Gut feelings about recovery after stroke: the organization and reorganization of human swallowing motor cortex.

Swallowing problems can affect as many as one in three patients in the period immediately after a stroke. In some cases this can lead to serious morbidity, in particular malnutrition and pulmonary aspiration. Despite this, swallowing usually recovers completely in the vast majority of patients within weeks. This impressive propensity for recovery is likely to relate to how the area of the motor cortex concerned with swallowing is organized and then reorganized after cerebral injury. Recent studies have indicated that swallowing has a bilateral but asymmetric inter-hemisphere representation within motor and premotor cortex. Damage to the hemisphere that has the greater swallowing output appears to predispose that individual to swallowing problems. However, because there is additional substrate for swallowing in the undamaged hemisphere, the capacity for compensatory reorganization in the contralateral motor cortex might be increased, leading to a greater likelihood of recovery. Swallowing might be an excellent system for studying cortical plasticity, and might prove useful in the development of new therapies aimed at accelerating reorganization in the undamaged hemisphere after unilateral cerebral injury.