The negative affect hypothesis of noise sensitivity

Qualitative data on triggers and coping of sensory hypersensitivity in acquired brain injury patients: A proposed model

Sensory hypersensitivity (SHS) is a frequently heard complaint after acquired brain injury (ABI) and is related to reduced quality of life and physical and mental health. This study aimed to identify triggers for SHS after ABI and investigate how individuals cope with SHS. Nineteen adults with ABI took part in 45-min individual interviews. Data were audio-recorded and transcribed verbatim. Inductive thematic analysis revealed five themes: (1) A mismatch between resources and demands, (2) Altered experience of ordinary stimuli, (3) It affects all aspects of living, (4) Avoid, approach, accept, (5) It's highly heterogeneous. A model explaining the impact of triggers on subjective SHS after ABI is proposed, which states that SHS arises from a mismatch between the demands of a sensory environment (triggers) and the available biopsychosocial resources of an individual to meet these demands. The elicited SHS can affect and be affected by levels of fatigue, which limits the resources and creates a loop. Coping strategies can act on various stages of this model, i.e., to reduce the mismatch and potentially alter the loop. This model can contribute to the identification of mechanisms behind SHS in ABI patients and other populations, ultimately leading to evidence-based treatments.

Prevalence of Hyperacusis Diagnosis in Veterans Who Use VA Healthcare

OBJECTIVES

The primary objective was to estimate the prevalence of hyperacusis diagnosis in treatment-seeking Veterans, paying attention to when it is diagnosed in conjuncture with common comorbid conditions.

DESIGN

This retrospective observational study used Veteran electronic health records from January 2015 to July 2021. Hyperacusis and comorbid conditions were identified using International Classification of Disease diagnostic codes.

RESULTS

The prevalence of hyperacusis diagnosis was 0.06%. Veterans diagnosed with tinnitus, posttraumatic stress disorder, headache, or traumatic brain injury were between two and seven times more likely to have an International Classification of Disease code for hyperacusis.

CONCLUSIONS

The estimated prevalence of hyperacusis diagnosis using electronic health records is grossly below what is reported in the literature. This is likely due to lack of standardized methods to diagnosis hyperacusis and when present with comorbid conditions, uncertainty when it should be coded as a secondary diagnosis. Future clinical and research efforts prioritizing hyperacusis are desperately needed.

Fear influences phantom sound percepts in an anechoic room

Aims and hypotheses

In an environment of absolute silence, researchers have found many of their participants to perceive phantom sounds (tinnitus). With this between-subject experiment, we aimed to elaborate on these research findings, and specifically investigated whether–in line with the fear-avoidance model of tinnitus perception and reactivity–fear or level of perceived threat influences the incidence and perceptual qualities of phantom sound percepts in an anechoic room. We investigated the potential role of individual differences in anxiety, negative affect, noise sensitivity and subclinical hearing loss. We hypothesized that participants who experience a higher level of threat would direct their attention more to the auditory system, leading to the perception of tinnitus-like sounds, which would otherwise be subaudible, and that under conditions of increased threat, narrowing of attention would lead to perceptual distortions.

Methods

In total, N = 78 normal-hearing volunteers participated in this study. In general, the study sample consisted of young, mostly female, university students. Their hearing was evaluated using gold-standard pure tone audiometry and a speech-in-noise self-test (Digit Triplet Test), which is a sensitive screening test to identify subclinical hearing loss. Prior to a four-minute stay in an anechoic room, we randomized participants block design-wise in a threat (N = 37) and no-threat condition (N = 41). Participants in the threat condition were deceived about their hearing and were led to believe that staying in the room would potentially harm their hearing temporarily. Participants were asked whether they perceived sounds during their stay in the room and rated the perceptual qualities of sound percepts (loudness and unpleasantness). They were also asked to fill-out standardized questionnaires measuring anxiety (State–Trait Anxiety Inventory), affect (Positive and Negative Affect Schedule) and noise sensitivity (Weinstein Noise Sensitivity Scale). The internal consistency of the questionnaires used was verified in our study sample and ranged between α = 0.61 and α = 0.90.

