1. Deafness Studies Unit, Faculty of Education, University of Melbourne, Australia
2. Taralye, Blackburn, Victoria, Australia
3. Renwick College, University of Newcastle, at the Royal Institute for Deaf and Blind Children, North Rocks, Australia
4. University of Western Ontario, Canada

This study investigated the impact of different output limiting levels upon the speech perception skills of 3 severely hearing impaired adolescents. It also explored the impact of reducing SSPL setting on sound field aided thresholds and hearing aid gain. AGCo settings were gradually decreased using the participants own programmable hearing aids. At each SSPL setting speech perception scores were assessed using a computer based 50 item CNC Word Test. Changes in aided sound field thresholds, gain and SPLograms were also measured. Speech perception scores decreased with reductions in SSPL settings, with the most marked reductions occurring at the lowest SSPL setting. Inspection of SPLograms indicated that these students were able to maximise speech perception over a wide dynamic range, however as the dynamic range was reduced speech perception scores began to deteriorate at the point where the reduced SSPL initiated a reduction in gain. When the reduction in gain reduced the AAI below 0.4, significant reductions in speech perception scores were observed. Reductions in SSPL showed little observed change in aided sound field thresholds.