The Ultimate Tickle Test


Interview with Dr. Leah Bent

Q. How did Hypersole come about?

A. Research into skin and vestibular input in balance has been an area of interest to me for quite some time. But it hadn't occurred to me to test healthy astronauts until Canadian astronaut Dave Williams mentioned in 2007 that he had experienced some tingling in his feet during a shuttle flight in 1998 and for a short period of time when he returned home. He told us that he knew of other astronauts who had also experienced the same sensation when they stood. Since then, we’ve talked to others who have been to space. One astronaut recounted how she’d bungee-cord herself in to run on a treadmill and every time her foot hit the treadmill it was suddenly tingly. She noted that it mostly happened when the foot was fully loaded [in full contact with the treadmill surface].

A Canadian research project that explores sudden changes in skin sensitivity experienced by some astronauts in space is unlocking down-to-earth secrets of the role played by our feet in the way we age.

The six-member research team from the University of Guelph (with one member from Wilfrid Laurier University) has been conducting a series of tests to collect balance and hypersensitivity data from the foot soles of ten astronauts who will have travelled aboard four NASA's shuttle missions.  Hypersole will be conducted for the last time, in July 2011, during STS-135, the ultimate scheduled shuttle flight of NASA's Space Shuttle Program.

Using vibration devices and filaments to "tickle" responses from the eight astronauts, researchers are documenting, for the first time, any changes in the skin sensitivity of each astronaut's foot sole in order to identify which receptors may be influenced by a period of weightlessness. Coupled with functional balance tests, these measures will help establish how hypersensitivity contributes to balance control.

Simulation of a data collection session with Canadian Space Agency Astronaut, Dr. Dave Williams. (Credit: Canadian Space Agency)

Anecdotal evidence from astronauts suggests that the tingling sensation some feel in their feet while in space and for short periods back on Earth may be the response of different sensory systems that naturally compensate for the re-weighting of sensory information due to the decreased input from the vestibular, or inner ear, system in an environment of microgravity.

Project results are expected to add significantly to existing studies of the aging process, which includes reductions in information relayed by skin sensors that lead to a loss of balance control and, among the elderly especially, a greater incidence of falls. The data will also provide knowledge that benefits astronauts as they perform their flight and post-flight duties.

Participating astronauts are tested before and after each of the following Shuttle flights. Pre-flight tests generally take place 20-40 days before launch, and post-flight tests are done as quickly as possible after landing (before astronauts adapt to Earth's gravity).

Three astronauts participated inthe first Hypersole session, which took place during STS 132 on May 14, 2010. Five additional astronauts from the crews of the Discovery mission in February-March 2011 and Endeavour in April-May 2011 underwent  identical trials before the launch of their shuttles and immediately upon their return to Earth. Two members of the STS-135 crew will be the last to participate in Hypersole.

Research Team Members:

University of Guelph
(Human Health and Nutritional Sciences, College of Biological Sciences)

  • Dr. Leah Bent, associate professor, Human Health and Nutritional Sciences, College of Biological Sciences
  • Catherine Lowrey, Ph.D. Candidate
  • Nick Strzalkowski, M.Sc. Candidate
  • Christopher Lam, M.Sc. Candidate
  • Stephanie Muise, research assistant

Wilfrid Laurier University

  • Dr. Stephen Perry, associate professor, Kinesiology & Physical Education