Selecting infants with OM that need referral and further assessment: creating a case-finding instrument.

OBJECTIVE: In the Netherlands, many children are surgically treated for OM. Recent publications question the need for surgical treatment in common uncomplicated OM, although there is certainly a subgroup of infants that do need further assessment and possible treatment. The present study explores the possibility of using known and presumed risk factors for OM as an instrument for selecting and routing an infant with OM to further care. METHODS: Two questionnaires were used. A questionnaire embracing a wide range of OM-related factors was sent to 6531 children aged nine months that were routinely invited for the hearing screen at nine months. In a second stage, a structured history questionnaire regarding ear and/or hearing problems, subsequent referral and/or treatment, was sent to all parents of children at age 21 months, responding to the first questionnaire. Univariate analysis was performed for identification of potential predictors for surgical treatment of OM for the whole sample as well as for 4 different subsets. Multivariable regression analysis with stepwise backward deletion was applied to arrive at a model for optimal prediction of tube insertion. A ROC (receiver operating characteristic) curve and the accompanying sensitivity and specificity values were analyzed to determine cut off values. RESULTS: Univariate analysis found 10 items predicting surgical treatment for OM. Multivariable regression analysis resulted in a model with a ROC curve having an area of 0.801 and estimated coefficients for risk factors which were used to calculate a OM-score for each case. CONCLUSION: The developed scoring sheet, e.g., to be used in combination with physical examinations and/or tympanometry looks promising as a predictor for those children that might benefit from further assessment and eventually surgically treatment for OM.

Grommets in otitis media with effusion: an individual patient data meta-analysis.

AIMS: To identify subgroups of children with otitis media with effusion (OME) that might benefit more than others from treatment with ventilation tubes. METHODS: An individual patient data (IPD) meta-analysis on seven randomised controlled trials (n = 1234 children in all), focusing on interactions between treatment and baseline characteristics--hearing level (HL), history of acute otitis media, common colds, attending day-care, gender, age, socioeconomic status, siblings, season, passive smoking, and history of breast feeding. Outcome measures that could be studied were mean time spent with effusion (n = 557), mean hearing levels (n = 557 in studies that randomised children, and n = 180 in studies that randomised ears), and language development (n = 381). RESULTS: In the trials that treated both ears the only significant interaction was between day-care and surgery, occurring where mean hearing level was the outcome measure. None of the other baseline variables showed an interaction effect with treatment that would justify subgrouping. In the trials that treated only one ear, the baseline hearing level showed a significant but not pervasive interaction with treatment-that is, only with a cut-off of 25 dB HL. CONCLUSIONS: The effects of conventional ventilation tubes in children studied so far are small and limited in duration. Observation (watchful waiting) therefore seems to be an adequate management strategy for most children with OME. Ventilation tubes might be used in young children that grow up in an environment with a high infection load (for example, children attending day-care), or in older children with a hearing level of 25 dB HL or greater in both ears persisting for at least 12 weeks.

Can meaningful effective connectivities be obtained between auditory cortical regions?

Structural equation modeling (SEM) of neuroimaging data can be evaluated both for the goodness of fit of the model and for the strength of path coefficients (as an index of effective connectivity). SEM of auditory fMRI data is made difficult by the necessary sparse temporal sampling of the time series (to avoid contamination of auditory activation by the response to scanner noise) and by the paucity of well-defined anatomical information to constrain the functional model. We used SEM (i.e., a model incorporating latent variables) to investigate how well fMRI data in four adjacent cortical fields can be described as an auditory network. Seven of the 14 models (2 hemispheres x (6 subjects and 1 group)) produced a plausible description of the measured data. Since the auditory model to be tested is not fully validated by anatomical data, our approach requires that goodness of fit be confirmed to ensure generalizability of connectivity patterns. For good-fitting models, connectivity patterns varied significantly across subjects and were not replicable across stimulus conditions. SEM of central auditory function therefore appears to be highly sensitive to the voxel-selection procedure and/or the sampling of the time series.

Behaviour and developmental effects of otitis media with effusion into the teens.

