Evaluation of digital hearing aid algorithms on wearable signal processor systems

The benefit of hearing aid algorithms in everyday life can hardly be estimated from results obtained in the laboratory. Extensive field tests with many hearing impaired subjects are necessary to evaluate these processing schemes. A wearable digital hearing aid prototype is described which was developed specifically for that purpose. It is based on a fixed-point digital signal processor. This unit enables the testing of even highly sophisticated algorithms, with a changing interval of the accumulator pack of 10 hours. As application examples, a very flexible three channel dynamic compression algorithm and a binaural processing scheme for enhancing speech signals in noisy and reverberant environments are described. Application of 20 units in 3 European clinics has been started recently.