Noise sensitivity or hyperacusis? Comparing the Weinstein and Khalfa questionnaires in a community and a clinical samples

Noise sensitivity and hyperacusis are decreased sound tolerance conditions that are not well delineated or defined. This paper presents the correlations and distributions of the Noise Sensitivity Scale (NSS) and the Hyperacusis Questionnaire (HQ) scores in two distinct large samples. In Study 1, a community-based sample of young healthy adults (n = 103) exhibited a strong correlation (r = 0.74) between the two questionnaires. The mean NSS and HQ scores were 54.4 ± 16.9 and 12.5 ± 7.5, respectively. NSS scores displayed a normal distribution, whereas HQ scores showed a slight positive skew. In Study 2, a clinical sample of Veterans with or without clinical comorbidities (n = 95) showed a moderate correlation (r = 0.58) between the two questionnaires. The mean scores were 66.6 ± 15.6 and 15.3 ± 7.3 on the NSS and HQ, respectively. Both questionnaires' scores followed a normal distribution. In both samples, participants who self-identified as having decreased sound tolerance scored higher on both questionnaires. These findings provide reference data from two diverse sample groups. The moderate to strong correlations observed in both studies suggest a significant overlap between noise sensitivity and hyperacusis. The results underscore that NSS and HQ should not be used interchangeably, as they aim to measure distinct constructs, however to what extent they actually do remains to be determined. Further investigation should distinguish between these conditions through a comprehensive psychometric analysis of the questionnaires and a thorough exploration of psychoacoustic, neurological, and physiological differences that set them apart.

The electrophysiological markers of hyperacusis: a scoping review

OBJECTIVE

Hyperacusis is known as a reduced tolerance to sounds perceived as normal to the majority of the population. There is currently no agreed definition, diagnostic tool, or objective measure of its occurrence. The purpose of this review is to catalogue the research to date on the use of auditory evoked potentials (AEP) to assess hyperacusis.

DESIGN

A step-by-step methodology was conducted following guidelines. Four databases were searched. A total of 3343 papers were identified. A final yield of 35 articles were retained for analysis.

RESULTS

The analysis identified four types of aetiologies to describe the hyperacusic population in AEP studies; developmental disorders (n = 19), neurological disorders (n = 3), induced hearing damage (n = 8) and idiopathic aetiology (n = 5). Electrophysiological measures were of short (n = 16), middle (n = 13) and long (n = 19) latencies, believed to reflect the activity of the ascending and descending pathways of the auditory system from periphery to cortex.

CONCLUSIONS

The results of this review revealed the potential use of electrophysiological measures for further understanding the mechanisms of hyperacusis. However, according to the disparity of concepts to define hyperacusis, definitions and populations need to be clarified before biomarkers specific to hyperacusis can be identified.

Low thermal conductivity in a modular inorganic material with bonding anisotropy and mismatch

The thermal conductivity of crystalline materials cannot be arbitrarily low, as the intrinsic limit depends on the phonon dispersion. We used complementary strategies to suppress the contribution of the longitudinal and transverse phonons to heat transport in layered materials that contain different types of intrinsic chemical interfaces. BiOCl and Bi₂O₂Se encapsulate these design principles for longitudinal and transverse modes, respectively, and the bulk superlattice material Bi₄O₄SeCl₂ combines these effects by ordering both interface types within its unit cell to reach an extremely low thermal conductivity of 0.1 watts per kelvin per meter at room temperature along its stacking direction. This value comes within a factor of four of the thermal conductivity of air. We demonstrated that chemical control of the spatial arrangement of distinct interfaces can synergically modify vibrational modes to minimize thermal conductivity.

Thermoelectric materials taking advantage of spin entropy: lessons from chalcogenides and oxides

The interplay between charges and spins may influence the dynamics of the carriers and determine their thermoelectric properties. In that respect, magneto-thermoelectric power MTEP, i.e. the measurements of the Seebeck coefficient S under the application of an external magnetic field, is a powerful technique to reveal the role of magnetic moments on S. This is illustrated by different transition metal chalcogenides: CuCrTiS4 and CuMnTiS4 magnetic thiospinels, which are compared with magnetic oxides, Curie-Weiss (CW) paramagnetic misfit cobaltites, ruthenates, either ferromagnetic perovskite or Pauli paramagnet quadruple perovskites, and CuGa1-x Mn x Te2 chalcopyrite telluride and Bi1.99Cr0.01Te3 in which diluted magnetism is induced by 3%-Mn and 1%-Cr substitution, respectively. In the case of a ferromagnet (below TC) and CW paramagnetic materials, the increase of magnetization at low T when a magnetic field is applied is accompanied by a decrease of the entropy of the carriers and hence S decreases. This is consistent with the lack of MTEP in the Pauli paramagnetic quadruple perovskites. Also, no significant MTEP is observed in CuGa1-x Mn x Te2 and Bi1.99Cr0.01Te3, for which Kondo-type interaction between magnetic moments and carriers prevails. In contrast, spin glass CuCrTiS4 exhibits negative MTEP like in ferromagnetic ruthenates and paramagnetic misfit cobaltites. This investigation of some chalcogenides and oxides provides key ingredients to select magnetic materials for which S benefits from spin entropy.

