Influence of transient pressure changes on speech intelligibility: Implications for nextgeneration train travel

High-speed trains are operated in increasingly complex railway networks and continual improvement of driver assistance systems is necessary to maintain safety. Speech offers the opportunity to provide information to the driver without disrupting visual attention. However, it is not known whether the transient pressure changes inside trains passing through tunnels interfere with speech intelligibility. Our primary goal was to test whether the most severe pressure variations occurring in high-speed trains (25 hPa in 2 s) affect speech intelligibility in individuals with normal hearing ability and secondly whether a potential effect would depend on the direction of the pressure change. A cross-over design was used to compare speech intelligibility, measured with the monosyllable word test by Wallenberg and Kollmeier, in steady ambient pressure versus subsequent to pressure events, both realised in a pressure chamber. Since data for a power calculation did not exist, we conducted a pilot study with 20 participants to estimate variance of intra-individual differences. The upper 80% confidence limit guided sample size of the main campaign, which was performed with 72 participants to identify a 10% difference while limiting alpha (5%) and beta error (10%). On average, a participant understood 0.7 fewer words following a pressure change event compared to listening in steady ambient pressure. However, this intra-individual differences varied strongly between participants, standard deviation (SD) +/- 4.5 words, resulting in a negligible effect size of 0.1 and the Wilcoxon signed rank test (Z = -1.26; p = 0.21) did not distinguish it from chance. When comparing decreasing and increasing pressure events an average of 0.2 fewer words were understood (+/- 3.9 SD). The most severe pressure changes expected to occur in high-speed trains passing through tunnels do not interfere with speech intelligibility and are in itself not a risk factor for loss of verbal information transmission

Interindividual variabilities in cognitive performance degradation after alcohol consuption and sleep loss are related

Introduction The sleep inducing effects of alcohol as well as the increase in sleep propensity and sleepiness after sleep loss have been linked to the adenosinergic system in the brain. While the performance impairing effects of ethanol have partly been related to the inhibitory effects of cerebral adenosine, sleep loss has been found to increase adenosine receptor density. The interindividual variability of cognitive performance impairments after alcohol intake as well as after sleep loss is extensive. Thus, we examined in humans whether performance degradations resulting from sleep loss and alcohol consumption are related. Methods Performance in a 10-min Psychomotor Vigilance Task (PVT) was tested in 47 healthy volunteers (mean age 27 ± 5 (SD) years, 21 females) at 6 pm 1) after an 8 hour control night, 2) after alcohol consumption (aiming at a blood alcohol concentration (BAC) of 0.08%), and 3) after 35 hours of total sleep deprivation. After alcohol intake, 35 of the participants reached a BAC of more than 0.06% prior to the performance testing (mean BAC 0.074%, SD 0.009%, min. 0.063%, max. 0.095%) and were included in the analyses. Two recovery nights were scheduled between conditions. Results Performance impairments due to acute alcohol intake and due to 35 hours of sustained wakefulness were calculated as differences from performance under control conditions. The degree in performance degradation correlated highly between both conditions (i.e. 10% slowest reaction times: Pearson’s r=0.73, p<0.0001; standard deviation of reaction times: r=0.75, p<0.0001; mean reaction time: r=0.59, p=0.0002). Conclusions Participants whose PVT performance proved to be vulnerable to the effects of alcohol consumption were also vulnerable to sleep loss, whereas individuals who were resilient against the effects of alcohol were also less susceptible to the impact of sleep deprivation. These results suggest that the effects of alcohol and sleep deprivation on performance are mediated – at least in part – by a common pathway that may involve the adenosinergic system in the brain

Residents’ negative attitude towards air traffic is associated with impaired objective sleep quality

Objectives: Nocturnal aircraft noise induces sleep disturbances and is associated with impaired quality of life. The magnitude of physiological and psychological responses to noise varies among individuals. Stable individual vulnerabilities have been reported for aircraft noise induced awakenings. To date it is unknown, whether the subjective attitude towards air traffic and residents' sleep quality impact on each other. Methods: Seventy-four out of 81 investigated residents around Frankfurt Airport (Germany) rated their attitude towards air traffic (from 1 = negative to 5 = positive; negative attitude: score ≤ 2, N=28, mean age 44 ± 16 years; moderate to positive attitude: score > 3, N=46, mean age 44 ± 15 years) and evaluated its necessity (from 1 = not necessary to 5 = highly necessary; no to moderate necessity: score ≤ 3, N=22, mean age 45 ± 10 years; high necessity: score > 3, N=52, mean age 43 ± 17 years). In addition, polysomnographical recordings were obtained in residents' home environment. These investigations were part of the NORAH sleep study in 2012. Results: Significant impairments in sleep quality (prolonged sleep onset latency, increased wake after sleep onset, reduced sleep efficiency, and less deep sleep) were found for participants with a negative attitude towards air traffic. The judgement of no or moderate necessity of air traffic was associated with a significantly reduced deep sleep duration. Conclusions: Residents' subjective attitude towards air traffic and their objective sleep quality are related. Cause and effect in this relationship remain to be identified

Impact Of Sleep Restriction And Recovery On Motivation During Repeated Cognitive Performance Testing

