Is it too loud? Ask your brain!

PURPOSE: In this study, the objectification of the subjective perception of loudness was investigated using electroencephalography (EEG). In particular, the emergence of objective markers in the domain of the acoustic discomfort threshold was examined. METHODS: A cohort of 27 adults with normal hearing, aged between 18 and 30, participated in the study. The participants were presented with 500 ms long noise stimuli via in-ear headphones. The acoustic signals were presented with sound levels of [55, 65, 75, 85, 95 dB]. After each stimulus, the subjects provided their subjective assessment of the perceived loudness using a colored scale on a touchscreen. EEG signals were recorded, and afterward, event-related potentials (ERPs) locked to sound onset were analyzed. RESULTS: Our findings reveal a linear dependency between the N100 components and both the sound level and the subjective loudness categorization of the sound. Additionally, the data demonstrated a nonlinear relationship between the P300 potential and the sound level as well as for the subjective loudness rating. The P300 potential was elicited exclusively when the stimuli had been subjectively rated as "very loud" or "too loud". CONCLUSION: The findings of the present study suggest the possibility of the identification of the subjective uncomfortable loudness level by objective neural parameters.

Electroconvulsive therapy modulates loudness dependence of auditory evoked potentials: a pilot MEG study.

Introduction: Electroconvulsive therapy (ECT) remains a critical intervention for treatment-resistant depression (MDD), yet its neurobiological underpinnings are not fully understood. This pilot study aims to investigate changes in loudness dependence of auditory evoked potentials (LDAEP), a proposed biomarker of serotonergic activity, in patients undergoing ECT. Methods: High-resolution magnetoencephalography (MEG) was utilized to measure LDAEP in nine depressed patients receiving right unilateral ECT. We hypothesized that ECT would reduce the LDAEP slope, reflecting enhanced serotonergic neurotransmission. Depression severity and cognitive performance were assessed using the 24-item Hamilton Depression Rating Scale (HDRS24) and the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS), respectively. Results: Contrary to our hypothesis, findings indicated a significant increase in LDAEP post-ECT (t 8 = 3.17, p = .013). The increase in LDAEP was not associated with changes in depression severity or cognitive performance. Discussion: The observed increase in LDAEP suggests a more complex interaction between ECT and neurobiological systems, rather than a direct reflection of serotonergic neurotransmission. Potential mechanisms for this increase include ECT's impact on serotonergic, dopaminergic, glutamatergic, and GABAergic receptor activity, neuroplasticity involving brain-derived neurotrophic factor (BDNF), and inflammatory modulators such as TNF-α. Our results highlight the multifaceted effects of ECT on brain function, necessitating further research to elucidate these interactions.

Narrative analysis in individuals with Parkinson's disease following intensive voice treatment: secondary outcome variables from a randomized controlled trial.

Communication is often impaired in individuals with Parkinson's disease (PD), typically secondary to sensorimotor deficits impacting voice and speech. Language may also be diminished in PD, particularly for production and comprehension of verbs. Evidence exists that verb processing is influenced by motor system modulation suggesting that verb deficits in PD are underpinned by similarities in the neural representations of actions that span motor and semantic systems. Conversely, subtle differences in cognition in PD may explain difficulty in processing of complex syntactic forms, which increases cognitive demand and is linked to verb use. Here we investigated whether optimizing motor system support for vocal function (improving loudness) affects change in lexical semantic, syntactic, or informativeness aspects of spoken discourse. Picture description narratives were compared for 20 Control participants and 39 with PD, 19 of whom underwent Lee Silverman Voice Treatment (LSVT LOUD®). Treated PD narratives were also contrasted with those of untreated PD and Control participants at Baseline and after treatment. Controls differed significantly from the 39 PD participants for verbs per utterance, but this difference was largely driven by untreated PD participants who produced few utterances but with verbs, inflating their verbs per utterance. Given intervention, there was a significant increase in vocal loudness but no significant changes in language performance. These data do not support the hypothesis that targeting this speech motor system results in improved language production. Instead, the data provide evidence of considerable variability in measures of language production across groups, particularly in verbs per utterance.

