Environmental and personal monitoring of exposure to urban noise and community response

Noise exposure of a population sample living in a city in northern Italy (Genoa) was assessed by measuring the noise in the area as well as with personal sound detectors. Sampling was conducted during a standard day and covered a period of time spent out-of-doors, at work (service sector) and at home. Ambient noise at home and at work was assessed with sound-level meters, personal exposure levels were assessed with personal sound-level/dosimeters. Information regarding each environment was obtained with an interview including also a subjective judgement on traffic intensity and noise levels. The mean individual equivalent continuous sound level (L_eq) of recorded noise was 74.5 dB(A) for 24 h and 63.9 dB(A) at night. A further distinction was made between noise exposure at home (L_eq 74.4), work (L_eq 74.0) and during city transfers (L_eq 79.3). L_eq values for individual hours, Leq daytime (L_{eq, d}), Leq nighttime (L_{eq, n}) and Leq day-night (L_dn) indices calculated in the different environments, i.e. at work, home and out-of-doors, are reported here. Individual noise levels have then been compared with environmental data and with subjective noise exposure judgement.     

High-frequency audiometry in the evaluation of critical noise intensity

Summary We investigated a total of 537 subjects (68 men, 469 women) working in the textile industry to ascertain their hearing level in the conventional hearing range as well as in the high-frequency (HF) range. The persons we tested work at three different noise-levels [80–84, 85–89, 90–94dB (A), measured as l_eq). The differences in the hearing thresholds between this three groups mentioned were checked by means of discriminant analysis. The first hearing level changes at a noise-level below 90 dB (A) l_eq develop mainly in the HF range. In the conventional hearing range, however, the hearing levels remain unchanged even over long exposure times. Noise-induced hearing loss in the conventional range occurs only in the sound level group of 90 to 94 dB (A) l_eq without attaining any social importance. The tests show that, if the noise-level 90 dB (A) leq is not exceeded, no noise-induced hearing impairments involving social hearing loss are to be observed. Thus we assume that an auditory risk criterion of 85 dB (A) l_eq is sufficient to prevent hearing loss of any social importance.     

Impairing effects of noise in high and low noise sensitive persons working on different mental tasks

Objective  There is no information of mental strain in noise sensitive persons working under moderate levels of noise. The aim of the study was to determine relevant dimensions of impairing effects differentiating between noise sensitive and insensitive persons. Methods  56 participants (27 men, 29 women; 18–31 years old) were classified into 28 low and 28 high noise sensitive persons. They worked either on a grammatical reasoning task (GRT) or a mental arithmetic task (MPT) under realistic road traffic scenarios [LAeq 55 dB(A)]. Afterwards they rated their annoyance and subjective mental strain. Results  A multivariate analysis of variance provided significant effects for the individual noise sensitivity (P < 0.01) and the kind of task being performed (P < 0.01). To determine to what extent the rating scales lead to a differentiation of the four groups, a 2-factorial discriminant analysis was carried out subsequently. Results showed, that psycho-physiological effort and emotional strain differentiated best between the noise sensitivity groups and psycho physiological effort and focus on tasks (attention) separated the tasks. Conclusion  Noise sensitive persons are more distracted by noise than insensitive persons. Furthermore the results suggest that noise sensitive subjects do not only evaluate a noisy situation as more annoying but experience higher levels of strain than insensitive persons.     

