Sensation Level Research Articles

Pacing sensation with a second generation intercostal extravascular ICD lead

Abstract Background/Introduction An investigational intercostal extravascular ICD lead (EV-ICD Lead) has been developed to provide antitachycardia pacing and shock treatment of ventricular tachyarrhythmias when connected to a commercially available ICD pulse generator. Unlike other available extravascular ICD systems that achieve pacing with ring electrodes which transmit undirected current to cardiac and non-cardiac tissue alike, the intercostal EV-ICD Lead uses button-shaped electrodes backed by an insulative paddle to direct current toward excitable myocytes while minimizing undesired excitation of the adjacent tissues. Purpose The purpose of this analysis was to evaluate pacing sensation with the intercostal EV-ICD Lead connected to a commercially-available ICD pulse generator programmed to the maximum voltage output and pulse width settings. Methods In the STEP ICD Study (n=20), pacing sensation was evaluated at the pre-discharge visit while pacing at the maximum programmable voltage output (7.5 or 8.0 V, depending on manufacturer) and pulse width (1.5 or 2.0 ms). Sensation was reported by the patient as one of four choices: No Sensation, Sensation Only, Tolerable Pain or Intolerable Pain. Results Pacing sensation was assessed in 18 of 20 patients. One (1) patient did not undergo a pacing evaluation due to atrial fibrillation with rapid ventricular response. Responses were as follows: No Sensation in 4 (22%) patients, Sensation Only in 10 (56%) patients, Tolerable Pain in 3 (17%) and Intolerable Pain in 1 (6%). In no patient was the pain so severe that pacing capture threshold testing could not be completed. Of note, the single report of intolerable pain was only reported in the sitting posture. When tested supine, the patient reported sensation only. Conclusion(s) The design of the investigational intercostal EV-ICD Lead, with button-shaped electrodes backed by an insulative paddle, produced low levels of patient sensation at maximum output and pulse width. These sensation levels represent an improvement over designs that employ ring electrodes and indicate that antitachycardia pacing will be well tolerated with the novel EV-ICD Lead. These results corroborate the predictions about patient discomfort from in silico models.

Industry-Scalable Reusable Textile Electrodes for Neurostimulation Applications.

Neurostimulation delivers electrical pulses to modulate neuromuscular activity. Commonly used in medical interventions from pain relief to rehabilitation, neurostimulation typically uses manually placed hydrogel electrodes over the treated region. However, this method limits interventions requiring frequent, long-term daily use. To address this, novel fully textile electrodes are developed using industrial programmable knitting machines. These electrodes are designed to be washable, reusable, flexible, and breathable, with embedded interconnects. Textile electrodes are made of yarns with stainless steel and PEDOT-coated stainless steel conductive components. The electrodes' performance are compared with gel electrodes, characterizing impedance, sensorimotor stimulation thresholds, recruitment of induced movements, sensation levels, and perceived sensations. The effects of residential wash cycles and continuous use duration are also investigated. The proposed electrodes are found to perform similarly to hydrogel electrodes in all characterized metrics. No degradation in electrode performance is found after at least 30 wash cycles. Electrodes remained functionally intact after 1000 cycles of stretch loading at 50% of break strain. The textile electrodes consistently induced comfortable sensorimotor responses for at least six hours after donning. The proposed textile electrodes offer a novel and effective solution for neurostimulation interventions, paving the way for integration into smart garments and long-term wearable health technologies.

Disentangling Contact Location for Stretchable Tactile Sensors from Soft Waveguide Ultrasonic Scatter Signals

Flexible tactile sensors have the ability to provide unparalleled levels of tactile sensation, including information regarding roughness, contact force, and contact location. However, it remains a challenge to achieve precise contact location sensing that is decoupled from sensor strain and touching forces. This paper proposes a novel data‐driven approach for force contact location sensing (FCLS) with the influence of sensor strain and forces based on scatter signals (SS) of the ultrasonic waveguide. First, the envelope of the force contact scatter signal (FCSS) is extracted via the Hilbert transform, which retrieves the global features of SS. The time‐frequency spectrogram is obtained via continuous wavelet transform, which extracts the local features of SS. Second, a deep convolutional neural network (CNN) is utilized to extract these features separately and concentrate them together. Third, based on the outputs of the CNN, a multilayer perception regression model is applied to acquire the force contact location. The experimental results indicate that the accuracy of the proposed FCLS method has a mean absolute error of 0.627 mm and a mean relative error of 3.19%. This research provides a foundation for further multimodal sensing using ultrasonic waveguides and its application in robotic sensing.