OBJECTIVE: To examine whether behavioural or cognitive sequelae of otitis media with effusion (OME) continue into late childhood and the early teens (11-18 years). SETTING: Data from a large multipurpose birth cohort study: the Dunedin multidisciplinary health and development study. PARTICIPANTS: Around 1000 children from the study. The main independent variable of interest was otological status of the child up to age 9. MAIN OUTCOME MEASURES: Parent and teacher rated behaviour problems, including antisocial, neurotic, hyperactive, and inattentive behaviours, and tests of academic achievement including intelligence quotient (IQ), reading, and spelling were available in a high proportion of the cohort at ages 11 to 18 years. RESULTS: After adjustments for covariates such as socioeconomic status, hyperactive and inattentive behaviour problems were evident as late as 15 years, and lower IQ associated with OME remained significant to 13 years. The largest effects were observed for deficits in reading ability between 11 and 18 years. CONCLUSIONS: No previous study considering behaviour problems as an outcome has followed children long enough to determine whether some of the early sequelae of OME are still present in the early to late teens. Some developmental sequelae of OME, particularly deficits in reading ability, can persist into late childhood and the early teens.

Functional magnetic resonance imaging measurements of sound-level encoding in the absence of background scanner noise.

Effects of sound level on auditory cortical activation are seen in neuroimaging data. However, factors such as the cortical response to the intense ambient scanner noise and to the bandwidth of the acoustic stimuli will both confound precise quantification and interpretation of such sound-level effects. The present study used temporally "sparse" imaging to reduce effects of scanner noise. To achieve control for stimulus bandwidth, three schemes were compared for sound-level matching across bandwidth: component level, root-mean-square power and loudness. The calculation of the loudness match was based on the model reported by Moore and Glasberg [Acta Acust. 82, 335-345 (1996)]. Ten normally hearing volunteers were scanned using functional magnetic resonance imaging (tMRI) while listening to a 300-Hz tone presented at six different sound levels between 66 and 91 dB SPL and a harmonic-complex tone (F0= 186 Hz) presented at 65 and 85 dB SPL. This range of sound levels encompassed all three bases of sound-level matching. Activation in the superior temporal gyrus, induced by each of the eight tone conditions relative to a quiet baseline condition, was quantified as to extent and magnitude. Sound level had a small, but significant, effect on the extent of activation for the pure tone, but not for the harmonic-complex tone, while it had a significant effect on the response magnitude for both types of stimulus. Response magnitude increased linearly as a function of sound level for the full range of levels for the pure tone. The harmonic-complex tone produced greater activation than the pure tone, irrespective of the matching scheme for sound level, indicating that bandwidth had a greater effect on the pattern of auditory activation than sound level. Nevertheless, when the data were collapsed across stimulus class, extent and magnitude were significantly correlated with the loudness scale (measured in phons), but not with the intensity scale (measured in SPL). We therefore recommend the loudness formula as the most appropriate basis of matching sound level to control for loudness effects when cortical responses to other stimulus attributes, such as stimulus class, are the principal concern.

Modulation and task effects in auditory processing measured using fMRI.

Active listening has been reported to elicit a different sensory response from passive listening and is generally observed as an increase in the magnitude of activation. Sensory activation differences may therefore be masked by the effect of attention. The present study measured activation induced by static and modulated tones, while controlling attention by using target-discrimination and passive listening tasks. The factorial design enabled us to determine whether the stimulus-induced activation in auditory cortex was independent of the information-processing demands of the task. Contrasted against a silent baseline, listening to the tones induced widespread activation in the temporal cortex, including Heschl's gyrus (HG), planum temporale, superior temporal gyrus (STG), and superior temporal sulcus. No additional auditory areas were recruited in the response to modulated tones compared to static tones, but there was an increase in the response in the STG, anterior to HG. Relative to passive listening, the active task increased the response in the STG, posterior to HG. The active task also recruited regions in the frontal and parietal cortex and subcortical areas. These findings indicate that preferential responses to the changing spectro-temporal properties of the stimuli and to the target-discrimination task involve distinct, non-overlapping areas of the secondary auditory cortex. Thus, in the present study, differences in sensory activation were not masked by the effects of attention.

Behaviour and cognitive outcomes from middle ear disease.

OBJECTIVES: To resolve controversies over associations between a history of middle ear disease and psychosocial or cognitive/educational outcomes. DESIGN: Multipurpose longitudinal birth cohort study. Original cohort comprised all UK births between 5 and 11 April 1970; data were available for approximately 12,000 children at 5 years old and 9000 children at 10 years old. METHODS: For 5 year old children, parent reported data were available on health, social, and behavioural factors, including data on two validated markers of middle ear disease. Cognitive tests were administered at 5 and 10 years of age, and behavioural problems rated at 10 years by the child's teacher. RESULTS: After adjustment for social background and maternal malaise, the developmental sequelae of middle ear disease remained significant even at 10 years. The largest effects were observed in behaviour problems and language test data at age 5, but effect sizes were modest overall. IMPLICATIONS: These results provide an epidemiological basis for policies that aim to minimise the sequelae of middle ear disease by awareness in parents and preschool teachers, early referral, and intervention for more serious or persistent cases.

