Hua Håkan, Emilsson Magnus, Kähäri Kim, Widén Stephen, Möller Claes, Lyxell Björn
Linnaeus Centre HEAD, Swedish Institute for Disability Research, Linköping University, Linköping, Sweden; Department of Behavioural Sciences and Learning, Linköping University, Linköping, Sweden.
Department of Audiology, Sahlgrenska Academy, Gothenburg University, Gothenburg, Sweden.
J Am Acad Audiol. 2014 Oct;25(9):859-68. doi: 10.3766/jaaa.25.9.8.
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 self-rated disturbance in individuals with HI than low-level noise.
The purpose of this study was 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.
A mixed factorial design was conducted to examine the effect of noise in four experimental conditions.
A total of 40 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.
The current study was conducted by using 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 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 occurred on two separate sessions, completed within 4 wk of each other. All tasks and experimental conditions were used in a counterbalanced order. Two-way analysis of variance with repeated measures was performed to analyze the results. To examine interaction effects, pairwise t-tests were used. Pearson correlation coefficients between reaction time and proportion of correct answers, and cognitive performance and PD were also calculated to examine the possible correlation between the different variables.
No significant between-group 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 demonstrated that the group with HI was more disturbed by higher than lower levels of noise (i.e., traffic and daycare setting compared with 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 settings compared with office noise.
The present results demonstrate that background noise does not impair cognitive performance in nonauditory tasks in employees with HI and normal hearing, but that PD is affected to a greater extent in employees with HI during higher levels of background noise exposure. In addition, this study also supports previous studies regarding the detrimental effects that high-level noise has on employees with HI. Therefore, we 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.
医疗保健专业人员经常会遇到有听力障碍（HI）的员工，他们在工作中会遇到困难。有迹象表明，这些困难中的大多数可能与背景噪音的存在有关。此外，研究还表明，与低水平噪音相比，高水平噪音对有听力障碍的个体的认知表现和自我评定的干扰有更大的不利影响。
本研究的目的是检验不同类型的背景噪音对佩戴助听器的听力障碍员工和听力正常员工的认知表现和感知干扰（PD）的影响。
采用混合因子设计来检验四种实验条件下噪音的影响。
共招募了40名参与者（21名男性和19名女性）参与该研究。研究样本包括听力障碍员工（n = 20）和听力正常员工（n = 20）。听力障碍组有轻度至中度感音神经性听力障碍，他们都是经常使用助听器的人。
本研究通过在四种不同的背景条件下使用四项一般的与工作相关的任务（心算、正字法解码、语音解码和序列回忆）来进行：（1）安静，（2）56分贝的办公室噪音，（3）73.5分贝的日托中心噪音，以及（4）72.5分贝的交通噪音。工作任务中的反应时间和正确答案的比例被用作认知表现的结果指标。使用博格CR-10量表来评估感知干扰。
数据收集在两个不同的时间段进行，彼此间隔不超过4周。所有任务和实验条件都以平衡的顺序使用。采用重复测量的双向方差分析来分析结果。为了检验交互作用效应，使用了成对t检验。还计算了反应时间与正确答案比例之间以及认知表现与感知干扰之间的皮尔逊相关系数，以检验不同变量之间可能的相关性。
在四种背景条件下，未观察到组间或组内认知表现的显著差异。感知干扰评分表明，两组都根据噪音水平对感知干扰进行评分，噪音水平越高，感知干扰越高。本研究结果还表明，听力障碍组受到高水平噪音的干扰比低水平噪音更大（即与办公室环境相比，日托中心和交通环境中的噪音）。在四项工作任务中都一致观察到这种模式，即听力障碍组在日托中心和交通环境中报告的感知干扰明显大于办公室噪音环境。
目前的结果表明，背景噪音不会损害听力障碍员工和听力正常员工在非听觉任务中的认知表现，但在高水平背景噪音暴露期间，听力障碍员工的感知干扰受到的影响更大。此外，本研究还支持了先前关于高水平噪音对听力障碍员工有害影响的研究。因此，我们强调在听力保健和职业健康服务中，对听力正常和听力障碍的员工都需要进行自我评定和认知测量。
