EP 4. Recruitment of premotor cortices in subacute stroke patients – A longitudinal fMRI study

Abstract

Objective In order to investigate changes in functional representation of hand movement after stroke we used functional magnetic resonance imaging (fMRI) during an active motor task of the affected hand before and after a three week comprehensive motor training. Methods 12 patients in the subacute phase after mild to moderate motor stroke (4.8 ± 2.1 weeks after stroke; age 58.5 ± 12.5 years, NIHSS: 2.4 ± 1.6) underwent a three week (1 hour daily) arm ability training (AAT; Platz et al., 2009 ). Before and after training active hand grip of both hand sides was measured with fMRI while controlling for frequency and force. Accuracy was calculated as deviation from mean amplitude and frequency. In order to compare brain activation with that of healthy controls (HC) representation maps of age-matched subjects were made. To evaluate the correlates of recovery processes we subtracted representation maps of pre- and post-measurement. Correlations of amplitude accuracy with fMRI activation maps were restricted to areas known to be involved in recovery ( Rehme et al., 2012 ). Results Before training performance of patients in the scanner was not as accurate as of controls. These differences decreased after training. Patients not only improved in trained tasks (t(13) = 20.315, p Conclusion Our data underline the importance of the premotor areas for recovered motor performance after stroke. However, the theoretically helpful support of premotor cortices may reach its maximum and performance levels do not attain those of healthy controls although more motor regions are recruited. It has to be evaluated if these recruitments are ineffective – comparable to the fMRI-activations of elder individuals compared to younger subjects ( Loibl et al., 2011 ).