Evidence for a left ear bias in incidence of Meniere's disease.

OBJECTIVE: To explore a side of lesion differences in Meniere's disease (MD). DESIGN: A retrospective review (2019-2021) was conducted of patients with definite MD, as defined by 2015 Bárány Society diagnostic criteria. Testing information included pure tone audiometry, tympanometry, and extra-tympanic electrocochleography (ECochG). Normative ECochG data from healthy subjects determined the 95% cut-off value for clinical abnormality. STUDY SAMPLE: 107 patients with definite MD were included in the study and 40 healthy controls. RESULTS: The review identified 75 patients with unilateral MD and 32 patients with bilateral MD according to their clinical histories. 79% of unilateral cases were found to have MD on the L ear. 94% of bilateral MD cases had L ears more affected than R ears. Objective ECochG testing indicated a greater incidence of elevated SP/AP area curve and amplitude ratios in L ears. On binomial testing, all results indicate a highly significant bias of MD to the L side. CONCLUSIONS: Unilateral MD appears more common on the L side than the R, suggesting that the disease process underlying MD is not symmetrical. MD also appears more common in females than males. It appears that there is a physiological asymmetry in the progression/cause of MD.

Measuring depth of anaesthesia using changes in directional connectivity: a comparison with auditory middle latency response and estimated bispectral index during propofol anaesthesia.

General anaesthesia is associated with changes in connectivity between different regions of the brain, the assessment of which has the potential to provide a novel marker of anaesthetic effect. We propose an index that quantifies the strength and direction of information flow in electroencephalographic signals collected across the scalp, assess its performance in discriminating 'wakefulness' from 'anaesthesia', and compare it with estimated bispectral index and the auditory middle latency response. We used a step-wise slow induction of anaesthesia in 10 patients to assess graded changes in electroencephalographic directional connectivity at propofol effect-site concentrations of 2 µg.ml-1 , 3 µg.ml-1 and 4 µg.ml-1 . For each stable effect-site concentration, connectivity was estimated from multichannel electroencephalograms using directed coherence, together with middle latency response and estimated bispectral index. We used a linear support vector machine classifier to compare the performance of the different electroencephalographic features in discriminating wakefulness from anaesthesia. We found a significant reduction in the strength of long-range connectivity (interelectrode distance > 10 cm) (p < 0.008), and a reversal of information flow from markedly postero-frontal to fronto-posterior (p < 0.006) between wakefulness and a propofol effect-site concentration of 2 µg.ml-1 . This then remained relatively constant as effect-site concentration increased, consistent with a step change in directed coherence with anaesthesia. This contrasted with the gradual change with increasing anaesthetic dose observed for estimated bispectral index and middle latency response. Directed coherence performed best in discriminating wakefulness from anaesthesia with an accuracy of 95%, indicating the potential of this new method (on its own or combined with others) for monitoring adequacy of anaesthesia.

A group sequential test for ABR detection.

Objective: To detect the auditory brainstem response (ABR) automatically using an innovative sequentially applied Hotelling's T 2 test, with the overall goal of optimising test time whilst controlling the false-positive rate (FPR). Design: The stage-wise critical decision boundaries for accepting or rejecting the null hypothesis were found using a new approach called the Convolutional Group Sequential Test (CGST). Specificity, sensitivity, and test time were evaluated using simulations and subject recorded data. Study sample: Data consists of click-evoked ABR threshold series from 12 normal hearing adults, and recordings of EEG background activity from 17 normal hearing adults. Results: Reductions in mean test time of up to 40-45% were observed for the sequential test, relative to a conventional "single shot" test where the statistical test is applied to the data just once. To obtain these results, it will occasionally be necessary to run the test to a higher number of stimuli, i.e. the maximum test time needs to be increased. Conclusions: The CGST can be used to control the specificity of a sequentially applied ABR detection method. Doing so can reduce test time, relative to the "single shot" test, when considered across a cohort of test subjects.

Objective measures for detecting the auditory brainstem response: comparisons of specificity, sensitivity and detection time.

OBJECTIVE: To evaluate and compare the specificity, sensitivity and detection time of various time-domain and multi-band frequency domain methods when detecting the auditory brainstem response (ABR). DESIGN: Simulations and subject recorded data were used to assess and compare the performance of the Hotelling's T2 test (applied in either time or frequency domain), two versions of the modified q-sample uniform scores test and both the Fsp and Fmp, which were evaluated using both conventional F-distributions with assumed degrees of freedom and a bootstrap approach. STUDY SAMPLE: Data consisted of click-evoked ABRs and recordings of EEG background activity from 12 to 17 normal hearing adults, respectively. RESULTS: An overall advantage in sensitivity and detection time was demonstrated for the Hotelling's T2 test. The false-positive rates (FPRs) of the Fsp and Fmp were also closer to the nominal alpha-level when evaluating statistical significance using the bootstrap approach, as opposed to using conventional F-distributions. The FPRs of the remaining methods were slightly higher than expected. CONCLUSIONS: In this work, Hotelling's T2 outperformed the alternative methods for automatically detecting ABRs. Its promise as a sensitive and efficient detection method should now be tested in a larger clinical study.

