COVCOG 1: Factors Predicting Physical, Neurological and Cognitive Symptoms in Long COVID in a Community Sample. A First Publication From the COVID and Cognition Study.

Since its first emergence in December 2019, coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has evolved into a global pandemic. Whilst often considered a respiratory disease, a large proportion of COVID-19 patients report neurological symptoms, and there is accumulating evidence for neural damage in some individuals, with recent studies suggesting loss of gray matter in multiple regions, particularly in the left hemisphere. There are a number of mechanisms by which COVID-19 infection may lead to neurological symptoms and structural and functional changes in the brain, and it is reasonable to expect that many of these may translate into cognitive problems. Indeed, cognitive problems are one of the most commonly reported symptoms in those experiencing "Long COVID"-the chronic illness following COVID-19 infection that affects between 10 and 25% of patients. The COVID and Cognition Study is a part cross-sectional, part longitudinal, study documenting and aiming to understand the cognitive problems in Long COVID. In this first paper from the study, we document the characteristics of our sample of 181 individuals who had experienced COVID-19 infection, and 185 who had not. We explore which factors may be predictive of ongoing symptoms and their severity, as well as conducting an in-depth analysis of symptom profiles. Finally, we explore which factors predict the presence and severity of cognitive symptoms, both throughout the ongoing illness and at the time of testing. The main finding from this first analysis is that that severity of initial illness is a significant predictor of the presence and severity of ongoing symptoms, and that some symptoms during the initial illness-particularly limb weakness-may be more common in those that have more severe ongoing symptoms. Symptom profiles can be well described in terms of 5 or 6 factors, reflecting the variety of this highly heterogenous condition experienced by the individual. Specifically, we found that neurological/psychiatric and fatigue/mixed symptoms during the initial illness, and that neurological, gastrointestinal, and cardiopulmonary/fatigue symptoms during the ongoing illness, predicted experience of cognitive symptoms.

COVCOG 2: Cognitive and Memory Deficits in Long COVID: A Second Publication From the COVID and Cognition Study.

COVID-19, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has been often characterized as a respiratory disease. However, it is increasingly being understood as an infection that impacts multiple systems, and many patients report neurological symptoms. Indeed, there is accumulating evidence for neural damage in some individuals, with recent studies suggesting loss of gray matter in multiple regions, particularly in the left hemisphere. There are several mechanisms by which the COVID-19 infection may lead to neurological symptoms and structural and functional changes in the brain, and cognitive problems are one of the most commonly reported symptoms in those experiencing Long COVID - the chronic illness following the COVID-19 infection that affects between 10 and 25% of patients. However, there is yet little research testing cognition in Long COVID. The COVID and Cognition Study is a cross-sectional/longitudinal study aiming to understand cognitive problems in Long COVID. The first paper from the study explored the characteristics of our sample of 181 individuals who had experienced the COVID-19 infection, and 185 who had not, and the factors that predicted ongoing symptoms and self-reported cognitive deficits. In this second paper from the study, we assess this sample on tests of memory, language, and executive function. We hypothesize that performance on "objective" cognitive tests will reflect self-reported cognitive symptoms. We further hypothesize that some symptom profiles may be more predictive of cognitive performance than others, perhaps giving some information about the mechanism. We found a consistent pattern of memory deficits in those that had experienced the COVID-19 infection, with deficits increasing with the severity of self-reported ongoing symptoms. Fatigue/Mixed symptoms during the initial illness and ongoing neurological symptoms were predictive of cognitive performance.

Hearing in Adults: A Digital Reprint of the Main Report From the MRC National Study of Hearing.

The 1011-page book, Hearing in Adults, published in 1995, contains the fullest report of the United Kingdom's Medical Research Council National Study of Hearing. It was designed to determine the prevalence and distribution in Great Britain of audiometrically measured hearing loss as a function of age, gender, occupation, and noise exposure. The study's size, quality, and breadth made it unique when it was done in the 1980s. These qualities remain, and its data are still the primary U.K. source for the prevalence of auditory problems. However, only 550 copies were printed, and the book is essentially unobtainable today. We describe here a fully searchable, open-access, digital (PDF) "reprinting" of Hearing in Adults, summarizing the study's design and the book's contents, together with a brief commentary in the light of subsequent developments.

