Stroke is an abnormality of brain function caused by disruption of the circulation of the brain. It is the third leading cause of death in the United States and is a significant source of disability. A disturbance in the circulatory system initiates damage to brain structures. The location of the brain injury determines the symptoms, signs and extent of disability of the stroke. The two main categories of cerebrovascular disease are ischemic and hemorrhagic. Ischemic vascular disease occurs from reduction of blood flow to a brain region because of occlusive disease condition of the blood vessel supplying that territory ( e.g. by lipid plaque accumulation as in patients with high cholesterol. Hemorrhagic vascular disease occurs when a blood vessel to the brain ruptures as in case of uncontrolled hypertension, or aneurysm. About 85% of strokes are ischemic and 15% are hemorrhagic.

The ability to predict the outcome can help us to assist families and service providers in planning for the future. The recovery from the motor and functional deficits following stroke may vary among individuals. Some of the motor functions may recover rapidly while some take longer or may remain permanently damaged. It is clinically evident that the site of damage of sensorimotor cortex of brain affects the pattern of motor deficit.

Various studies have evaluated the correlation between the size and the location of the brain lesion to the final motor and functional outcome following stroke using computer tomography (CT) or magnetic resonance imaging (MRI) technology. These studies have come up with conflicting results. Some found the size of the lesion to be a better predictor than the location of the lesion, while others found the opposite result. One possible explanation for these findings is that different dependent variables were used in the studies. In some studies a measures of motor functioning were the outcome measures while in other studies functional activity measures were used. According to Chen et.al. (1999), another potential explanation is that a combination of size and location of lesion could predict outcome.

Recently Chen et.al. (1999) attempted to resolve this controversy by combining size and location of brain lesion into one predictor variable called the " brain lesion profile (BLP)". Fifty-Five BLPs were established based on the MRI findings I month post stroke, Motor and functional outcome was measured at both 1 month and 6 months post stroke.

The result indicated that at both the early and the late stages of recovery, BLPs (lesion size and location combined together) predicted motor recovery and functional outcome better than the lesion size alone, which was a weak predictor of motor outcome and was not a significant predictor of functional outcome. Further studies with larger number of patients will be needed in the future to verify these findings.

For further information:

Chen C-L, Tang F-T, Chen H-C, Chung C-Y, Wong M-K. Brain lesion size and location: effects on motor recovery and functional outcome in stroke patients. Arch Phys Med Rehabil April 2000;81:447-52

Syed S Rahman , M.D.