Gaussian Processes for Hearing Threshold Estimation Using Auditory Brainstem Responses.

The Auditory Brainstem Response (ABR) plays an important role in diagnosing and managing hearing loss, but can be challenging and time-consuming to measure. Test times are especially long when multiple ABR measurements are needed, e.g., when estimating hearing threshold at a range of frequencies. While many detection methods have been developed to reduce ABR test times, the majority were designed to detect the ABR at a single stimulus level and do not consider correlations in ABR waveforms across levels. These correlations hold valuable information, and can be exploited for more efficient hearing threshold estimation. This was achieved in the current work using a Gaussian Process (GP), i.e., a Bayesian approach for non-linear regression. The function to estimate with the GP was the ABR's amplitude across stimulus levels, from which hearing threshold was ultimately inferred. Active learning rules were also designed to automatically adjust the stimulus level and efficiently locate hearing threshold. Simulation results show test time reductions of up to  âˆ¼ 50% for the GP compared to a sequentially applied Hotelling's T2 test, which does not consider correlations across ABR waveforms. A case study was also included to briefly assess the GP approach in ABR data from an adult volunteer.

A fragmented sense of home: Reconfiguring therapeutic coastal encounters in Covid-19 times.

A growing body of research suggests positive links between coastal proximity, interaction, human health and wellbeing. In 2020, following the onset of the Covid-19 pandemic, many people in the UK could not engage in their usual coastal practices due to a national lockdown and associated restrictions, including government bans in entering the sea. This paper shares findings from an exploratory study examining how these restrictions shaped the recreational coastal practices, perceptions and emotions of residents in the case study region of Devon, South West England. In-depth semi-structured interviews were conducted with a purposive sample of 12 residents, with varying domestic and employment circumstances in the pandemic. We foreground three key themes identified through an inductive thematic analysis of the interviews: feeling 'at home' with the sea, experiencing a fragmented sense of home with Covid-19, and reconfiguring the coast as a therapeutic landscape. While important to understand the links between coastal proximity, health and wellbeing, we highlight the value of gaining more nuanced insights into the emotional, social, material and temporal dynamics that can re-shape the therapeutic potential of coastal encounter in the largely unprecedented situation of a global pandemic.

Controlling test specificity for auditory evoked response detection using a frequency domain bootstrap.

BACKGROUND: Statistical detection methods are routinely used to automate auditory evoked response (AER) detection and assist clinicians with AER measurements. However, many of these methods are built around statistical assumptions that can be violated for AER data, potentially resulting in reduced or unpredictable test performances. This study explores a frequency domain bootstrap (FDB) and some FDB modifications to preserve test performance in serially correlated non-stationary data. METHOD: The FDB aims to generate many surrogate recordings, all with similar serial correlation as the original recording being analysed. Analysing the surrogates with the detection method then gives a distribution of values that can be used for inference. A potential limitation of the conventional FDB is the assumption of stationary data with a smooth power spectral density (PSD) function, which is addressed through two modifications. COMPARISONS WITH EXISTING METHODS: The FDB was compared to a conventional parametric approach and two modified FDB approaches that aim to account for heteroskedasticity and non-smooth PSD functions. Hotelling's T2(HT2) test applied to auditory brainstem responses was the test case. RESULTS: When using conventional HT2, false-positive rates deviated significantly from the nominal alpha-levels due to serial correlation. The false-positive rates of the modified FDB were consistently closer to the nominal alpha-levels, especially when data was strongly heteroskedastic or the underlying PSD function was not smooth due to e.g. power lines noise. CONCLUSION: The FDB and its modifications provide accurate, recording-dependent approximations of null distributions, and an improved control of false-positive rates relative to parametric inference for auditory brainstem response detection.

An exploration of vestibular function pre and post unilateral cochlear implantation.

Objectives: To examine the effects of unilateral cochlear implantation on the balance system for adult patients with bilateral severe to profound sensory neural hearing loss. Methods: 7 CI candidates. The function of the sacculus, utricle, and three semi-circular canals (SCCs) was assessed separately using air conduction cervical vestibular evoked myogenic potentials (VEMP), vibration ocular VEMP and the video head impulse test (vHIT) respectively on each side, pre- and post-operatively. Results: The Otoliths appear more affected by implantation than SCCs. In 3 of 7 cases VEMP was affected by implantation. In 2 cases this was associated with short-term dizziness. Discussion: Differential assessment of vestibular end organ function may elucidate how cochlear implantation affects the vestibular system. As many CI candidates have some vestibular function, pre-implant vestibular assessment may help to inform which side of implantation may best preserve that function if other audiology and surgical considerations are equal. Post-implant assessment with VEMP may help to predict short-term dizziness. More work with a larger sample will be needed to make the case for routine clinical assessment. Conclusions: There is potential benefit of conducting multimodal vestibularassessment pre and post cochlear implantation. The otoliths appear more affected by implantation than the SCC.

