Middle cerebral artery stroke that includes the premotor cortex reduces mobility outcome

The premotor cortex (PMC) (Brodmann 6) contributes uniquely to proximal upper and lower limb power and plays a role in the organization of motor behaviors. We assessed the degree to which PMC damage affected functional outcome.

We prospectively compared the functional outcome of patients with a first stroke in the middle cerebral artery distribution that either left the PMC intact (PMC-; n=19) or damaged the PMC (PMC+; n=12). The Functional Independence Measure for disability and the motor score of the Stroke Impairment Assessment Set for impairment assessed outcome.

Demographic and clinical features and lesion volume were comparable for the PMC+ and PMC- groups. However, the PMC- group demonstrated significant gain in mobility and in proximal leg movement. This focal improvement contributed to the trend in the PMC- group toward greater independent ambulation.

Decreased motor recovery of proximal lower limbs in humans with PMC damage supports the idea that it is the origin of corticoreticulospinal pathways that subserve proximal lower extremity function. Furthermore, persistent proximal weakness after PMC damage may amplify other motor impairments, which include defects in planning, initiating, and sequencing. Neurorehabilitation outcomes may contribute to a more detailed functional anatomy after stroke and partial recovery.