Motor imagery ability in patients with traumatic brain injury Objective: To assess motor imagery (MI) ability in patients with a moderate to severe traumatic brain injury (TBI). Design: Prospective, behavioral study with matched control subjects Setting: Rehabilitation unit in a university hospital Participants: Patients with a TBI (mean coma duration 18 days) receiving rehabilitation (n=20) and healthy control subjects (n=17) matched for age and level of education Interventions: not applicable Main Outcome Measures: The vividness of MI using a revised version of the Movement Imagery Questionnaire (MIQ-RS), temporal features of MI using the Time Dependent Motor Imagery test (TDMI), the temporal congruence test, and a walking trajectory imagery test. A mental rotation test was used to measure MI accuracy. Results: The results of the MIQ-RS revealed a decrease of MI vividness in the TBI group. For the TDMI test, an increasing number of stepping movements was observed with increasing time periods in both groups. The TBI group performed a significantly smaller number of imagined movements in the same movement time. The temporal congruence test showed a significant correlation between imagined and actual stepping time in both groups. The walking trajectory test disclosed an increase of the imagined and actual walking time with increasing path length in both groups. The results of the hand mental rotation test indicated a significant effect of rotation angles on imagery movement times in both groups, but rotation time was significantly slower in the TBI group. Conclusions: Patients with a TBI demonstrated a preserved MI ability, although the results of the extensive clinical test battery indicated a significant decrease of MI vividness, temporal coupling and accuracy.