"Sparse" temporal sampling in auditory fMRI.

The use of functional magnetic resonance imaging (fMRI) to explore central auditory function may be compromised by the intense bursts of stray acoustic noise produced by the scanner whenever the magnetic resonance signal is read out. We present results evaluating the use of one method to reduce the effect of the scanner noise: "sparse" temporal sampling. Using this technique, single volumes of brain images are acquired at the end of stimulus and baseline conditions. To optimize detection of the activation, images are taken near to the maxima and minima of the hemodynamic response during the experimental cycle. Thus, the effective auditory stimulus for the activation is not masked by the scanner noise. In experiment 1, the course of the hemodynamic response to auditory stimulation was mapped during continuous task performance. The mean peak of the response was at 10.5 sec after stimulus onset, with little further change until stimulus offset. In experiment 2, sparse imaging was used to acquire activation images. Despite the fewer samples with sparse imaging, this method successfully delimited broadly the same regions of activation as conventional continuous imaging. However, the mean percentage MR signal change within the region of interest was greater using sparse imaging. Auditory experiments that use continuous imaging methods may measure activation that is a result of an interaction between the stimulus and task factors (e.g., attentive effort) induced by the intense background noise. We suggest that sparse imaging is advantageous in auditory experiments as it ensures that the obtained activation depends on the stimulus alone.

Alternatives in screening at school entry: comparison of the childhood middle ear disease and hearing questionnaire (CMEDHQ) and the pure tone sweep test.

Some health authorities in the UK are discontinuing hearing screening at school entry, mainly because the pure tone sweep test is under-specific (i.e. fails too many children) and thus leads to unnecessary and costly, but unproductive, follow-up assessment. A screening method with different properties such as a questionnaire could be a more cost-effective method of mass screening children. The MRC Institute of Hearing Research has developed and evaluated through several stages such a screening questionnaire (the Childhood Middle Ear Disease and Hearing Questionnaire (CMEDHQ), containing 11 scored questions under two broad headings: history and presentation of the disease, and consultation/treatment history. In a service-based evaluation, 2860 mainstream reception-year school children from two consecutive years, attending schools in south west Cumbria in the North-West Regional Health Authority received the sweep test and the CMEDHQ. (Although predominantly designed to detect middle ear problems, the questionnaire also has some potential to detect permanent hearing loss; thus providing a useful backstop for detection of permanent losses either missed or not present in earlier infancy.) The screening CMEDHQ obtained a very high response rate (90%). Follow-up included 235 control cases as well as all pure tone sweep test failures. Analysis, by use of a definition of cases conservative with respect to the sensitivity of the questionnaire, showed that the CMEDHQ has better specificity, but slightly lower sensitivity, than the pure tone sweep test for composite system decision (where 'case' = treated at ENT; 'non-case' = pass at whatever stage was reached before discharge). Follow-up indicated that the limited method available for assessing sensitivity might give an over-favourable view of the pure tone sweep test. Possible improvement of questionnaire sensitivity by further refinements is under examination. The findings show that it is worth conducting a fully parallel multi-district cost-effectiveness comparison of the pure tone sweep test versus the CMEDHQ.

Accumulation of factors influencing children's middle ear disease: risk factor modelling on a large population cohort.

STUDY OBJECTIVES: Data were analysed from a large national birth cohort to examine cumulative and interactive prediction from various risk factors for childhood middle ear disease, and to resolve conflicting evidence arising from small and incompletely controlled studies. The large sample size permitted appropriate covariate adjustment to give generality, and permit demographic breakdown of the risk factors. SETTING: A large multi-purpose longitudinal birth cohort study of all births in the UK in one week in 1970, with multiple questionnaire sweeps. PARTICIPANTS: Over 13,000 children were entered into the original cohort. Data on over 12,000 children were available at the five year follow up. MAIN OUTCOME MEASURES: For children at 5 years, parent reported data were available on health and social factors including data on two markers for middle ear disease: the occurrence of purulent (nonwax) ear discharge and suspected or confirmed hearing difficulty. MAIN RESULTS: In those children who had ever had reported hearing difficulty (suspected or confirmed), after control for socioeconomic status, three of the classic factors (male sex, mother's smoking habits since birth, and attending day care) were significantly more frequent. In those who had ever had ear discharge reported, only mother's smoking habit since birth was significantly more frequent. However, it showed an orderly dose response relation. In addition, a derived general child health score was found to be significantly associated with both the middle ear disease markers. Control for this variable in the analysis of those having reported hearing difficulty reduced the effect size of mother's smoking habit, but it remained statistically significant. For reported ear discharge, even after control for the general health score and social index, mother's smoking habits and day care attendance were both significant predictors. Mother's (but not father's) smoking habits and day care attendance were found to be significant risk factors for middle ear disease. Breast feeding effects were weak and did not generally survive statistical control. CONCLUSIONS: A child having all three risk factors (attends day care, a mother who smokes, and male sex) is 3.4 times more likely to have problems with hearing than a child who has none, based on cumulative risk. Further studies should focus on preventative risk modification and well specified intervention.

