title: What Do Eye Gaze Metrics Tell Us about Motor Imagery?
abstract: Many of the brain structures involved in performing real movements also have increased activity during imagined movements or during motor observation, and this could be the neural substrate underlying the effects of motor imagery in motor learning or motor rehabilitation. In the absence of any objective physiological method of measurement, it is currently impossible to be sure that the patient is indeed performing the task as instructed. Eye gaze recording during a motor imagery task could be a possible way to "spy" on the activity an individual is really engaged in. The aim of the present study was to compare the pattern of eye movement metrics during motor observation, visual and kinesthetic motor imagery (VI, KI), target fixation, and mental calculation. Twenty-two healthy subjects (16 females and 6 males), were required to perform tests in five conditions using imagery in the Box and Block Test tasks following the procedure described by Liepert et al. Eye movements were analysed by a non-invasive oculometric measure (SMI RED250 system). Two parameters describing gaze pattern were calculated: the index of ocular mobility (saccade duration over saccade + fixation duration) and the number of midline crossings (i.e. the number of times the subjects gaze crossed the midline of the screen when performing the different tasks). Both parameters were significantly different between visual imagery and kinesthesic imagery, visual imagery and mental calculation, and visual imagery and target fixation. For the first time we were able to show that eye movement patterns are different during VI and KI tasks. Our results suggest gaze metric parameters could be used as an objective unobtrusive approach to assess engagement in a motor imagery task. Further studies should define how oculomotor parameters could be used as an indicator of the rehabilitation task a patient is engaged in.
authors.affiliation: LUNAM, Université d'Angers, Laboratoire Angevin de Recherche en Ingénierie des Systèmes (LARIS), EA 7315 F-49000, Angers, France.|LUNAM, Université d'Angers, Département de Médecine Physique et de Réadaptation, CHU d'Angers, 4 rue Larrey, 49933, Angers, Cedex 9, France.
authors.forename: Elodie
authors.initials: E
authors.lastname: Poiroux
authors.affiliation: LUNAM, Université d'Angers, Laboratoire Angevin de Recherche en Ingénierie des Systèmes (LARIS), EA 7315 F-49000, Angers, France.
authors.forename: Christine
authors.initials: C
authors.lastname: Cavaro-Ménard
authors.affiliation: LUNAM, Université d'Angers, Laboratoire Angevin de Recherche en Ingénierie des Systèmes (LARIS), EA 7315 F-49000, Angers, France.|LUNAM, Université d'Angers, Département d'Ophtalmologie, CHU d'Angers, 4 rue Larrey, 49933, Angers, Cedex 9, France.
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Leruez
authors.affiliation: LUNAM, Université d'Angers, Département de Neurochirurgie, CHU d'Angers, 4 rue Larrey, 49933, Angers, Cedex 9, France.|LUNAM, Université d'Angers, INSERM U1066 « Micro- et nano-médecines biomimétiques », bâtiment IRIS 3e étage, CHU d'Angers, 4 rue Larrey, 49933, Angers, Cedex 9, France.
authors.forename: Jean Michel
authors.initials: JM
authors.lastname: Lemée
authors.affiliation: LUNAM, Université d'Angers, Département de Médecine Physique et de Réadaptation, CHU d'Angers, 4 rue Larrey, 49933, Angers, Cedex 9, France.|LUNAM, Université d'Angers, Laboratoire d'épidémiologie, ergonomie et santé au travail, EA 4626 F-49000, Angers, France.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Richard
authors.affiliation: LUNAM, Université d'Angers, Laboratoire Angevin de Recherche en Ingénierie des Systèmes (LARIS), EA 7315 F-49000, Angers, France.|LUNAM, Université d'Angers, Département de Médecine Physique et de Réadaptation, CHU d'Angers, 4 rue Larrey, 49933, Angers, Cedex 9, France.
authors.forename: Mickael
authors.initials: M
authors.lastname: Dinomais
mesh_terms: D000328:Adult; D005133:Eye Movements; D005260:Female; D006801:Humans; D007092:Imagination; D008297:Male; D008875:Middle Aged; D014785:Vision, Ocular; D055815:Young Adult