Impact of corticofugal fibre involvement in subcortical stroke

Abstract

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.

Keywords: Rehabilitation Medicine; Stroke Medicine.

Figure 1

The corticofugal fibres from motor cortex (blue), dorsal and ventral premotor area (green) and supplementary motor area (red).

Figure 2

Examples of patients with infarct involving the posterior limb of the internal capsule but no motor deficit at 90 days. (A) 67-year-old male. Dysarthria on admission. (B) 75-year-old male. Motor deficit and aphasia on admission. No motor deficit at 90 days.