Aircraft noise and incidence of hypertension--gender specific effects

Recent studies show associations between aircraft noise and cardiovascular outcomes such as hypertension. However, these studies were mostly cross-sectional and there are uncertainties regarding potential gender differences as well as sensitive subgroups. In this study, we investigated the cumulative incidence of hypertension in relation to aircraft noise exposure among Swedish men and women living in Stockholm County. A total of 4721 subjects, aged 35–56 at baseline, were followed for 8–10 years. The population was selected according to family history of diabetes, which was present for half of the subjects. The exposure assessment was performed by geographical information systems and based on residential history during the period of follow-up. Blood pressure was measured at baseline and at the end of follow-up. Additional information regarding diagnosis and treatment of hypertension as well as various lifestyle factors was provided by questionnaires. In the overall population, no increased risk for hypertension was found among subjects exposed to aircraft noise ≥50 dB(A) L_den; relative risk (RR) 1.02 (95% CI 0.90–1.15). When restricting the cohort to those not using tobacco at the blood pressure measurements, a significant risk increase per 5 dB(A) of aircraft noise exposure was found in men; RR 1.21 (1.05–1.39), but not in women; RR 0.97 (0.83–1.13). In both sexes combined, an increased risk of hypertension related to aircraft noise exposure was indicated primarily among those reporting annoyance to aircraft noise; RR 1.42 (1.11–1.82). No consistent effect modification was detected for any of the cardiovascular risk factors under investigation although a family history of diabetes appeared to modify the risk in women. In conclusion, the results suggest an increased risk of hypertension following long-term aircraft noise exposure in men, and that subjects annoyed by aircraft noise may be particularly sensitive to noise related hypertension.     

Prospective noise induced changes to hearing among construction industry apprentices

Aims: To characterise the development of noise induced damage to hearing.

Methods: Hearing and noise exposure were prospectively monitored among a cohort of newly enrolled construction industry apprentices and a comparison group of graduate students, using standard pure tone audiometry and distortion product otoacoustic emissions (DPOAEs). A total of 328 subjects (632 ears) were monitored annually an average of 3.4 times. In parallel to these measures, noise exposure and hearing protection device (HPD) use were extensively monitored during construction work tasks. Recreational/non-occupational exposures also were queried and monitored in subgroups of subjects. Trade specific mean exposure L_eq levels, with and without accounting for the variable use of hearing protection in each trade, were calculated and used to group subjects by trade specific exposure level. Mixed effects models were used to estimate the change in hearing outcomes over time for each exposure group.

Results: Small but significant exposure related changes in DPOAEs over time were observed, especially at 4 kHz with stimulus levels (L1) between 50 and 75 dB, with less clear but similar patterns observed at 3 kHz. After controlling for covariates, the high exposure group had annual changes in 4 kHz emissions of about 0.5 dB per year. Pure tone audiometric thresholds displayed only slight trends towards increased threshold levels with increasing exposure groups. Some unexpected results were observed, including an apparent increase in DPOAEs among controls over time, and improvement in behavioural thresholds among controls at 6 kHz only.

Conclusions: Results indicate that construction apprentices in their first three years of work, with average noise exposures under 90 dBA, have measurable losses of hearing function. Despite numerous challenges in using DPOAEs for hearing surveillance in an industrial setting, they appear somewhat more sensitive to these early changes than is evident with standard pure tone audiometry.

     

Industrie- und Gewerbel?rm

Zusammenfassung In der Umgebung von fünf Industrie- und Gewerbeanlagen wurden die Lärmimmissionen gemessen und mittels schriftlicher Befragung die Auswirkungen derselben auf die dort wohnenden Menschen erfasst.Es zeigte sich, dass gehäufte Störungen und Reaktionen bei Betriebslärmimmissionen tagsüber ab einemL _eq von ungefähr 50 dB(A) auftreten und nachts ab einemL _eq von ungefähr 40 dB(A).

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Noise immissions of industrial plants

Summary In the surroundings of five industrial plants noise immissions were measured, and people were asked by questionnaire about the effects caused by noise.The results show that increased disturbances and reactions to industrial noise immissions occur at daytime with anL _eq of about 50 dB(A) and at nighttime with anL _eq of about 40 dB(A).

