Learning Objectives: Parametric speaker system can be used for targeted sound delivery to the hearing impaired.
Introduction: An ultrasonic transducer together with a traditional transducer were implemented as a Parametric Assistive Listening System(PALS), to produce a directional narrow beam of sound at a target location. We aim to investigate the efficacy of utilizing PALS when compared to a traditional transducer.
Methods: This abstract is part of a currently ongoing(n = 300), double blinded controlled study. The system was constructed such that the PALS can be enabled(parametric condition) or disabled(non-parametric condition). Under non parametric condition, the system acts like a traditional omnidirectional transducer.
Results: We present the initial analysis of the data available from some subjects with normal hearing (n = 10) and mild hearing loss(n = 10). Free-field hearing thresholds and speech discrimination scores in +10 dB SNR using recorded NAL-AB words were studied in both the transducer conditions. The order of transducer conditions were randomized such that both the subject and the tester were blinded to the condition being tested. Parametric condition resulted in a significantly improved(>30%) speech discrimination scores in both the groups tested.
Conclusion: Results of this small sample data available so far are in support of PALS for superior audibility as well as speech intelligibility. Further data collection is under way from a population of normal hearing and various degrees of hearing loss.