Optic flow improves step width and length in older adults while performing dual task



Dual-task paradigms are used to investigate gait and cognitive declines in older adults (OA). Optic-flow is a virtual reality environment where the scene flows past the subject while walking on a treadmill, mimicking real-life locomotion.


To investigate cost of environment (no optic-flow v. optic-flow) while completing single- and dual-task walking and dual-task costs (DTC; single- v. dual-task) in optic-flow and no optic-flow environments.


Twenty OA and seven younger adults (YA) walked on a self-paced treadmill in 3-min segments per task and both environments. Five task conditions included: no task, semantic fluency (category), phonemic fluency (letters), word reading, and serial-subtraction.


OAs had a benefit of optic-flow compared to no optic-flow for step width (p = 0.015) and step length (p = 0.045) during letters compared to the YA. During letters, OA experienced improvement in step width DTC; whereas YA had a decrement in step width DTC from no optic-flow to optic-flow (p = 0.038). During serial-subtraction, OA had less step width DTC when compared to YA in both environments (p = 0.02).


During letters, step width and step length improved in OA while walking in optic-flow. Also, step width DTC differed between the two groups. Sensory information from optic-flow appears to benefit OA. Letters relies more on verbal ability and word knowledge, which are preserved in aging. However, YA use a complex speech style during dual tasking, searching for complex words and an increased speed of speech.


OA can benefit from optic-flow by improving spatial gait parameters, specifically, step width, during dual-task walking.

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The authors would like to thank Angie Helseth for her assistance in data collection and processing.


This work was supported by the National Institutes of Health (P20 GM109090 to SAM, JBB, JMY, and R01 HD090333 to SAM) and the University of Nebraska at Omaha Graduate Research and Creative Activity Fund (TL).

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Corresponding author

Correspondence to Jennifer M. Yentes.

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All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.

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Appendix A

Appendix A

Version A

Phonemic (Letter) Fluency: F, L, S.

Semantic (Category) Fluency: Animals, Parts of the Body, Kitchen Utensils.

Serial Subtractions: 233, 650, 502.

Word reading: indices, hose, lamb, acquisitiveness, equivocal, fountain, corps, pout, subtle, détente, casserole, debt, browbeat, asked, statistics, epitome, shield, chord, flower, subpoena, banal, chrysanthemum, rarefy, diverse, irrelevant, generate, bell, eccentricities, bouquet, thyme.

Version B

Phonemic (Letter) Fluency: W, G, T.

Semantic (Category) Fluency: Sports, Furniture, Supermarket Items.

Serial Subtractions: 805, 297, 483.

Word Reading: asphyxiation, doll, paradigm, simile, reify, gauge, recipe, procreate, fifth, magnanimity, gouge, naïve, idyll, machine, hospital, sieve, youth, colony, cloud, façade, indict, confide, amicable, synthesis, deny, epic, fly, labile, crayon, clasped.

Version C

Phonemic (Letter) Fluency: M, B, R.

Semantic (Category) Fluency: Professions, Fruits & Vegetables, Things you Wear.

Serial Subtractions: 738, 369, 922.

Word Reading: ache, aisle, ballad, bibliography, caveat, cellist, colonel, courteous, curtain, debris, depot, efficacy, evolve, gigantic, gist, heir, hiatus, joker, ladder, lily, lingerie, nausea, placebo, pony, psalm, pugnacious, stranger, superfluous, yesterday, zealot.

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Leeder, T., Fallahtafti, F., Schieber, M. et al. Optic flow improves step width and length in older adults while performing dual task. Aging Clin Exp Res 31, 1077–1086 (2019). https://doi.org/10.1007/s40520-018-1059-x

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  • Dual task cost
  • Gait
  • Virtual reality
  • Environment
  • Spatiotemporal