Participants were randomly divided into 4 groups : ( 1 ) AL ( n = 30 ) , which included the application of active IFC combined with a limited TA ; ( 2 ) SL ( n = 29 ) , which received sham IFC combined with a limited TA ; ( 3 ) AE ( n = 29 ) , which received active IFC combined with an enhanced TA ; and ( 4 ) SE ( n = 29 ) , which received sham IFC combined with an enhanced TA .