Results

In line with incidence rates reported in the literature, 74% of our participants reported having heard tinnitus-like sounds in the anechoic room. Speech-in-noise identification ability was comparable for both groups of participants. The experimental manipulation of threat was proven to be effective, as indicated by significantly higher scores on a Threat Manipulation Checklist among participants in the threat condition as compared to those in the no-threat condition (p < 0.01). Nevertheless, participants in the threat condition were as likely to report tinnitus percepts as participants in the no-threat condition (p = 1), and tinnitus percepts were not rated as being louder (p = 0.76) or more unpleasant (p = 0.64) as a function of level of threat. For participants who did experience tinnitus percepts, a higher level of threat was associated with a higher degree of experienced unpleasantness (p < 0.01). These associations were absent in those who did not experience tinnitus. Higher negative affect was only slightly associated with higher ratings of tinnitus unpleasantness (p < 0.01).

Conclusion

Whereas our threat manipulation was successful in elevating the level of fear, it did not contribute to a higher percentage of participants perceiving tinnitus-like sounds in the threat condition. However, higher levels of perceived threat were related to a higher degree of perceived tinnitus unpleasantness. The findings of our study are drawn from a rather homogenous participant pool in terms of age, gender, and educational background, challenging conclusions that are applicable for the general population. Participants generally obtained normophoric scores on independent variables of interest: they were low anxious, low noise-sensitive, and there was little evidence for the presence of subclinical hearing loss. Possibly, there was insufficient variation in scores to find effects.

Sound Tolerance Conditions (Hyperacusis, Misophonia, Noise Sensitivity, and Phonophobia): Definitions and Clinical Management

Purpose: For some people, exposure to everyday sounds presents a significant problem. The purpose of this tutorial was to define and differentiate between the various sound tolerance conditions and to review some options for their clinical management.

METHOD

We informally reviewed the literature regarding sound tolerance conditions. The terminology and definitions provided are mostly consistent with how these terms are defined. However, many inconsistencies are noted. Methods of assessment and treatment also differ, and different methodologies are briefly described.

RESULTS

Hyperacusis describes physical discomfort or pain when any sound reaches a certain level of loudness that would be tolerable for most people. Misophonia refers to intense emotional reactions to certain sounds (often body sounds such as chewing and sniffing) that are not influenced by the perceived loudness of those sounds. Noise sensitivity refers to increased reactivity to sounds that may include general discomfort (annoyance or feeling overwhelmed) due to a perceived noisy environment, regardless of its loudness. Phonophobia, as addressed in the audiology profession, describes anticipatory fear of sound. Phonophobia is an emotional response such as anxiety and avoidance of sound due to the "fear" that sound(s) may occur that will cause a comorbid condition to get worse (e.g., tinnitus) or the sound itself will result in discomfort or pain. (Note that phonophobia is a term used by neurologists to describe "migraineur phonophobia"-a different condition not addressed herein.) Conclusions: The literature addresses sound tolerance conditions but reveals many inconsistencies, indicating lack of consensus in the field. When doing an assessment for decreased sound tolerance, it is important to define any terms used so that the patient and all health care professionals involved in the care of the patient are aligned with the goals of the treatment plan. Treatment generally involves gradual and systematic sound desensitization and counseling.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.20164130.

What is Noise Sensitivity?

Background

Noise sensitivity moderates the association between environmental noise exposure and annoyance and health outcomes.

Methods

In normally hearing adults, we measured noise sensitivity in three ways: using the noise sensitivity questionnaire, a 3-point self-rating, and the loudness discomfort level (LDL; mean reported discomfort level for tone bursts). We then presented recordings of a 15-second 80 dBLAeq aeroplane overflight and participants rated the annoyance and loudness they experienced.

Results

The three measures of noise sensitivity were not well correlated with each other, and only the overall LDL was associated with the ratings of loudness and annoyance in response to the aeroplane sounds.

Conclusions

This implies that our current measures of noise sensitivity may only capture parts of the underlying construct, and therefore underestimate effects due to it on the association between environmental noise and annoyance and health outcomes. We developed a theoretical model to describe the set of factors that may influence a person's sensitivity to noise and propose that interaction between the systems described is the basis for noise sensitivity. This paradigm alters the focus of noise research from the annoyance caused by the sound, to the sensitization to noise that may occur as a result of the interplay of many factors. We hope that our model will allow research to explore the sensitizing factors for noise more easily and systematically.

