Model simulations of masked thresholds for tones in dichotic noise maskers (A)

The study of masked thresholds in dichotic noise maskers is important for understanding the processing in binaural hearing. To simulate these thresholds a psychoacoustically motivated perception model was used [T. Dau et al. (1995). ``A quantitative model of the ``effective'' signal processing in the auditory system: I. Model structure,'' submitted to J. Acoust. Soc. Am.]. This model, which has been successfully applied to several monaural psychoacoustical experiments, was extended by an additional binaural processing unit. It consists of a filterbank, half-wave rectifier, low-pass filter, and adaptation loops, which model the temporal processing. The binaural processing unit detects the interaural correlation and makes decisions based on the difference between the signals from both ears. Masked thresholds in the NoS and NSo configurations, obtained as a function of noise masker frequency and bandwidth, were simulated and compared to new experimental measurements. The dependence on interaural delay and interaural decorrelation of the noise masker was also modeled and compared to data in the literature. In general, model simulations agree well with the main features seen in the measurements. [Work supported by DFG (Ho 1627/1-1) and by NIDCD (Grant DC00100).

Modeling the reliability of the Freiburg monosyllabic speech test in quiet with the Poisson binomial distribution. Does the Freiburg monosyllabic speech test contain 29 words per list?

Every speech test can be modeled as a Bernoulli experiment; this also applies to the Freiburg monosyllabic speech test. The model enables a quantitative calculation of the reliability based on the binomial distribution. Generally, the same probability is assumed for the recognition of each test word. Since the recognition of words within test lists of the Freiburg monosyllabic speech test differs, modeling with the Poisson binomial distribution is reasonable, and results in a narrower confidence interval than the simple binomial distribution. The variance of the Poisson binomial distribution for test lists of the Freiburg monosyllabic speech test with 20 words can be approximated using the variance of the simple binomial distribution based on test lists with 29 equally-recognizable words

Modeling and verifying the test-retest reliability of the Freiburg monosyllabic speech test in quiet with the Poisson binomial distribution

The test-retest reliability of the Freiburg monosyllabic speech test was modeled using different methods. The results were compared to measurements from listeners with and without hearing impairment. The methods are based on the models of Thornton and Raffin as well as Altman et al. Both papers took into account differences in word recognition within the test lists by applying the Poisson binomial distribution and included the variance of the test-list results. The methods allow calculating the bounds of the 90% and 95% confidence intervals when using test lists with 20 words and double lists with 40 words. The data in the current report confirm these bounds. The confidence intervals are broadest for speech recognition scores of 50%. At this score and for test lists with 20 words, the 90% confidence interval has a width of ±20%, corresponding to ±6.0 dB, and the 95% confidence interval has a width of ±25%, corresponding to ±7.4 dB. Thus when evaluating hearing-aid fittings, only differences exceeding this range can be regarded as significantly different.Die Test-Retest-Reliabilität des Freiburger Einsilbertests wurde mit verschiedenen Methoden modelliert und mit Messdaten von Probanden mit und ohne Hörbeeinträchtigung verglichen. Die Methoden bauen auf den Verfahren von Thornton und Raffin sowie Altman et al. auf. Sie berücksichtigen durch die Verwendung der verallgemeinerten Binomialverteilung die Unterschiede im Wortverstehen innerhalb der Testlisten und beinhalten die Varianz der Testlisten. Die Methoden ermöglichen die Bestimmung der Grenzen für die 90%- und 95%-Konfidenzintervalle bei Verwendung von Testlisten mit 20 Wörtern und von Doppellisten mit 40 Wörtern. Diese Grenzen wurden durch die Messdaten bestätigt. Bei einem Sprachverstehen von 50% sind die Konfidenzintervalle am breitesten. Dort hat für Testlisten mit 20 Wörtern das 90%-Konfidenzintervall eine Breite von ±20% bzw. ±6,0 dB und das 95%-Konfidenzintervall eine Breite von ±25% bzw. ±7,4 dB. Für die Hörgeräte-Anpasspraxis bedeutet dies, dass erst Unterschiede, die diese Spanne übersteigen, als signifikant unterschiedlich gewertet werden können

A Representative Study of Hearing Ability in North West Germany

The estimated hearing ability of German citizens is based on a comprehensive study published by von Stackelberg in 1986[...