Contrasting Effects of Pressure Compensation on TEOAE and DPOAE in Children With Negative Middle Ear Pressure.

In children with normal cochlear acuity, middle ear fluid often abolishes otoacoustic emissions (OAEs), and negative middle ear pressure (NMEP) reduces them. No convincing evidence of beneficial pressure compensation on distortion product OAE (DPOAE) has yet been presented. Two studies aimed to document effects of NMEP on transient OAE (TEOAE) and DPOAE. In Study 1, TEOAE and DPOAE pass/fail responses were analyzed before and after pressure compensation in 50 consecutive qualifying referrals having NMEP from -100 to -299 daPa. Study 2 concentrated on DPOAE, recording both amplitude (distortion product amplitude) and signal-to-noise ratio (SNR) before and after pressure compensation. Of the 20 participants, 5 had both ears qualifying. An effect of compensation on meeting a pass criterion was present in TEOAE for both left and right ear data in Study 1 but not demonstrable in DPOAE. In Study 2, the distortion product amplitude compensation effect was marginal overall, and depended on recording frequency band. SNR values improved moderately after pressure compensation in the two (overlapping) sets of single-ear data. In the five cases with both ears qualifying, a stronger compensation effect size, over 3 dB, was seen. The absolute dependence of SNR on frequency was also strongly replicated, but in no analysis, the frequency × compensation interaction was significant. Independent of particular frequency range, the data support a limited SNR improvement in 2 to 3 dB for compensation in DPOAE, with slightly larger effects in ears giving SNRs between 0 dB and +6 dB, where pass/fail cutoffs would generally be located.

Otitis media.

Otitis media (OM) or middle ear inflammation is a spectrum of diseases, including acute otitis media (AOM), otitis media with effusion (OME; 'glue ear') and chronic suppurative otitis media (CSOM). OM is among the most common diseases in young children worldwide. Although OM may resolve spontaneously without complications, it can be associated with hearing loss and life-long sequelae. In developing countries, CSOM is a leading cause of hearing loss. OM can be of bacterial or viral origin; during 'colds', viruses can ascend through the Eustachian tube to the middle ear and pave the way for bacterial otopathogens that reside in the nasopharynx. Diagnosis depends on typical signs and symptoms, such as acute ear pain and bulging of the tympanic membrane (eardrum) for AOM and hearing loss for OME; diagnostic modalities include (pneumatic) otoscopy, tympanometry and audiometry. Symptomatic management of ear pain and fever is the mainstay of AOM treatment, reserving antibiotics for children with severe, persistent or recurrent infections. Management of OME largely consists of watchful waiting, with ventilation (tympanostomy) tubes primarily for children with chronic effusions and hearing loss, developmental delays or learning difficulties. The role of hearing aids to alleviate symptoms of hearing loss in the management of OME needs further study. Insertion of ventilation tubes and adenoidectomy are common operations for recurrent AOM to prevent recurrences, but their effectiveness is still debated. Despite reports of a decline in the incidence of OM over the past decade, attributed to the implementation of clinical guidelines that promote accurate diagnosis and judicious use of antibiotics and to pneumococcal conjugate vaccination, OM continues to be a leading cause for medical consultation, antibiotic prescription and surgery in high-income countries.

Precision-scored parental report questions and HL-scaled tympanometry as informative measures of hearing in otitis media 1: Large-sample evidence on determinants and complementarity to pure-tone audiometry.

