The last stage is marked by reduced mobility, muscle weakness and scoliosis. It starts when walking ceases and the girl becomes wheelchair-dependent, and can last for years or decades.

 

Cognition, communication, or hand skills generally do not decline in stage IV. Repetitive hand movements may decrease and eye gaze usually improves. Although sudden death can occur, the average life span of people with Rett syndrome is more than 50 years.