The accuracy of the THIM wearable device for estimating sleep onset latency

Hannah Scott, Ashwin Whitelaw, Alex Canty, Nicole Lovato, Leon Lack

Research output: Contribution to journalArticlepeer-review

6 Citations (Scopus)


Study Objectives: THIM is a wearable device designed to accurately estimate sleep onset. This article presents 2 studies that tested the original (study 1) and a refined (study 2) THIM algorithm against polysomnography (PSG) for estimating sleep onset latency. Methods: Twelve (study 1) and 20 (study 2) individuals slept in the laboratory on 2 nightswhere participants underwent THIM-administered sleep onset trials with simultaneous PSG recording. Participants attempted to fall asleep while using THIM, which woke them once it determined sleep onset. Results: In study 1, there was no significant difference between PSG(mean = 1.94minutes, SD = 1.32) and THIM sleep onset latency (mean = 2.05minutes, SD = 1.38) on the first or second night (P >.07). There were moderate correlations between PSG and THIM on both nights [r(s) > .57, P <.001]. In 23.74% of trials, PSG sleep onset could not be determined before THIM ended the trial.With a revised THIM algorithm in study 2, there was no significant difference between PSG (mean = 3.41 minutes, SD = 2.21) and THIMsleep onset latency (mean = 3.65 minutes, SD = 2.18) (P =.25). There was strong correspondence between the two devices [r(s) > .73, P <.001], narrow levels of agreement on Bland-Altman plots, and significantly fewer trials where PSG sleep onset had not occurred (10.24%), P = .04. Conclusions: THIM showed a high degree of correspondence and agreement with PSG for estimating sleep onset latency. Future research will investigate whether THIM is accurate with an insomnia sample for clinical purposes.

Original languageEnglish
Pages (from-to)973-981
Number of pages9
JournalJournal of Clinical Sleep Medicine
Issue number5
Early online date13 Jan 2021
Publication statusPublished - 1 May 2021


  • wearable device
  • Consumer sleep technology
  • Polysomnography
  • Actigraphy
  • Sleep onset latency
  • Intensive sleep retraining
  • Wearable device


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