 To evaluate speech comprehension, the HSM Hochmair-Schulz-Moser sentence test is used. This is a test mainly applied to evaluate the speech comprehension in patients with cochlear implants and consists of 30 lists each including 20 short sentences. After initial presentation of exercise sentences without background noise, additional noise is added while the speech signal is kept at a constant volume level. The percentage of speech comprehension is determined by the quantity of correctly understood sentences at a certain signal-to-noise ratio SN Ratio. In this study a SN Ratio of 10dB, with a signal at 70dB and noise at 60dB, will be analysed. 