tourrettes syndrome and massage??

Hi I have a new client who has a 13 year old son with Tourettes Syndrome. He has some fairly obvious tics and jerks especialy when he gets nervous or upset about something. With the teen years just ahead of him, she expects things to get worse before they get better. She notes that he seems to respond well to "homemade massage". When he appears to be nervous, or anxious, she gives him small massages and she can tell that he very obviously calms down. She is wondering if there is any research out there regarding the efficacy of massage for those suffering from Tourettes. Has anyone out there heard of or experienced anything of the sort?? .

Thank you for any help you can offer.