S. Gäumann1, A. Aksöz1,2, L. Cappelletti3, A. Krug4, D. Mörder5, C. Schuster-Amft1,6,7
1Reha Rheinfelden, Research Department, Rheinfelden, Switzerland, 2University of Bern, ARTORG Center for Biomedical Engineering Research, Motor Learning and Neurorehabilitation Laboratory, Bern, Switzerland, 3Bern University of Applied Science, Department of Health Professions, Bern, Switzerland, 4Zurich University of Applied Sciences, School of Health Professions, Institute for Physiotherapy, Winterthur, Switzerland, 5University of Konstanz, Department of Sport Science, Faculty of Humanities, Konstanz, Germany, 6Bern University of Applied Science, Institute for Rehabilitation and Performance Technology, Burgdorf, Switzerland, 7University of Basel, Department of Sport, Exercise and Health, Basel, Switzerland

Background: Motor imagery (MI) is a powerful training technique. If combined with physical practice (PP) it can improve recovery in patients with neurological conditions. However, the main challenge in measuring MI performance in clinical practice is the lack of valid and reliable mobile measurement devices.

Purpose: To evaluate validity and test-retest reliability of the J!NS MEME smart eyeglasses (SE) compared to conventional electrooculography (EOG) to detect eye movements during physical practice and mental simulation in patients after stroke.

Methods: Patients after first-ever stroke were assessed at two measurement events within 7 days. MI ability was evaluated using the short form of the Kinaesthetic and the Visual Imagery Questionnaire (KVIQ-10), the test of mental rotation (MenRo) and the mental chronometry (MenChr).
To assess eye movements, the EOG signal was recorded with electrodes placed above and under the eye on the vertical axis of the pupil on the patients’ affected body-side. Simultaneously, SE signals were recorded using EOG sensors integrated in the nose pads.
Patients sat in front of a computer screen and received auditory and visual instructions. A chinrest restricted head movements. After a 30-second resting phase, patients imagined or executed a unilateral upper- and lower limb movement task. In a random order, they placed a cup to marked fields A, B, or C. After a break, patients imagined or executed to tap a foot to A, B, or C. Both PP and MI conditions were repeated 40 times.
Validity of the SE compared to conventional EOG was calculated with cross correlations to measure similarity in shape between signals for each patient. To determine test-retest reliability, Intraclass Correlation Coefficients (ICCs, 95% confidence interval) were calculated for all patients and for each condition.

Results: So far, 13 patients (2 females; mean time (days) since stroke: 570.9±1607.5; mean age 58.46±15.2) were measured. Mean KVIQ-10 score was 38.5±7.7. Mean MenRo was 29.85±1.99 out of 32. Mean MenChr congruency ratio was 0.88±0.3. Mean correlation between signals from EOG and SE during PP was r= 0.47 and during MI r= 0.45. ICCs for PP and MI were 0.51 and 0.52.

Conclusion(s): The SE could be considered as a valid and a reliable instrument to assess eye movements during PP and MI of a movement. SE might be a mobile measurement option to evaluate MI in clinical routine.

Implications: The real-time measurement of MI performance during simple and complex activities of daily living would provide an objective MI ability assessment. This, in turn, would allow us to optimise and tailor MI training for the clinic and home training.

Funding, acknowledgements: The study received funding from the Stiftung zur Förderung von Wissenschaft, Forschung, Bildung und Gesundheit, Vaduz, Liechtenstein.

Keywords: motor imagery in stroke, validity, test-retest reliability

Topic: Neurology: stroke

Did this work require ethics approval? Yes
Institution: Ethics committee of Central- and Northwestern Switzerland
Committee: Ethics committee of Central- and Northwestern Switzerland
Ethics number: 2019-00348

All authors, affiliations and abstracts have been published as submitted.

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