Turning away from sound: The role of fear avoidance in noise sensitivity following mild traumatic brain injury

BACKGROUND

Noise sensitivity (NS) following mild traumatic brain injury (mTBI) is common impacts functioning and outcomes. Recent research suggests psychological factors may have a significant role in the development of NS after mTBI. Psychological interventions have been advocated for to reduce this experience. To be effective, these interventions must aim to target the psychological processes that contribute to this relationship. Fear avoidance holds promise in this regard. The current study aimed to explore the role of fear avoidance in NS and examine its role in mediating the relationship between psychological distress and NS.

METHOD

Adults (n = 234) diagnosed with mTBI were recruited from outpatient mTBI clinics throughout New Zealand. Participants completed self-report measures of pre-injury mental health status, as well as current post-concussion symptoms, psychological distress (anxiety, stress, depression, fear avoidance and post-traumatic stress symptoms) and functional status upon entry to an mTBI outpatient clinic (M = 8.9, SD = 9.2, post injury).

RESULTS

A pre-injury mental health diagnosis was associated with NS after mTBI, as were symptoms of anxiety, stress, depression, and post-traumatic stress. Regression analyses revealed that fear avoidance (β = 0.45, p = .01), as well as stress (β = 0.07, p = .01) and PTSD symptoms (β = 0.02, p = .01), made a significant and unique contribution to NS. A series of mediation analyses found that fear avoidance had a significant indirect effect on the relationships between psychological distress and NS.

CONCLUSIONS

Fear avoidance is related to NS following mTBI. Targeting fear avoidance behaviours and beliefs may represent a treatment target for reducing NS after mTBI.

Sensitivity to Noise Following a Mild Traumatic Brain Injury: A Longitudinal Study

OBJECTIVE

To describe changes in the prevalence and clinical correlates of noise sensitivity (NS) in mild traumatic brain injury (mTBI) across a 12-month period and to determine whether NS at an early stage of recovery has predictive value for later postconcussive symptoms.

SETTING

A mixed urban and rural region of New Zealand.

PARTICIPANTS

Data for 341 adults (201 males, 140 females; age range from 16 to 91 years) were extracted from a 1-year TBI incidence, and outcomes study was conducted in New Zealand.

DESIGN

Secondary analysis of data from a community-based, longitudinal population study of an mTBI incidence cohort collected within 1 week of injury (baseline) and at 1, 6, and 12 months postinjury.

MAIN MEASURES

Measures at baseline (within 2 weeks of the injury) and 1, 6, and 12 months included the Rivermead Post-concussion Symptoms Questionnaire and its NS item, the Hospital Depression and Anxiety Scale, and the computerized CNS-Vital Signs neurocognitive test.

RESULTS

NS progressively declined postinjury, from 45% at baseline to 28% at 12 months. In turn, NS showed itself as a significant predictor of future postconcussive symptoms.

CONCLUSION

Taken together with previous research, the findings of the current study indicate that NS may have clinical utility in flagging vulnerability to persistent postconcussive symptoms.

Functional connectivity of the visual cortex differentiates anxiety comorbidity from episodic migraineurs without aura

Background

Migraine is a common neurological disease that is often accompanied by psychiatric comorbidities. However, the relationship between abnormal brain function and psychiatric comorbidities in migraine patients remains largely unclear. Therefore, the present study sought to explore the correlations between the resting-state functional deficits and psychiatric comorbidities in migraine without aura (MwoA) patients.

Methods

Resting-state functional magnetic resonance images were obtained. In addition, the amplitude of low-frequency fluctuation (ALFF) and regional homogeneity (ReHo) values were obtained. Thereafter regional abnormalities in MwoA patients with and without anxiety (MwoA-A and MwoA-OA) were chosen as seeds to conduct functional connectivity (FC) analysis.

