Ipsilateral Motor Control Without Mirror Movements?

Abstract

Aims: Some children with unilateral-spastic cerebral palsy (=congenital hemiparesis) control their paretic hands via ipsilateral cortico-spinal projections from the contra-lesional hemisphere, which, in these cases, therefore controls both hands. This is typically associated with mirror movements both during voluntary unimanual movements of the paretic and of the non-paretic hand. It is still unclear, however, whether ipsilateral motor control can also exist without mirror movements. Methods: A former term-born child with congenital hemiparesis due to unilateral white matter damage probably resulting from intrauterine periventricular hemorrhage with venous infarction and therapy-refractory epilepsy received hemispherotomy at the age of 5 years. Results: Postoperatively, the paretic hand was still able to grasp; neurological examination at the age of 9 years showed no mirror movements despite (obvious) unihemispheric motor control of both hands. Conclusion: Since transcranial magnetic stimulation has not yet been performed in this patient, there is no formal proof for the existence of ipsilateral cortico-spinal projections from the contra-lesional hemisphere to the paretic hand. The preserved grasp function after hemispherotomy, however, is highly suggestive. Therefore, this case report demonstrates that at least in some children with ipsilateral motor control, the contra-lesional hemisphere can control both hands independently from each other, so that no mirror movements occur. Thus, the absence of mirror movements is not a valid sign for contralateral motor control; this question still requires transcranial magnetic stimulation.