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Immissions de bruit des entreprises industrielles

Résumé Dans les environs de cinq entreprises industrielles, on a mesuré les immissions de bruit, et les habitants ont été questionnés sur les effets causés par le bruit.Les résultats montrent que les troubles et réactions augmentent à partir d'une valeurL _eq située environ à 50 dB(A) pour le jour et à 40 dB(A) environ pour la nuit.

     

Cardiovascular effects of environmental noise: research in Serbia

Research on the cardiovascular effects of noise in Serbia started in the year 2002, including experimental studies on humans and epidemiological studies on the adult and children population of Belgrade and Pancevo. Experimental exposure to noise [L eq = 89 dB (A)] had a hypodynamic effect, significantly lowering the cardiac index, cardiac work, and pump performance (P < 0.01). The vasoconstrictive effect of noise was shown through the significant elevation of after-load (P < 0.01). In a cross-sectional population study that was carried out on 2874 residents [1243 males and 1631 females] in Pancevo City, a significant odds ratio (adjusted for age, body mass index (BMI), and smoking habits) was found for self-reported hypertension (OR = 1.8, 95% CI = 1.0 - 2.4, P < 0.01) in men with a high level of noise annoyance compared to those with a low level of noise annoyance. In another study on 2503 residents (995 men and 1508 women) residents of Belgrade, the proportions of men with hypertension in the noisy [(L night , 8h > 45 dB (A)] and quiet areas [(L night , 8h ≤ 45 dB (A)] were 23.6% and 17.5%, respectively. The adjusted odds ratio (OR) for hypertension of the exposed group was 1.58 (95% CI = 1.03 - 2.42, P = 0.038), where men living in quiet streets were taken as a reference category. Associations between road traffic noise and blood pressure were also investigated in 328 preschool children in Belgrade. The systolic blood pressure was significantly higher among children from noisy residences and kindergartens, compared to children from both quiet environments (97.30 ± 8.15 and 92.33 ± 8.64 mmHg, respectively, P < 0.01). As a continuation of the study on preschool children, investigations were also carried out on 856 school children, aged between seven and eleven years, in Belgrade. It was found that systolic pressure was significantly higher among children from noisy schools and quiet residences, compared to children from both quiet environments (102.1 ± 9,3 and 100.4 ± 10.4 mmHg, respectively, P < 0.01).     

Life span and organ pathology in rats after life-long noise exposure

The role of ambient sound level in longevity, cause of death, and incidence of disease was investigated in rats. Two hundred twenty-seven rats (154 Sprague-Dawley (N), 73 spontaneously hypertensive Wistar (SH)), were housed in three sound isolated boxes and subjected to controlled acoustic milieus from approximately three months of age until their natural death. Thirty-nine of the N rats were kept as external controls in a regular animal room. In one of the boxes, no noise was introduced (control). In the other two, the rats were exposed, respectively, to a frequency-modulated, chopped noise with an equivalent level of 80 dB L_eq and 100 dB L_eq, ten hours daily. It was found that the SH animals had a shorter life span and a higher incidence of cardiovascular disease than the N rats but a lower rate of malignant tumors. No measurable effects on life span or total incidence of disease were seen. Minor differences in incidence of various disease entities were observed but were not consistent across groups. The results do not support the hypothesis that physical sound environment represents a significant cause of somatic disease.     

Road traffic noise around schools: a risk for pupil's performance?

Summary Noise levels around educational centres can negatively affect the performance of both teachers and pupils. Two public schools in Valencia, Spain, were selected for study. One of these schools was exposed to excessively high road traffic noise levels while the other was located in a relatively quiet area. The socioeconomic level of those attending the schools was very similar. A set of external and internal noise measurements were carried out, along with two different attention tests among the children. Test results were consistently better (both for tests and for children from different classrooms in each school) in the quiet school. Exposure to high traffic noise levels in the noisy school over the whole school year is a plausible determinant of these results.     