Modulation of hyperacusis and tinnitus loudness in tinnitus patients with and without hearing loss following 3 weeks of acoustic stimulation: A proof-of-concept study

Tinnitus and hyperacusis are two debilitating conditions that are highly comorbid. It has been postulated that they may originate from similar pathophysiological mechanisms such as an increase in central gain. Interestingly, sound stimulation has been shown to reduce central gain and is currently used for the treatment of both conditions. This study investigates the effect of sound stimulation on both tinnitus and hyperacusis in the same patients. Two distinct series of tinnitus participants were tested: one with normal or near-normal hearing (n=16) and one with hearing loss (n=14). A broadband noise shaped to cover most of the tinnitus frequency spectrum was delivered through hearing aids using the noise generator feature (no amplification) and verified through real-ear measurements. Participants received sound stimulation for 3 weeks and were tested before (at baseline), then after 1 week and at the end of the 3 weeks of sound stimulation. There was also a 1-month follow-up after the end of the stimulation protocol. The measurements included self-reported measures of tinnitus and hyperacusis (VAS), validated questionnaires (THI, HQ) and psychoacoustic measurements (tinnitus battery and loudness functions). On both self-assessment (VAS of sound tolerance and tinnitus loudness) and psychoacoustic measures (loudness function and tinnitus loudness in dB), about 50% of tinnitus participants had a synchronous (either a decrease or an increase) modulation of hyperacusis and tinnitus loudness after 1 week and 3 weeks of acoustic stimulation and up to about 70% of participants at 1-M follow-up. The decrease of hyperacusis and tinnitus loudness was more prevalent in normal-hearing participants. There was a significant increase in tinnitus loudness during and following the stimulation in the group with hearing loss. Hyperacusis improvement as assessed by loudness function was significantly correlated with the intensity level of the acoustic stimulation (dB level of the noise produced by the noise generator) in tinnitus participants with normal/near-normal hearing thresholds. Our study partly supports the central gain hypothesis by showing synchronous modulation of hyperacusis and tinnitus loudness. It also shows beneficial effects of acoustic stimulation in some tinnitus individuals, in particular those with normal or near-normal hearing, while highlighting the importance of a careful fitting of sound generators to prevent increase. Since the amplification feature was not turned on in our study, future work should determine whether amplification alone, or in addition to acoustic stimulation (sound generators), would benefit to those with hearing loss.

The gap prepulse inhibition of the acoustic startle (GPIAS) paradigm to assess auditory temporal processing: Monaural versus binaural presentation

The Gap Prepulse Inhibition of the Acoustic Startle Reflex (GPIAS) is a paradigm used to assess auditory temporal processing in both animals and humans. It consists of the presentation of a silent gap embedded in noise and presented a few milliseconds before a startle sound. The silent gap produces the inhibition of the startle reflex, a phenomenon called gap-prepulse inhibition (GPI). This paradigm is also used to detect tinnitus in animal models. The lack of inhibition by the silent gaps is suggested to be indicative of the presence of tinnitus "filling-in" the gaps. The current research aims at improving the GPIAS technique by comparing the GPI produced by monaural versus binaural silent gaps in 29 normal-hearing subjects. Two gap durations (5 or 50 ms), each embedded in two different frequency backgrounds (centered around 500 or 4 kHz). Both low- and high- frequency narrowband noises had a bandwidth of half an octave. Overall, the startle magnitude was greater for the binaural versus the monaural presentation, which might reflect binaural loudness summation. In addition, the GPI was similar between the monaural and the binaural presentations for the high-frequency background noise. However, the GPI was greater for the low-frequency background noise for the binaural, compared to the monaural, presentation. These findings suggest that monaural GPIAS might be more suited to detect tinnitus compared to the binaural presentation.

Does Tinnitus Fill in the Gap Using Electrophysiology? A Scoping Review

The results showed a trend of increased post-gap amplitudes and reduced gap salience; however, the small number of articles yield and limited consensus prohibit any conclusions for clinical use. Nevertheless, gap-induced EPs may be further explored as a potential tool for tinnitus detection.

Individual Reliability of the Standard Clinical Method vs Patient-Centered Tinnitus Likeness Rating for Assessment of Tinnitus Pitch and Loudness Matching

Importance

Current individualized sound therapies for tinnitus rely on tinnitus pitch assessment, which is commonly derived from the standard clinical 2-alternative forced-choice (2-AFC) approach driven by the examiner. However, this method is limited by lack of individual test-retest reliability and focuses on a single rather than multiple tinnitus frequencies.

Objective

To assess individual test-retest reliability of the 2-AFC, with a single final frequency (and corresponding loudness), and the tinnitus likeness rating (TLR), with the participant exposed to the entire audible frequency spectrum, from which 3 dominant frequencies and corresponding loudness were extracted.

Design, Setting, and Participants

In this case series, participants with tinnitus underwent testing twice with both methods at a 1-month interval by experienced clinicians from January 6 through March 17, 2017. Each clinician tested each patient only once at visit 1 or 2 in a university audiology training setting with standardized equipment and was blind to previous assessment. Participants with bilateral or unilateral chronic tinnitus for longer than 6 months, in good health, without total deafness in either ear, and without cerumen in the ear canal were recruited through advertisements (community and clinics) and word of mouth (volunteer sample). The audiologists were likewise participants in the planned comparison between TLR and 2-AFC in the test-retest measures.

Main Outcomes and Measures

Test-retest concordance with 95% CIs for each method, calculated as the proportion of participants with the same final frequency between the 2 visits (2-AFC) or with at least 1 concordant dominant frequency (TLR) as well as loudness differences of no greater than 10 dB.

Results

The study sample included 31 participants (55% men; mean [SD] age, 50.7 [13.7] years). For TLR, 26 of 31 participants had at least 1 concordant dominant frequency between the 2 visits (proportion, 0.84; 95% CI, 0.66-0.95), whereas for 2-AFC, 7 of 31 participants had a concordant final tinnitus pitch in either ear (proportion, 0.23; 95% CI, 0.10-0.41). Loudness reliability followed the same pattern, with more concordant loudness levels in the TLR (proportion, 0.73; 95% CI, 0.52-0.88) than in the 2-AFC (proportion, 0.40; 95% CI, 0.05-0.85). Mean time taken to complete the tests was less than 15 minutes, and general appreciation by participants with tinnitus and audiologists were overall similar for both.

Conclusions and Relevance

Superior test-retest concordance can be demonstrated at the individual level using the several dominant frequencies extracted from the patient-centered TLR.

