is characterized by significantly worsened postural stability.
• The findings support the SLST as a valuable tool for assessing disease progression and fall risk in PD.