Effect of road traffic noise on sleep. A paired comparison between sleep polygraphic parameters recorded in a noisy apartment along a road with heavy traffic and those recorded in a quiet suburban house

Effects of road traffic noise on sleep were studied comparing 15 sleep polygraphic parameters and 6 subjective sleep complaints in a noisy apartment with those in a quiet house. Subjects were 8 persons (5 young men aged 19-38, one woman aged 65 and 2 men aged 66) and were studied for 76 nights. The average equivalent sound pressure level (Leq) from 10 p.m. to 7 a.m. was 46.67 dB (A) in the noisy apartment's bedroom compared to 27.72 dB(A) in the bedroom of the quiet house. Of the 15 parameters, proportion of REM sleep for the younger subjects was significantly less (p = 0.0046, paired t-test) in the apartment compared to the quiet house. No significant difference was seen in the remaining 14 parameters between the apartment and the house. Of the 6 subjective sleep complaints, "awakened early in the morning," was significantly less for young subjects (p = 0.031, Two-tailed sign test) in the apartment than in the house. There was no significant difference seen for the older subjects in the 6 subjective sleep complaints and 15 sleep polygraphic parameters between the two places. It appears that a small difference in the effect of road traffic noise on sleep between young and old may exist.     

Human performance capability in psychomotor tasks at variable difficulty levels and physiological reactions under noise and heat conditions.

The effects of noise and heat on the efficiency of human performance of psychomotor tasks at variable difficulty levels were investigated. Twenty four young, healthy volunteers with normal hearing, randomly divided into 4 equal sized groups, were tested in a climatic chamber under 4 combinations of two environmental conditions made up of noise and heat, each at two levels: 70 dB (A) (quiet), 100 dB (A) (noise): 28 degrees C (comfortable), 35 degrees C (heat). A statistically balanced procedure was followed. Three physiological variables were also recorded: Heart rate, blood pressure and body temperature. A 2 x 2 analysis of variance showed rise in the physiological variables by noise and heat respectively as well as by their interactions. Performances of the psychomotor tasks were affected differently by noise and heat depending on the difficulty levels of the tasks. The interaction of noise and heat entailed superior performance of the tasks of memory and search, two hand coordination and reaction time, at moderate difficulty levels, but no distinct interaction effect was observed on the performance of tweezer dexterity.     

Spatial Variation in Environmental Noise and Air Pollution in New York City

Exposure to environmental noise from traffic is common in urban areas and has been linked to increased risks of adverse health effects including cardiovascular disease. Because traffic sources also produce air pollutants that increase the risk of cardiovascular morbidity, associations between traffic exposures and health outcomes may involve confounding and/or synergisms between air pollution and noise. While prior studies have characterized intraurban spatial variation in air pollution in New York City (NYC), limited data exists on the levels and spatial variation in noise levels. We measured 1-week equivalent continuous sound pressure levels (L_eq) at 56 sites during the fall of 2012 across NYC locations with varying traffic intensity and building density that are routinely monitored for combustion-related air pollutants. We evaluated correlations among several noise metrics used to characterize noise exposures, including L_eq during different time periods (night, day, weekday, weekend), L_dn (day-night noise), and measures of intermittent noise defined as the ratio of peak levels to median and background levels. We also examined correlations between sound pressure levels and co-located simultaneous measures of nitric oxide (NO), nitrogen dioxide (NO₂), fine particulate matter (PM_2.5), and black carbon (BC) as well as estimates of traffic and building density around the monitoring sites. Noise levels varied widely across the 56 monitoring sites; 1-week L_eq varied by 21.6 dBA (range 59.1–80.7 dBA) with the highest levels observed during the weekday, daytime hours. Indices of average noise were well correlated with each other (r > 0.83), while indices of intermittent noise were not well correlated with average noise levels (r < 0.41). One-week L_eq correlated well with NO, NO₂, and EC levels (r = 0.61 to 0.68) and less so with PM_2.5 levels (r = 0.45). We observed associations between 1-week noise levels and traffic intensity within 100 m of the monitoring sites (r = 0.58). The high levels of noise observed in NYC often exceed recommended guidelines for outdoor and personal exposures, suggesting unhealthy levels in many locations. Associations between noise, traffic, and combustion air pollutants suggest the possibility for confounding and/or synergism in intraurban epidemiological studies of traffic-related health effects. The different spatial pattern of intermittent noise compared to average noise level may suggest different sources.     