Results

Compared to the healthy controls (HCs), the MwoA-A and MwoA-OA patients had abnormal ALFF and ReHo values in the right lingual gyrus (LG). They also had abnormal FC of the right LG with the ipsilateral superior frontal gyrus (SFG) and middle cingulate cortex (MCC). Additionally, the MwoA-A patients showed higher ReHo values in the left posterior intraparietal sulcus (pIPS) and abnormal FC of the right LG with ipsilateral pIPS and primary visual cortex, compared to the MwoA-OA patients. Moreover, the MwoA-OA patients showed an increase in the FC with the right posterior cingulate cortex/precuneus (PCC/PCUN), left middle frontal gyrus (MFG) and left inferior temporal gyrus (ITG) relative to the HCs. Furthermore, the ALFF values of the right LG positively were correlated with anxiety scores in MwoA-A patients. The abnormal LG-related FCs with the PCC/PCUN, MFG and ITG were negatively associated with the frequency of headaches in MwoA-OA patients.

Conclusions

This study identified abnormal visual FC along with other core networks differentiating anxiety comorbidity from MwoA. This may therefore enhance the understanding of the neuropsychological basis of psychiatric comorbidities and provide novel insights that may help in the discovery of new marks or even treatment targets.

Road traffic noise, noise sensitivity, noise annoyance, psychological and physical health and mortality

BACKGROUND

Both physical and psychological health outcomes have been associated with exposure to environmental noise. Noise sensitivity could have the same moderating effect on physical and psychological health outcomes related to environmental noise exposure as on annoyance but this has been little tested.

METHODS

A cohort of 2398 men between 45 and 59 years, the longitudinal Caerphilly Collaborative Heart Disease study, was established in 1984/88 and followed into the mid-1990s. Road traffic noise maps were assessed at baseline. Psychological ill-health was measured in phase 2 in 1984/88, phase 3 (1989/93) and phase 4 (1993/7). Ischaemic heart disease was measured in clinic at baseline and through hospital records and records of deaths during follow up. We examined the longitudinal associations between road traffic noise and ischaemic heart disease morbidity and mortality using Cox Proportional Hazard Models and psychological ill-health using Logistic Regression; we also examined whether noise sensitivity and noise annoyance might moderate these associations. We also tested if noise sensitivity and noise annoyance were longitudinal predictors of ischaemic heart disease morbidity and mortality and psychological ill-health.

RESULTS

Road traffic noise was not associated with ischaemic heart disease morbidity or mortality. Neither noise sensitivity nor noise annoyance moderated the effects of road traffic noise on ischaemic heart disease morbidity or mortality. High noise sensitivity was associated with lower ischaemic heart disease mortality risk (HR = 0.74, 95%CI 0.57, 0.97). Road traffic noise was associated with Phase 4 psychological ill-health but only among those exposed to 56-60dBA (fully adjusted OR = 1.82 95%CI 1.07, 3.07). Noise sensitivity moderated the association of road traffic noise exposure with psychological ill-health. High noise sensitivity was associated longitudinally with psychological ill-health at phase 3 (OR = 1.85 95%CI 1.23, 2.78) and phase 4 (OR = 1.65 95%CI 1.09, 2.50). Noise annoyance predicted psychological ill-health at phase 4 (OR = 2.47 95%CI 1.00, 6.13).

CONCLUSIONS

Noise sensitivity is a specific predictor of psychological ill-health and may be part of a wider construct of environmental susceptibility. Noise sensitivity may increase the risk of psychological ill-health when exposed to road traffic noise. Noise annoyance may be a mediator of the effects of road traffic noise on psychological ill-health.

The Epidemiology of Noise Sensitivity in New Zealand

BACKGROUND

Sensitivity to noise, or nuisance sounds that interrupt relaxation and task-related activities, has been shown to vary significantly across individuals. The current study sought to uncover predictors of noise sensitivity, focussing on possible social and cultural determinants, including social position, education, ethnicity, gender, and the presence of an illness.

METHOD

Data were collected from 746 New Zealand adults residing in 6 areas differentiated by social position. Participants responded to questions probing personal characteristics, noise sensitivity, illness, neighbourhood problems, and noise annoyance. It was hypothesized that those in high-deprivation areas and/or experiencing illness report higher levels of noise sensitivity.