Effects of fundamental frequency changes on spoken sound loudness.

This study aimed to investigate the perception of loudness in response to changes in fundamental frequency (F0) in spoken sounds, as well as the influence of linguistic background on this perceptual process. The results revealed that participants perceived changes in F0 to have accompanying changes in loudness, with a trend of lower F0 sounds being perceived as louder than higher F0 sounds. This finding contrasts with previous studies on pure tones, where increases in frequency typically led to increases in loudness. Furthermore, the study examined differences between two distinct groups of participants: Chinese-speaking and English-speaking individuals. It was observed that English-speaking participants exhibited a greater sensitivity to minor intensity changes compared to Chinese-speaking participants. This discrepancy in sensitivity suggests that linguistic background may play a significant role in shaping the perception of loudness in spoken sound. The study's findings contribute to our understanding of how F0 variations are perceived in terms of loudness, and highlight the potential impact of language experience on this perceptual process.

Difference between Quantitative Electroencephalography, Loudness Dependence of Auditory Evoked Potential, and Mismatch Negativity between a Manic and a Depressive Episode in a Single Bipolar Patient with Mixed Features.

This study compares the changes in Quantitative electroencephalography (QEEG), loudness dependence of auditory evoked potentials (LDAEP), and mismatch negativity (MMN) in the case of bipolar depression, mania, and euthymia in a single patient. the characteristic of QEEG in this patient with mixed depression was an increase in alpha; in mixed mania, there was little increase in alpha, and the decrease in delta, theta, and beta was noticeable. LDAEP increased more in the manic phase than in the depressive phase. In contrast, MMN decreased more in the manic than in the depressive phase. After remission of mania, QEEG, LDAEP, and MMN were re-measured. Compared with the manic phase, the decrease in delta, theta, and beta bands in the occipital, temporal, and parietal lobes improved significantly. The LDAEP decreased from LDAEP 1.67 to 0.97. However, in spite of the euthymic phase, MMN amplitude showed a further decrease, from -1.7 to -0.9. In conclusion, using QEEG, LDAEP, and MMN can help clinicians predict a patient's bipolar state and evaluate serotonin intensity and cognitive function, enabling customized treatment. However, there are still few consistent research results; therefore, there is a need to utilize a larger sample size.

The Cambridge aided loudness profile (CALP): item choices and data for unaided listening by young and older normal-hearing listeners and older hearing-impaired listeners.

OBJECTIVE: To develop an improved version of the profile of aided loudness (PAL), intended for assessment of the appropriateness of the loudness of everyday sounds. DESIGN: Initially, 16 participants with a range of ages and degrees of hearing loss indicated whether they encountered each situation described in the PAL and how specific they considered the description to be. Based on the responses, most situations from the PAL were eliminated and new situations were introduced, giving the Cambridge Aided Loudness Profile (CALP). The CALP was administered to 80 young and 22 older participants with normal hearing, who rated the loudness of each situation and satisfaction with this loudness (as for the original PAL). Satisfaction was strongly negatively correlated with loudness, suggesting that satisfaction was largely based on loudness. The CALP was then administered to 32 new young normal-hearing participants and 49 older participants with hearing loss, most of whom used hearing aids, who rated loudness and the appropriateness of loudness. RESULTS: Some situations were rated as loud but appropriate in loudness, indicating that the CALP can distinguish these aspects. CONCLUSIONS: The CALP questions were understood by all participants. The CALP may be useful for assessing the appropriateness of loudness.

Voice self-assessment in individuals with Parkinson's Disease as compared to general voice disorders.