Introduction: Both motivation and sleep deprivation affect cognitive performance. Especially during long-lasting studies with repeated cognitive performance tasks there is concern that subjects will lose motivation over time. Results may be confounded due to changes in motivation. Methods: In an ongoing study, 29 healthy volunteers performed 55 cognitive performance tasks at three-hourly intervals in a 12-day inpatient study. After two baseline nights with 8 h time in bed (TIB) the intervention group (N=20; mean age 26 ± 4 years, 9 females) underwent chronic sleep restriction for 5 nights (5 h TIB) with a following recovery night of 8 h TIB. The control group (N=9; mean age 25 ± 5 years, 3 females) had the opportunity to sleep 8 hours every night. Participants completed the Karolinska Sleepiness Scale (KSS) and a questionnaire about their motivation (from 1=very little/not motivated to 5=very motivated) at 6 p.m. on all days. Results: Wilcoxon signed-rank tests showed a significant decrease in motivation (p=.0439) and a significant increase in subjective sleepiness (p=.0184) from baseline (motivation: 2.8 ± 0.6 (SD), sleepiness: 3.2 ± 1.2) to the last day of chronic sleep restriction (motivation: 2.2 ± 0.5, sleepiness: 5.1 ± 1.8) for the experimental group. Motivation remained low after recovery sleep (2.2 ± 0.8; p=.0198). Sleepiness and motivation scores showed a significant Spearman correlation (r=-0.43, p<0.001). Discussion: Chronic sleep restriction for five days leads to an increase in sleepiness and a decrease in motivation. One night of recovery is insufficient to reverse the motivation loss, contrasting with the beneficial effect on sleepiness. During chronic sleep restriction conditions subjective motivation seems to decrease as a function of subjective sleepiness

Effects of Nocturnal Aircraft Noise and Non-Acoustical Factors on Short-Term Annoyance in Primary School Children

Children are considered at higher risk for harmful noise effects due to their sensitive development phase. Here, we investigated the effects of nocturnal aircraft noise exposure on short-term annoyance assessed in the morning in 51 primary school children (8–10 years) living in the surrounding community of Cologne-Bonn Airport. Child-appropriate short-term annoyance assessments and associated non-acoustical variables were surveyed. Nocturnal aircraft noise exposure was recorded inside the children’s bedrooms. Exposure–response models were calculated by using random effects logistic regression models. The present data were compared with those from a previous study near Cologne-Bonn Airport in adults using very similar methodology. Short-term annoyance reaction in children was not affected by the nocturnal aircraft noise exposure. Non-acoustical factors (e.g., the attitude that “aircraft are dangerous” or noise sensitivity), however, significantly impacted on children’s short-term annoyance. In contrast to children, the probability of moderate to high annoyance in adults increased with the number of aircraft flyovers during the time in bed. It is concluded that short-term annoyance from nocturnal aircraft noise in children is mainly determined by non-acoustical factors. Unlike in adults, acoustical factors did not play a significant role

Coffee Effectively Attenuates Impaired Attention in ADORA2A C/C-Allele Carriers During Chronic Sleep Restriction

Many people consume coffee to attenuate increased sleepiness and impaired vigilance and attention due to insufficient sleep. We investigated in genetically caffeine sensitive individuals whether 'real world' coffee consumption during a simulated busy work week counteracts disabling consequences of chronically restricted sleep. We subjected homozygous C-allele carriers of ADORA2A (gene encoding adenosine A2A receptors) to 5 nights of only 5 h time-in-bed. We administered regular coffee (n = 12; 200 mg caffeine at breakfast and 100 mg caffeine after lunch) and decaffeinated coffee (n = 14) in double-blind fashion on all days following sleep restriction. At regular intervals 4 times each day, participants rated their sleepiness and performed the psychomotor vigilance test, the visual search task, and the visuo-spatial and letter n-back tasks. At bedtime, we quantified caffeine and the major caffeine metabolites paraxanthine, theobromine and theophylline in saliva. The 2 groups did not differ in age, body-mass-index, sex-ratio, chronotype and mood states. Subjective sleepiness increased in both groups across consecutive sleep restriction days and did not differ. By contrast, regular coffee counteracted the impact of repeated sleep loss on sustained and selective attention, as well as executive control when compared to decaffeinated coffee. The coffee induced benefits on different aspects of performance lasted for 4-5 days of insufficient sleep. All differences between the groups disappeared after the recovery night and the cessation of coffee administration. The data suggest that 'real world' coffee consumption can efficiently attenuate sleep restriction-induced impairments in vigilance and attention in genetically caffeine sensitive individuals. German Clinical Trial Registry: # DRSK00014379

Short-Term Annoyance Due to Night-Time Road, Railway, and Air Traffic Noise: Role of the Noise Source, the Acoustical Metric, and Non-Acoustical Factors

Field studies on traffic noise-induced annoyance have predominantly used estimated outside noise levels. We intended to complement existing knowledge with exposure–response relationships that are based on precise indoor noise measurements. Acoustic recordings inside the bedrooms of nightly road traffic and annoyance ratings in the following morning were obtained from 40 suburban residents (mean age 29.1 years ± 11.7; 26 females). We derived exposure–response functions for the probability to be “annoyed at least a little” (%LA). Further analyses compared data from the current study with those from two earlier studies on railway and aircraft noise. Annoyance increased with the number of traffic events and the equivalent sound pressure level. The inclusion of non-acoustical factors (such as assessment of road transport) improved the prediction considerably. When comparing the different traffic noise sources, %LA was higher for road than for air traffic at a given LAeq,night, but higher for road and railway than for air traffic at a given number of noise events. Acoustical as well as non-acoustical factors impact short-term annoyance induced by road, railway, and air traffic. Annoyance varies across noise sources, which may be due to differences in acoustical characteristics or in the temporal noise distribution throughout the night