Auditory decision-making deficits after permanent noise-induced hearing loss.

Loud noise exposure is one of the leading causes of permanent hearing loss. Individuals with noise-induced hearing loss (NIHL) suffer from speech comprehension deficits and experience impairments to cognitive functions such as attention and decision-making. Here, we tested whether a specific sensory deficit, NIHL, can directly impair auditory cognitive function. Gerbils were trained to perform an auditory decision-making task that involves discriminating between slow and fast presentation rates of amplitude-modulated (AM) noise. Decision-making task performance was assessed across pre-versus post-NIHL sessions within the same gerbils. A single exposure session (2 hours) to loud broadband noise (120 dB SPL) produced permanent NIHL with elevated threshold shifts in auditory brainstem responses (ABRs). Following NIHL, decision-making task performance was tested at sensation levels comparable to those prior to noise exposure in all animals. Our findings demonstrate NIHL diminished perceptual acuity, reduced attentional focus, altered choice bias, and slowed down evidence accumulation speed. Finally, video-tracking analysis of motor behavior during task performance demonstrates that NIHL can impact sensory-guided decision-based motor execution. Together, these results suggest that NIHL impairs the sensory, cognitive, and motor factors that support auditory decision-making.

Proprioceptive Sensation Levels of The Elbows of Physically Disabled Athletes.

The aim of this study was to compare elbow joint proprioception measurements between physically disabled individuals who are active in sports and those who are not. The study included 30 athletes, 30 sedentary individuals, 30 physically disabled athletes, and 30 physically disabled sedentary individuals as volunteers. Elbow joint proprioception measurements were conducted using a sensitive digital goniometer with a precision of 1 degree. The joint position sense test method was used to perform the active angle repetition technique. Target angles were determined to be 30°, 60°, and 120°. A significant difference was observed in the comparison of proprioception between the dominant and non-dominant elbow joints of athletes and physically disabled sedentary individuals (p<0.05). Elbow joint proprioception was found to be highest in physically disabled athletes at the target angles. Conversely, the lowest elbow joint proprioception levels were found in physically disabled sedentary patients compared with the other groups.

Effect of stimulus duration on estimates of human cochlear tuning

Auditory masking methods originally employed to assess behavioral frequency selectivity have evolved over the years to infer cochlear tuning. Behavioral forward masking thresholds for spectrally notched noise maskers and a fixed, low-level probe tone provide accurate estimates of cochlear tuning. Here, we use this method to investigate the effect of stimulus duration on human cochlear tuning at 500 Hz and 4 kHz. Probes were 20-ms sinusoids at 10 dB sensation level. Maskers were noises with a spectral notch symmetrically and asymmetrically placed around the probe frequency. For seven participants with normal hearing, masker levels at masking threshold were measured in forward masking for various notch widths and for masker durations of 30 and 400 ms. Measurements were fitted assuming rounded exponential filter shapes and the power spectrum model of masking, and equivalent rectangular bandwidths (ERBs) were inferred from the fits. At 4 kHz, masker thresholds were higher for the shorter maskers but ERBs were not significantly different for the two masker durations (ERB30ms=294 Hz vs. ERB400ms=277 Hz). At 500 Hz, by contrast, notched-noise curves were shallower for the 30-ms than the 400-ms masker, and ERBs were significantly broader for the shorter masker (ERB30ms=126 Hz vs. ERB400ms=55 Hz). We discuss possible factors that may underlay the duration effect at low frequencies and argue that it may not be possible to fully control for those factors. We conclude that tuning estimates are not affected by maker duration at high frequencies but should be measured and interpreted with caution at low frequencies.

Attenuation and distortion components of age-related hearing loss: Contributions to recognizing temporal-envelope filtered speech in modulated noise.

