RESUMO
BACKGROUND: Slalom walking wearing distorting prisms has been used to study multitasking during adaptation to spatial disorientation. We address the hypothesis that slalom-prism walking could interfere specifically with concurrent spatial tasks. METHODS: Subjects (16 men, 16 women) sat for 30 s then slalom walked through 5 aligned batons. This exercise was performed with normal vision and with prisms deviating gaze laterally by 15.50 Both conditions were done without any tasks, with a verbal task (matching the sex of male and female names uttered by male and female voices), and a spatial task (matching laterality of the words 'right' and 'left' delivered to the right or left ear). Conditions were balanced with instructions to perform rapidly and accurately. RESULTS: Time to walk the slalom was extended by the prisms from 16 s to 33 s, but unaffected by tasks. Slalom increased error rates on the spatial task by 8% above baseline, but verbal task errors remained unchanged. Prisms did not affect task errors. The rates of processing cognitive task items were slowed by approximately 0.5 s by slalom and by 1 s slalom walking with prisms. Prisms increased task reaction times by 340 ms during slalom. Contact with the poles occurred when multitasking, with men making three times more contacts than women. CONCLUSIONS: Slowing of all performance parameters is consistent with a 'bottleneck' caused by task multiplexing. Competition for spatial processing resources and confusion because of similar features may cause interference between the lateralized spatial task and slalom.