Describe paradoxical improvement of the motor function after a second stroke located in the area of the first stroke.

Animal studies have shown that humoral factors induced by acute stroke facilitate recovery more if rehabilitation is commenced earlier than later. Moreover, a second stroke may improve recovery from the first stroke. It is unknown if this phenomenon occurs in humans.

53-year-old right-handed woman with a history of hypertension and ischemic stroke 2 years before, with residual left hemiplegia, and post-stroke epilepsy presented with acute onset of mild weakness and numbness of the right arm and leg.

Neurological examination revealed mild weakness and numbness of the left face, power of 4/5 and 5/5 in the right arm and leg respectively, and 0/5 in the left arm and leg. Sensation to light touch and pin was decreased in the left arm and leg. Vibration was decreased on left and proprioception was impaired distally bilaterally. Reflexes were 1+ at right triceps and biceps, 2+ at right patella, 3+ at left triceps, biceps, patella, and 0 at ankle bilaterally.

Next day, she developed dysarthria and the power of right limbs decreased to 2/5. By the third day, dysarthria and right hemiparesis resolved. Additionally, the patient noted spontaneous increased power of the proximal left side to 3/5 in both arm and leg . However, distally, power remained 0/5 in both left arm and leg.

MRI demonstrated acute infarction located in the center of a chronic infarct corresponding to the territory of right anterior cerebral artery. CT angiogram showed right anterior cerebral artery occlusion.

The patient had spontaneous paradoxical improvement of the motor deficit after a second stroke. There is no similar case report in humans. This may confirm the limited window of improved recovery triggered by another stroke.