Reliability of mental chronometry for assessing motor imagery ability after stroke

Objective: To examine the reproducibility of 2 chronometric 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 research 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 physically executed (E) and imagined (1) stepping movements is recorded, was evaluated. Main Outcome Measures: The test-retest reliability of the number of imagined movements (TDMI screening test), movement duration and I/E time ratios (temporal congruence test), and intrasession reliability of the temporal congruence test were assessed 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, respectively. 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 reproducibility 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.