RESULTS

Approximately 50 and 10% of the participants reported being moderately or very noise sensitive, respectively. Significant predictors of noise sensitivity included age, length of residence, level of social deprivation, and self-reported illness.

CONCLUSION

There is evidence of social determinants of noise sensitivity, including social position and residential factors.

Incidence of depression in relation to transportation noise exposure and noise annoyance in the SAPALDIA study

Prospective evidence on the risk of depression in relation to transportation noise exposure and noise annoyance is limited and mixed. We aimed to investigate the associations of long-term exposure to source-specific transportation noise and noise annoyance with incidence of depression in the SAPALDIA (Swiss cohort study on air pollution and lung and heart diseases in adults) cohort. We investigated 4,581 SAPALDIA participants without depression in the year 2001/2002. Corresponding one-year mean road, railway and aircraft day-evening-night noise (Lden) was calculated at the most exposed façade of the participants' residential floors, and transportation noise annoyance was assessed on an 11-point scale. Incident cases of depression were identified in 2010/2011, and comprised participants reporting physician diagnosis, intake of antidepressant medication or having a short form-36 mental health score < 50. We used robust Poisson regressions to estimate the mutually adjusted relative risks (RR) and 95% confidence intervals (CI) of depression, independent of traffic-related air pollution and other potential confounders. Incidence of depression was 11 cases per 1,000 person-years. In single exposure models, we observed positive but in part, statistically non-significant associations (per 10 dB) of road traffic Lden [RR: 1.06 (0.93, 1.22)] and aircraft Lden [RR: 1.19 (0.93, 1.53)], and (per 1-point difference) of noise annoyance [RR: 1.05 (1.02, 1.08)] with depression risk. In multi-exposure model, noise annoyance effect remained unchanged, with weaker effects of road traffic Lden [(RR: 1.02 (0.89, 1.17)] and aircraft Lden [(RR: 1.17 (0.90, 1.50)]. However, there were statistically significant indirect effects of road traffic Lden [(β: 0.02 (0.01, 0.03)] and aircraft Lden [β: 0.01 (0.002, 0.02)] via noise annoyance. There were no associations with railway Lden in the single and multi-exposure models [(RR_{both models}: 0.88 (0.75, 1.03)]. We made similar findings among 2,885 non-movers, where the effect modification and cumulative risks were more distinct. Noise annoyance effect in non-movers was stronger among the insufficiently active (RR: 1.09; 95%CI: 1.02, 1.17; p_interaction = 0.07) and those with daytime sleepiness [RR: 1.07 (1.02, 1.12); p_interaction = 0.008]. Cumulative risks of Lden in non-movers showed additive tendencies for the linear cumulative risk [(RR_{per 10dB of combined sources}: 1.31 (0.90, 1.91)] and the categorical cumulative risk [(RR_{triple- vs. zero-source ≥45 dB}: 2.29 (1.02, 5.14)], and remained stable to noise annoyance. Transportation noise level and noise annoyance may jointly and independently influence the risk of depression. Combined long-term exposures to noise level seems to be most detrimental, largely acting via annoyance. The moderation of noise annoyance effect by daytime sleepiness and physical activity further contribute to clarifying the involved mechanisms. More evidence is needed to confirm these findings for effective public health control of depression and noise exposure burden.

The association between health-related quality of life and noise or light sensitivity in survivors of a mild traumatic brain injury

PURPOSE

Sensory impairment is a common aftereffect of mild traumatic brain injury (TBI); however, their influence upon treatment outcomes and quality of life has yet to be investigated. This study sought to determine the effects of noise and light sensitivity upon the quality of life of individuals diagnosed with a TBI.

METHODS

A cross-sectional adult sample obtained from a longitudinal study (n = 293) provided measures of light and noise sensitivity and quality of life 12 months post injury. Sensitivities were taken from the Rivermead Post-concussion Symptoms Questionnaire, while quality of life was estimated using the Short-Form 36 health survey (SF-36).

RESULTS

Approximately 42% of participants reported ongoing difficulties with noise and light sensitivity. Additionally, those reporting sensory difficulties also reported lower SF-36 domain and composite scores compared to those reporting no such symptoms. After controlling for known co-factors, hierarchical multiple regression analyses indicated that the combination of light and noise sensitivity explained between 8 and 35% of the variance in SF-36 scores.