BACKGROUND: Individuals with Parkinson's Disease (IwPD) often fail to adjust their voice in different situations, without awareness of this limitation. Clinicians use self-report questionnaires that are typically designed for individuals with General Voice Disorders (GVD) in the vocal assessment of IwPD. However, these instruments may not consider that IwPD have a reduced self-perception of their vocal deficits. This study aimed to compare self-reported vocal symptoms and voice loudness between IwPD and GVD. METHODS: 28 IwPD and 26 with GVD completed the Voice Symptom Scale (VoiSS) questionnaire to evaluate their voice self-perception. Vocal loudness (dB) was also assessed. Univariate and multivariate analyses were used to compare the outcomes from these measures between the two groups. Principal Component Analysis and Hierarchical Clustering Analysis were applied to explore data patterns related to voice symptoms. RESULTS: IwPD reported significantly fewer vocal symptoms than those with GVD in all VoiSS questionnaire domains. Multivariate principal component analysis found no significant correlations between VoiSS scores and participant similarities in voice measures. Despite experiencing hypophonia, IwPD scored lower in all VoiSS domains but still fell in the healthy voice range. Hierarchical Clustering Analysis grouped participants into three distinct categories, primarily based on age, vocal loudness, and VoiSS domain scores, distinguishing between PD and GVD individuals. CONCLUSIONS: IwPD reported fewer vocal symptoms than GVD. The voice self-assessment seems to be unreliable to assess vocal symptoms in IwPD, at least regarding loudness. New self-report instruments tailored to PD individuals are needed due to their particular voice characteristics.

Evaluative audiometry after cochlear implant provision.

BACKGROUND: One of the main treatment goals in cochlear implant (CI) patients is to improve speech perception. One of the target parameters is speech intelligibility in quiet. However, treatment results show a high variability, which has not been sufficiently explained so far. The aim of this noninterventional retrospective study was to elucidate this variability using a selected population of patients in whom etiology was not expected to have a negative impact on postoperative speech intelligibility. MATERIALS AND METHODS: Audiometric findings of the CI follow-up of 28 adult patients after 6 months of CI experience were evaluated. These were related to the preoperative audiometric examination and evaluated with respect to a recently published predictive model for the postoperative monosyllabic score. RESULTS: Inclusion of postoperative categorical loudness scaling and hearing loss for Freiburg numbers in the model explained 55% of the variability in fitting outcomes with respect to monosyllabic word recognition. CONCLUSION: The results of this study suggest that much of the cause of variability in fitting outcomes can be captured by systematic postoperative audiometric checks. Immediate conclusions for CI system fitting adjustments may be drawn from these results. However, the extent to which these are accepted by individual patients and thus lead to an improvement in outcome must be subject of further studies, preferably prospective.

Early fitting in cochlear implant surgery: preliminary results.

PURPOSE: Cochlear implants are usually activated 3-5 weeks after surgery; to date, no universal protocol exists regarding switch on and fitting of these devices. The aim of the study was to assess safety and functional results of activation and fitting of cochlear implant within 24 h following surgery. METHODS: In this retrospective case-control study, 15 adult patients who underwent cochlear implant surgery, for a total of 20 cochlear implant procedures were analyzed. In particular, clinical safety and feasibility were investigated by examinating patients at activation and at each follow-up. Values of electrodes' impedance and most comfortable loudness (MCL) were analyzed from the time of surgery to 12 months after activation. Free-field pure tone average (PTA) was also recorded. RESULTS: No major or minor complications were reported and all patients could perform the early fitting. Activation modality influenced impedance values only in the short term but the differences were not statistically significant (p > 0.05). Mean MCL values in the early fitting group were lower than MCL of the late fitting in all follow-up sessions, and the difference was statistically significant (p < 0.05). The mean PTA was lower in the early fitting group but the difference was not statistically significant (p < 0.05). CONCLUSIONS: Early fitting of cochlear implants is safe, allows for an early rehabilitation and can have possible beneficial effects on stimulation levels and dynamic range.

On the Effect of High Stimulation Rates on Temporal Loudness Integration in Cochlear Implant Users.