Older adults with hearing loss may experience difficulty recognizing speech in noise due to factors related to attenuation (e.g., reduced audibility and sensation levels, SLs) and distortion (e.g., reduced temporal fine structure, TFS, processing). Furthermore, speech recognition may improve when the amplitude modulation spectrum of the speech and masker are non-overlapping. The current study investigated this by filtering the amplitude modulation spectrum into different modulation rates for speech and speech-modulated noise. The modulation depth of the noise was manipulated to vary the SL of speech glimpses. Younger adults with normal hearing and older adults with normal or impaired hearing listened to natural speech or speech vocoded to degrade TFS cues. Control groups of younger adults were tested on all conditions with spectrally shaped speech and threshold matching noise, which reduced audibility to match that of the older hearing-impaired group. All groups benefitted from increased masker modulation depth and preservation of syllabic-rate speech modulations. Older adults with hearing loss had reduced speech recognition across all conditions. This was explained by factors related to attenuation, due to reduced SLs, and distortion, due to reduced TFS processing, which resulted in poorer auditory processing of speech cues during the dips of the masker.

Pharmacokinetics, safety, and efficacy of Fuqi Guben Gao in the treatment of kidney-yang deficiency syndrome: a randomized, double-blind phase I trial.

Introduction: Fuqi Guben Gao (FQGBG) is a botanical drug formulation composed of FuZi (FZ; Aconitum carmichaelii Debeaux [Ranunculaceae; Aconiti radix cocta]), Wolfberry (Lycium barbarum L. [Solanaceae; Lycii fructus]), and Cinnamon (Neolitsea cassia (L.) Kosterm. [Lauraceae; Cinnamomi cortex]). It has been used to clinically treat nocturia caused by kidney-yang deficiency syndrome (KYDS) for over 30years and warms kidney yang. However, the pharmacological mechanism and the safety of FQGBG in humans require further exploration and evaluation. Methods: We investigated the efficacy of FQGBG in reducing urination and improving immune organ damage in two kinds of KYDS model rats (hydrocortisone-induced model and natural aging model), and evaluated the safety of different oral FQGBG doses through pharmacokinetic (PK) parameters, metabonomics, and occurrence of adverse reactions in healthy Chinese participants in a randomized, double-blind, placebo-controlled, single ascending dose clinical trial. Forty-two participants were allocated to six cohorts with FQGBG doses of 12.5, 25, 50, 75, 100, and 125g. The PKs of FQGBG in plasma were determined using a fully validated LC-MS/MS method. Results: FQGBG significantly and rapidly improved the symptoms of increased urination in both two KYDS model rats and significantly resisted the adrenal atrophy in hydrocortisone-induced KYDS model rats. No apparent increase in adverse events was observed with dose escalation. Major adverse drug reactions included toothache, thirst, heat sensation, gum pain, diarrhea, abdominal distension, T-wave changes, and elevated creatinine levels. The PK results showed a higher exposure level of benzoylhypaconine (BHA) than benzoylmesaconine (BMA) and a shorter half-life of BMA than BHA. Toxic diester alkaloids, aconitine, mesaconitine, and hypaconitine were below the lower quantitative limit. Drug-induced metabolite markers primarily included lysophosphatidylcholines, fatty acids, phenylalanine, and arginine metabolites; no safety-related metabolite changes were observed. Conclusion: Under the investigated dosing regimen, FQGBG was safe. The efficacy mechanism of FQGBG in treating nocturia caused by KYDS may be related to the improvement of the hypothalamus-pituitary-adrenal axis function and increased energy metabolism. Clinical Trial Registration: https://www.chictr.org.cn/showproj.html?proj=26934, identifier ChiCTR1800015840.

Evaluation of Virtual Reality in the Reduction of Pain During Dressing Changes in Patients with Burn Wounds: A pilot study.

