Associations between heat wave during pregnancy and term birth weight outcomes: The PARIS birth cohort.

BACKGROUND: Climate change will make extreme weather events more frequent in the 21st century. Extreme ambient temperatures during the prenatal period have been associated with adverse pregnancy outcomes such as preterm birth. It is unclear, however, whether heat waves during pregnancy impact fetal growth in apparently healthy term newborns. OBJECTIVES: We aimed to investigate associations between heat wave during pregnancy and birth weight outcomes in term newborns from the PARIS birth cohort, and to explore meteorological conditions and air pollution as possible intermediate factors. METHODS: We examined data on 3,359 newborns born between 37 and 42 weeks in Paris, France, between 2003 and 2006. Associations of maternal exposure to heat wave (during whole pregnancy and each trimester) with birth weight and small for gestational age (SGA) at term were studied using linear and logistic regression models adjusted for potential confounders. Maternal characteristics were investigated as possible modifiers. We explored the mediating role of ambient temperature, relative humidity, and air pollution levels in the relationship between heat wave during the first trimester and term SGA. RESULTS: Mothers who were pregnant during the 2003 French heat wave (n = 506, 15 %) were more likely to have a term SGA baby (aOR = 2.70; 95 %CI: 1.38, 5.28) compared to mothers who did not experience heat wave during pregnancy. The association was stronger when heat wave occurred during the first trimester (aOR = 4.18; 95 %CI: 1.69, 10.35). Primiparous women were identified as more vulnerable than multiparous women. Average ambient temperature and air quality index explained about 36 % and 56 % of the association between heat wave during the first trimester and term SGA, respectively. CONCLUSIONS: This study suggests prenatal exposure to heat wave, especially during the first trimester, may adversely affect fetal growth of term newborns, which could be explained by both increasing ambient temperatures and worsening air quality.

Morphometry and localization of the temporal transverse Heschl's gyrus in magnetic resonance imaging: a guide for cortical stimulation of chronic tinnitus.

PURPOSE: Subjective tinnitus is considered a phantom auditory phenomenon. Recent studies show that electrical or magnetic stimulation of the cortex can alleviate some tinnitus. The usual target of the stimulation is the primary auditory cortex (PAC) on Heschl's gyrus (HG). The objective of this study was to specify the anatomy of HG by magnetic resonance imaging (MRI). METHODS: Cerebral MRI of 60 patients with chronic tinnitus, carried out before neuronavigated repetitive transcranial magnetic stimulation targeting the auditory cortex, were included. 3D-T1 MRI was reformatted in Talairach-Tournoux's stereotactic space, then the following steps were performed: morphometry of HG, localization of the probabilistic center of the PAC (pcPAC) chosen at the junction between the medial third and the lateral two-thirds of HG, relative to external and cortical landmarks, and identification of its coordinates relative to the bicommissural line (AC-PC). RESULTS: In relation to external landmarks, the pcPAC was identified around 5 cm above the root of the helix of the ear in the direction of a point on the vertex located 4 cm behind the coronal suture, for both sides. In Talairach-Tournoux's stereotactic space with the anterior commissure as the origin, the pcPAC coordinates were x = 43, y = -20, z = 6.8 on the right side, and x = -42.5, y = -21.5, and z = 6.5 on the left. Probabilistic maps of the presence of HG pointed to a relative contraction of data in space, despite inter- and intraindividual differences. CONCLUSION: The choice of our stimulation target was established in the middle of the theoretical position of the PAC. MRI allows a reliable identification of the target structure.

Using prism adaptation to alleviate perception of unilateral tinnitus: A case study.