50—65dB（A）白噪声对小学生认识能力影响的研究

In order to work out a hygienic standard for classroom-noise, 149 school children 8-9 yrs of age were put to psychological cognitive tests under the quiet [42 +/- 1dB(A)] and various white noise levels [50-65dB(A)] classroom conditions in 1986. The main results were as follows: Students under the three white noise levels [greater than or equal to 55dB(A)], all obtained significantly higher means of error scores along with the raising of the noise levels, also lower means of brain work-ability index than under the quiet classroom condition [42 +/- 1dB(A)]. The differences obtained between the three white noise levels [greater than or equal to 55dB(A)] groups and the control group were all statistically significant.     

Noise characterization of “effective quiet” areas on a U.S. Navy aircraft carrier

The purpose of this investigation was to characterize noise levels in spaces designated as “effective quiet” areas on a U.S. Navy aircraft carrier. Noise dosimetry samples were collected in 15 designated spaces, representing 15 noise measurements, while at-sea during airwing carrier qualifications. Equivalent sound level (L_eq) measurements were collected during flight operations (L_{eq (flt ops)}), non-flight operations (L_{eq (non-flt ops)}), and over 24-hr periods (L_{eq (24-hr)}). These data were compared to the 70 dBA American Conference of Governmental Industrial Hygienists (ACGIH^®) Threshold Limit Value (TLV^®) for “effective quiet” areas intended for temporary threshold shift recovery when personnel live and work in a potentially noise hazardous environment for periods greater than 24?hr. The monitored areas were selected based on personnel occupancy/use during off-duty time periods. Areas were classified by either (1) leisure areas that included mess (eating areas), gyms, lounges, an internet cafe, and the fantail social area or (2) berthing (sleeping) areas. The L_eq measurements in decibels “A” weighted (dBA) were compared to determine significant differences between L_{eq (flt ops)}, L_{eq (non-flt ops)}, and L_{eq (24-hr)} and were compared between leisure area and berthing area. Measured noise levels according to time period ranged as follows: (1) L_{eq (24-hr)}: 70.8–105.4 dBA; (2) L_{eq (flt ops)}: 70–101.2 dBA; and (3) L_{eq (non-flt ops)}: 39.4–104.6 dBA. All area measurements over the 24-hr period and during flight operations and 46.7% of the areas during the non-flight operation time period exceeded the “effective quiet” 70 dBA ACGIH TLV. Mean L_eqs were 15 dBA higher during flight operations compared to non-flight operations in “effective quiet” areas (p?=?0.001). The L_eqs in leisure areas were significantly higher than berthing areas by approximately 21 dBA during non-flight operation periods (p?=?0.001). Results suggest noise levels in “effective quiet” areas frequented by aircraft carrier personnel during off-duty hours when at-sea may inhibit auditory recovery from occupational noise exposures that occur on-duty.     

Hearing, communication and cognition in low-frequency noise from armoured vehicles

