Hearing impaired professional musicians or industrial workers often report that they were able to identify mistuned chords in a music piece or even slight changes in the noise of their machines (usually > 100 dB SPL) though they were handicapped in listening tasks in daily routine. In order to assess central processing of acoustic stimuli, we analyzed auditory evoked potentials (AEP) and EEG spectra after stimulation with work-related auditory stimuli in healthy controls, in hearing impaired musicians or hearing impaired workers from the beverage industry. Stimuli were series of in-tune or mistuned synthetic piano chords or the original machine noise the workers heard in daily routine and the same noise with disturbing signals. Professional musicians identified the mistuned stimuli and the AEP differed significantly. The workers recognized the disturb signals. In both groups the spectral analysis confirmed a frequency shift towards higher alpha frequencies and an altered spatial distribution of the EEG frequencies during presentation of the disturb signals. We assume that professionalism causes learning of typical auditory stimuli that is important for auditory processing after hearing impairment. AEP component analysis © 2015 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. and spectral analysis of the EEG are important tools to objectify this processing, in particular in hearing impaired employees.