Burn injuries are among the most common life-threatening injuries for which medical attention is sought, and are accompanied by intense, severe pain, particularly during treatment. Burn therapy pain management with opioid and non-opioid analgesics is often insufficient when administered alone. Virtual reality (VR) interfaces provide an immersive experience that has demonstrable therapeutic benefits, including distraction from, and reduction of, pain. In this interventional pilot study, we assessed the correlation between VR and passive distraction and pain tolerance during burn wound treatment. This pilot study assessed patients undergoing burn wound dressing changes while receiving both pharmacological and VR intervention at [Removed for masked review]. Questionnaires and evaluation forms were subjectively completed by both patients and medical staff before and after treatment, and clinical metrics were recorded throughout the treatment. Forty-one patients ≥18 years old and 76.9% male that had primarily undergone ≥4 dressing changes before the study were included. Correlations were found between VR engagement during treatment and a decrease in subjective levels of nausea, anxiety, and pain sensation. Furthermore, high levels of VR engagement were correlated with high levels of VR enjoyment. These results suggest that highly engaging and enjoyable VR interfaces may reduce sensations of anxiety and pain in burn patients during dressing changes. Furthermore, these data suggest that VR technology may be applied as an adjunct therapy to pharmacological treatment in the standardization of burn wound care management. Further studies with control groups and larger sample populations are needed for better quantification of these benefits.

Acoustic change complex (ACC) as a new tool in assessment of hearing aid performance in children

ObjectiveTo evaluate the clinical use of acoustic change complex (ACC) as an objective tool in children who use hearing aids (H.As) and explore how far ACC threshold could be correlated to behavioral measures.Study designSixty Arabic-speaking children (34 boys & 26 girls) using binaural H.As participated in the present study. Their age ranged from 6 to 12 years. The short stimulus used in the present study to elicit ACC response was “gap in tone.” Evaluation of H.As of children was performed in the form of questionnaire, aided sound field thresholds, central auditory tests, and aided/unaided cortical ACC recordings. The replicated ACC waveforms were collected and analyzed, and the aided ACC responses were compared with unaided ACC in addition to correlation of ACC-GDT to behavioral thresholds/scores.ResultsThe highest percent of ACC detectability achieved with gap in tone with 50-ms duration. Percent detectability reached 65% in aided condition and decreased to 25% in unaided test condition. The aided ACC wave morphology showed no significant difference when compared with unaided condition; however, a significant decrease in ACC latency was observed in the aided condition. The ACC response was elicited easily at 40-dB sensation levels or at MCL in both conditions. The ACC-GDT showed correlation to questionnaire scores rather than behavioral test (AFT).ConclusionsACC to relatively short duration stimulus can be successfully recorded in hearing-impaired children in aided and unaided conditions. ACC response parameters (detectability and P1 latency) can reflect the benefit from H.As as an objective measure in evaluation of young children and difficult to test subjects with the usual subjective measures, and finally, ACC-GDT may add a predictive value to questionnaire scores which may help in case of inability of parents or caregivers to fulfill the entire questionnaire items.

Integrating the Living Wall with Mechanical Ventilation to Improve Indoor Thermal Environment in the Transition Season

A living wall, when integrated with a mechanical ventilation system, can effectively improve the indoor thermal environment and reduce indoor CO2 concentration during the transition season. In this study, a control experiment was conducted to analyze the effect of a living wall integrated with mechanical ventilation (LW-V) on indoor air quality. During the experiment, indoor air temperature, relative humidity, indoor air speed, and CO2 concentration were measured, while the skin temperature was monitored and subjective questionnaires were administered to 60 subjects. The results show that the indoor environment was effectively improved by employing the LW-V system, with the average indoor temperature decreasing by 1.45 °C, while relative humidity increased by 19.1%. Due to the plant photosynthesis, CO2 concentrations were reduced by 13.83 ppm. Meanwhile, the mean skin temperature was reduced by 0.18 °C and was closer to the neutral mean skin temperature. Questionnaire analysis reveals the LW-V system improved overall air freshness sensation and thermal comfort level by 1.09 and 0.53, respectively. The LW-V system improved the indoor thermal environment as well as air quality during the transition season significantly.

The Rapid Decline in Interaural-Time-Difference Sensitivity for Pure Tones Can Be Explained by Peripheral Filtering.

