Table 1.
Clinical characteristics of the participants.
Fig 1.
a. Auditory Stroop Task (AST) with the congruent signals (e.g. male voice speaking the Dutch translation of ‘man’) signaling the participant to start or continue walking, and incongruent signals (e.g. ‘woman’ spoken by a male voice) signaling to stand still. The high load AST (‘AST_high’) consisted of only the male voice, the low load AST (‘AST_low’) of both a male and female voice. b. Random Numbers Task (RNT) in which the numbers 1 to 9 were played in a random order and at random time intervals. Participants were instructed to mentally count how often two (‘RNT_high’) or one (‘RNT_low’) given number(s) occurred in the sequence (here ‘3’ and ‘8’, represented in orange and blue).
Fig 2.
Gait parameters under different conditions of Experiment 1.
Boxplots of the gait velocity (m/s), cadence (steps/min), stride length (m), stride length coefficient of variation (COV), stride time (sec), and stride time coefficient of variation (COV). Cognitive load conditions are illustrated in red (control cognitive load, noCL), blue (Auditory Stroop Task, AST), and green (Random Numbers Task, RNT). Conditions with no visual cues (‘noVC’) are displayed at the left sides of the plots, conditions with visual cues (‘VC’) at the right sides. Asterisks above indicate significant differences between cognitive load conditions (within the left or right half of a plot), and between visual cueing conditions (crossing the midline of the plot).
Table 2.
Results per aim/hypothesis.
Fig 3.
Gait parameters in different conditions of Experiment 2.
Boxplots of the gait velocity (m/s), cadence (steps/min), stride length (m), stride length coefficient of variation (COV), stride time (sec), and stride time coefficient of variation (COV) for persons with Parkinson’s disease and freezing of gait (‘PD’) and healthy control subjects (‘Healthy’). The number of freezing of gait episodes (nrFOG) and percent time frozen (PTF) are given for PD patients. Cognitive load conditions are illustrated in red (control cognitive load, noCL), and blue (Auditory Stroop Task, AST). Conditions with no visual cues (‘noVC’) are displayed at the left sides of the plots, conditions with visual cues (‘VC’) at the right sides. Asterisks above indicate significant differences between cognitive load conditions (within the left or right half of a plot), and between visual cueing conditions (crossing the midline of the plot).