Table 2

Summary of experimental tasks used in our previous study.
acronym	description	dependent variable

walk	walk at preferred speed down a 2.2 m wide hallway, or along a 0.8 m wide circular path	mean speed

walk_n	walk at preferred speed along a 0.2 m wide circle	mean speed

walk_nf	walk at maximum speed along a 0.2 m wide circle	mean speed

treadmill_o	walk on a treadmill (elderly 0.8, younger 1.2 m/s), while obstacles appear at unknown intervals	percent of obstacles negotiated without contact

spell	spell a word of 18–21 letters	number of correctly spelled letters per 20 s

shape	hear names of 10 geometrical shapes while walking, and repeat them afterwards	number of correctly repeated shapes

button	close nine different buttons on a jacket, open them, close them again, etc.	number of completed button actions per 120 s

detect	press knob when a dot appearing in a random-dot pattern forms a square with three pre-existing dots	percent and RT of hits, percent of correct rejections

Bock Journal of NeuroEngineering and Rehabilitation 2008 5:27 doi:10.1186/1743-0003-5-27