Between-sessions test-retest reliability of prefrontal cortical activity during usual walking in patients with Parkinson's Disease: A fNIRS study.

Examining between-sessions test-retest reliability of functional near-infrared spectroscopy (fNIRS) data is crucial to better interpret rehabilitation-related changes in the hemodynamic response. This study investigated test-retest reliability of prefrontal activity during usual walking in 14 patients with Parkinson's Disease with a fixed retest intervals of five weeks. Fourteen patients performed usual walking in two sessions (T0 and T1). Relative changes in cortical activity (oxy and deoxyhemoglobin: ∆HbO 2 and ∆HbR, respectively) in the dorsolateral prefrontal cortex (DLPFC) using fNIRS system and gait performance were measured. Test-retest reliability of mean ∆HbO 2 for the total DLPFC and for each hemisphere were measured using paired t-test, intraclass correlation coefficient (ICC), and Bland-Altman plots with 95% agreement. Pearson correlations between cortical activity and gait performance were also performed. Moderate reliability was found for ∆HbO 2 in the total DLPFC (mean difference of ∆HbO 2 between T1 and T0 = −0.005 µmol, p = 0.93; ICC average = 0.72). However, test-retest reliability of ∆HbO 2 was poorer when considering each hemisphere. Findings suggest that fNIRS may be used as a reliable tool for rehabilitation studies in patients with PD. Test-retest reliability of fNIRS data between 2 sessions during walking tasks should be interpreted respectively of gait performance. • Test-retest reliability help to interpret between-sessions changes in cortical activity. • No studies investigated reliability of fNIRS data during walking in Parkinson's Disease. • Test-retest reliability of prefrontal activity during usual walking was examined. • Moderate, almost excellent reliability was found for ΔHbO 2 in the total DLPFC. • fNIRS may be used as a reliable tool for rehabilitation studies in PD patients. [ABSTRACT FROM AUTHOR]