The interaural time difference (ITD) is a primary horizontal-plane sound localization cue computed in the auditory brainstem. ITDs are accessible in the temporal fine structure of pure tones with a frequency of no higher than about 1400Hz. How listeners' ITD sensitivity transitions from very best sensitivity near 700Hz to impossible to detect within 1 octave currently lacks a fully compelling physiological explanation. Here, it was hypothesized that the rapid decline in ITD sensitivity is dictated not by a central neural limitation but by initial peripheral sound encoding, specifically, the low-frequency (apical) portion of the cochlear excitation pattern produced by a pure tone. ITD sensitivity was measured in 16 normal-hearing listeners as a joint function of frequency (900-1500Hz) and level (10-50dB sensation level). Performance decreased with increasing frequency and decreasing sound level. The slope of performance decline was 90dB/octave, consistent with the low-frequency slope of the cochlear excitation pattern. Fine-structure ITD sensitivity near 1400Hz may be conveyed primarily by "off-frequency" activation of neurons tuned to lower frequencies near 700Hz. Physiologically, this could be realized by having neurons sensitive to fine-structure ITD up to only about 700Hz. A more extreme model would have only a single narrow channel near 700Hz that conveys fine-structure ITDs. Such a model is a major simplification and departure from the classic formulation of the binaural display, which consists of a matrix of neurons tuned to a wide range of relevant frequencies and ITDs.

Patient-reported outcomes during accelerating the en-masse retraction of the upper anterior teeth using low-intensity electrical stimulation: a randomized controlled trial

BackgroundLow-intensity electrical stimulation (LIES) is considered a relatively recent technology that has received little attention in orthodontics as a method of acceleration. This study aimed to evaluate patient-reported outcome measures when LIES is used to accelerate the en-masse retraction of the upper anterior teeth.Materials and methodsThe sample consisted of 40 patients (8 males, 32 females; mean age 21.1 ± 2.3 years), with Class II division I malocclusion who required extraction of the first premolars to retract upper anterior teeth. They were randomly assigned to the LIES group (n = 20) and the conventional en-masse retraction group (CER; n = 20). Patient responses regarding pain, discomfort, burning sensation, swelling, chewing difficulty, speech difficulty, and painkillers’ consumption were recorded at these nine assessment times: 24 h (T1), 3 days (T2), and 7 days (T3) after force application, then in the second month after 24 h (T4), 3 days (T5), and 7 days (T6) of force re-activation, and finally after 24 h (T7), 3 days (T8), and 7 days (T9) of force re-activation in the third month.ResultsThe mean values of pain perception were smaller in the LIES group than those in the CER group at all assessment times with no statistically significant differences between the two groups except during the second and third months (T5, T6, T8, and T9; P < 0.005). However, discomfort mean values were greater in the LIES group with significant differences compared to CER group during the first week of the follow-up only (T1, T2, and T3; P < 0.005). Burning sensation levels were very mild in the LIES group, with significant differences between the two groups at T1 and T2 only (P < 0.001). Speech difficulty was significantly greater in the LIES group compared to CER group at all studied times (P < 0.001). High levels of satisfaction and acceptance were reported in both groups, without any significant difference.ConclusionBoth the LIES-based acceleration of en-masse retraction of upper anterior teeth and the conventional retraction were accompanied by mild to moderate pain, discomfort, and chewing difficulty on the first day of retraction. These sensations gradually decreased and almost disappeared over a week after force application or re-activation.Trial registrationClinicalTrials.gov, ClinicalTrials.gov, NCT05920525. Registered 17 June 2023 - retrospectively registered, http://clinicaltrials.gov/study/NCT05920525?term=NCT05920525&rank=1.

Respiratory symptom perception during exercise in patients with heart failure with preserved ejection fraction

We investigated whether central or peripheral limitations to oxygen uptake elicit different respiratory sensations and whether dyspnea on exertion (DOE) provokes unpleasantness and negative emotions in patients with heart failure with preserved ejection fraction (HFpEF). 48 patients were categorized based on their cardiac output (Q̇c)/oxygen uptake (V̇O2) slope and stroke volume (SV) reserve during an incremental cycling test. 15 were classified as centrally limited and 33 were classified as peripherally limited. Ratings of perceived breathlessness (RPB) and unpleasantness (RPU) were assessed (Borg 0–10 scale) during a 20 W cycling test. 15 respiratory sensations statements (1–10 scale) and 5 negative emotions statements (1−10) were subsequently rated. RPB (Central: 3.5±2.0 vs. Peripheral: 3.4±2.0, p=0.86), respiratory sensations, or negative emotions were not different between groups (p>0.05). RPB correlated (p<0.05) with RPU (r=0.925), “anxious” (r=0.610), and “afraid” (r=0.383). While DOE provokes elevated levels of negative emotions, DOE and respiratory sensations seem more related to a common mechanism rather than central and/or peripheral limitations in HFpEF.

