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BACKGROUND: The heterogeneity of tinnitus is thought to underlie the lack of objective diagnostic measures. METHODS: Longitudinal data from 20,349 participants of the Swedish Longitudinal Occupational Survey of Health (SLOSH) cohort from 2008 to 2018 were used to understand the dynamics of transition between occasional and constant tinnitus. The second part of the study included electrophysiological data from 405 participants of the Swedish Tinnitus Outreach Project (STOP) cohort. RESULTS: We determined that with increasing frequency of the occasional perception of self-reported tinnitus, the odds of reporting constant tinnitus after 2 years increases from 5.62 (95% CI, 4.83–6.55) for previous tinnitus (sometimes) to 29.74 (4.82–6.55) for previous tinnitus (often). When previous tinnitus was reported to be constant, the odds of reporting it as constant after 2 years rose to 603.02 (524.74–692.98), suggesting that once transitioned to constant tinnitus, the likelihood of tinnitus to persist was much greater. Auditory brain stem responses (ABRs) from subjects reporting nontinnitus (controls), occasional tinnitus, and constant tinnitus show that wave V latency increased in constant tinnitus when compared with occasional tinnitus or nontinnitus. The ABR from occasional tinnitus was indistinguishable from that of the nontinnitus controls. CONCLUSIONS: Our results support the hypothesis that the transition from occasional to constant tinnitus is accompanied by neuronal changes in the midbrain leading to a persisting tinnitus, which is then less likely to remit. FUNDING: This study was supported by the GENDER-Net Co-Plus Fund (GNP-182), the European Union's Horizon 2020 grants no. 848261 (Unification of Treatments and Interventions for Tinnitus [UNITI]) and no. 722046 (European School for Interdisciplinary Tinnitus Research [ESIT]).

Organs for donation are in short supply in the United Kingdom, resulting in allegations that relatives of potential donors are not being asked for consent. Legislation on "required request" has been proposed to overcome this. The incidence, causes, complications, and patterns of organ donation in brain stem dead patients in one referral centre were studied over 12 months. Data were collected on all patients fulfilling criteria for brain stem death or considered suitable for donating organs after circulatory arrest. Forty two patients fulfilled the criteria for brain stem death, and in 10 further patients circulatory arrest occurred before formal testing was finished. The major causes of brain stem death were head injury (28) and intracranial haemorrhage (17). Consent to organ donation was obtained for 24 potential donors, and organs were donated by 23 of them. Twenty nine patients did not donate organs. The commonest reasons for failure to donate were medical unsuitability (13) and the coroner not releasing the body (eight). Consent was not sought in three cases, and the relatives refused consent in the remaining five. This study suggests that required request will not considerably increase the supply of donor organs.

OBJECTIVES: Determine whether auditory brainstem response (ABR) wave I amplitude is associated with measures of auditory perception in young people with normal distortion product otoacoustic emissions (DPOAEs) and varying levels of noise exposure history. DESIGN: Tinnitus, loudness tolerance, and speech perception ability were measured in 31 young military Veterans and 43 non-Veterans (19–35 years of age) with normal pure tone thresholds and DPOAEs. Speech perception was evaluated in quiet using NU-6 word lists and in background noise using the words in noise (WIN) test. Loudness discomfort levels were measured using 1, 3, 4, and 6 kHz pulsed pure tones. DPOAEs and ABRs were collected in each participant to assess outer hair cell (OHC) and auditory nerve function. RESULTS: The probability of reporting tinnitus in this sample increased by a factor of 2.0 per 0.1 μV decrease in ABR wave I amplitude (95% Bayesian confidence interval = 1.1 to 5.0) for males and by a factor of 2.2 (95% confidence interval = 1.0 to 6.4) for females after adjusting for sex and DPOAE levels. Similar results were obtained in an alternate model adjusted for pure tone thresholds in addition to sex and DPOAE levels. No apparent relationship was found between wave I amplitude and either loudness tolerance or speech perception in quiet or noise. CONCLUSIONS: Reduced ABR wave I amplitude was associated with an increased risk of tinnitus, even after adjusting for DPOAEs and sex. In contrast, wave III and V amplitudes had little effect on tinnitus risk. This suggests that changes in peripheral input at the level of the inner hair cell (IHC) or auditory nerve may lead to increases in central gain that give rise to the perception of tinnitus. Although the extent of synaptopathy in the study participants cannot be measured directly, these findings are consistent with the prediction that tinnitus may be a perceptual consequence of cochlear synaptopathy.

