The Effect of Road Traffic Noise on Reaction Time.

BACKGROUND: Traffic noise is one of the main important sources in urban noise pollution, which causes various physiological and psychological effects that can cause disturbs in performance, sleep disturbances, hearing loss and impact on job performance. This study was conducted to verify the impact of road traffic noise on reaction time in terms of extraversion and sex. METHODS: Traffic noise was measured and recorded in 10 arterial streets in Tehran, and then the recorded noise was emitted towards participants in an acoustic room. The participants were 80 (40 cases and 40 controls) students. Personality type was determined by Eysenck Personality Inventory (EPI) questioner. Reaction time before and after exposure to traffic noise was measured. RESULTS: Reaction time before exposure to traffic noise did not differ (P=0.437) significantly between introverts and extraverts. However, it was increased significantly in both groups after exposure to traffic noise (P<0.01). Introvert's reaction time was more increased than that of extraverts. CONCLUSION: Traffic noise augmented reaction time of both males and females. This study also revealed that exposure to traffic noise leads to increase in reaction time.

The effects of road traffic noise on mental performance.

BACKGROUND: Noise is one of the more widespread pollutions of road transportation system, which can cause deterioration in performance. This experimental study was designed to assess the effect of road traffic noise on performance with regard to extra/introversion and sex of participants. The personality trait of extra/introversion has been remarked as relevant factor to mental performance. RESULTS: Thirty six (26 males and 10 females) medical sciences students of Tehran University participated in the study. The students were placed in an unechoing room and performed the Cognitrone test from Vienna Test System in quiet condition and under road traffic noise (71 dBA). The results of this study pointed out that noise increased the percentage of sum of correct answers but had no effect on the speed of performance. Furthermore this study showed that performance was enhanced in extroverts (P=0.001) but no significant difference was found in introverts (P ≤0.05). CONCLUSIONS: The regression analysis revealed that extra/introversion was more important than sex to predict the performance parameters.

The effects of low frequency noise on mental performance and annoyance.

Low frequency noise (LFN) as background noise in urban and work environments is emitted from many artificial sources such as road vehicles, aircraft, and air movement machinery including wind turbines, compressors, and ventilation or air conditioning units. In addition to objective effects, LFN could also cause noise annoyance and influence mental performance; however, there are no homogenous findings regarding this issue. The purpose of this research was to study the effects of LFN on mental performance and annoyance, as well as to consider the role of extraversion and neuroticism on the issue. This study was conducted on 90 students of Iran University of Medical Sciences (54 males and 36 females). The mean age of the students was 23.46 years (SD = 1.97). Personality traits and noise annoyance were measured by using Eysenck Personality Inventory and a 12-scale self-reported questionnaire, respectively. Stroop and Cognitrone computerized tests measured mental performance of participants each exposed to 50 and 70 dBA of LFN and silence. LFNs were produced by Cool Edit Pro 2.1 software. There was no significant difference between mental performance parameters under 50 and 70 dBA of LFN, whereas there were significant differences between most mental performance parameters in quiet and under LFN (50 and 70 dBA). This research showed that LFN, compared to silence, increased the accuracy and the test performance speed (p < 0.01). There was no association between LFN and noise annoyance (p > 0.01). Introverts conducted the tests faster than extraverts (p < 0.05). This research showed that neuroticism does not influence mental performance. It seems that LFN has increased arousal level of participants, and extraversion has a considerable impact on mental performance.

Do intensity ratings and skin conductance responses reliably discriminate between different stimulus intensities in experimentally induced pain?

