The aim of this work is to present problems related to tinnitus symptoms, its pathogenesis, hypotheses on tinnitus causes, and therapy treatment to reduce or mask the phantom noise. In addition, the hypothesis on the existence of parasitic quantization that accompanies hearing loss has been recalled. Moreover, the paper describes a study carried out by the Authors with the application of high-frequency dither having specially formed spectral characteristics. Discussion on preliminary results obtained and conclusions are also contained.

The study presents evaluating the effectiveness of the hearing aid fitting process in the short-term use (7 days). The evaluation method consists of a survey based on the APHAB (Abbreviated Profile of Hearing Aid Benefit) questionnaire. Additional criteria such as a degree of hearing loss, number of hours and days of hearing aid use as well as the user’s experience were also taken into consideration. The outcomes of the benefit obtained from the hearing aid use in various listening environments for 109 hearing aid users are presented, including a degree of their hearing loss. The research study results show that it is possible to obtain relevant and reliable information helpful in assessing the effectiveness of the shortterm (7 days) hearing aid use. The overall percentage of subjects gaining a benefit when communicating in noise is the highest of all the analyzed and the lowest in the environment with reverberation. The statistical analysis performed confirms that in the listening environments in which conversation is held, a subjective indicator determined by averaging benefits for listening situations individually is statistically significant with respect to the degree of hearing loss. Statistically significant differences depending on the degree of hearing loss are also found separately for noisy as well as reverberant environments. However, it should be remembered that this study is limited to three types of hearing loss, i.e. mild, moderate and severe. The acceptance of unpleasant sounds gets the lowest rating. It has also been observed that in the initial period of hearing aid use, the perception of unpleasant sounds has a big influence on the evaluation of hearing improvement.

The paper shows a study on the relationship between noise measures and sound quality (SQ) features that

are related to annoyance caused by the traffic noise. First, a methodology to perform analyses related to

the traffic noise annoyance is described including references to parameters of the assessment of road noise

sources. Next, the measurement setup, location and results are presented along with the derived sound quality

features. Then, statistical analyses are performed to compare the measurement results and sound quality

features. The included conclusions are focused on showing that the obtained loudness values, regardless of

the used system, are similar in a statistical sense. Contrarily, sharpness, roughness and fluctuation strength

values differ for the tools employed.