CONCLUSIONS

Light and noise sensitivity appear to degrade the quality of life of those with a mild TBI. Our findings challenge contemporary rehabilitation practices that tend to sideline sensory complaints and instead focus on the remediation of acute TBI symptoms.

Clinical correlates of noise sensitivity in patients with acute TBI

Primary objective: The impact of noise sensitivity (NS) on the daily functioning of people who have experienced a traumatic brain injury (mTBI) is an understudied area, particularly following mTBI. The primary objective of this cross-sectional study was to investigate clinical markers of NS in a sample of New Zealand adults following mTBI. Research design: Cross-sectional study. Methods and procedures: A community-based sample of 151 adults who had experienced a brain injury in the last two weeks completed assessments estimating cognitive functioning, postconcussion symptoms (including NS), and affective state. Results: Over half the sample (59%) reported some degree of NS. Exploratory statistical analyses indicated that NS was associated with being female, living in a rural area, number of previous brain injuries, cognitive flexibility scores, reaction time, perceptions of recovery, anxiety, and depression. Regression analyses revealed that anxiety was the dominant correlate of NS (B = .120, p < .001, 95% CI [0.069, 1.71]). Conclusions: As the first study to explore the correlates of NS following mild TBI, the findings have important clinical and research implications. The present findings suggest that treatment approaches targeting anxiety may be effective in reducing NS in people who have experienced a brain injury. Moreover, evidence is presented suggesting that NS is unlikely to reflect malingering, and should be treated as a genuine somatic symptom of brain injury.

Health-related quality of life is impacted by proximity to an airport in noise-sensitive people

INTRODUCTION

The aim of the study was to determine whether those who are noise sensitive are more adversely affected by airport noise than those who are not noise sensitive.

PARTICIPANTS AND METHODS

One area was very close to Wellington International Airport and the other was distant from the airport and any other major sources of noise such as motorways and railways. Noise sensitivity was self-rated on a three-point scale as follows: non-noise sensitive, moderately noise sensitive, or highly noise sensitive. Statistical analysis consisted of analyses of variance using the domains of the WHOQOL score with the year, area (airport or the control), and noise sensitivity as covariates.

RESULTS

Noise-sensitive people were found to have a significantly poorer HRQOL than others when they lived near an airport, but not when they lived in the control area. The same effect was present at both of the time points investigated, suggesting that it is a general finding.

DISCUSSION

This finding is consistent with similar studies using the WHOQOL-BREF for investigating noise from road traffic, suggesting consistency in effect across transport noise sources.

Neuroanatomical substrate of noise sensitivity

Recent functional studies suggest that noise sensitivity, a trait describing attitudes towards noise and predicting noise annoyance, is associated with altered processing in the central auditory system. In the present work, we examined whether noise sensitivity could be related to the structural anatomy of auditory and limbic brain areas. Anatomical MR brain images of 80 subjects were parcellated with FreeSurfer to measure grey matter volume, cortical thickness, cortical area and folding index of anatomical structures in the temporal lobe and insular cortex. The grey matter volume of amygdala and hippocampus was measured as well. According to our findings, noise sensitivity is associated with the grey matter volume in the selected structures. Among those, we propose and discuss particular areas, previously linked to auditory perceptual, emotional and interoceptive processing, in which larger grey matter volume seems to be related to higher noise sensitivity.

Cognitive-Motivational Determinants of Residents' Civic Engagement and Health (Inequities) in the Context of Noise Action Planning: A Conceptual Model

The Environmental Noise Directive expects residents to be actively involved in localising and selecting noise abatement interventions during the noise action planning process. Its intervention impact is meant to be homogeneous across population groups. Against the background of social heterogeneity and environmental disparities, however, the impact of noise action planning on exposure to traffic-related noise and its health effects is unlikely to follow homogenous distributions. Until now, there has been no study evaluating the impact of noise action measures on the social distribution of traffic-related noise exposure and health outcomes. We develop a conceptual (logic) model on cognitive-motivational determinants of residents’ civic engagement and health (inequities) by integrating arguments from the Model on household’s Vulnerability to the local Environment, the learned helplessness model in environmental psychology, the Cognitive Activation Theory of Stress, and the reserve capacity model. Specifically, we derive four hypothetical patterns of cognitive-motivational determinants yielding different levels of sustained physiological activation and expectancies of civic engagement. These patterns may help us understand why health inequities arise in the context of noise action planning and learn how to transform noise action planning into an instrument conducive to health equity. While building on existing frameworks, our conceptual model will be tested empirically in the next stage of our research process.

