Relative efficacy of intensive and spaced behavioral treatment of stuttering.

Twenty adult and adolescent stutterers were randomly assigned to two treatment formats consisting of either 16 two-hour sessions of fluency training administered within a concentrated period of four consecutive days (intensive treatment), or two two-hour sessions per week for eight weeks (spaced treatment). Frequency of stuttering and rate of speaking were repeatedly assessed from speech samples obtained in six different clinic and extra-clinic speech settings. The efficiency of treatment, subject compliance, and communication "attitudes" were also measured. Fluency training produced significant reductions in stuttering frequency, and significant improvements in speaking rate and communication attitudes for both treatment formats. Both formats were found equivalent on all measures. In addition, generalization of treatment effects was observed in all settings. However, maintenance of generalization effects was uneven across settings, suggesting the possible need for differential levels of training for different speaking situations.