Tinnitus is described as an uncomfortable sound or noise heard by an individual in the absence of an external sound source. Treating this phantom perception remains difficult even if drug and nondrug therapies are used to alleviate symptoms. The present case study aimed to investigate whether prism adaptation could induce beneficial aftereffects in a tinnitus sufferer. A 75-year-old man, R. B., with chronic unilateral tinnitus in the left ear reported a self-estimation of parameters of his tinnitus-discomfort, pitch and loudness-and performed a manual line-bisection task to study the consequences of lateralized auditory disorder on spatial representation. Aftereffects of prism adaptation were assessed using a sensorimotor open-loop pointing task. In parallel, a control group completed the line-bisection task and the open-loop pointing task before and after lens exposure, under the same experimental condition as those of R. B. Throughout the pretests, the patient assessed his tinnitus at a constant medium pitch (around 3000 Hz), and he was biased toward the affected ear in both the sensorimotor task and the estimation of the subjective center in the manual line-bisection task. Although both optical deviations were effective, an exposure to prism adaptation to a rightward optical deviation (i.e., toward the unaffected ear) produced stronger aftereffects. In posttests, the tinnitus pitch decreased to 50 Hz and the subjective center was shifted toward the right side (i.e., unaffected ear side). Furthermore, the line-bisection task seemed to reflect the changes in the tinnitus perception, and spatial representation could be a new tool to assess tinnitus indirectly. Our findings suggest that prism adaptation may have benefits on unilateral tinnitus and open a new avenue for its treatment.

Traffic-related Air Pollution, Lung Function, and Host Vulnerability. New Insights from the PARIS Birth Cohort.

RATIONALE: Although the effects of traffic-related air pollution on respiratory exacerbations have been well documented, its impact on lung function in childhood remains unclear. OBJECTIVES: Our aim was to investigate the associations of prenatal, early, and lifetime traffic-related air pollution exposure with lung function at 8-9 years studying possible effect modification by sex, sensitization at 8-9 years, and early lower respiratory tract infections. METHODS: We conducted this study among 788 children from the PARIS (Pollution and Asthma Risk: an Infant Study) birth cohort. Lung function tests were performed during the medical examination at 8-9 years. Traffic-related air pollution exposure during each trimester of pregnancy was estimated using nitrogen oxides background measurements. Postnatal traffic-related air pollution exposure was assessed by a nitrogen oxides air dispersion model at both residential and daycare/school addresses. Associations between lung function and traffic-related air pollution exposure were analyzed by multiple linear regression models. RESULTS: Higher prenatal nitrogen oxides levels, especially during the second trimester of pregnancy, were associated with a lower forced expiratory flow at 25-75% of the forced vital capacity, but there were no significant associations between prenatal nitrogen oxide levels and forced vital capacity, forced expiratory volume during 1 second, or the forced expiratory volume during 1 second/forced vital capacity ratio overall. Postnatal traffic-related air pollution exposure was associated with lower lung function among children with early lower respiratory tract infections or sensitization at 8-9 years, but not in the full cohort. In children with early repeated lower respiratory tract infections, an interquartile increase in lifetime nitrogen oxides exposure was associated with both a lower forced expiratory volume during 1 second (-62.6 ml; 95% confidence interval = -107.0 to -18.1) and forced vital capacity (-55.7 ml; 95% confidence interval = -109.5 to -1.8), but was not associated with the forced expiratory volume during 1 second/forced vital capacity ratio. There was an association between greater early postnatal nitrogen oxide exposure and a lower forced expiratory volume during 1 second/forced vital capacity ratio among sensitized children (-0.65%; 95% confidence interval = -1.25 to -0.05). CONCLUSIONS: This study sheds new light, suggesting associations between postnatal traffic-related air pollution exposure and reduced lung function may be enhanced by early, repeated lower respiratory tract infections or allergic sensitization.

[Alzheimer's disease, hearing impairment and hearing-aids: a review]. / Maladie d'Alzheimer, troubles de l'audition et appareillage auditif: une revue des données actuelles.

Alzheimer's disease has major social and family consequences. However, therapeutic strategies are still limited. Non-pharmacological therapeutic approaches are known to be useful to protect the intellectual abilities of the patients, or at least, to slow down their decline. Therefore, it is important to pay attention to the consequences of sensory impairment in these old patients. Indeed, sensory troubles, mainly concerning hearing, may have an impact on the cognitive and behavioral symptoms. Several studies showed that the management of hearing impairment could afford cognitive and behavioral benefits in demented subjects as well as for the non-demented people. These results are encouraging, and suggest that hearing management should be applied to all hearing impaired patients with Alzheimer's disease.

