Results of a 9-mo longitudinal study designed to evaluate the efficacy of a vibrotactile aid, the SRA-l o, with four profoundly deaf preschool children are reported. During the study the subjects were enrolled in 30-min triweekly language therapy sessions, and changes in communication skills in connected discourse (vocalization only, sign language only, and vocalization PIUS sign language) were measured using a computer-based observation system. Changes in structural and semantic aspects of language were also measured. The four subjects were evaluated during one 16-week phase in which the aid was used (aid-on condition) and another 8 weeks in duration in which the aid was not used (aid-off condition). Communication skills improved in the aid-on condition and decreased in the aid-off condition. The changes were found to be significant for the communication involving the vocalization plus sign language (Total Communication) measure, indicating that the vibrotactile stimulation was Positively associated with the communicative act.