INTRODUCTION: In otitis media with effusion (OME), hearing loss is a core sign/symptom and basis of concern, with absolute pure-tone threshold sensitivity (in dB HL) by air-conduction providing the default measure of hearing. However several fundamental problems limiting the value of HL measures in otitis media are insufficiently appreciated. To appraise the joint value and implications of multiple hearing measures towards more comprehensive hearing assessment in OM, we examine in two related articles the interrelations and common or diverging determinants of three measures, two of them objective: binaural HL, and ACET (the published quasi-continuous scaling of binaural tympanometry to HL). The third measure is partly subjective: parentally reported hearing difficulties (RHD-4); this is the precision-scored total of the 4 items selected for the OM8-30 general purpose questionnaire for parents in OM. METHODS: The Eurotitis-2 study (Total N=2886) internationally standardises OM8-30 and its OMQ-14 short form. The clinical and parent-response variables acquired cover many issues in diagnosis, symptomatology and impact of OM. Data acquisition was built upon routine clinic practice, enabling us also to document some properties of that practice, such as patterns of missing HL data. To address possible confounding or loss of representativeness from this, we investigated the implications of substituting tympanometry-based ACET for missing HL to give an HL/ACET hybrid. ACET is the mapping of categorical tympanometry to continuous HL. We simulated degrees of artificial missingness of HL up to 35% on the 1430 complete-data cases, using random deletion, with 1000-version bootstrapping. Correlations of this HL/ACET hybrid with pure (100%) HL then documented the degree of correlation retained under dilution of HL by an admixture of ACET; we also documented distribution shapes. For RHD-4, we then probed the determining influences on severity of score as an auditory disability measure, both background ones (from centre, age, sex, socio-economic status, length of history, diagnosis and season) and the two underlying objective hearing measures (HL, ACET). We ran these multiple regressions (GLMs), for representativeness and generality, both on 1430 complete-data cases (i.e. all 3 hearing variables present) and also on supplemented samples according to data required only for particular analyses (N increased by +56% to +68%). A further method of sample supplementation (by up to +96%) used the HL/ACET hybrid. RESULTS: Sex made negligible difference in any analysis. The particular collaborating centre, age, season and diagnosis collectively influenced presence/absence of HL data very strongly. (Area under ROC 0.944). Socio-economic status did not influence HL presence; surprisingly, nor did RHD, ACET or length of history, after control for centre, age, diagnosis and season. Of the inter-correlations between hearing measures, only the one between ACET and RHD was influenced (slightly reduced) by the inclusion of cases without HL data. In the simulated substitutions, Pearson correlation of hybrid HL/ACET with true HL remained above 0.90 for substitution by ACET of up to 30% rate of artificially 'missing' HL. Centre differences were adequately summarised by simple absolute additive differences in mean local case severity. In the determinant models for RHD on the 1430 complete-data cases, HL and the set of background determinants collectively explained broadly similar proportions of RHD's variability, totalling 36.8% explained. On the larger maximum case samples, slightly less absolute variability was explicable than on complete-case data, but relative magnitudes of contribution from individual determinants, both background and hearing measures, remained similar. The expected mean differences in RHD between diagnoses (RAOM, OME, and combined) were found, but the patterns of background and objective measure influences determining RHD did not differ significantly between the diagnoses. CONCLUSIONS: (1) In the Eurotitis-2 database, descriptive differences in various background demographic and clinical measures between cases on whom HL data were obtained versus not, were only of material magnitude for length of history and reported hearing difficulties. Such descriptive differences are not necessarily bases of confounding, so using our framework of 6 background adjuster variables, (particular collaborating centre, age, season, diagnosis, socioeconomic status and length of history) we isolated the determinants of HL data presence. The first four listed strongly predicted HL data presence/absence so are sufficient to control analyses well for any bias or confounding by HL data presence. (2) Diagnoses as OME and combined (OME+RAOM) had higher probability of HL data being present relative to RAOM, indicating that HL acquisition is chiefly seen as confirming and quantifying hearing loss in (suspect) OME, not as ruling it out (e.g. in suspected RAOM). Given this, also using RHD and or ACET as pre-triage to efficiently target capacity and/or reduce costs and opportunity costs of acquiring HL would be rational, but there was no evidence of such precise use of initial hearing-related information to decide on HL acquisition. (3) The full six background variables explained comparable variance in Reported Hearing Difficulties (RHD) to what was explained by ACET, but not quite as much as by HL. Achieving a high percentage explained (32-37% from good models) required both classes of determinant to be entered as predictors. The pattern of background determining influences for RHD was largely stable, with or without objective measures as additional predictors, and on maximum or complete-data cases. Length of history strongly determines RHD for a given concurrent HL. (4) Accepting ACET as substitute where HL was missing in OM cases gave a sample-size enhancement of 17% in Eurotitis-2, with negligible difference in the pattern of determinants. This hybrid measure can be recommended as reasonable next-best when moderate percentages of HL data are missing. (5) The stable pattern of prediction of RHD suggests that our six background determinants provide a very promising low-cost yet comprehensive framework for determination. It hence offers pluripotent statistical adjustment against confounding, applicable to RAOM, OME and combined diagnoses in any analysis using this database. Claims that it thereby offers a sufficient framework for full European standardisation of all the scores from the OM8-30 questionnaire measures await parallel demonstrations for symptom areas other than RHD. As 25% of the variance in RHD severity can be explained by the six adjusters in our framework, none of the six variables should be omitted from acquisition and analytic use in future OM research.

