Motor imagery in stroke patients, or plegic patients with spinal cord or peripheral diseases.

OBJECTIVE

When motor imagery (MI) is impaired in stroke patients, it is not clear, whether this is caused by the central lesion with a disruption of networks or this may be due to inactivity/lack of practice following hemiparesis. To answer this question, we investigated MI in two groups of patients: stroke patients and patients with no central lesion, who suffered high-grade tetraparesis caused by myopathy or spinal muscular atrophy.

METHODS

The first study measured MI in 31 sub-acute and chronic stroke patients with hand paresis. We used self-assessment questionnaires [Kinaesthetic and Visual Imagery Questionnaire (KVIQ), the Vividness of Motor Imagery Questionnaire (VMIQ)] as well as a new chronometric test (mental version and normal/physical version of Box and Block Test). The second study assessed MI in 10 patients without a central lesion, but with severe tetraparesis of peripheral origin. They were incapable of performing the requested task physically.

RESULTS

MI in patients was better (i) for the third-person (VMIQ(3.P) ) compared to the first-person perspective (VMIQ(1.P) ), (ii) in patients without sensory impairment compared to those with impaired proprioception, (iii) in patients with light paresis compared to severe paresis and (iv) for the non-affected than the affected hand (KVIQ-10). Patients with severe tetraparesis were able to imagine another person's knee bends, but were not capable of imagining themselves performing knee bends.

CONCLUSIONS

MI may be hampered on the affected side in severely paretic patients, particularly in the presence of impaired proprioception. Remarkably, the second study illustrates that motor experiences shape MI. This confirms the close relationship between MI and movement execution. The study advocates the careful use of test batteries for assessment of MI when investigating mental training in clinical trials. Not all patients might benefit to the same extent from MI training. This is possibly contingent on intact proprioception and preserved MI.