Neuropediatrics 2006; 37 - MP34
DOI: 10.1055/s-2006-943631

INCREASED MOTOR-CORTEX EXCITABILITY IN PATIENTS WITH CONGENITAL HEMIPARESIS AFTER CONSTRAINT-INDUCED MOVEMENT THERAPY

M Walther 1, V Brodbeck 2, M Staudt 3, S Berweck 2, V Mall 1
  • 1Children's Hospital, University of Freiburg, Germany
  • 2Dr. von Hauners' Children's Hospital, University of Munich, Germany
  • 3Children's Hospital, University of Tuebingen, Germany

Objectives: Constraint-induced movement therapy (CIMT) in adult stroke patients increases motor-cortex excitability combined with improvement of motor-function. This increase in motor-cortex excitability reflects modulation of intracortical structures by effective motor-training. This study tests the hypothesis whether CIMT in patients with congenital hemiparesis increases motor-cortex excitability as well.

Subjects: Eleven patients (10–30 years, median 12 years) with congenital hemiparesis due to infarction of the middle cerebral artery participated. All possessed preserved contralateral cortico-spinal projections from the affected hemisphere to the paretic hand, 4 patients showed additional ipsilateral cortico-spinal pathways.

Methods: Single-pulse transcranial magnetic stimulation (TMS) was used to investigate motor evoked potential (MEP) -amplitude of the affected motor cortex before and after a 12 day periode of CIMT and in a 3-month follow-up. Stimulus-output was set to produce a control MEP of 0.2–0.5 mV prior CIMT and was kept constant in all TMS-measurements. MEPs were recorded from the affected M. flexor pollicis brevis. In case of bilateral organization, both cortical projections were evaluated.

Results: In patients with only contralateral cortico-spinal projections, measurements revealed significantly higher MEP-amplitudes of the affected hemisphere after CIMT (mean-amplitude pre: 0.38 mV, SD 0.22/ mean-amplitude post: 1.09 mV, SD 0.97/ mean-amplitude follow-up: 0.79 mV, SD 0.52; p<0.03). Bilaterally organized patients showed decreased MEP-amplitudes in the affected cortex, whereas, in the contralesional hemisphere, increased cortical excitability could be seen in three of four subjects.

Conclusion: Increased MEP-amplitudes after CIMT revealed increased motor-cortex excitability in patients with congenital hemiparesis and only contralateral cortico-spinal projections. Our results indicate cortical plasticity mechanisms in congenital hemiparesis comparable to the findings in adult hemiparetic stroke.