Screening for hearing loss versus parental concern regarding hearing problems: Subsequent referral and treatment for otitis media in the Netherlands.

OBJECTIVE: The present study investigates whether general practitioner (GP) consultation initiated by failing the population hearing screening at age nine months or GP consultation because of parental concern over ear/hearing problems was more important in deciding on referral and/or surgical treatment of otitis media (OM). DESIGN: A questionnaire covering the history between birth and 21 months of age was used to obtain information on referral after failing the hearing screening, GP consultations for ear/hearing problems, and subsequent referral to a specialist and possible surgical treatment at an ENT department. SETTING: The province of Limburg, the Netherlands. SUBJECTS: Healthy infants invited for the hearing screening at age nine months, who responded in an earlier study called PEPPER (Persistent Ear Problems, Providing Evidence for Referral, response rate 58%). MAIN OUTCOME MEASURES: The odds of a child being surgically treated for OM. RESULTS: The response rate for the present questionnaire was 72%. Of all children tested, 3.9% failed the hearing screening and were referred to their GP. Of all 2619 children in this study, 18.6% visited their GP with ear/hearing problems. Children failing the hearing screening without GP consultation for ear/hearing problems were significantly more often treated surgically for OM than children passing the hearing screening but with GP consultation for ear/hearing problems. CONCLUSION: Objectified hearing loss, i.e. failing the hearing screening, was important in the decision for surgical treatment in infants in the Netherlands.

Risk factors for failing the hearing screen due to otitis media in Dutch infants.

Hearing loss from otitis media (OM) can affect young children's development. Some children with persistent OM-related hearing loss and associated problems can benefit from treatment, but researchers and clinicians are still unclear on how to identify them best. The present study aims to determine which factors are most related to the hearing loss in OM, as a first step towards an effective case-finding instrument for detecting infants with persistent OM-related hearing loss. The full PEPPER ('Persistent Ear Problems, Providing Evidence for Referral') item pool includes a wide range of risk factors for OM in a single questionnaire, and is easily completed by parents or guardians. The questionnaire was sent to all children invited for the universal hearing screen at age 9 months in Limburg, The Netherlands. Repeatedly failing of the hearing screen was used as outcome marker indicative of OM-related chronic hearing loss. Univariate analyses were conducted to determine statistically significant risk factors predicting 'fail' cases at this hearing screen. Five items were found as individually predictive of hearing screen failure and subsequent referral: 'having severe cold symptoms', 'attending day care with >4 children', 'having siblings', 'severe nasal congestion' and 'male gender'. Suitably worded parental questions document risk factors for OM-related hearing loss in infants, broadly consistent with past general literature on OM risk factors, but more focused. The findings justify further optimising and evaluation of an additive or multiplicative combination of these questions as a means for selecting and routing an infant with diagnosed or suspected OM to further care.

Spatially extended FMRI signal response to stimulus in non-functionally relevant regions of the human brain: preliminary results.

The blood-oxygenation level dependent (BOLD) haemodynamic response function (HDR) in functional magnetic resonance imaging (fMRI) is a delayed and indirect marker of brain activity. In this single case study a small BOLD response synchronised with the stimulus paradigm is found globally, i.e. in all areas outside those of expected activation in a single subject study. The nature of the global response has similar shape properties to the archetypal BOLD HDR, with an early positive signal and a late negative response typical of the negative overshoot. Fitting Poisson curves to these responses showed that voxels were potentially split into two sets: one with dominantly positive signal and the other predominantly negative. A description, quantification and mapping of the global BOLD response is provided along with a 2 × 2 classification table test to demonstrate existence with very high statistical confidence. Potential explanations of the global response are proposed in terms of 1) global HDR balancing; 2) resting state network modulation; and 3) biological systems synchronised with the stimulus cycle. Whilst these widespread and low-level patterns seem unlikely to provide additional information for determining activation in functional neuroimaging studies as conceived in the last 15 years, knowledge of their properties may assist more comprehensive accounts of brain connectivity in the future.

