Figure 4: Example for typical hearing aid care. The figure shows the understanding of monosyllabic words without (circles) and with hearing aid (rectangles) in dependence from the speech level. For everyday speech, the speech intelligibility was improved from 10 to 75%. The average understanding of monosyllables of 90% is only merely achieved with hearing aids. The standard curve for normally hearing people is significantly better. In the level area, the discrimination curve is shifted of 20–25 dB to the lower values.