Extrinsic feedback facilitates mental chronometry abilities in stroke patients

BACKGROUND: Motor imagery (MI) can serve as a treatment for stroke rehabilitation. MI abilities can be assessed by testing mental chronometry (MC) as the degree of conformity between imagined and real performance of a task. A good MC performance is supposed to indicate good MI capacities. OBJECTIVE: To explore if MC abilities can be modified by extrinsic feedback in stroke patients. METHODS: 60 subacute stroke patients were randomized into three groups. MC was evaluated by executing a modified version of the Box and Block Test (BBT) mentally and in real before and after a training session. For Groups 1 and 2 the training consisted of repeated performance of the BBT in a mental and then a real version. The time needed to complete each task was measured. Only participants of Group 1 received feedback about how well mental and real performance matched. Group 3 executed the same number of BBTs but without MI. RESULTS: MC ability only improved in Group 1. The improvement lasted for at least 24 hours. In all groups, BBT real performance was improved post-training. CONCLUSION: External feedback was able to enhance MC capability which might be an approach for improving MI abilities.