The Four Square Step Test in individuals with Parkinson's disease: association with executive function and comparison with older adults.

BACKGROUND

In Parkinson's disease (PD), motor and cognitive impairments interact to affect functional performance adversely. A valid mobility test, the Four Square Step Test (FSST) involves multidirectional stepping over obstacles. FSST performance may also be associated with cognitive performance.

OBJECTIVES

This study determined the feasibility and reliability of an obstacle-based FSST in older individuals with versus without PD, and evaluated the association of PD performance of FSST with tests of cognition.

METHODS

Thirty-one individuals with mild-moderate PD, evaluated while ON medications, completed the obstacle-based FSST, other mobility and cognitive measures. FSST performance was compared between a PD participant sub-set (n = 24) and 24 age-matched older adults. Data were analyzed with independent t-tests, correlations, and linear regression.

RESULTS

Obstacle-based FSST was feasible and reliable within sessions in those with PD. Median best FSST time among individuals with PD was 11.72 s (9.99, 13.98) and FSST had concurrent validity with tests of mobility, and cognitive dual-tasking. Among cognitive tests, Trails Making Test B, which evaluates executive function, emerged as a sole contributor (49%) of variance. FSST performance did not differ between those with PD and older adults.

CONCLUSION

The obstacle-based FSST is feasible and reliable in those with PD. The relationship between cognitive status and performance on the FSST did not appear to be strongly disease-stage dependent. Using FSST in the clinic may help assess the health status of a motor-cognitive interaction in individuals with PD.