Impact of the iron substitution on the thermoelectric properties of Co1- xFe xS2 ( x ≤ 0.30)

The strong interplay between magnetism and transport can tune the thermoelectric properties in chalcogenides and oxides. In the case of ferromagnetic CoS₂ pyrite, it was previously shown that the power factor is large at room temperature, reaching 1 mW m^-1K^-2 and abruptly increases for temperatures below the Curie transition ( T_C), an increase potentially due to a magnonic effect on the Seebeck ( S) coefficient. The too large thermal conductivity approximately equal to 10.5 W m^-1K^-1 at room temperature prevents this pyrite from being a good thermoelectric material. In this work, samples belonging to the Co_{1- x}Fe _xS₂ pyrite family ( x = 0, 0.15 and 0.30) have thus been investigated in order to modify the thermal properties by the introduction of disorder on the Co site. We show here that the thermal conductivity can indeed be reduced by such a substitution, but that this substitution predominantly induces a reduction of the electronic part of the thermal conductivity and not of the lattice part. Interestingly, the magnonic contribution to S below T_C disappears as x increases, while at high T, S tends to a very similar value (close to -42 µV K^-1) for all the samples investigated. This article is part of a discussion meeting issue 'Energy materials for a low carbon future'.

Sr2Fe1+xRe1−xO6 double perovskites: magnetoresistance and (magneto)thermopower

Polycrystalline Sr₂Fe_1+xRe_1−xO₆ samples have been synthesized, structurally characterized by X-ray powder diffraction, transmission electron microscopy, X-ray absorption spectroscopy, and measurements of their magnetotransport properties were performed.

Unconventional aspects of electronic transport in delafossite oxides

The electronic transport properties of the delafossite oxides [Formula: see text] are usually understood in terms of two well-separated entities, namely the triangular [Formula: see text] and ([Formula: see text] layers. Here, we review several cases among this extensive family of materials where the transport depends on the interlayer coupling and displays unconventional properties. We review the doped thermoelectrics based on [Formula: see text] and [Formula: see text], which show a high-temperature recovery of Fermi-liquid transport exponents, as well as the highly anisotropic metals [Formula: see text], [Formula: see text], and [Formula: see text], where the sheer simplicity of the Fermi surface leads to unconventional transport. We present some of the theoretical tools that have been used to investigate these transport properties and review what can and cannot be learned from the extensive set of electronic structure calculations that have been performed.

Clinical Validation of a New Tinnitus Assessment Technology

Current clinical assessment of tinnitus relies mainly on self-report. Psychoacoustic assessment of tinnitus pitch and loudness are recommended but methods yield variable results. Herein, we investigated the proposition that a previously validated fixed laboratory-based method (Touchscreen) and a newly developed clinically relevant portable prototype (Stand-alone) yield comparable results in the assessment of psychoacoustic tinnitus pitch and loudness. Participants with tinnitus [N = 15, 7 with normal hearing and 8 with hearing loss (HL)] and participants simulating tinnitus (simulators, N = 15) were instructed to rate the likeness of pure tones (250-16 kHz) to their tinnitus pitch and match their loudness using both methods presented in a counterbalanced order. Results indicate that simulators rated their "tinnitus" at lower frequencies and at louder levels (~10 dB) compared to tinnitus participants. Tinnitus subgroups (with vs. without HL) differed in their predominant tinnitus pitch (i.e., lower in the tinnitus with HL subgroups), but not in their loudness matching in decibel SL. Loudness at the predominant pitch was identified as a factor yielding significant sensitivity and specificity in discriminating between the two groups of participants. Importantly, despite differences in the devices' physical presentations, likeness and loudness ratings were globally consistent between the two methods and, moreover, highly reproducible from one method to the other in both groups. All in all, both methods yielded robust tinnitus data in less than 12 min, with the Stand-alone having the advantage of not being dependent of learning effects, being user-friendly, and being adapted to the audiogram of each patient to further reduce testing time.

Abstract P1-06-11: A targetable EGFR-driven tumor-initiating program in breast cancer

Background: Inter- and intra-tumour heterogeneity underlies variability in therapeutic response. Although targeting of the epidermal growth factor receptor (EGFR) in breast cancer has failed to demonstrate clinical efficacy at the population level, complete and durable responses have been reported at low frequencies. The molecular determinants of these responses are unknown, but are of importance in the era of precision medicine.

Results: We performed a patient-derived xenograft (PDX) clinical trial with gefitinib in a breast cancer PDX cohort. Consistent with clinical trial data, gefitinib exhibited limited efficacy across most models. One PDX, however, demonstrated a complete and durable (>6 months) clinical response, and was subject to deep molecular profiling to identify determinants of response. Exome sequencing revealed no single nucleotide variants or copy number alterations in EGFR pathway members. EGFR was differentially expressed between the two major cellular subpopulations identified by single-cell RNAseq and this cellular heterogeneity in EGFR expression was validated immunohistochemically. Fluorescence-activated cell sorting of the EGFRhi subpopulation revealed cells with enhanced stem-like properties, including ALDH activity, sphere-forming capacity in vitro, ability to form tumours in vivo and seeding lung micrometastases from orthotopically transplanted tumours. Tumourspheres derived from EGFRhi cells developed into mixed EGFRhi and EGFRlo subpopulations, as did macrometastases, supporting that EGFRhi subpopulation can self-renew and re-populate. Analysis of expressed SNVs in the single-cell RNAseq data, filtered by variants identified from exome sequencing, showed no clonal segregation, supporting a non-clonal origin of the functionally distinct EGFRhi and EGFRlo subpopulations. This EGFR-driven tumour initiating cell program was observed in independent PDX models, some which showed growth inhibition in response to gefitinib.

Conclusions: Using bulk and single-cell genomic profiling, we identified and functionally validated an EGFR-driven tumour-initiating program in a subset of aggressive breast tumours, which may be predictive of gefitinib sensitivity. This contradicts traditional beliefs that good therapeutic targets are homogenously expressed, in that we show that a target displaying intra-tumour heterogeneity can be effective so long that it is expressed in the tumour-initiating population.