Directional connectivity in the EEG is able to discriminate wakefulness from NREM sleep.

A reliable measure of consciousness is of great interest for various clinical applications including sleep studies and the assessment of depth of anaesthesia. A number of measures of consciousness based on the EEG have been proposed in the literature and tested in studies of dreamless sleep, general anaesthesia and disorders of consciousness. However, reliability has remained a persistent challenge. Despite considerable theoretical and experimental effort, the neural mechanisms underlying consciousness remain unclear, but connectivity between brain regions is thought to be disrupted, impairing information flow. OBJECTIVE: The objective of the current work was to assess directional connectivity between brain regions using directed coherence and propose and assess an index that robustly reflects changes associated with non-REM sleep. APPROACH: We tested the performance on polysomnographic recordings from ten healthy subjects and compared directed coherence (and derived features) with more established measures calculated from EEG spectra. We compared the performance of the different indexes to discriminate the level of consciousness at group and individual level. MAIN RESULTS: At a group level all EEG measures could significantly discriminate NREM sleep from waking, but there was considerable individual variation. Across all individuals, normalized power, the strength of long-range connections and the direction of functional links strongly correlate with NREM sleep stages over the experimental timeline. At an individual level, of the EEG measures considered, the direction of functional links constitutes the most reliable index of the level of consciousness, highly correlating with the individual experimental time-line of sleep in all subjects. SIGNIFICANCE: Directed coherence provides a promising new means of assessing level of consciousness, firmly based on current physiological understanding of consciousness.

Control of gastrointestinal parasitism with an oxfendazole pulse-release anthelmintic device.

The efficacy of a pulse-release oxfendazole bolus (OPRB) against gastrointestinal nematodes was evaluated under field conditions and compared with a sustained release morantel bolus (MSRB). Three groups of 10 calves were grazed from May to September on adjacent, similarly contaminated 3-acre paddocks. One group was dosed at turnout with the OPRB, the second group with the MSRB and the third group left as nontreated controls. Pasture larval counts peaked at greater than 60,000 larvae/kg dry weight of herbage in September on the control paddock, associated with a mean egg count of 1040 eggs/g faeces and clinical symptoms. A low rise in larval counts occurred on the MSRB plot, and also low helminth egg counts. On the OPRB plot, pasture larvae and faecal egg counts were recorded only intermittently; the September egg counts were only 3.5% of those of the controls; serum pepsinogen data showed a similar picture. At the end of the experiment, the OPRB calves had a mean weight advantage of 40 kg over the controls, and 12 kg over the MSRB group. Feed intakes were highest in the OPRB group in July and September.

The efficacy of an albendazole intraruminal controlled-release device against gastrointestinal parasitism in lambs.

The effectiveness of albendazole in a controlled-release bolus in controlling gastrointestinal nematodes in lambs was assessed during the summer of 1986. Faecal egg counts were almost entirely negative throughout in the treated group and larval challenge remained low at below 2000 larvae kg-1. Untreated control lambs showed a characteristic pattern of auto-infection, culminating in a peak pasture larval count of over 70,000 larvae kg-1 and an outbreak of parasitic gastroenteritis in September associated with a serum pepsinogen concentration of 1.183 IU tyrosine and a mean worm burden of 91,165 nematodes at necropsy, including Ostertagia, Trichostrongylus and Nematodirus species. Subject to the restrictions imposed by the size of the bolus, this was considered to be a highly effective method of seasonal parasite control.

Control of gastrointestinal parasitism in calves with albendazole delivered via an intraruminal controlled-release device.

The efficacy of albendazole in an intraruminal controlled-release device against gastrointestinal nematodes in calves was evaluated under field conditions. Calf productivity was monitored during the first and second grazing seasons. Two groups of parasite-naive Holstein Friesian heifer calves were grazed from May to October on adjacent, similarly contaminated paddocks. One group was given a Captec bolus at turnout, the group was left untreated. Pasture larval counts peaked on the paddock grazed by the untreated calves at 23,000 1 kg-1 dry matter in October. This precipitated clinical parasitic gastro-enteritis in the untreated calves with a mean peak faecal egg count of 335 epg, high blood pepsinogen and gastrin concentrations and a mean worm burden of 79,614 at 100 days post-turnout. Pasture larval counts on the paddock grazed by the treated calves remained less than 3000 1 kg-1 DM and the mean faecal egg count was zero until mid-August, peaking at 146 eggs per gram of faeces (epg) in October. The treated calves had body liveweight advantage of 19 kg at the end of September. During the second grazing season the first season untreated calves were refractory to infection. The first season treated calves showed signs of parasitic gastro-enteritis, although not to the extent exhibited by a group of first season parasite-naive tracer calves which were grazed on the same paddock.