Do Hearing Aids Influence Behavioral and Psychological Symptoms of Dementia and Quality of Life in Hearing Impaired Alzheimer's Disease Patients and Their Caregivers?

BACKGROUND: It has been suggested that age-related hearing loss (ARHL) and Alzheimer's disease (AD) are commonly associated. OBJECTIVE: The Alzheimer Disease, Presbycusis and Hearing Aids (ADPHA) clinical trial assessed the influence of hearing aids (HAs) on patients affected by ARHL and AD, as judged by behavioral symptoms and functional abilities, as well as patient and caregiver quality of life (QoL). METHODS: A multicenter double-blind randomized placebo-controlled trial, with a semi-crossover procedure over 12 months, was conducted from 2006 to 2012. For the first 6 months, the active group was treated with active HAs and the placebo group with inactive HAs. For the last 6 months, HAs in the placebo group were activated. Assessment was conducted at baseline, 6 months, and 12 months. We performed intergroup and intragroup comparisons. Behavioral symptoms were assessed by neuropsychiatric inventory (NPI), functional abilities by instrumental activities of daily living, and QoL by Zarit, Alzheimer's disease related quality of life, and simplified Duke scales. RESULTS: Fifty-one patients were included and randomized: 22 in active group (mean NPI 17.6; mean age 83±6.2) and 26 in placebo group (mean NPI 25.8; mean age 82.3±7.2) were fitted with HAs. At 6-month follow-up, all scores worsened without significant difference between the two groups. In placebo group, activation of HAs had no effect on the change of these scores. CONCLUSION: These findings do not provide evidence of improvement in behavioral symptoms, functional status, or QoL of hearing impaired AD patients and their caregivers after 6 months of HA use. However, we cannot exclude that HAs may have a positive effect in patients aged less than 75 years.

Efficacy of Hearing Aids on the Cognitive Status of Patients with Alzheimer's Disease and Hearing Loss: A Multicenter Controlled Randomized Trial.

BACKGROUND/OBJECTIVE: This study evaluated the cognitive benefit of hearing aids (HA) in older patients with Alzheimer's disease (AD) and hearing loss (HL) after a 6- and 12-month period of utilization. METHODS: A multicenter double-blind randomized placebo-controlled trial was conducted in patients aged more than 65 years. A group was equipped with active HA for 6 months (active group) and a second group had placebo HA for 6 months (placebo group) followed by a secondary activation phase for a further 6 months (semi crossover procedure). Both groups were retested after a 12-month period. The primary endpoint was the change from baseline of the Alzheimer's Disease Assessment Scale-Cognitive subscale (ADAS Cog) after a 6-month period in both groups and after 6 months of secondary HA activation in the placebo group. A smaller cognitive decline should be obtained with HA use; an increase in ADAS Cog score of less than 6 points was defined a success. RESULTS: Fifty-one patients aged 68 to 99 years were included; 38 attended the 6-month visit: 18 in the active group and 20 in the placebo group. At 6 months, 14 (82.4%) successes were noticed in the active group, and 15 (88.2%) in the placebo group (p = 1.0); delta ADAS Cog in the active group was 1.8±5.3 and 1.3±5.3 in the placebo group (p = 0.8). In the placebo group, after the secondary HA activation, no significant improvement was observed. CONCLUSION: No significant effect of HA use was observed after 6 months of follow-up in patients with AD and HL.

Influence of musical and psychoacoustical training on pitch discrimination.

This study compared the influence of musical and psychoacoustical training on auditory pitch discrimination abilities. In a first experiment, pitch discrimination thresholds for pure and complex tones were measured in 30 classical musicians and 30 non-musicians, none of whom had prior psychoacoustical training. The non-musicians' mean thresholds were more than six times larger than those of the classical musicians initially, and still about four times larger after 2h of training using an adaptive two-interval forced-choice procedure; this difference is two to three times larger than suggested by previous studies. The musicians' thresholds were close to those measured in earlier psychoacoustical studies using highly trained listeners, and showed little improvement with training; this suggests that classical musical training can lead to optimal or nearly optimal pitch discrimination performance. A second experiment was performed to determine how much additional training was required for the non-musicians to obtain thresholds as low as those of the classical musicians from experiment 1. Eight new non-musicians with no prior training practiced the frequency discrimination task for a total of 14 h. It took between 4 and 8h of training for their thresholds to become as small as those measured in the classical musicians from experiment 1. These findings supplement and qualify earlier data in the literature regarding the respective influence of musical and psychoacoustical training on pitch discrimination performance.