Citation Format: Savage P, Saleh SMI, Wang Y-C, Revil T, Badescu D, Liu L, Iacucci E, Zuo D, Bertos N, Munoz-Ramos V, Asselah J, Meterissian S, Omeroglu A, Hébert S, Kleinman C, Park M, Ragoussis J. A targetable EGFR-driven tumor-initiating program in breast cancer [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P1-06-11.

Magnetic and thermoelectric properties of the ternary pseudo-hollandite BaxCr5Se8 (0.5 < x < 0.55) solid solution

The structure of Ba0.5Cr5Se8 has been recently resolved, and its thermoelectric and magnetic properties have been studied. A ZT of 0.12 was found at around 800 K. Here, we report a study on the pseudo-hollandite BaxCr5Se8 solid-solution with 0.5 ≤ x ≤ 0.55 and its thermoelectric and magnetic properties. There is no significant impact either on the cell parameters depending on the cation content or on the magnetic properties. However, thermoelectric properties are radically changed depending on x content. While the low thermal conductivity, around 0.8 W m(-1) K(-1), remains similar for all samples, a respective increase and decrease of the resistivity and the Seebeck coefficient are observed with increasing Ba content. The maximum Seebeck coefficient is found with Ba0.5Cr5Se8 at around 635 K with 315 μV K(-1), and the Seebeck coefficient then decreases and is correlated with an activation of minority charge carriers confirmed by Hall measurements. A similar but steeper behavior is observed for the Ba0.55Cr5Se8 temperature dependence plot at around 573 K. Finally, the best thermoelectric performances are found using the lowest content of Ba, unlike when x tends to 0.55, ZT approaches a tenth of the initial best value. BaxCr5Se8 compounds are antiferromagnetic with TN = 58 K. A large peak in thermal conductivity is observed around the antiferromagnetic transition for all stoichiometry.

The impact of charge transfer and structural disorder on the thermoelectric properties of cobalt intercalated TiS2

A family of phases, Co _x TiS₂ (0 ≤ x ≤ 0.75) has been prepared and characterised by powder X-ray and neutron diffraction, electrical and thermal transport property measurements, thermal analysis and SQUID magnetometry. With increasing cobalt content, the structure evolves from a disordered arrangement of cobalt ions in octahedral sites located in the van der Waals' gap (x ≤ 0.2), through three different ordered vacancy phases, to a second disordered phase at x ≥ 0.67. Powder neutron diffraction reveals that both octahedral and tetrahedral inter-layer sites are occupied in Co_0.67TiS₂. Charge transfer from the cobalt guest to the TiS₂ host affords a systematic tuning of the electrical and thermal transport properties. At low levels of cobalt intercalation (x < 0.1), the charge transfer increases the electrical conductivity sufficiently to offset the concomitant reduction in |S|. This, together with a reduction in the overall thermal conductivity leads to thermoelectric figures of merit that are 25% higher than that of TiS₂, ZT reaching 0.30 at 573 K for Co _x TiS₂ with 0.04 ≤ x ≤ 0.08. Whilst the electrical conductivity is further increased at higher cobalt contents, the reduction in |S| is more marked due to the higher charge carrier concentration. Furthermore both the charge carrier and lattice contributions to the thermal conductivity are increased in the electrically conductive ordered-vacancy phases, with the result that the thermoelectric performance is significantly degraded. These results illustrate the competition between the effects of charge transfer from guest to host and the disorder generated when cobalt cations are incorporated in the inter-layer space.

Modulation of Prepulse Inhibition and Startle Reflex by Emotions: A Comparison between Young and Older Adults

This study examined whether or not the acoustic startle response and sensorimotor gating may be modulated by emotions differentially between young and older adults. Two groups of participants (mean age Young: 24 years old; Elderly: 63.6 years old) were presented with three types of auditory stimuli (Startle alone, High or Low frequency Prepulse) while viewing pleasant, neutral, or unpleasant images. Electromyographic activity of the eyeblink response was measured. Results show that older adults displayed diminished eyeblink responses whereas younger adults displayed enhanced eyeblink responses when viewing negative images. Sensorimotor gating also differed between young and older adults, with enhanced sensorimotor gating abilities while viewing positive pictures in older adults and diminished abilities while viewing negative pictures among younger adults. These results argue in favor of a differential emotional influence on the sensorimotor abilities of young and older adults, with a positivity bias among the latter.

The gap-startle paradigm to assess auditory temporal processing: Bridging animal and human research

The gap-prepulse inhibition of the acoustic startle (GPIAS) paradigm is the primary test used in animal research to identify gap detection thresholds and impairment. When a silent gap is presented shortly before a loud startling stimulus, the startle reflex is inhibited and the extent of inhibition is assumed to reflect detection. Here, we applied the same paradigm in humans. One hundred and fifty-seven normal-hearing participants were tested using one of five gap durations (5, 25, 50, 100, 200 ms) in one of the following two paradigms-gap-embedded in or gap-following-the continuous background noise. The duration-inhibition relationship was observable for both conditions but followed different patterns. In the gap-embedded paradigm, GPIAS increased significantly with gap duration up to 50 ms and then more slowly up to 200 ms (trend only). In contrast, in the gap-following paradigm, significant inhibition-different from 0--was observable only at gap durations from 50 to 200 ms. The finding that different patterns are found depending on gap position within the background noise is compatible with distinct mechanisms underlying each of the two paradigms.