AbstractCortical function and related cognitive, language, and communication skills are genetically influenced. The auditory brainstem response to speech is linked to language skill, reading ability, cognitive skills, and speech‐in‐noise perception; however, the impact of shared genetic and environmental factors on the response has not been investigated. We assessed auditory brainstem responses to speech presented in quiet and background noise from (1) 23 pairs of same sex, same learning diagnosis siblings (Siblings), (2) 23 unrelated children matched on age, sex, IQ, and reading ability to one of the siblings (Reading‐Matched), and (3) 22 pairs of unrelated children matched on age and sex but not on reading ability to the same sibling (Age/Sex‐Matched). By quantifying response similarity as the intersubject response‐to‐response correlation for sibling pairs, reading‐matched pairs, and age‐ and sex‐matched pairs, we found that siblings had more similar responses than age‐ and sex‐matched pairs and reading‐matched pairs. Similarity of responses between siblings was as high as the similarity of responses collected from an individual over the course of the recording session. Responses from unrelated children matched on reading were more similar than responses from unrelated children matched only on age and sex, supporting previous data linking variations in auditory brainstem activity with variations in reading ability. These results suggest that auditory brainstem function can be influenced by siblingship and auditory‐based communication skills such as reading, motivating the use of speech‐evoked auditory brainstem responses for assessing risk of reading and communication impairments in family members.

Former public school teacher Eric Eisenbrey started a microschool in rural West Virginia because he wanted to help children in an individualized, not standardized, way.

AbstractThis study investigated neural activation patterns during verb processing in children, using fMRI (functional Magnetic Resonance Imaging). Preschool children (aged 4–6) passively listened to lists of verbs and adjectives while neural activation was measured. Findings indicated that verbs were processed differently than adjectives, as the verbs recruited motor systems in the frontal cortex during auditory perception, but the adjectives did not. Further evidence suggested that different types of verbs activated different regions in the motor cortex. The results demonstrate that the motor system is recruited during verb perception in the developing brain, reflecting the embodied nature of language learning and processing.

AbstractDeficits in identification and discrimination of sounds with short inter‐stimulus intervals or short formant transitions in children with specific language impairment (SLI) have been taken to reflect an underlying temporal auditory processing deficit. Using the sustained frequency following response (FFR) and the onset auditory brainstem responses (ABR) we evaluated if children with SLI show abnormalities at the brainstem level consistent with a temporal processing deficit. To this end, the neural encoding of tonal sweeps, as reflected in the FFR, for different rates of frequency change, and the effects of reducing inter‐stimulus interval on the ABR components were evaluated in 10 4–11‐year‐old SLI children and their age‐matched controls. Results for the SLI group showed degraded FFR phase‐locked neural activity that failed to faithfully track the frequency change presented in the tonal sweeps, particularly at the faster sweep rates. SLI children also showed longer latencies for waves III and V of the ABR and a greater prolongation of wave III at high stimulus rates (>30/sec), suggesting greater susceptibility to neural adaptation. These results taken together appear to suggest a disruption in the temporal pattern of phase‐locked neural activity necessary to encode rapid frequency change and an increased susceptibility to desynchronizing factors related to faster rates of stimulus presentation in children with SLI.

In vivo intracellular responses to auditory stimuli revealed that, in a particular population of cells of the ventral nucleus of the lateral lemniscus (VNLL) of rats, fast inhibition occurred before the first action potential. These experimental data were used to constrain a leaky integrate-and-fire (LIF) model of the neurons in this circuit. The post-synaptic potentials of the VNLL cell population were characterized using a method of triggered averaging. Analysis suggested that these inhibited VNLL cells produce action potentials in response to a particular magnitude of the rate of change of their membrane potential. The LIF model was modified to incorporate the VNLL cells' distinctive action potential production mechanism. The model was used to explore the response of the population of VNLL cells to simple speech-like sounds. These sounds consisted of a simple tone modulated by a saw tooth with exponential decays, similar to glottal pulses that are the repeated impulses seen in vocalizations. It was found that the harmonic component of the sound was enhanced in the VNLL cell population when compared to a population of auditory nerve fibers. This was because the broadband onset noise, also termed spectral splatter, was suppressed by the fast onset inhibition. This mechanism has the potential to greatly improve the clarity of the representation of the harmonic content of certain kinds of natural sounds.