Music therapy addresses non-musical goals. It can be esp. effective for children with autism. Therapy addresses specific areas of the child. Many children who are non-verbal can sing entire songs. Musical instruments are used for motor planning exercises. There are often no delays in musical perception in children with autism. Musical therapy provides a venue where children with autism can often feel a great deal of success. Music therapy works with the child to further develop that feeling of success.
For an example of a musical therapy program see: http://www.creativeexchangemusic.com.
In Atlanta or Florida, look at: http://www.workingthepuzzle.com/
They currently offer Music Therapy (MTx) in individual and group settings, designed to utilize the effectiveness of intervention through Music.