Long stimuli have lower detection thresholds or are perceived louder than short stimuli with the same intensity, an effect known as temporal loudness integration (TLI). In electric hearing, TLI for pulse trains with a fixed rate but varying number of pulses, i.e. stimulus duration, has mainly been investigated at clinically used stimulation rates. To study the effect of an overall effective stimulation rate at 100% channel crosstalk, we investigated TLI with (a) a clinically used single-channel stimulation rate of 1,500 pps and (b) a high stimulation rate of 18,000 pps, both for an apical and a basal electrode. Thresholds (THR), a line of equal loudness (BAL), and maximum acceptable levels (MALs) were measured in 10 MED-EL cochlear implant users. Stimulus durations varied from a single pulse to 300 ms long pulse trains. At 18,000 pps, the dynamic range (DR) increased by 7.36±3.16 dB for the 300 ms pulse train. Amplitudes at THR, BAL, and MAL decreased monotonically with increasing stimulus duration. The decline was fitted with high accuracy with a power law function (R2=0.94±0.06). Threshold slopes were -1.05±0.36 and -1.66±0.30 dB per doubling of duration for the low and high rate, respectively, and were shallower than for acoustic hearing. The electrode location did not affect the amplitudes or slopes of the TLI curves. THR, BAL, and MAL were always lower for the higher rate and the DR was larger at the higher rate at all measured durations.

Acoustic and Subjective Basis of Emotional Perception in Comatose Patients: A Comparative Study.

Objective: : The acoustic stimulation in consciousness patients may improve the diagnosis assessment and the effectiveness of rehabilitation procedures. We aimed to investigate the event-related potential (ERP) response to emotional auditory stimuli in comatose patients. Methods: : We measured the nonlinear and linear electroencephalogram (EEG) features, prepared the acoustic analysis of stimuli parameters, and assessed the subjective emotional rates of stimuli characteristics. Results: : Patients with better outcomes had recognizable ERP responses and significant changes of the nonlinear EEG features to emotional sounds, unlike patients with worse outcomes. The response of comatose patients was attributed to acoustical features of emotional sounds, whereas the EEG response of healthy subjects was associated with their subjective feelings. The comatose patients demonstrated the variable EEG activity for neutral and emotional sounds. Conclusion: : Thus, the EEG reactivity followed the better outcome of comatose patients to emotional stimuli. The study assumed the substantial differences of emotional stimuli perception in the healthy and unconscious brain.

Distinguishing between straight and curved sounds: Auditory shape in pitch, loudness, and tempo gestures.

Sound-based trajectories or sound gestures draw links to spatiokinetic processes. For instance, a gliding, decreasing pitch conveys an analogous downward motion or fall. Whereas the gesture's pitch orientation and range convey its meaning and magnitude, respectively, the way in which pitch changes over time can be conceived of as gesture shape, which to date has rarely been studied in isolation. This article reports on an experiment that studied the perception of shape in uni-directional pitch, loudness, and tempo gestures, each assessed for four physical scalings. Gestures could increase or decrease over time and comprised different frequency and sound level ranges, durations, and different scaling contexts. Using a crossmodal-matching task, participants could reliably distinguish between pitch and loudness gestures and relate them to analogous visual line segments. Scalings based on equivalent-rectangular bandwidth (ERB) rate for pitch and raw signal amplitude for loudness were matched closest to a straight line, whereas other scalings led to perceptions of exponential or logarithmic curvatures. The investigated tempo gestures, by contrast, did not yield reliable differences. The reliable, robust perception of gesture shape for pitch and loudness has implications on various sound-design applications, especially those cases that rely on crossmodal mappings, e.g., visual analysis or control interfaces like audio waveforms or spectrograms. Given its perceptual relevance, auditory shape appears to be an integral part of sound gestures, while illustrating how crossmodal correspondences can underpin auditory perception.