Abstract TP148: The Montreal Assessment of Connected Speech Offers Good Psychometric Properties to Monitor Ecological Language Recovery in Post-stroke Aphasia

Introduction: Clinical trials in post-stroke aphasia measure language outcomes with available standardized tests. Most of these are primarily diagnostic tools and without evaluated test-retest reliability and responsiveness to change. They do not have parallel versions to prevent learning bias, and their language tasks (e.g., naming) lack ecological validity. The Montreal Assessment of Connected Speech (MACS) was designed to address these issues. Patients are asked to freely describe five pictures illustrating scenes of daily life. Speech samples are scored for their efficiency in transmitting correct information (% correct content units out of the total number of words). Inter-rater reliability (r = .84; R2 = 0.70) and three parallel versions were validated with 105 healthy young and older francophone adults.

Hypothesis: The MACS has good test-retest reliability (Spearman’s coefficient > .8; Wilcoxon signed-rank test p > .05) and responsiveness to change (discriminates between improved and unimproved patients with area under the receiver operating characteristic curve [AUC] >.8).

Methods: Patients with subacute or chronic aphasia undergoing intensive speech therapy at the Jewish General Hospital in Montreal with improvement in the Boston Naming Test were included in the improved group (n = 7; 3 females; age mean = 64.1 [SD = 10.8]). Patients with chronic post-stroke aphasia receiving no speech therapy were recruited from an association in the Montreal area for the unimproved group (n = 12; 7 females; age mean 62.4 [SD = 11.6]). All participants were French-speaking, had good or corrected visual acuity and underwent pseudorandomized parallel versions of the MACS at T1 and T2 with a two-week interval between them.

Results: Correlation between scores at T1 and T2 (rs(12) = .97, p < .001) and stability (Z = -1.38, p = .17) were found in unimproved patients. Score changes showed good discriminative ability between groups (AUC = .81, p = .03).

Conclusion: Good test-retest reliability and responsiveness to change make the MACS a promising standardized tool for aphasia clinical trials in stroke patients.

Searching for new thermoelectric materials: some examples among oxides, sulfides and selenides

Different families of thermoelectric materials have been investigated since the discovery of thermoelectric effects in the mid-19th century, materials mostly belonging to the family of degenerate semi-conductors. In the last 20 years, new thermoelectric materials have been investigated following different theoretical proposals, showing that nanostructuration, electronic correlations and complex crystallographic structures (low dimensional structures, large number of atoms per lattice, presence of 'rattlers'…) could enhance the thermoelectric properties by enhancing the Seebeck coefficient and/or reducing the thermal conductivity. In this review, the different strategies used to optimize the thermoelectric properties of oxides and chalcogenides will be presented, starting with a review on thermoelectric oxides. The thermoelectric properties of sulfides and selenides will then be discussed, focusing on layered materials and low dimensional structures (TiS2 and pseudo-hollandites). Some sulfides with promising ZT values will also be presented (tetrahedrites and chalcopyrites).

Gap-Prepulse Inhibition of the Acoustic Startle Reflex (GPIAS) for Tinnitus Assessment: Current Status and Future Directions

The progress in the field of tinnitus largely depends on the development of a reliable tinnitus animal model. Recently, a new method based on the acoustic startle reflex modification was introduced for tinnitus screening in laboratory animals. This method was enthusiastically adopted and now widely used by many scientists in the field due to its seeming simplicity and a number of advantages over the other methods of tinnitus assessment. Furthermore, this method opened an opportunity for tinnitus assessment in humans as well. Unfortunately, multiple modifications of data collection and interpretation implemented in different labs make comparisons across studies very difficult. In addition, recent animal and human studies have challenged the original “filling-in” interpretation of the paradigm. Here, we review the current literature to emphasize on the commonalities and differences in data collection and interpretation across laboratories that are using this method for tinnitus assessment. We also propose future research directions that could be taken in order to establish whether or not this method is warranted as an indicator of the presence of tinnitus.

Invited article: A round robin test of the uncertainty on the measurement of the thermoelectric dimensionless figure of merit of Co0.97Ni0.03Sb3

A round robin test aiming at measuring the high-temperature thermoelectric properties was carried out by a group of European (mainly French) laboratories (labs). Polycrystalline skutterudite Co0.97Ni0.03Sb3 was characterized by Seebeck coefficient (8 labs), electrical resistivity (9 labs), thermal diffusivity (6 labs), mass volume density (6 labs), and specific heat (6 labs) measurements. These data were statistically processed to determine the uncertainty on all these measured quantities as a function of temperature and combined to obtain an overall uncertainty on the thermal conductivity (product of thermal diffusivity by density and by specific heat) and on the thermoelectric figure of merit ZT. An increase with temperature of all these uncertainties is observed, in agreement with growing difficulties to measure these quantities when temperature increases. The uncertainties on the electrical resistivity and thermal diffusivity are most likely dominated by the uncertainty on the sample dimensions. The temperature-averaged (300-700 K) relative standard uncertainties at the confidence level of 68% amount to 6%, 8%, 11%, and 19% for the Seebeck coefficient, electrical resistivity, thermal conductivity, and figure of merit ZT, respectively. Thermal conductivity measurements appear as the least accurate. The moderate value of the temperature-averaged relative expanded (confidence level of 95%) uncertainty of 17% on the mean of ZT is essential in establishing Co0.97Ni0.03Sb3 as a high temperature standard n-type thermoelectric material.

Loudness modulation after transient and permanent hearing loss: implications for tinnitus and hyperacusis

Loudness is the primary perceptual correlate of sound intensity. The relationship between sound intensity and loudness is not fixed, and can be modified by short-term sound deprivation or stimulation. Deprivation increases sound sensitivity, whereas stimulation decreases it. We review the effects of short-term auditory deprivation and stimulation on the auditory central nervous system of humans and animals, and we extend the discussion to permanent auditory deprivation (hearing loss) and auditory pathologies of loudness perception. Although there is sufficient evidence to conclude that loudness can be modulated in normal hearing listeners by temporary sound deprivation and stimulation, evidence is scanter for the hearing-impaired listeners. In addition, cortical effects of sound deprivation and stimulation in humans, which may correlate with loudness coding, are still largely unknown and should be the target of future research.