Central Auditory Changes Associated with Age-related Hearing Loss.

Objective. This study aimed to investigate age-related changes in cortical auditory evoked potentials (CAEPs) while considering three crucial factors: aging, high-frequency hearing loss and sensation level of the CAEP stimulus. Method. The electrophysiological and audiometric data of 71 elderly participants were analyzed using multiple regression analysis to investigate the association of CAEPs with the factors of aging, high-frequency hearing loss and sensation level of the CAEP test stimulus. Results. Aging was significantly associated with prolonged N1 and P2 latencies and reduced P2 amplitude. Elevated thresholds related to the sensation level of the CAEP stimulus were significantly associated with increased N1 and P2 amplitudes and decreased N1 latency. A significant relationship was detected between high-frequency hearing thresholds and the shortening of P2 latencies and the reduction of P2 amplitudes. Conclusion. The results of this study highlight the complex interplay of aging, high-frequency hearing loss and the sensation level of the CAEP stimulus on CAEP components in elderly people. These factors should be considered in future research using CAEPs to enhance overall understanding of auditory processing in the aging population.

Towards ASSR-based hearing assessment using natural sounds

Objective. The auditory steady-state response (ASSR) allows estimation of hearing thresholds. The ASSR can be estimated from electroencephalography (EEG) recordings from electrodes positioned on both the scalp and within the ear (ear-EEG). Ear-EEG can potentially be integrated into hearing aids, which would enable automatic fitting of the hearing device in daily life. The conventional stimuli for ASSR-based hearing assessment, such as pure tones and chirps, are monotonous and tiresome, making them inconvenient for repeated use in everyday situations. In this study we investigate the use of natural speech sounds for ASSR estimation. Approach. EEG was recorded from 22 normal hearing subjects from both scalp and ear electrodes. Subjects were stimulated monaurally with 180 min of speech stimulus modified by applying a 40 Hz amplitude modulation (AM) to an octave frequency sub-band centered at 1 kHz. Each 50 ms sub-interval in the AM sub-band was scaled to match one of 10 pre-defined levels (0–45 dB sensation level, 5 dB steps). The apparent latency for the ASSR was estimated as the maximum average cross-correlation between the envelope of the AM sub-band and the recorded EEG and was used to align the EEG signal with the audio signal. The EEG was then split up into sub-epochs of 50 ms length and sorted according to the stimulation level. ASSR was estimated for each level for both scalp- and ear-EEG. Main results. Significant ASSRs with increasing amplitude as a function of presentation level were recorded from both scalp and ear electrode configurations. Significance. Utilizing natural sounds in ASSR estimation offers the potential for electrophysiological hearing assessment that are more comfortable and less fatiguing compared to existing ASSR methods. Combined with ear-EEG, this approach may allow convenient hearing threshold estimation in everyday life, utilizing ambient sounds. Additionally, it may facilitate both initial fitting and subsequent adjustments of hearing aids outside of clinical settings.

Hot, cold, or just right? An infrared biometric sensor to improve occupant comfort and reduce overcooling in buildings via closed-loop control

To improve occupant comfort and save energy in buildings, we have developed a closed-loop air conditioning (AC) sensor-controller that predicts occupant thermal sensation from the thermographic measurement of skin temperature distribution, then uses this information to reduce overcooling (cooling-energy overuse that discomforts occupants) by regulating AC output. Taking measures to protect privacy, it combines thermal-infrared (TIR) and color (visible spectrum) cameras with machine vision to measure the skin-surface temperature profile. Since the human thermoregulation system uses skin blood flow to maintain thermoneutrality, the distribution of skin temperature can be used to predict warm, neutral, and cool thermal states. We conducted a series of human-subject thermal-sensation trials in cold-to-hot environments, measuring skin temperatures and recording thermal sensation votes. We then trained random-forest classification machine-learning models (classifiers) to estimate thermal sensation from skin temperatures or skin-temperature differences. The estimated thermal sensation was input to a proportional integral (PI) control algorithm for the AC, targeting a sensation level between neutral and warm. Our sensor-controller includes a sensor assembly, server software, and client software. The server software orients the cameras and transmits images to the client software, which in turn assesses occupant skin temperature distribution, estimates occupant thermal sensation, and controls AC operation. A demonstration conducted in a conference room in an office building near Houston, TX showed that our system reduced overcooling, decreasing AC load by 42% when the room was occupied while improving occupant comfort (fraction of “comfortable” votes) by 15 percentage points.