Psychometric evaluation of the OM8-30 questionnaire in Dutch children with otitis media.

The Dutch translation of the OM8-30 questionnaire, originally developed in the UK on a large clinical sample, has been applied for validation in an ENT sample, with the aim of assessing otitis media impact and identifying treatment needs in children suffering from chronic otitis media (OM) and/or upper respiratory tract infections (URTI). Caregivers of 246 children completed the OM8-30 and also the generic Strengths and Difficulties Questionnaire (SDQ), prior to otolaryngologist consultation. Factor analysis confirmed the hypothesized six-factor structure, accounting for 55.5% of the variance. The internal consistency was satisfactory to good for all of the physical and developmental facets (alpha-values > or = 0.68). The correlation matrix with the SDQ scales and total difficulties score showed significant relationships for almost all of the OM8-30 developmental facets and sub-aggregate (Ps < 0.01), supporting the concurrent validity of the OM8-30 as a measure of impact in otitis media. This first examination of the Dutch OM8-30 shows that the psychometric characteristics are sufficiently good for the assessment of disease impact, and that this can be subdivided into impact on physical health and on developmental aspects. Recommendations for further research include the study of confounders such as hearing, age and previous operations so that these can be adjusted out, and the determination of which subgroup of children may benefit from tympanostomy tubes.

A method for determining venous contribution to BOLD contrast sensory activation.

While BOLD contrast reflects hemodynamic changes within capillaries serving neural tissue, it also has a venous component. Studies that have determined the relation of large blood vessels to the activation map indicate that veins are the source of the largest response, and the most delayed in time. It would be informative if the location of these large veins could be extracted from the properties of the functional responses, since vessels are not visible in BOLD contrast images. The present study describes a method for investigating whether measures taken from the functional response can reliably predict vein location, or at least be useful in down-weighting the venous contribution to the activation response, and illustrates this method using data from one subject. We combined fMRI at 3 Tesla with high-resolution anatomic imaging and MR venography to test whether the intrinsic properties of activation time courses corresponded to tissue type. Measures were taken from a gamma fit to the functional response. Mean magnitude showed a significant effect of tissue type (p < 0.001) where CSF > veins approximately gray matter > white matter. Mean delays displayed the same ranking across tissue types (p < 0.001), except that veins > gray matter. However, measures for all tissue types were distributed across an overlapping range. A logistic regression model correctly discriminated 72% of the veins from gray matter in the absence of independent information of macroscopic vessels (ROC = 0.72). While tissue classification was not perfect for this subject, weighting the T contrast by the predicted probabilities materially reduced the venous component to the activation map.

Spectral and temporal processing in human auditory cortex.

Hierarchical processing suggests that spectrally and temporally complex stimuli will evoke more activation than do simple stimuli, particularly in non-primary auditory fields. This hypothesis was tested using two tones, a single frequency tone and a harmonic tone, that were either static or frequency modulated to create four stimuli. We interpret the location of differences in activation by drawing comparisons between fMRI and human cytoarchitectonic data, reported in the same brain space. Harmonic tones produced more activation than single tones in right Heschl's gyrus (HG) and bilaterally in the lateral supratemporal plane (STP). Activation was also greater to frequency-modulated tones than to static tones in these areas, plus in left HG and bilaterally in an anterolateral part of the STP and the superior temporal sulcus. An elevated response magnitude to both frequency-modulated tones was found in the lateral portion of the primary area, and putatively in three surrounding non-primary regions on the lateral STP (one anterior and two posterior to HG). A focal site on the posterolateral STP showed an especially high response to the frequency-modulated harmonic tone. Our data highlight the involvement of both primary and lateral non-primary auditory regions.