Gaze Pattern and Motion Control During Walking While Multitasking

Abstract: In Sweden almost three persons over the age of 65 years dies every daybecause of fall injuries. The overall societal costs of elderly fall accidentswere estimated to to be 14 billion SEK, and if no action is taken this cost isestimated to increase to 22 billion SEK until 2050. The individual decreasein life of quality due to pain, decrease of independence and, for those stillworking, a decrease in income is of course also well worth considering.It is well known that multitasking while walking will decrease attentionon the surroundings and gait behaviour which increases the risk of falling. Itis known that walking uses both sensory input and visual inputs to guide themotion. The visual input prepares the body to adjust itself before a step istaken to optimize the outcome.This study aimed to investigate the effect of multitasking on gaze strategiesand gait performance. Five healthy adults walked over a setup of ramps and astep while performing three different levels of cognitive loading: just walking,walking and performing mental arithmetic’s and walking and scrolling on amobile cell phone.The eye tracking device Pupil Core (Pupil Labs, Berlin, Germany) wasused to capture the gaze points of the participants and Vicon Nexus togetherwith force plates were used to capture data to compute the kinematics of theparticipants during the walking.The results revealed that four out of four participants had a lower ratio ofgaze fixations on objects of interest when scrolling on the phone comparedto just walking, and three out of four participants had a lower ratio of gazefixations on objects of interest when doing mental arithmetic’s compared tojust walking. Simultaneously the gait parameters and kinematics changed in away that might increase the risk of falling. Four out of four participants had adecrease in average stride length and average stride velocity when walkingwhile scrolling on a phone and a decrease in average stride velocity whenperforming mental arithmetic’s compared to just walking. Three out of fourparticipants had a decrease in average stride length when performing mentalarithmetic’s compared to just walking.Since the participant number was low more studies are needed to confirmthese results. The experimental design would benefit from adjustments to tryto separate the effect on gaze behaviour between altered cognitive loading andaltered gait pattern, but are a good base to use for further studies.