Function and plasticity of the medial olivocochlear system in musicians: a review.

The outer hair cells of the organ of Corti are the target of abundant efferent projections from the olivocochlear system. This peripheral efferent auditory subsystem is currently thought to be modulated by central activity via corticofugal descending auditory system, and to modulate active cochlear micromechanics. Although the function of this efferent subsystem remains unclear, physiological, psychophysical, and modeling data suggest that it may be involved in ear protection against noise damage and auditory perception, especially in the presence of background noise. Moreover, there is mounting evidence that its activity is modulated by auditory and visual attention. A commonly used approach to measure olivocochlear activity noninvasively in humans relies on the suppression of otoacoustic emissions by contralateral noise. Previous studies have found substantial interindividual variability in this effect, and statistical differences have been observed between professional musicians and non-musicians, with stronger bilateral suppression effects in the former. In this paper, we review these studies and discuss various possible interpretations for these findings, including experience-dependent neuroplasticity. We ask whether differences in olivocochlear function between musicians and non-musicians reflect differences in peripheral auditory function or in more central factors, such as top-down attentional modulation.

Speech processing: from peripheral to hemispheric asymmetry of the auditory system.

Language processing from the cochlea to auditory association cortices shows side-dependent specificities with an apparent left hemispheric dominance. The aim of this article was to propose to nonspeech specialists a didactic review of two complementary theories about hemispheric asymmetry in speech processing. Starting from anatomico-physiological and clinical observations of auditory asymmetry and interhemispheric connections, this review then exposes behavioral (dichotic listening paradigm) as well as functional (functional magnetic resonance imaging and positron emission tomography) experiments that assessed hemispheric specialization for speech processing. Even though speech at an early phonological level is regarded as being processed bilaterally, a left-hemispheric dominance exists for higher-level processing. This asymmetry may arise from a segregation of the speech signal, broken apart within nonprimary auditory areas in two distinct temporal integration windows--a fast one on the left and a slower one on the right--modeled through the asymmetric sampling in time theory or a spectro-temporal trade-off, with a higher temporal resolution in the left hemisphere and a higher spectral resolution in the right hemisphere, modeled through the spectral/temporal resolution trade-off theory. Both theories deal with the concept that lower-order tuning principles for acoustic signal might drive higher-order organization for speech processing. However, the precise nature, mechanisms, and origin of speech processing asymmetry are still being debated. Finally, an example of hemispheric asymmetry alteration, which has direct clinical implications, is given through the case of auditory aging that mixes peripheral disorder and modifications of central processing.

Repetitive transcranial magnetic stimulation: hearing safety considerations.

BACKGROUND: The guidelines for use of repetitive transcranial magnetic stimulation (rTMS) advise frequent updating of rTMS safety guidelines and recommendations. Although rTMS can produce sound of more than 120 dB C, which is sufficient to induce hearing loss, the effect of rTMS noise on the hearing of both patients and rTMS practitioners is understudied. OBJECTIVE: This study investigated the effects of rTMS noise on subjects' hearing using otoacoustic emissions evoked by clicks (transiently evoked otoacoustic emissions, TEOAEs), which is an objective and sensitive method of cochlear exploration. METHODS: Hearing thresholds and TEOAEs were recorded in 24 normal-hearing healthy subjects before and after a real or sham rTMS session (a single 20-minute session applied to the superior temporal gyrus with 1200 pulses at 100% of the individual motor threshold). RESULTS: No significant difference in hearing thresholds was observed between subjects exposed to real or sham rTMS. However, the difference in TEOAE amplitude between pre- and post-rTMS sessions increased significantly with rTMS noise for those subjects the least protected by earplugs, showing a post-rTMS slight decrease of TEOAE amplitude for high rTMS intensities and hence minor hearing function alteration. However, this correlation was no longer found 1 hour after the rTMS session. CONCLUSIONS: These findings suggest that, even when rTMS is used within normal safety limits and with good hearing protection, rTMS noise can transiently disturb hearing mechanisms in normal-hearing healthy subjects. This transient effect of rTMS on hearing may be an important consideration for Institutional Review Boards when rTMS is used at higher stimulation intensities.

