Purpose: To examine the relation between speech recognition and cognitive skills in bimodal cochlear implant (CI) and hearing aid users.

Method: Seventeen bimodal CI users (28-74 years) were recruited to the study. Speech recognition tests were carried out in quiet and in noise. The cognitive tests employed included the Reading Span Test and the Trail Making Test (Daneman & Carpenter, 1980; Reitan, 1958, 1992), measuring working memory capacity and processing speed and executive functioning, respectively. Data were analyzed using paired-sample t tests, Pearson correlations, and partial correlations controlling for age.

Results: The results indicate that performance on some cognitive tests predicts speech recognition and that bimodal listening generates a significant improvement in speech in quiet compared to unilateral CI listening. However, the current results also suggest that bimodal listening requires different cognitive skills than does unimodal CI listening. This is likely to relate to the relative difficulty of having to integrate 2 different signals and then map the integrated signal to representations stored in the long-term memory.

Conclusions: Even though participants obtained speech recognition benefit from bimodal listening, the results suggest that processing bimodal stimuli involves different cognitive skills than does unimodal conditions in quiet. Thus, clinically, it is important to consider this when assessing treatment outcomes.

Objectives: The aim was to explore the conceptions of working life among employees with mild-moderate aided hearing impairment (HI). Design: This study has a descriptive design, in which data was collected by means of semi-structured interviews. All interviews were audio-recorded and transcribed verbatim. The text was analysed in accordance with the phenomenographic approach. Study sample: Fifteen participants with mild-moderate aided HI were recruited to the current study. Results: The analysis of the interviews resulted in four main categories describing the participants conceptions of working life: (1) diffiiculties in daily work, (2) communication strategies, (3) facilitating factors in work environment, and (4) impact on daily life. The four identified descriptive categories show that the effects of HI on the lives of working adults generate far-reaching psychosocial consequences for the individual. Conclusions: This study demonstrates that difficulties and impact of having a HI interact with strategies used by the individual and contextual facilitators made in the work environment. We argue that there is a need for extensive services in aural rehabilitation for this population. This includes identifying the need of assistive listening devices, teaching the individual with HI about communication strategies and informing stakeholders about the consequence of having a HI.

The aim of the following study was to examine the relationship between working memory capacity (WMC), executive functions (EFs) and perceived effort (PE) after completing a work-related task in quiet and in noise in employees with aided hearing impairment (HI) and normal hearing. The study sample consisted of 20 hearing-impaired and 20 normally hearing participants. Measures of hearing ability, WMC and EFs were tested prior to performing a work-related task in quiet and in simulated traffic noise. PE of the work-related task was also measured. Analysis of variance was used to analyze within-and between-group differences in cognitive skills, performance on the work-related task and PE. The presence of noise yielded a significantly higher PE for both groups. However, no significant group differences were observed in WMC, EFs, PE and performance in the work-related task. Interestingly, significant negative correlations were only found between PE in the noise condition and the ability to update information for both groups. In summary, noise generates a significantly higher PE and brings explicit processing capacity into play, irrespective of hearing. This suggest that increased PE involves other factors such as type of task that is to be performed, performance in the cognitive skill required solving the task at hand and whether noise is present. We therefore suggest that special consideration in hearing care should be made to the individuals prerequisites on these factors in the labor market.

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.

Background: Health care professionals frequently meet employees with hearing impairment (HI) who experience difficulties at work. There are indications that the majority of these difficulties might be related to the presence of background noise. Moreover, research has also shown that high level noise has a more detrimental effect on cognitive performance and selfrated disturbance in individuals with HI than low level noise.

Purpose: To examine the impact of different types of background noise on cognitive performance and perceived disturbance (PD) in employees with aided HI and normal hearing.

Research Design: A mixed factorial design was conducted to examine the effect of noise under four experimental conditions.

Study Sample: Forty participants (21 men and 19 women) were recruited to take part in the study .The study sample consisted of employees with HI (n =20) and normal hearing (n = 20). The group with HI had a mild-moderate sensorineural HI and they were all frequent hearing aid users.

Intervention: The current study was conducted by employing four general work-related tasks (mental arithmetic, orthographic decoding, phonological decoding and serial recall) in four different background conditions: (1) quiet, (2) office noise at 56 dBA, (3) daycare noise at 73.5 dBA and (4) traffic noise at 72.5 dBA. Reaction time (RT) and the proportion of correct answers in the working tasks were used as outcome measures of cognitive performance. The Borg CR-10 scale was used to assess PD.

Data Collection and Analysis: Data collection occurred on two separate sessions, completed within four weeks of each other. All tasks and experimental conditions were employed in a counterbalanced order. Two-way analysis of variance (ANOVA) was performed to analyze the results. To examine interaction effects, pairwise t-tests were used. Pearson’s correlation coefficients between RT and proportion of correct answers, and cognitive performance and PD were also calculated to  examine the possible correlation between the different variables.

Results: No significant between or within-group differences in cognitive performance were observed across the four background conditions. Ratings of PD showed that both groups rated PD according to noise level, where higher noise level generated a higher PD. The present findings also demonstrate that the group with HI was more disturbed by higher than lower levels of noise (i.e. traffic and daycare setting compared to the office setting). This pattern was observed consistently throughout four working tasks where the group with HI reported a significantly greater PD in the daycare and traffic setting compared to the office noise.