An experiment was performed to study auditory perception and cognitive function in the presence of low-frequency dominant armoured vehicle noise (LAV III). Thirty-six normal hearing subjects were assigned to one of three noise backgrounds: Quiet, pink noise and vehicle noise. The pink and vehicle noise were presented at 80 dBA. Each subject performed an auditory detection test, modified rhyme test (MRT) and cognitive test battery for three different ear conditions: Unoccluded and fitted with an active noise reduction (ANR) headset in passive and ANR modes. Auditory detection was measured at six 1/3 octave band frequencies from 0.25 to 8 kHz. The cognitive test battery consisted of two subjective questionnaires and five performance tasks. The earmuff, both in the conventional and ANR modes, did not significantly affect detection thresholds at any frequency in the pink and vehicle noise backgrounds. For the MRT, there were no significant differences between the speech levels required for 60% correct responses for three ear conditions in the pink and vehicle noise backgrounds. A small but significant (4 dB) increase in speech level was required in pink noise as compared to vehicle noise. For the serial reaction time task, the mean response time in the vehicle noise background (751 ms) was significantly higher than in pink noise and quiet (709 and 651 ms, respectively). The mean response time in the pink noise background was also significantly higher than in quiet. Thus, the presence of noise, especially low-frequency noise, had a negative effect on reaction time.     

The spatial relationship between traffic-generated air pollution and noise in 2 US cities

Traffic-generated air pollution and noise have both been linked to cardiovascular morbidity. Since traffic is a shared source, there is potential for correlated exposures that may lead to confounding in epidemiologic studies. As part of the Multi-Ethnic Study of Atherosclerosis and Air Pollution (MESA Air), 2-week NO and NO₂ concentrations were measured at up to 105 locations, selected primarily to characterize gradients near major roads, in each of 9 US communities. We measured 5-min A-weighted equivalent continuous sound pressure levels (L_eq) and ultrafine particle (UFP) counts at a subset of these NO/NO₂ monitoring locations in Chicago, IL (N=69 in December 2006; N=36 in April 2007) and Riverside County, CA (N=46 in April 2007). L_eq and UFP were measured during non-“rush hour” periods (10:00–16:00) to maximize comparability between measurements. We evaluated roadway proximity exposure surrogates in relation to the measured levels, estimated noise–air pollution correlation coefficients, and evaluated the impact of regional-scale pollution gradients, wind direction, and roadway proximity on the correlations. Five-minute L_eq measurements in December 2006 and April 2007 were highly correlated (r=0.84), and measurements made at different times of day were similar (coefficients of variation: 0.5–13%), indicating that 5-min measurements are representative of long-term L_eq. Binary and continuous roadway proximity metrics characterized L_eq as well or better than NO or NO₂. We found strong regional-scale gradients in NO and NO₂, particularly in Chicago, but only weak regional-scale gradients in L_eq and UFP. L_eq was most consistently correlated with NO, but the correlations were moderate (0.20–0.60). After removing the influence of regional-scale gradients the correlations generally increased (L_eq–NO: r=0.49–0.62), and correlations downwind of major roads (L_eq–NO: r=0.53–0.74) were consistently higher than those upwind (0.35–0.65). There was not a consistent effect of roadway proximity on the correlations. In conclusion, roadway proximity variables are not unique exposure surrogates in studies of endpoints hypothesized to be related to both air pollution and noise. Moderate correlations between traffic-generated air pollution and noise suggest the possibility of confounding, which might be minimized by considering regional pollution gradients and/or prevailing wind direction(s) in epidemiologic studies.     

Investigation of road-traffic noise and annoyance in Beijing: a cross-sectional study of 4th Ring Road

The authors aimed to evaluate traffic noise level and noise annoyance in Beijing and the impact of the noise on the quality of life of the residences. The authors performed a cross-sectional study in a 12-floor college dormitory near 4th Ring Road in Beijing, China. The north-side rooms of the building were noisy and had windows facing the road. The authors measured both indoor and outdoor noise. Using both a 5-item verbal scale and a 0-10 numerical scale, they questioned a sample of 1,293 college students living in the dormitory about road-traffic noise annoyance. The results showed that the average outdoor day-to-night noise level was 79.2 dB(A) in the noisy rooms and 64.0 dB(A) in the quiet rooms. Nearly 39% of the respondents living in the noisy rooms indicated that they were highly annoyed by traffic noise according to the response on the verbal scale, and 50% of the respondents living in the noisy rooms were highly annoyed according to the numerical scale.     

