ORIGINAL ARTICLE Reliability of Mental Chronometry for Assessing Motor Imagery Ability After Stroke Francine Malouin, PhD, Carol L. Richards, PhD, Anne Durand, PhD, Julien Doyon, PhD ABSTRACT. Malouin F, Richards CL, Durand A, Doyon J. Reliability of mental chronometry for assessing motor imagery ability after stroke. Arch Phys Med Rehabil 2008;89:311-9. Objective: To examine the reproducibility of 2 chronomet- ric tests: time-dependent motor imagery (TDMI) screening test and temporal congruence test. Design: Test-retest 10 to 14 days apart. Setting: Laboratory of a university-affiliated center for re- search in rehabilitation. Participants: Twenty persons post cerebrovascular accident (CVA) and 46 healthy persons (controls). Intervention: The reproducibility of the TDMI screening test, wherein the number of stepping movements (performed in sitting) imagined over 15, 25, and 45 seconds is recorded, and of the temporal congruence test wherein the duration of phys- ically executed (E) and imagined (I) stepping movements is recorded, was evaluated. Main Outcome Measures: The test-retest reliability of the number of imagined movements (TDMI screening test), move- ment duration and I/E time ratios (temporal congruence test), and intrasession reliability of the temporal congruence test were as- sessed by using intraclass correlation coefficients (ICCs). Results: For the TDMI screening test, the ICCs ranged from .88 to .93 (CVA, n=20) and from .87 to .92 (controls, n=9). For the temporal congruence test, when the total duration of 2 series of 5 stepping movements was averaged, ICCs ranged from .76 to .97 (CVA, n=20) and from .77 to .93 (controls, n=46), whereas for 1 series the ICCs ranged from .71 to .95 and from .63 to .95 in the CVA and control groups, respec- tively. The ICCs for intrasession reliability for the CVA (n=20) and control (n=46) groups, respectively, ranged from .90 to .98 and .95 to .97. Conclusions: The present findings support the reproducibil- ity of both tests in both groups. Mental chronometry can be used reliably for the screening of patients capable of motor imagery or for measuring temporal congruence between real and imagined movements poststroke. Key Words: Cerebrovascular accident; Imagery (psycho- therapy); Motor skills; Movement; Rehabilitation; Reliability and validity. © 2008 by the American Congress of Rehabilitation Medi- cine and the American Academy of Physical Medicine and Rehabilitation M OTOR IMAGERY ABILITY is required for the mental rehearsal of movements during mental practice; hence, it is necessary to assess whether a person is able to engage in motor imagery prior to mental practice training. Motor imagery can be defined as an active process during which the represen- tation of a specific action is internally reproduced within work- ing memory without any overt output 1 or the imagination of actions without their execution. Because of its concealed na- ture, however, motor imagery is difficult to assess and although several approaches have been used 2,3 none appears totally satisfactory. 3 To date, approaches such as mental chronome- try, 4-8 mental rotation, 9,10 and motor imagery questionnaires 11 have been used to assess motor imagery in persons with stroke. Whereas mental chronometry informs about the temporal cou- pling between real and simulated movements, mental rotation offers information about the accuracy of imagined movements, and motor imagery questionnaires assess the vividness of mo- tor imagery. The temporal coupling between real and simulated move- ments can be impaired after stroke, 5,8,12 particularly after le- sions located in the superior region of the parietal cortex. 12 On the other hand, the accuracy of motor imagery during the simulation of prehensile movements has been found to be preserved in most patients. 9,10 When accuracy of motor imag- ery was impaired, lesions involved the posterior-parietal-occip- ital cortex (n=1) or the frontal cortex (n=1). It was notewor- thy, however, that other patients with lesions located in the frontal region or involving part of the parietal cortex retained good motor imagery accuracy, 9 indicating that these cortical lesions are not systematically associated with motor imagery impairment. Finally, motor imagery accuracy was also retained in all patients (n=8) with subcortical lesions (chronic or acute) who were completetly paralyzed, indicating that motor imagery accuracy is not motor activity-dependent. 10 Thus, findings from mental chronometry and mental rotation studies suggest that damage to cortical structures may interfere with the tem- poral organization of motor imagery and accuracy of prehensile tasks, thus emphasizing the importance of assessing motor imagery ability of patients before considering the use of mental practice as a therapeutic approach. 3,13,14 Recently, the psychometric properties (test-retest reproduc- ibility, construct validity) of the Kinesthetic and Visual Imag- ery Questionnaire (KVIQ), a questionnaire developed for per- sons with physical disabilities, have been confirmed. 11 The KVIQ, which assesses the clarity of images and intensity of sensations during motor imagery (vividness), has been used in conjunction with a motor imagery screening test to assess motor imagery ability in a group of persons with stroke. 15 Based on the KVIQ scores, it was found that the vividness of motor imagery of simple body movements (head, trunk, upper and lower limbs) in the group of patients was similar to that of a group of age-matched healthy subjects. 15 From the Department of Rehabilitation, Laval University and Center for Interdis- ciplinary Research in Rehabilitation Social Integration (CIRRIS), Quebec City, QC, Canada (Malouin, Richards); Department of Psychology, Unité de Neuroimagerie Fonctionnelle, Institut Universitaire de Gériatrie, University of Montreal, Montreal, QC, Canada (Doyon); and Institut de Réadaptation en Déficience Physique de Québec, Quebec City, QC, Canada (Durand). Supported by the Quebec Provincial Rehabilitation Research Network and the Canadian Institutes of Health Research. No commercial party having a direct financial interest in the results of the research supporting this article has or will confer a benefit upon the authors or upon any organization with which the authors are associated. Reprint requests to Francine Malouin, PhD, Center for Interdisciplinary Research in Rehabilitation and Social Integration, IRDPQ, 525 Blvd Hamel E, Quebec City, QC G1M 2S8, Canada, e-mail: Francine.Malouin@rea.ulaval.ca. 0003-9993/08/8902-11657$34.00/0 doi:10.1016/j.apmr.2007.11.006 311 Arch Phys Med Rehabil Vol 89, February 2008