Ceramic-on-Ceramic Total Hip Arthroplasty: I Can Hear You.

Background: Squeaking is a known complication of ceramic-on-ceramic (CoC) total hip arthroplasty (THA), yet there is a lack of studies specifically quantifying its loudness. The aims of this study were: (1) to determine the incidence of squeaking in CoC THAs at long-term follow-up; (2) to identify risk factors; and (3) to quantify the loudness of the squeaking. Methods: A specifically designed prospective questionnaire was used to determine the prevalence, characteristics, and loudness of squeaking in 130 (110 patients) primary THAs with fourth-generation CoC bearings at a mean follow-up of 10.5 years. The loudness of the squeaking was determined by the decibel (dB) scale from the Centers for Disease Control and Prevention. Results: Overall, 28% of the CoC hips experienced squeaking. The mean onset was 5.7 years postoperatively, with 39% of the cases having their onset more than 5 years after their THA. Patients with a lower body mass index were more likely to report squeaking (P = .009). The mean loudness of the squeak was 35 dB (range, 10-70 dB) and was loud in 36% of the hips. Patients who developed squeaking early postoperatively had louder squeaking than those with a later onset (P = .007). The loudness of the squeaking sound progressed in 25% of the cases, and these hips had louder squeaking (P = .04). Conclusions: Squeaking after CoC THA is not uncommon, can be relatively loud, and increases over time. This needs to be considered in young patients that are candidates for CoC THAs.

Development and Validation of a Nomogram to Predict the Risk of Tinnitus Severity in Patients With Unilateral Subjective Tinnitus.

Purpose: To develop and validate a nomogram for predicting the risk of tinnitus severity in patients with unilateral subjective tinnitus. Methods: The objective of this study was to establish and validate a nomogram specifically designed for patients with unilateral subjective tinnitus. We collected data on unilateral subjective tinnitus from the Air Force Medical Center, including 146 participants between January 2021 and June 2022. Risk factors for unilateral subjective tinnitus severity were evaluated by least absolute shrinkage and selection operator (LASSO) and binary logistic regression analysis. Internal verification was used to evaluate the performance of the nomogram. The discriminative ability was measured by the consistency index (C-indices) and the area under the curve (AUC) of the receiver operating characteristic (ROC) curves. Results: All included patients were randomized according to a 7:3 ratio into the training cohort (104 patients) and the validation cohort (42 patients). The LASSO regression model identified sex, tinnitus loudness, and hearing loss as candidate variables. Binary logistic regression analysis showed that gender (OR: 0.76; 95% CI: 0.6-0.95; P = 0.021) and tinnitus loudness (OR: 1.37; 95% CI: 1.09-1.72; P = 0.009) were significant predictors of unilateral subjective tinnitus severity, while age, tinnitus matching frequency, and tinnitus duration were not. The significant predictors were included in the nomogram. Hearing loss was included in the nomogram based on prior clinical experience and previous studies. The training and validation cohorts C-indexes were 0.707 (95% CI: 0.607-0.806) and 0.706 (95% CI: 0.548-0.863), respectively. The training and validation cohort's AUC of the ROC curves were 0.692 and 0.705, respectively. Conclusion: We have developed and validated a nomogram based on gender, hearing loss, and tinnitus loudness, which can effectively predict the risk of tinnitus severity in patients with unilateral subjective tinnitus. The nomogram provides personalized prediction results for patients with unilateral subjective tinnitus, which is beneficial for clinical decision-making and treatment plan development.

Sound Level Changes the Auditory Cortical Activation Detected with Functional Near-Infrared Spectroscopy.