冷轧厂工人个体噪声暴露测量的初步分析

目的采用个体噪声暴露测量方法,了解冷轧厂工人噪声暴露的水平和特点,为防治轧钢工的噪声职业危害提供基础数据。方法以轧钢厂4个主要工艺中的11个工种为分组单位,每组抽取3～5人,用SH-126记录式个体声剂量计对白班（8：00至16：00）工人进行个体噪声暴露测量,同时填写工时记录,计算8h等效A声级。结果轧钢厂现场复杂,噪声源数量多、不稳定,工人同时受到多个噪声源的影响,个体噪声暴露声压级波动大。53名工人中个体噪声暴露最大值为100．0dB（A）。最小值为81．2dB（A）;噪声暴露水平最高的头部焊工为94．20dB（A）,最低的纵切剪切工为89．02dB（A）;质量枪验工组内极差最大,为16．3dB（A）;轧机主操作上极差最小,为2．3dB（A）。提示采取个体噪声暴露测量方法能比较准确、完整地反映冷轧厂作业工人的复杂噪声暴露情况。结论冷轧厂个体噪声暴露均超过85dB（A）,应加强噪声防护。个体噪声剂量计是以工人为主体,反映个体的噪声暴露情况和接触水平。     

Factors influencing subjective noise sensitivity in an urban population

This study was designed to define the individual variables influencing subjective noise sensitivity in an urban population and to investigate the distribution of subjective noise sensitivity with regard to noise exposure. A general questionnaire, a ten-graded noise annoyance scale, the Weinstein's Noise Sensitivity Scale, and the Eysenck Personality Questionnaire were applied to a sample of 413 inhabitants of Belgrade. Distribution of noise sensitivity scores was normal and independent of noise exposure. No significant differences in average noise sensitivity scores were observed concerning gender and exposure to low (Leq < 55 dBA), and high level of traffic noise (Leq > 65 dBA). Multiple regression analysis revealed that neuroticism was the best individual predictor for SNS, for both sexes in the noisy area and for women only, in the quiet area (P < 0.001). Age, education level and introversion were not significantly related to noise sensitivity. Positive relation between reported noise annoyance and noise sensitivity was highly significant (P < 0.0001).     

The benefit method: fitting hearing aids in noise

The most common complaint among individuals with hearing impairment is the inability to follow a conversation when several people are talking simultaneously, a noisy listening situation which is completely different from the quiet surrounding of the conventional pure tone audiometry used as basis for the hearing aid settings. The purpose of this report was to present important characteristics of the BeneFit Method (BFM), a procedure that fits the hearing aid under simulated conditions of competing speech and also a clinical pilot evaluation study comparing the BFM to the NAL-R recommendations and also to the Logic procedure, a GN resound proprietary fitting algorithm representing a modern digital hearing aid fitting procedure. Speech recognition scores in noise (SRSN) using monosyllabic words presented under different background noise levels were evaluated on 21 randomly selected subjects with hearing impairment. The subjects were fitted with the same type of hearing aid Danalogic 163D according to the BFM procedure as well as the logic procedure, the latter developed and recommended by the manufacturer. A comparison of the SRSN when using the subjects' current hearing aid fitted according to the NAL-R procedure was also made. Only the BFM procedure provided a significant SRSN improvement compared to the unaided condition (P< 0.01) in a signal/speech-noise level of 75/65 dB corresponding to a normal cocktail party condition. Moreover, patients performed significantly higher SRSN when fitted according to the BFM, than when fitted according the Logic or NAL-R procedures. The BFM procedure, which is based on individual and functional detection of hearing thresholds in noise levels corresponding to a cocktail party condition, can improve SRSN significantly. Hearing aids should be fitted under conditions similar to those when the hearing disability is perceived the most, i.e, in an environment with background noise.