Repetitive transcranial magnetic stimulation noise levels: methodological implications for tinnitus treatment.

OBJECTIVE: To measure noise levels generated by repetitive transcranial magnetic stimulation. INTERVENTION: Repetitive transcranial magnetic stimulation (rTMS). MAIN OUTCOME MEASURES: rTMS noise levels measured in equivalent continuous sound level (LAeq) and in peak level (LC, peak), as a function of maximum power output of the equipment. METHODS: rTMS noise levels were measured for an active and a corresponding sham coil, as a function of distance and percentage power output of a MagPro X100 system (Medtronic) and compared with occupational noise exposure standards, using parameters classically used for rTMS tinnitus treatment. RESULTS: Significant differences in frequency composition and intensity levels were observed between sham and active coil noises. The active coil noise reached, at 50% power, 96 LAeq (peak at 132 LC, peak), varying by 3.9 LAeq (3.9 LC, peak) per 10% of power increase, whereas the sham coil reached 87 LAeq (114 LC, peak), varying by 3.2 LAeq (3.6 LC, peak) per 10% of power increase. CONCLUSION: rTMS noise levels differ significantly between active and sham coils, and can go beyond the American and European legal occupational noise limits, hence making ear protection a specific issue, particularly relevant to rTMS treatment for tinnitus.

Otologics middle ear transducer with contralateral conventional hearing aid in severe sensorineural hearing loss: evolution during the first 24 months.

OBJECTIVES: To report the audiometric outcomes of patients with severe sensorineural hearing loss and who have been fitted with a Middle Ear Transducer (MET) on one side and fitted with an optimized conventional hearing aid on the other side. STUDY DESIGN: The MET fitting results were measured and compared with contralateral conventional hearing aids in a prospective study. SETTING: Tertiary referral center. PATIENTS: Seven patients (ages, 53-77 yr) with severe sensorineural hearing loss (pure-tone average, 71-90 dB HL) were implanted between December 2004 and March 2006. METHOD: Audiometric testing was performed the day of activation (2 mo postoperative) and after 8 days and 1, 3, 6, 9, 12, and 24 months. For each follow-up, MET and conventional hearing aid were optimized according to the patient's hearing loss. RESULTS: Mean functional gains were 29 dB for conventional hearing aid and 35 dB the first day of the study with the MET and 39 dB after 6 months. DISCUSSION: The performance of the MET and the absence of occlusion of the external auditory canal could explain the improved benefit. For maximum gain, the MET requires a regular follow-up during the first 6 months. CONCLUSION: MET seems to be a suitable and successful treatment option resulting in significant improvement in speech comprehension, especially after 6 months, in patients with severe sensorineural hearing loss. During the 24-month follow-up of this study, the MET has been a safe and effective treatment for severe hearing loss.

Evidence for corticofugal modulation of peripheral auditory activity in humans.

Active cochlear micromechanisms, involved in auditory sensitivity, are modulated by the medial olivocochlear efferent system, which projects directly onto the organ of Corti. Both processes can be assessed non-invasively by means of evoked otoacoustic emissions. Animal experiments have revealed top-down control from the auditory cortex to peripheral auditory receptor, supported by anatomical descriptions of descending auditory pathways from auditory areas to the medial olivocochlear efferent system and organ of Corti. Through recording of evoked otoacoustic emissions during presurgical functional brain mapping for refractory epilepsy, we showed that corticofugal modulation of peripheral auditory activity also exists in humans. In 10 epileptic patients, electrical stimulation of the contralateral auditory cortex led to a significant decrease in evoked otoacoustic emission amplitude, whereas no change occurred under stimulation of non-auditory contralateral areas. These findings provide evidence of a cortico-olivocochlear pathway, originating in the auditory cortex and modulating contralateral active cochlear micromechanisms via the medial olivocochlear efferent system, in humans.