BACKGROUND: Functional near-infrared spectroscopy (fNIRS) is a viable non-invasive technique for functional neuroimaging in the cochlear implant (CI) population; however, the effects of acoustic stimulus features on the fNIRS signal have not been thoroughly examined. This study examined the effect of stimulus level on fNIRS responses in adults with normal hearing or bilateral CIs. We hypothesized that fNIRS responses would correlate with both stimulus level and subjective loudness ratings, but that the correlation would be weaker with CIs due to the compression of acoustic input to electric output. METHODS: Thirteen adults with bilateral CIs and 16 with normal hearing (NH) completed the study. Signal-correlated noise, a speech-shaped noise modulated by the temporal envelope of speech stimuli, was used to determine the effect of stimulus level in an unintelligible speech-like stimulus between the range of soft to loud speech. Cortical activity in the left hemisphere was recorded. RESULTS: Results indicated a positive correlation of cortical activation in the left superior temporal gyrus with stimulus level in both NH and CI listeners with an additional correlation between cortical activity and perceived loudness for the CI group. The results are consistent with the literature and our hypothesis. CONCLUSIONS: These results support the potential of fNIRS to examine auditory stimulus level effects at a group level and the importance of controlling for stimulus level and loudness in speech recognition studies. Further research is needed to better understand cortical activation patterns for speech recognition as a function of both stimulus presentation level and perceived loudness.

[Evaluative audiometry after cochlear implant provision. German Version]. / Zur evaluierenden Audiometrie nach Cochlea-Implantat-Versorgung.

BACKGROUND: One of the main treatment goals in cochlear implant (CI) patients is to improve speech perception. One of the target parameters is speech intelligibility in quiet. However, treatment results show a high variability, which has not been sufficiently explained so far. The aim of this noninterventional retrospective study was to elucidate this variability using a selected population of patients in whom etiology was not expected to have a negative impact on postoperative speech intelligibility. MATERIALS AND METHODS: Audiometric findings of the CI follow-up of 28 adult patients after 6 months of CI experience were evaluated. These were related to the preoperative audiometric examination and evaluated with respect to a recently published predictive model for the postoperative monosyllabic score. RESULTS: Inclusion of postoperative categorical loudness scaling and hearing loss for Freiburg numbers in the model explained 55% of the variability in fitting outcomes with respect to monosyllabic comprehension. CONCLUSION: The results of this study suggest that much of the cause of variability in fitting outcomes can be captured by systematic postoperative audiometric checks. Immediate conclusions for CI system adjustments may be drawn from these results. However, the extent to which these are accepted by individual patients and thus lead to an improvement in outcome must be subject to further study, preferably prospective.

Loudness constancy for noise and speech: How instructions and source information affect loudness of distant sounds.

The physical properties of a sound evolve when traveling away from its source. As an example, the sound pressure level at the listener's ears will vary according to their respective distance and azimuth. However, several studies have reported loudness to remain constant when varying the distance between the source and the listener. This loudness constancy has been reported to occur when the listener focused attention on the sound as emitted by the source (namely the distal stimulus). Instead, the listener can focus on the sound as reaching the ears (namely the proximal stimulus). The instructions given to the listener when assessing loudness can drive focus toward the proximal or distal stimulus. However, focusing on the distal stimulus requires to have sufficient information about the sound source, which could be provided by either the environment or by the stimulus itself. The present study gathers three experiments designed to assess loudness when driving listeners' focus toward the proximal or distal stimuli. Listeners were provided with different quality and quantity of information about the source depending on the environment (visible or hidden sources, free field or reverberant rooms) and on the stimulus itself (noise or speech). The results show that listeners reported constant loudness when asked to focus on the distal stimulus only, provided enough information about the source was available. These results highlight that loudness relies on the way the listener focuses on the stimuli and emphasize the importance of the instructions that are given in loudness studies.

Machine learning-based classification using electroencephalographic multi-paradigms between drug-naïve patients with depression and healthy controls.