The Combination of Rhythm and Pitch Can Account for the Beneficial Effect of Melodic Intonation Therapy on Connected Speech Improvements in Broca's Aphasia

Melodic intonation therapy (MIT) is a structured protocol for language rehabilitation in people with Broca's aphasia. The main particularity of MIT is the use of intoned speech, a technique in which the clinician stylizes the prosody of short sentences using simple pitch and rhythm patterns. In the original MIT protocol, patients must repeat diverse sentences in order to espouse this way of speaking, with the goal of improving their natural, connected speech. MIT has long been regarded as a promising treatment but its mechanisms are still debated. Recent work showed that rhythm plays a key role in variations of MIT, leading to consider the use of pitch as relatively unnecessary in MIT. Our study primarily aimed to assess the relative contribution of rhythm and pitch in MIT's generalization effect to non-trained stimuli and to connected speech. We compared a melodic therapy (with pitch and rhythm) to a rhythmic therapy (with rhythm only) and to a normally spoken therapy (without melodic elements). Three participants with chronic post-stroke Broca's aphasia underwent the treatments in hourly sessions, 3 days per week for 6 weeks, in a cross-over design. The informativeness of connected speech, speech accuracy of trained and non-trained sentences, motor-speech agility, and mood was assessed before and after the treatments. The results show that the three treatments improved speech accuracy in trained sentences, but that the combination of rhythm and pitch elicited the strongest generalization effect both to non-trained stimuli and connected speech. No significant change was measured in motor-speech agility or mood measures with either treatment. The results emphasize the beneficial effect of both rhythm and pitch in the efficacy of original MIT on connected speech, an outcome of primary clinical importance in aphasia therapy.

Melodic intonation therapy: back to basics for future research

We present a critical review of the literature on melodic intonation therapy (MIT), one of the most formalized treatments used by speech-language therapist in Broca's aphasia. We suggest basic clarifications to enhance the scientific support of this promising treatment. First, therapeutic protocols using singing as a speech facilitation technique are not necessarily MIT. The goal of MIT is to restore propositional speech. The rationale is that patients can learn a new way to speak through singing by using language-capable regions of the right cerebral hemisphere. Eventually, patients are supposed to use this way of speaking permanently but not to sing overtly. We argue that many treatment programs covered in systematic reviews on MIT's efficacy do not match MIT's therapeutic goal and rationale. Critically, we identified two main variations of MIT: the French thérapie mélodique et rythmée (TMR) that trains patients to use singing overtly as a facilitation technique in case of speech struggle and palliative versions of MIT that help patients with the most severe expressive deficits produce a limited set of useful, readymade phrases. Second, we distinguish between the immediate effect of singing on speech production and the long-term effect of the entire program on language recovery. Many results in the MIT literature can be explained by this temporal perspective. Finally, we propose that MIT can be viewed as a treatment of apraxia of speech more than aphasia. This issue should be explored in future experimental studies.

Psychoacoustic assessment to improve tinnitus diagnosis

The diagnosis of tinnitus relies on self-report. Psychoacoustic measurements of tinnitus pitch and loudness are essential for assessing claims and discriminating true from false ones. For this reason, the quantification of tinnitus remains a challenging research goal. We aimed to: (1) assess the precision of a new tinnitus likeness rating procedure with a continuous-pitch presentation method, controlling for music training, and (2) test whether tinnitus psychoacoustic measurements have the sensitivity and specificity required to detect people faking tinnitus. Musicians and non-musicians with tinnitus, as well as simulated malingerers without tinnitus, were tested. Most were retested several weeks later. Tinnitus pitch matching was first assessed using the likeness rating method: pure tones from 0.25 to 16 kHz were presented randomly to participants, who had to rate the likeness of each tone to their tinnitus, and to adjust its level from 0 to 100 dB SPL. Tinnitus pitch matching was then assessed with a continuous-pitch method: participants had to match the pitch of their tinnitus to an external tone by moving their finger across a touch-sensitive strip, which generated a continuous pure tone from 0.5 to 20 kHz in 1-Hz steps. The predominant tinnitus pitch was consistent across both methods for both musicians and non-musicians, although musicians displayed better external tone pitch matching abilities. Simulated malingerers rated loudness much higher than did the other groups with a high degree of specificity (94.4%) and were unreliable in loudness (not pitch) matching from one session to the other. Retest data showed similar pitch matching responses for both methods for all participants. In conclusion, tinnitus pitch and loudness reliably correspond to the tinnitus percept, and psychoacoustic loudness matches are sensitive and specific to the presence of tinnitus.

Sr7Co4(CO3)O(13-δ) (δ = 1.64), an original cobaltite derivative of the Ruddlesden-Popper series

The oxycarbonate Sr7Co4(CO3)O11.36 exhibits a peculiar structure that has been characterized by combining transmission electron microscopy analyses and neutron diffraction. It consists of a regular intergrowth between the m = 2 and carbonated m = 3 members of the Sr(m+1)Co(m)O3(m+1) Ruddlesden-Popper (RP) series, Sr3Co2O5.87 and Sr4Co2(CO3)O5.49, respectively. A description of the structure is proposed to provide identification of the different building blocks. This material is semiconducting and presents a complex magnetic behavior, characteristic of what is observed for the RP(2) or RP(3) series, with a cobalt valency close to 2.7.

Gap detection deficits in humans with tinnitus as assessed with the acoustic startle paradigm: does tinnitus fill in the gap?

