Alternating hemiplegia of childhood (AHC) is a rare but serious neurological disorder. The hallmark of AHC is the onset of frequent, recurrent, transient episodes of hemiplegia (paralysis of a body part). Hemiplegia manifestations run the gamut from numbness to complete loss of movement and feeling. Hemiplegia may affect either side of the body and may occasionally affect both sides simultaneously. These attacks may last a few minutes or may go on for days. In most cases, sleep induces resolution of a hemiplegia episode.