In Sweden 13% of the general adult population (16-84 years), with or without hearing aids (HAs), report that they have difficulties following a conversation when more than two people are involved. This means that more than one million people in Sweden (9 500 000 inhabitants in total) report subjective hearing difficulties. Observations further indicate that that people with hearing impairment (HI) have an unfavorable position in the labor market. Individuals with HI report poorer health more frequently and estimate their own health to be worse than their normally-hearing peers. Increased unemployment, early health-related retirement and sick leaves are also more common for people with hearing loss compared to the population at large.

The focus of the present thesis is employees with mild-moderate aided HI in the labor market. The research project had three general aims: 1) to develop knowledge about how HI interacts with cognitive abilities, and different types of work-related sound environments and workrelated tasks, 2) develop tests and assessment methods that allow for the analysis and assessment of perceived problems in clinical settings and 3) to develop knowledge that enables the possibility to provide recommendations of room acoustics and work-related tasks for employees with HI. Four studies were carried out. The studies presented in papers I-III are quantitative laboratory studies focusing on health related quality of life, cognition and effort and disturbance perceived in different types of occupational noise (daycare, office and traffic). Paper IV is a qualitative interview study aiming at exploring the conceptions of working life among employees with mild-moderate aided HI.

The results from papers I-IV clearly demonstrate that noise has negative effects on employees with mild-moderate aided HI. In addition to generating significantly greater effort and disturbance, it is further reported from the participants that noise at work in combination with a HI has an impact on daily life. This includes a sense of exposure during work hours, physical and mental fatigue after work, and withdrawal from social situations in the work environment and leisure activities. None of the participants with HI performed significantly worse on the visual working tasks employed in this project compared to their normallyhearing peers. This thesis shows that employees with HI objectively perform the employed  working tasks at a level similar to a well-matched normally-hearing control group. Instead, the findings of this thesis indicates that working in a noisy environment with a HI occurs at the expense of this group reporting significantly worse results on subjective measurements, including greater effort and disturbance, and lower physical health status. Interviews with these participants further confirm that these effects are indeed mostly due to noise at the workplace which could have a negative impact both physically, mentally and socially during and after work hours.

The main findings of this thesis demonstrate that there is a need for extensive services for employees with HI even after a HA fitting. This thesis therefore emphasizes the importance of identifying the need for assistive listening devices, examining the room acoustics of the individual’s work setting and providing the workplace with information about the consequences of having a HI in order to facilitate communication at work. The latter is especially important as colleagues showing support and employers making adjustments at the workplace (technically or acoustically) are facilitating factors that would benefit both employees with HI and those with normal hearing. Additional research should focus on including and comparing other types of cognitive tests, work-related noises and working tasks. More research is also needed to unravel the complex area of research between factors such as cognitive processes, hearing and effort.

Tidigare forskning har visat att yrkesverksamma hörselskadade oftast har en mindre gynnsam position på arbetsmarknaden. Statistik visar att gruppen upplever en högre grad av trötthet och en lägre grad av arbetstillfredställelse. Avhandlingen har tre övergripande syften: 1) att utveckla ny teoretisk kunskap om hur hörselnedsättning samspelar med kognitiva förmågor, arbetsrelaterad ljudmiljö och typ av arbetsuppgifter, och 2) utveckla test- och utredningsmetoder ger möjlighet till analys och diagnos av upplevda problem samt 3) utveckla kunskap som ger möjlighet till åtgärd och anpassning av ljudmiljöer och arbetsuppgifter på arbetsplatser för hörselskadade. Projektets resultat visar på att yrkesverksamma med hörselnedsättning rapporterar en lägre fysisk hälsostatus och att en högre grad av upplevd ansträngning samt störning kan upplevas när de utför olika arbetsuppgifter i buller. Detta beror bland annat på att de kognitiva förmågorna blir mer belastade i en bullrig miljö och att hörselskadade är mer känsliga för höga bullernivåer. Djupintervjuer med gruppen visar även på att fysisk trötthet upplevs även efter jobbet som i sin tur kan leda till psykosociala konsekvenser för individen. Denna avhandling visar att de negativa effekterna av buller redan ses vid en lätt-måttlig hörselnedsättning hos en grupp som redan använder hörapparater. Från ett kliniskt perspektiv innebär det att dagens rehabiliteringsåtgärder bör vara mer omfattande än endast hörapparaturprovning för denna grupp. Tekniska hjälpmedel (FM-system, streamers, hörslinga, etc.) är viktiga för yrkesverksamma med hörselskada och information om konsekvenserna av att leva med en hörselnedsättning bör nås ut till arbetsgivare och kollegor för att underlätta kommunikation på jobbet.