The measurement of tinnitus in humans relies on subjective measures such as self-report, visual analog scales and questionnaires. Gap detection impairments have been tested in animals in an attempt to objectify the presence of tinnitus. The main purpose of this study was to investigate the gap startle paradigm in human participants with high-frequency tinnitus. Fifteen adults with bilateral high-frequency tinnitus but normal hearing at standard frequencies and seventeen matched controls without tinnitus were tested. The psychoacoustic characteristics of the tinnitus spectrum (pitch and loudness) were assessed using novel participant-directed custom-made methods. The startle task consisted of startle-alone, prepulse inhibition and gap-in-noise condition at low- and high-background noise frequencies. All measurements were retested after several months. Data indicate normal prepulse inhibition but higher reactivity to the startle sounds in the tinnitus group in comparison with controls. Most importantly, the tinnitus group displayed a consistent deficit in gap processing at both low- and high-background noise frequencies. All effects were identified consistently and were reproducible at retest. We propose that the higher reactivity to startle might reflect hyperacusis and that the gap deficit might be an index of abnormal cortical auditory processing in tinnitus.

Tinnitus severity is reduced with reduction of depressive mood--a prospective population study in Sweden

Tinnitus, the perception of sound without external source, is a highly prevalent public health problem with about 8% of the population having frequently occurring tinnitus, and about 1-2% experiencing significant distress from it. Population studies, as well as studies on self-selected samples, have reported poor psychological well-being in individuals with tinnitus. However, no study has examined the long-term co-variation between mood and tinnitus prevalence or tinnitus severity. In this study, the relationship between depression and tinnitus prevalence and severity over a 2-year period was examined in a representative sample of the general Swedish working population. Results show that a decrease in depression is associated with a decrease in tinnitus prevalence, and even more markedly with tinnitus severity. Hearing loss was a more potent predictor than depression for tinnitus prevalence, but was a weaker predictor than depression for tinnitus severity. In addition, there were sex differences for tinnitus prevalence, but not for tinnitus severity. This study shows a direct and long-term association between tinnitus severity and depression.

Cortisol suppression and hearing thresholds in tinnitus after low-dose dexamethasone challenge

BACKGROUND

Tinnitus is a frequent, debilitating hearing disorder associated with severe emotional and psychological suffering. Although a link between stress and tinnitus has been widely recognized, the empirical evidence is scant. Our aims were to test for dysregulation of the stress-related hypothalamus-pituitary adrenal (HPA) axis in tinnitus and to examine ear sensitivity variations with cortisol manipulation.

METHODS

Twenty-one tinnitus participants and 21 controls comparable in age, education, and overall health status but without tinnitus underwent basal cortisol assessments on three non-consecutive days and took 0.5 mg of dexamethasone (DEX) at 23:00 on the first day. Cortisol levels were measured hourly the next morning. Detection and discomfort hearing thresholds were measured before and after dexamethasone suppression test.

RESULTS

Both groups displayed similar basal cortisol levels, but tinnitus participants showed stronger and longer-lasting cortisol suppression after DEX administration. Suppression was unrelated to hearing loss. Discomfort threshold was lower after cortisol suppression in tinnitus ears.

CONCLUSIONS

Our findings suggest heightened glucocorticoid sensitivity in tinnitus in terms of an abnormally strong glucocorticoid receptor (GR)-mediated HPA-axis feedback (despite a normal mineralocorticoid receptor (MR)-mediated tone) and lower tolerance for sound loudness with suppressed cortisol levels. Long-term stress exposure and its deleterious effects therefore constitute an important predisposing factor for, or a significant pathological consequence of, this debilitating hearing disorder.

Water quality trends in the last decade for ten watersheds dominated by diffuse pollution in Québec (Canada)

The aim of this work is to evaluate and discuss river water quality trends over the last decade in ten watersheds where diffuse pollution represents more than half of the annual load of phosphorus (P) and nitrogen (N). Trend analyses taking into account flow data indicate a significant reduction of total P in eight rivers, of ammonia N in five rivers, of nitrate + nitrite in four rivers, of total filtered N in three rivers and of suspended solids in two rivers. An increase of turbidity was observed in four rivers and, for fecal coliforms, no trends. P decrease can be explained by reduced mineral P inputs on cropped lands related to means such as agro-environmental fertilization plans and addition of phytase in pig and poultry feed. However, for seven of them, median P concentrations remain at least two times greater than the Québec water quality guideline for protection of rivers against eutrophication. Concentrations of other parameters remain problematic in some rivers too. These results indicate the need to continue the efforts for further diffuse pollution reduction. Future work should better quantify actions taken at the watershed scale to reduce diffuse pollution.

Polysomnographic and quantitative electroencephalographic correlates of subjective sleep complaints in chronic tinnitus

Chronic tinnitus, or the perception of hearing sounds without the presence of external stimulation, is estimated at about 10-15% of the population, with highest prevalence after 50 years of age. Sleep complaints are among the most prominent complaints accompanying tinnitus, but objective data are rare. In this study, we examined prospectively the subjective and objective sleep parameters of this patient population in order to determine differences in sleep disturbances associated with chronic tinnitus compared to matched controls. Forty-four subjects (22 with tinnitus and 22 controls without tinnitus), unselected with respect to sleep complaints, participated in this study. The analysis involved 1-week sleep diaries, subjective sleep questionnaires and 1 night of polysomnographic (PSG) assessment. Compared to matched controls, the tinnitus group showed lower subjective sleep quality as measured with the Pittsburgh Sleep Quality Index (PSQI) and sleep diaries, but no significant difference in objective polysomnograph sleep parameters (i.e. sleep latency, efficiency). However, quantitative non-rapid eye movement sleep analysis revealed lower spectral power in the delta frequency band in the tinnitus group compared to controls, and this decrease was correlated with subjective sleep complaints (the lower the delta spectral power, the greater the complaints). This is the first report of an electrophysiological correlate of sleep difficulties supportive of subjective sleep complaints in the tinnitus population.

