Untersuchung zum Sprachverständnis im Störgeräusch mit dem Oldenburger Satztest mit und ohne FM-Anlage

The term “central auditory processing disorder”, (CAPD), is characterized by a normal peripheral hearing ability with a deficit in neural processing. Affected people have difficulties listening in a situation with moderate background noise as well as following oral instructions and understanding rapid or degraded speech. Poor conditions concerning reverberation and disturbing noises are found in classrooms in school, leading to poor signal to noise ratios (SNR). Children suffering from CAPD are not able to manage the distraction in these situations which results in learning disabilities especially in the development of speech. In consequence these children are in danger of achieving a lower academic niveau. In addition to auditory training and linguistic and cognitive strategies there is the possibility of using signal enhancement strategies to improve the signal to noise ratio. One of these possibilities could be an FM device. The purpose of the present investigation is to prove the efficacy of a personal FM system by performing the Adaptive Oldenbourg Sentence Test (AOST) with and without a personal FM system. The difference exhibits the speech reception threshold (SRT) for a word reception of 50 percent. 54 subjects participated the study. All of them were recruited in the Centre for Phoniology and Pedaudiology in Marburg. 20 children (mean age 9,13 ± 1,44 years) came to our clinic with suspicion of CAPD and performed the AOST by achieving a normal test result. They serve as controls. Another 34 children performed the AOST in previous years and achieved a poor test result. Most of them were diagnosed as having CAPD. Retesting in this investigation emerged for the half of them a normal test result (group 2a, mean age 8,67 ± 1,33 years). Half of them again obtained a poor test result (group 2b, mean age 8,95 ± 1,54 years). The results of the AOST without and with an FM device differ highly significant (p = 0,001). The mean improvement of the SRT amount to 8,77 ± 2,68 dB S/N for the whole sample (group 1: 8,86 ± 2,18 dB S/N; group 2a: 7,89 ± 3,10 dB S/N; group 2b: 9,53 ± 2,66 dB S/N). We found no significant correlation to age – neither for the result without FM device nor for the result with FM. Differences between the three groups are also not significant. For these reasons we assume an improvement of the SRT with FM device in the amount of 8-9 dB – regardless of the result without any devices. The above-mentioned improved speech perception is caused by the FM device´s effect of overcoming the distance to the speaker and amplifiing his voice. Hence better speech perception and relieved communication can be accomplished. Especially for children participating in group 2b and other CAPD-affected children, this advantage makes a substantial difference. According to these results and observations children with CAPD will benefit from using an FM device while having an improved school performance and changing their behaviour. Some investigations seem prove these assumptions. Nevertheless further, especially long-termed, studies are necessery to verifiy an improvement in school performance by using a personal FM system.