Impact of corticofugal fibre involvement in subcortical stroke

OBJECTIVE To correlate motor deficit with involvement of corticofugal fibres in patients with subcortical stroke. The descending motor corticofugal fibres originate from the primary motor cortex (M1), dorsal and ventral premotor area (PMdv) and supplementary motor area (SMA). DESIGN Retrospective study. SETTING Single tertiary teaching hospital. PARTICIPANTS 57 patients (57% men) with subcortical infarcts on MRI (2009-2011) were included. The mean age was 64.3±14.4 years. INTERVENTIONS None. PRIMARY AND SECONDARY OUTCOME MEASURES National Institute of Health Stroke Scale subscores for arm and leg motor deficit at 90 days. RESULTS An area under the receiver operating characteristics curve (AUC) for the volume of overlap with infarct (and M1/PMdv/SMA fibres) and motor outcome was calculated. The AUC for the association with arm motor deficit from M1 fibres involvement was 0.80 (95% CI 0.66 to 0.94), PMdv was 0.76 (95% CI 0.61 to 0.91) and SMA was 0.73 (95% CI 0.58 to 0.88). The AUC for leg motor deficit from M1 fibres involvement was 0.69 (95% CI 0.52 to 0.85), PMdv was 0.67 (95% CI 0.50 to 0.85), SMA was 0.66 (95% CI 0.48 to 0.84). CONCLUSIONS Following subcortical stroke, the correlations between involvement of the corticofugal fibres for upper and lower limbs motor deficit were variable. A poor motor outcome was not universal following subcortical stroke.