Experimental study of the incoherent spectral weight in the photoemission spectra of the misfit cobaltate [Bi_{2}Ba{2}O{4}][CoO{2}]{2}

Previous angle-resolved photoemission spectroscopy experiments in NaxCoO2 reported both a strongly renormalized bandwidth near the Fermi level and moderately renormalized Fermi velocities, leaving it unclear whether the correlations are weak or strong and how they could be quantified. We explain why this situation occurs and solve the problem by extracting clearly the coherent and incoherent parts of the band crossing the Fermi level. We show that one can use their relative weight to estimate self-consistently a quasiparticle weight Z=0.15+/-0.05. We suggest this method could be a reliable way to study the evolution of correlations in cobaltates and for comparison with other strongly correlated systems.

Metallicity and positive magnetoresistance induced by Pb substitution in a misfit cobaltate crystal

We have synthesized single crystals of the misfit-layered cobalt oxide, [Bi(1.5)Pb(0.5)Sr(2)O(4-δ)][CoO(2)](1.86), with quadruple NaCl-type layers, using a flux method, and measured their transport properties. From structural refinements, it is found that the modulation in the BiO layer observed in [Bi(1.74)Sr(2)O(4-δ)](RS)[CoO(2)](1.82) is suppressed by Pb substitution. The in-plane resistivity, thermopower, and Hall coefficient are 4.3  mΩ cm, 101  µV K(-1), and 1 × 10(-2) cm(3) C(-1) at 300 K, respectively; these are consistent with those of the misfit-layered cobalt oxides. All of these values are smaller than those of [Bi(1.74)Sr(2)O(4)][CoO(2)](1.82), indicating that the carrier concentration is larger than that of the undoped crystal. Moreover, the low T upturn of resistivity observed for most of the cobalt misfit oxides is replaced by a metallic behavior, following a T(2) dependence, indicating strong correlations in the Pb-doped crystal. Also, the magnetoresistance, usually negative for misfit oxides, is replaced by a small positive magnetoresistance. Doping with Pb is thus an efficient way to suppress the low T localized behavior usually observed for misfits.

Sleep complaints in elderly tinnitus patients: a controlled study

OBJECTIVES

Sleep difficulties are among the most frequent complaints associated with tinnitus. Yet most studies reporting on this problem are rather succinct, and all of them lack proper age- and health-matched control subjects.

DESIGN

The present study reports on 102 participants (51 with and 51 without tinnitus), assessed with the Pittsburgh Sleep Quality Index (PSQI), the Beck-II depression inventory, a hyperacusis questionnaire, and a tinnitus-reaction questionnaire (tinnitus group only). Participants were matched for health and relevant socioeconomic factors.

RESULTS

Results show that tinnitus patients have greater self-reported sleep difficulties compared with control subjects, specifically sleep efficiency and sleep quality, and that high tinnitus-related distress is associated with greater sleep disturbance.

CONCLUSIONS

Rather than hearing loss, sleep complaints in this population are mainly explained by hyperacusis, a hallmark of tinnitus, and to a lesser extent by subclinical depressive symptoms.

Correlation of structural, magnetic and transport properties with the tolerance factor in a low-doped La(0.875)Sr(0.125-x)Ca(x)MnO(3), (0 ≤x≤0.125) system: cross-over from Mott to Shklovskii-Efros variable range hopping conduction

Samples of the low-doped manganite La(0.875)Sr(0.125-x)Ca(x)MnO(3) (0≤x≤0.125) have been synthesized and the effect on the structural, magnetic and transport properties of decreasing the tolerance factor by replacing larger Sr(2+) ions with smaller Ca(2+) ions are reported. For samples with x≥0.0625, a concentration (x) dependent structural transition (rhombohedral ([Formula: see text]) to orthorhombic (Pnma)) has been detected at room temperature and the Curie temperature T(C) is found to decrease with increased Ca doping level. For samples with x≤0.0625, a narrow metallic region exists and the corresponding insulator to metal transition temperature T(MI) decreases with increasing Ca content, i.e. decreasing tolerance factor. In the paramagnetic region, x dependent crossover from Mott variable range hopping (Mott-VRH) to Shklovskii-Efros variable range hopping (SE-VRH) occurs as the Ca content increases. The thermoelectric power (TEP) of the samples increases substantially, varying inversely with the tolerance factor. These results are analysed from the consideration of increased bending of the Mn-O-Mn bond with the decrease of the average ionic radius of the A-site element [Formula: see text] and the tolerance factor t, which causes narrowing of the bandwidth, decrease of mobility of e(g) electrons and weakening of the double exchange (DE) interaction associated with the substitution of Ca.

Electronic correlations in CoO2, the parent compound of triangular cobaltates

A 59Co NMR study of CoO2, the x=0 end member of AxCoO2 (A=Na,Li,...) cobaltates, reveals a metallic ground state, though with clear signs of strong electron correlations: low-energy spin fluctuations develop at wave vectors q not equal to 0 and a crossover to a Fermi-liquid regime occurs below a characteristic temperature T* approximately 7 K. Despite some uncertainty over the exact cobalt oxidation state in this material, the results show that electronic correlations are revealed as x is reduced below 0.3. The data are consistent with NaxCoO2 being close to the Mott transition in the x-->0 limit.

The sound of stress: Blunted cortisol reactivity to psychosocial stress in tinnitus sufferers

Clinical observations suggest that tinnitus is modulated by stress. However, there is little empirical data to support the link between stress and tinnitus. In this study, we measured the stress hormone cortisol to examine the reactivity of the hypothalamic-pituitary-adrenal (HPA) axis in tinnitus participants as well as in healthy controls without tinnitus. Eighteen participants with tinnitus and 18 controls without tinnitus were exposed to the Trier Social Stress Task and cortisol sampling and subjective ratings were obtained at regular intervals. Tinnitus participants displayed a blunted cortisol response to psychosocial stress, in comparison with healthy controls who had a typical cortisol release about 30 min after the beginning of the experiment. The blunted cortisol response displayed by the tinnitus participants suggests that they have an anomaly along the HPA axis. Their cortisol response is similar to that found in other bodily stress-related diseases and thus suggests that tinnitus is related to stress. However, tinnitus intensity might not be modulated by stress in a concurrent manner.