UNLABELLED: The present study addresses the question whether pain-intensity ratings and skin conductance responses (SCRs) are able to detect different intensities of phasic painful stimuli and to determine the reliability of this discrimination. For this purpose, 42 healthy participants of both genders were assigned to either electrical, mechanical, or laser heat-pain stimulation (each n = 14). A whole range of single brief painful stimuli were delivered on the right volar forearm of the dominant hand in a randomized order. Pain-intensity ratings and SCRs were analyzed. Using generalizability theory, individual and gender differences were the main contributors to the variability of both intensity ratings and SCRs. Most importantly, we showed that pain-intensity ratings are a reliable measure for the discrimination of different pain stimulus intensities in the applied modalities. The reliability of SCR was adequate when mechanical and heat stimuli were tested but failed for the discrimination of electrical stimuli. Further studies are needed to reveal the reason for this lack of accuracy for SCRs when applying electrical pain stimuli. PERSPECTIVE: Our study could help researchers to better understand the relationship between pain and activation of the sympathetic nervous system. Pain researchers are furthermore encouraged to consider individual and gender differences when measuring pain intensity and the concomitant SCRs in experimental settings.

Mental strain and annoyance during cognitive performance in different traffic noise conditions.

In built-up areas, an increasing number of persons are affected by road traffic noise while performing mental work. This experimental study focused on annoyance and mental strain due to various noise scenarios. A total of 102 healthy, young persons (51 women, 51 men, aged 18-31 years) were randomly assigned to one of five experimental conditions determined by traffic flow (even, lumped) and traffic composition (20%, 40% heavy vehicles). While exposed to noise they performed a grammatical reasoning and a mathematical processing task. Performance and mental strain were not affected by any of the five noisy conditions. Individuals with high noise sensitivity were partially more annoyed and performed less than persons with low sensitivity. STATEMENT OF RELEVANCE: The present study provides information about mental strain due to tasks with different cognitive demands and the role of noise sensitivity in various traffic noise conditions. The results show that measures aiming at the reduction of the proportion of heavy vehicles should additionally consider particular traffic flow.

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.

Factorial validity of the noise sensitivity questionnaire.

The Noise Sensitivity Questionnaire (NoiSeQ) aims at the measurement of global noise sensitivity as well as the sensitivity for five domains of everyday life namely 'Leisure', 'Work', 'Habitation', 'Communication' and 'Sleep'. The present investigation examined the factorial validity of the NoiSeQ to determine whether the items of the NoiSeQ cover the different factors as assumed. The analysis was done using the method of Confirmatory Factor Analysis (CFA). The linear structural model took into consideration only the scales of the NoiSeQ for which reliability could be demonstrated, namely, 'Sleep', 'Communication', 'Habitation' and 'Work'. The linear structural model presumed that each of the 28 items has a relation only to one corresponding factor. Furthermore, the model allowed for correlations between the four factors. The data base encompassed 293 persons. Parameter estimation was based on the General Least Square method. The data was checked with respect to the occurrence of multivariate outliers, deviation from multivariate normality and existing collinearities. The data met the overall requirements of a CFA. The evaluation of model fit was based on the relative chi2 -value, the Root Mean Square Error of Approximation, the Goodness of Fit Index, the Adjusted Goodness of Fit Index and the Root Mean Square Residual. All fit indices indicated an acceptable match of the model. As the postulated structure of the NoiSeQ was consistent with the empirical data, the classification of the items as well as the claimed interdependencies between the scales can be maintained. The regression weights of all items as well as the correlations between the latent variables were statistically significant. The estimated reliability of the latent variables took values of >/=0.84. The findings generally justified the conclusion that there is no urgent need to modify the four scales of the NoiSeQ thus, indicating the factorial validity of the NoiSeQ.

The reliability of the noise sensitivity questionnaire in a cross-national analysis.

Noise sensitivity is regarded as a relevant predictor for annoyance reactions. Since many studies have focused on noise sensitivity at an international level, the present analysis was conducted to detect national peculiarities concerning noise sensitivity. Using the approach of the generalizability theory, reliability of the noise sensitivity questionnaire was analyzed taking into consideration relevant facets assumed to contribute to the measurement error. A total of 126 individuals from seven European countries participated in this study. The reliability coefficients for the global noise sensitivity score ranged from 0.90 to 0.91. It was determined that the translated questionnaires are comparable.