A window into the brain mechanisms associated with noise sensitivity

Noise sensitive individuals are more likely to experience negative emotions from unwanted sounds and they show greater susceptibility to adverse effects of noise on health. Noise sensitivity does not originate from dysfunctions of the peripheral auditory system, and it is thus far unknown whether and how it relates to abnormalities of auditory processing in the central nervous system. We conducted a combined electroencephalography and magnetoencephalography (M/EEG) study to measure neural sound feature processing in the central auditory system in relation to the individual noise sensitivity. Our results show that high noise sensitivity is associated with altered sound feature encoding and attenuated discrimination of sound noisiness in the auditory cortex. This finding makes a step towards objective measures of noise sensitivity instead of self-evaluation questionnaires and the development of strategies to prevent negative effects of noise on the susceptible population.

Noise sensitivity and hyperacusis in patients affected by multiple chemical sensitivity

PURPOSE

The aim of this study was to investigate the presence of noise sensitivity and hyperacusis in patients suffering from multiple chemical sensitivity (MCS), a chronic condition characterized by several symptoms following low-level chemical exposure. Moreover, distortion product otoacoustic emissions (DPOAE) were performed to further study cochlear function.

METHODS

A questionnaire-based survey was performed. Eighteen MCS patients, selected with strict diagnostic criteria, and 20 healthy age- and gender-matched subjects filled Weinstein's Noise Sensitivity Questionnaire (WNS) and Khalfa's Hyperacusis Questionnaire (HQ). Results were compared with scores from the quick Environmental Exposure Sensitivity Index (qEESI), a routinarily used questionnaire to screen MCS symptoms, and with DPOAE values. An analysis of variance (ANOVA) was performed between MCS and control subjects scores; moreover, Spearman's rank correlation test was performed between questionnaire results.

RESULTS

ANOVA testing on DPOAE values showed any significant difference between groups, while WNS, HQ and qEESI scores were significantly higher in MCS group compared to controls. Correlation analysis showed strong positive correlation between WNS, HQ and qEESI in MCS subjects.

CONCLUSIONS

For the first time, auditory-related perceptual disorders were studied in MCS. A strong association between WNS, HQ results and MCS symptoms severity has been highlighted. These findings suggest that decreased sound tolerance and noise sensitivity could be considered as possible new aspects of this syndrome, contributing to its peculiar phenotype. Furthermore, as DPOAE values did not differ from healthy subjects, present findings might suggest a 'central' source for such disorders in this group of patients.

Noise sensitivity: A neurophenomenological perspective

This paper addresses the current limitations of noise sensitivity research and the benefit of undertaking a neurophenomenological approach of investigation. It begins by questioning the invariance of noise sensitivity across different studies and contexts and argues that these are issues associated with the psychometric construct rather than the underlying reaction patterns. It suggest that our definition and operationalization of noise sensitivity might have been misspecified and that it needs to be revised on the basis of heuristically derived first-person data about our experiences of noise. It then shows why the basic principles of the neurophenomenological program are applicable to psychoacoustic research. Namely, it argues that phenomenological training leading to reflexive introspection and verbalization of our susceptibility to noise might have three-fold implication - (i) it will generate deeper understanding of noise sensitivity which will then allow us to deduce a hierarchical structure of meaning and concepts to supplement and be fed to quantitative research, (ii) it will provide better interpretation of neuroimaging and electroencephalographic data related to noise reaction and perception, which in turn will allow a process of reciprocal validation, (iii) and, most importantly, it presents a promising technique for emotional regulation of noise processing via modulation of the amygdalar function, when a state of awareness of this processing has been achieved.