Validation of a miniature thermochron for monitoring thoracolumbosacral orthosis wear time

Brian M. Benish, Kristin J. Smith, Michael H Schwartz

Research output: Contribution to journalArticlepeer-review

33 Scopus citations


Study Design: Prospective validation study. Objective: To establish the accuracy of miniature thermochrons for estimating thoracolumbosacral orthosis (TLSO) wear time in patients with adolescent idiopathic scoliosis. Summary of Background Data: There has been an emphasis in recent years on measuring wear time as opposed to using subjective methods such as relying on the patient or parent estimation. By measuring the amount of time that was spent in the orthosis, uncertainty is reduced and the validity of the research is improved. Several types of devices have been employed for direct monitoring of orthosis wear time including strap tension monitors, pressure sensors, and temperature-time sensors (thermochrons). Direct monitoring studies have shown that relying on patient or parent report is inaccurate; the patient/parent report is clearly biased towards overestimation of wear time. Methods: Three miniature thermochrons (DS1922L iButton, Maxim Integrated Products, Inc., Sunnyvale, CA) were mounted underneath padding in the TLSOs of 7 participants diagnosed with adolescent idiopathic scoliosis. The participants wore their TLSO for 1 month. During this time, participants kept meticulous records of wear time in diaries. An algorithm was developed to automatically detect donning/doffing of the orthosis, and the results of the data reduction algorithm were compared with the diary (gold standard). Results: Total wear time accuracy was 98.5% (0.37 hours/day), while the precise timing of donning/doffing was 92% accurate. Conclusion: An inexpensive, commercially available miniature thermochron and a simple robust algorithm can estimate TLSO wear time to a high degree of accuracy. This method is suitable for large-scale prospective studies examining the efficacy of bracing in adolescent idiopathic scoliosis, which remains a topic of controversy.

Original languageEnglish (US)
Pages (from-to)309-315
Number of pages7
Issue number4
StatePublished - Feb 15 2012


  • adolescent idiopathic scoliosis
  • iButton
  • orthosis
  • scoliosis
  • thermochron
  • thoracolumbosacral orthosis
  • TLSO
  • wear time


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