Conclusions: The present results demonstrate that background noise does not impair cognitive performance in non-auditory tasks in employees with HI and normal hearing, but that PD is affected to a greater extent in employees with HI during higher level of background noise exposure. In addition, this study also supports previous studies regarding the detrimental effects high level noise has on employees with HI. We therefore emphasize the need of both self-rated and cognitive measurements in hearing care and occupational health services for both employees with normal hearing and HI.

Objectives: The aims were to compare health related quality of life (HRQOL) between two groups of employees with normal hearing and hearing impairment (HI) and the results were compared to a normative population. The second aim was to examine self-reported hearing handicap in employees with HI.Design: Data collection occurred in two separate sessions. A validated Swedish version of the Short form-36 (SF-36) was employed to determine HRQOL and The Hearing Handicap Inventory for Adults (HHIA) was used to measure self-perceived hearing handicap.Study Sample: The study sample consisted of hearing-impaired (n = 20) and normally hearing (n = 20) participants. The normative sample comprised of 597 matched respondents.Results: Hearing-impaired employees do not report significantly different HRQOL in comparison with a normative population, nor do they report significantly different HRQOL than their normally hearing peers except in physical functioning (p = 0.04). Results from the HHIA showed mild self-perceived hearing handicap.Conclusions: Employees with mild-moderate HI report good HRQOL and mild self-perceived hearing handicap. However, physical health can be affected even at a mild-moderate HI. This study supports previous literature that HA use, having a job and severity of HI may play a vital role for this group’s well-being.

Objectives: The aims were to compare health-related quality of life (HRQOL) and hearing handicap between two groups of employees with normal hearing and aided hearing impairment (HI). HRQOL was also compared to a normative population. The second aim was to compare perceived effort (PE) and disturbance after completing a task in office noise between the two study groups. Design: A Swedish version of the short form-36 (SF-36) and the hearing handicap inventory for adults (HHIA) was used to determine HRQOL and hearing handicap. The Borg-CR 10 scale was used to measure PE and disturbance. Study sample: Hearing impaired (n = 20) and normally hearing (n = 20) participants. The normative sample comprised of 597 matched respondents. Results: Hearing-impaired employees report relatively good HRQOL in relation to the normative population, but significantly lower physical functioning and higher PE than their normally-hearing peers in noise. Results from the HHIA showed mild self-perceived hearing handicap. Conclusions: The current results demonstrate that physical health status can be negatively affected even at a mild-moderate severity of HI, and that a higher PE is reported from this group when performing a task in noise, despite the regular use of hearing aids.

Background: Adults with cochlear implants (CIs) are usually implanted unilaterally. To preserve binaural advantages, a noninvasive method involves maintaining the hearing aid (HA) on the contralateral ear; the choice of HA for this purpose is therefore crucial. In recent years, the use of frequency transposition has gained a renewed interest in clinical practice. This type of processing records information from the high-frequency region and conveys it to a low-frequency region where there is still some residual hearing. Purpose: To conduct an investigation and examine whether adults with unilateral CI derive benefits from a HA utilizing linear frequency transposition (LFT) on the contralateral ear. Research Design: A two-period, single-blind, repeated-measures crossover design was conducted to examine the combination of LFT in conjunction with a CI. Speech recognition tests were performed in quiet and in noise with LFT either activated or deactivated. The Speech, Spatial and Qualities of Hearing Questionnaire (SSQ) was used to measure subjective benefit. Study Sample: The participants were nine frequent bimodal users, five males and four females, with a moderate to profound high-frequency sensorineural hearing loss in the nonimplanted ear. Intervention: The current study was conducted using the Widex Mind440 power (m4-19) behind-the-ear HA. The participants acted as their own control in a total of seven conditions: (1) bimodal with own HA, (2) CI only, (3) own HA alone, (4) bimodal new HA LFT-off, (5) new HA LFT-off, (6) bimodal new HA LFT-on, and (7) new HA LFT-on. Data Collection and Analysis: Monosyllabic words in quiet and the Swedish version of Hearing in Noise Test (HINT) were used as speech test materials. Stimuli were presented in sound field at a speech level of 65 dB sound pressure level (SPL) via a loudspeaker at a distance of 1 m from the participant in a sound-treated room. The SSQ was administered in each session evaluating the three bimodal conditions. SPSS software was used for statistical analyses. General linear model (GLM) analysis of variance for repeated measures was performed and followed with Bonferroni-adjusted post hoc pairwise comparisons. Results: Participants performed better with CI only than with HA alone, and the bimodal conditions were superior to the CI alone. No significant differences (p > .05) were observed when comparing the LFT-on with LFT-off regardless of whether the use of CI was included in the different listening conditions in objective and subjective measurements. Conclusions: The results suggest an advantage for CI patients with a HA in the opposite ear, and that the LFT neither degraded nor enhanced speech performance in conjunction with a CI in quiet or in noise in comparison to when it was deactivated.