BACKGROUND: Electroencephalography (EEG) is a supplementary diagnostic tool in psychiatry but lacks practical usage. EEG has demonstrated inconsistent diagnostic ability because major depressive disorder (MDD) is a heterogeneous psychiatric disorder with complex pathologies. In clinical psychiatry, it is essential to detect these complexities using multiple EEG paradigms. Though the application of machine learning to EEG signals in psychiatry has increased, an improvement in its classification performance is still required clinically. We tested the classification performance of multiple EEG paradigms in drug-naïve patients with MDD and healthy controls (HCs). METHODS: Thirty-one drug-naïve patients with MDD and 31 HCs were recruited in this study. Resting-state EEG (REEG), the loudness dependence of auditory evoked potentials (LDAEP), and P300 were recorded for all participants. Linear discriminant analysis (LDA) and support vector machine (SVM) classifiers with t-test-based feature selection were used to classify patients and HCs. RESULTS: The highest accuracy was 94.52 % when 14 selected features, including 12 P300 amplitudes (P300A) and two LDAEP features, were layered. The accuracy was 90.32 % when a SVM classifier for 30 selected features (14 P300A, 14 LDAEP, and 2 REEG) was layered in comparison to each REEG, P300A, and LDAEP, the best accuracies of which were 71.57 % (2-layered with LDA), 87.12 % (1-layered with LDA), and 83.87 % (6-layered with SVM), respectively. LIMITATIONS: The present study was limited by small sample size and difference in formal education year. CONCLUSIONS: Multiple EEG paradigms are more beneficial than a single EEG paradigm for classifying drug-naïve patients with MDD and HCs.

Segregation and integration of sensory features by flexible temporal characteristics of independent neural representations.

Segregation and integration are two fundamental yet competing computations in cognition. For example, in serial speech processing, stable perception necessitates the sequential establishment of perceptual representations to remove irrelevant features for achieving invariance. Whereas multiple features need to combine to create a coherent percept. How to simultaneously achieve seemingly contradicted computations of segregation and integration in a serial process is unclear. To investigate their neural mechanisms, we used loudness and lexical tones as a research model and employed a novel multilevel oddball paradigm with Electroencephalogram (EEG) recordings to explore the dynamics of mismatch negativity (MMN) responses to their deviants. When two types of deviants were presented separately, distinct topographies of MMNs to loudness and tones were observed at different latencies (loudness earlier), supporting the sequential dynamics of independent representations for two features. When they changed simultaneously, the latency of responses to tones became shorter and aligned with that to loudness, while the topographies remained independent, yielding the combined MMN as a linear additive of single MMNs of loudness and tones. These results suggest that neural dynamics can be temporally synchronized to distinct sensory features and balance the computational demands of segregation and integration, grounding for invariance and feature binding in serial processing.

Limited Link of Common Blood Parameters with Tinnitus.

Background: Tinnitus severity is generally assessed by psychometric and audiological instruments. However, no objective measure exists to evaluate the subjective discomfort and suffering caused by this hearing phenomenon. The objective of this work was to determine the possible blood parameters for diagnostics and therapy. Methods: We measured tinnitus distress by using the Tinnitus Questionnaire (TQ) and collected tinnitus-related audiological measures, namely the hearing threshold (HT), tinnitus loudness (TL), and sensation level (SL, i.e., the tinnitus loudness/hearing threshold at a tinnitus frequency). Blood samples were taken from 200 outpatients of the Tinnitus Centre of the Charité, and 46 routine blood count parameters were examined. The possible interactions were determined by (robust) linear models. Results: Tinnitus distress and audiological measurements were largely uncorrelated but could partly be predicted by selected blood parameters. First, the erythrocyte counts predicted tinnitus distress to a small extent. Second, the levels of vitamin D3 explained about 6% of tinnitus loudness and, age-dependently, the hearing threshold variability. Last, the levels of uric acid explained about 5% of the sensation level variability. Conclusions: Tinnitus is a multidimensional phenomenon. The marginal influences of blood markers suggest the possible roles of inflammation and oxidative stress produced by psychological or somatic burdens. Clinically, a vitamin D substitution (in older patients) might have a hearing-protective effect.