Appetite, digestive efficiency, feed utilization and carcass evaluation of housed calves naturally infected with gastrointestinal nematodes.

The progress of two groups of 10 calves, which had previously been exposed to trichostrongyle infections by grazing infected pastures, was monitored from housing in October to slaughter the following April. Each of the animals of one group had received a morantel sustained release bolus, the other control group remained untreated. The high faecal egg counts and serum pepsinogen concentrations, together with the clinical signs of ostertagiosis observed in the controls in October, persisted during the first month of housing but improved thereafter. From late November onwards, no difference in feed intake and digestive efficiency was observed between the groups. The control calves exhibited a significantly greater feed conversion efficiency over the period February-April, (7.5 vs. 12.3 kg feed kg-1 liveweight gain, P less than 0.001). This reduced the liveweight advantage of the MSRB group over the controls at housing to 25 kg.

Feed intake of grazing calves exposed to trichostrongyle infection and treated with the morantel sustained release bolus.

Herbage intake was measured in two groups of 20 first-year grazing cattle. The animals in one group each received a morantel sustained release bolus at turnout to control nematode parasitism and the animals in the other group remained untreated. The latter group showed a mean peak faecal egg count of 655 eggs per gram (e.p.g.) in October associated with high serum pepsinogen concentration and clinical signs of ostertagiasis, compared with a peak of 119 e.p.g. in the treated group which remained in good health. In September the daily voluntary feed intake of the untreated animals was significantly depressed (94 g kg-1 body weight vs. 77 g kg-1 P less than 0.001), but no difference in digestive efficiency was recorded between the two groups. This difference in feed intake was associated with a 47 kg mean live weight advantage of the treated animals at housing.

Genetic engineering of hybridoma glutamine metabolism.

The murine hybridoma PQXB1/2 cannot be adapted to grow in culture media containing < 0.5 mM glutamine. Transformants selected following electroporation of PQXB1/2 cells with vectors containing a Chinese hamster glutamine synthetase (GS) cDNA under the control of the SV40 early promoter also failed to grow in the absence of glutamine in the culture medium. PQXB1/2 cells have, however, been transformed to glutamine independence following electroporation with a vector containing this glutamine synthetase cDNA under the control of the human cytomegalovirus immediate early promoter. In these cells, sufficient active glutamine synthetase was expressed from one vector per cell to enable growth in glutamine-free media. The specific activity of glutamine synthetase in two transformed cell lines producing parental levels of antibody was increased by 128 and 152%, respectively (0.57 and 0.63 mumol min-1 per 10(6) cells in transformants compared with parental levels of 0.25 mumol min-1 per 10(6) cells). This reprogramming of glutamine synthetase expression and glutamine metabolism is important for developing strategies to deal with ammonia toxicity and the production of cell lines with improved metabolic processes.

Hospital-sponsored rural health clinics: an effective diversification alternative for rural hospitals.

Changes in rural health care are resulting in new challenges for the administrators of rural hospitals. The lack of available care, economic deterioration, and demographic changes in rural America are contributing factors to rural health care problems and are detrimental to the financial well-being of rural hospitals. Diversification is becoming commonplace in these hospitals as administrators seek strategies to gain financial viability for their facilities. The concept of hospital-sponsored rural health clinics is more than a decade old, yet there are fewer than 30 such clinics nationwide. Reasons for the underutilization of such clinics may include the lack of knowledge that such clinics exist as well as inadequate information describing the establishment, operation, and financial feasibility of the clinics. The hospital-sponsored rural health clinic "concept" will be introduced, including potential benefits of such clinics to both the hospital and the communities they serve, factors to be considered in developing such a system, and problems that may arise in this development. This article presents a case study of how one rural hospital incorporated such clinics into its long-range plans.

The foot and ankle: an overview of arthrokinematics and selected joint techniques.

Limited range of motion of the ankle is common following a period of immobilization or injury to the lower extremity. If not corrected, this limited range of motion will disturb normal joint arthrokinematics and could affect the athlete's performance. Consequently, the athletic trainer must thoroughly evaluate the various joints of the ankle and foot in order to determine appropriate treatment. A comprehensive evaluation should include assessment of passive accessory motions at the foot and ankle. If accessory movements are restricted at any joint, mobilization techniques can be used to restore normal ankle/foot joint arthrokinematics. This article describes the biomechanics of the tibiofibular, talocrural, subtalar, and midtarsal joints and is a presentation of basic mobilization techniques for the ankle and related joints.