Characterizing inner-hair-cell specific dysfunction from spike-train-derived transduction functions using a phenomenological auditory-nerve model

The impact of outer-hair-cell damage on sensorineural hearing loss (SNHL) has been extensively studied compared with inner-hair-cell (IHC) damage (e.g., stereocilial). Pre-clinical SNHL animal models provide unique data to directly address IHC-specific deficits (e.g., carboplatin-exposed chinchillas). Spike-train data (period histograms) to low sound level tones can be used to derive IHC-transduction functions by mapping instantaneous spike rates to corresponding sinusoidal pressure values (Horst et al., 2018). However, this approach depends on sensation level and spontaneous rate, which are both affected by IHC dysfunction. To better understand the effect of these dependencies, we used a phenomenological auditory-nerve (AN) model (Bruce et al., 2018) that provides parametric control over IHC and OHC dysfunction allowing exploration of optimal experimental design. Here, we explore the utility of spike-train-derived IHC-transduction functions in capturing parametric changes in IHC dysfunction as currently implemented in the AN model. We used unsupervised methods and information-theoretic approaches to quantify the dependency of transduction functions on IHC dysfunction. We also compared model findings with AN-fiber data recorded from carboplatin-exposed chinchillas. Preliminary findings suggest that transduction functions obtained from the AN model can capture IHC-specific dysfunction within specific regimes of controllable model parameters, thus showing promise for characterizing IHC dysfunction.

Self-administered, internet-enabled, modified rhyme test (MRT) for evaluating consonant confusion in remote subjects

A self-administered MRT has been developed for persons unable to attend on-site for testing. Subjects remotely log on to a website and are instructed to use their own computer and headphones or earphones/earbuds and seek a quiet location without distractions for the test. After inputting personal identification, the software produces the maximum and minimum intensity sounds that will be heard to allow the subject to adjust the audio gain to a comfortable listening level. The subject is then instructed not to re-adjust the audio gain during the MRT. Each trial is initiated by the subject and consists of the forced choice of one of six rhyming words, which is embedded in a carrier sentence. The pre-recorded speech in a single test, consisting of 25 trials, is replayed at a pre-selected, fixed speech signal-to-noise ratio. The internet-enabled MRT has been validated for subjects with believed normal hearing (N = 18) by comparison with a conventional MRT in our audiology clinic in which subjects' hearing thresholds were determined, and stimuli were presented at a prescribed sensation level (N = 7). Results were also compatible with word scores obtained on-site without audiological controls when subjects wore high-fidelity headphones (N = 6). [Work supported by NIOSH and the Alpha Foundation.]

An audibility model of the headband trial with a bone conduction device in single-sided deaf subjects

Objective Modelling the head-shadow effect compensation and speech recognition outcomes, we aimed to study the benefits of a bone conduction device (BCD) during the headband trial for single-sided deafened (SSD) subjects. Design This study is based on a database of individual patient measurements, fitting parameters, and acoustic BCD properties retrospectively measured on a skull simulator or from existing literature. The sensation levels of the Bone-Conduction and Air-Conduction sound paths were compared, modelling three spatial conditions with speech in quiet. We calculated the phoneme score using the Speech Intelligibility Index for the three conditions in quiet and seven in noise. Study sample Eighty-five SSD adults fitted with BCD during headband trial. Results According to our model, most subjects did not achieve a full head-shadow effect compensation with the signal at the BCD side and in front. The modelled speech recognition in the quiet conditions did not improve with the BCD on the headband. In noise, we found a slight improvement in some specific conditions and minimal worsening in others. Conclusions Based on an audibility model, this study challenges the fundamentals of a BCD headband trial in SSD subjects. Patients should be counselled regarding the potential outcome and alternative approaches.