The acoustic reflex in adults with histories of otitis media in childhood.

OBJECTIVE: To investigate the effects of a history of otitis media (OM) in childhood on the acoustic reflex threshold (ART) in young adults. DESIGN: Questionnaire responses on childhood ear and hearing problems were obtained from populations of university students. In Study 1, 31 students reporting histories of persistent childhood OM and 34 students with no known OM histories were identified. They received pure-tone audiometry, otomicroscopy, and measurement of ARTs for a 500 Hz pure tone. In Study 2, 20 students with OM histories and 20 students with no known OM histories received pure-tone audiometry, otomicroscopy, and measurement of ARTs for a broadband noise. RESULTS: Subjects with OM histories had higher ARTs than did subjects with no known OM histories. Multiple regression analyses showed that the main variables contributing to elevated reflex thresholds were raised hearing thresholds on the activator ear and tympanic membrane abnormalities on the probe ear. CONCLUSIONS: The elevated ARTs in adults with histories of childhood OM result from peripheral sequelae of OM. Further evidence is required to determine any functional significance of these raised reflex thresholds.

Auditory performance and acoustic reflexes in young adults reporting listening difficulties.

We aimed to determine whether reported difficulties in speech understanding are associated with abnormal acoustic reflex thresholds (ARTs). The acoustic reflex has been shown to have a role in the understanding of speech at high intensities by ensuring that the strong low-frequency components of sound do not excessively mask the higher-frequency components, which are important for speech understanding. There is also wide variance in individual ARTs. Hence, the possibility arises that subjects reporting listening difficulties in noise have abnormal acoustic reflex function. In this investigation, a questionnaire to 2395 university students was used to obtain 20 subjects reporting listening difficulties in background noise and requesting advice about their hearing problems; it also screened out significant histories of middle ear disease in childhood. These subjects, and 20 control subjects reporting no listening difficulties, received a battery of performance tests and measures of acoustic reflex thresholds. Results showed significant differences in auditory performance between subjects reporting listening difficulties and those with no such difficulties, but no differences in acoustic reflex thresholds. These findings extend the relationship between reported listening difficulties and auditory performance within the "normal hearing' range, but this relationship is unlikely to be due to abnormal acoustic reflex thresholds.

Binaural summation of the acoustic reflex.

OBJECTIVE: The ways in which summation of energy or of information occurs have long been used to explore sensory mechanisms. In the case of the acoustic reflex, some binaural summation is known to occur, but both data and specification of method have been sketchy. Accurate estimates of mean and standard deviation were therefore sought to compare binaural acoustic reflex summation (BARS) with binaural loudness summation (BLS) to determine whether these have a common basis. DESIGN: A specified method was developed for determining reliable acoustic reflex values from admittance/intensity functions. Subjects were 34 university students; the ages ranged from 18 through 25 yr. For each, the contralateral component of the binaural stimulus was presented at a level above the ipsilateral component corresponding to the difference in monaural reflex thresholds ("physiologically equivalent"). RESULTS: BARS had a mean of 4.4 dB (SD = 3.5 dB), which was significantly different from the BLS (mean = 7.6 dB, SD = 1.2 dB). The contralateral-ipsilateral difference had a mean of 11.0 dB (SD = 5.1 dB). The BARS estimate was not appreciably larger than that found in studies lacking correction for physiologic equivalence. CONCLUSIONS: Although the presence of a contralateral component elicits a summation or facilitation effect, the particular intensity value contributes little to the magnitude of that effect.

Developmental implications of early-life otitis media.

This symposium addressed possible relationships between early-life otitis media (OM) and various components of child development. The existence and nature of such relationships are of substantial theoretical and practical consequence. Particularly at issue are policies concerning optimal frequencies of examination and screening for middle-ear disease as well as the relative appropriateness of conservative vs. aggressive regimens of management.

Long-term effects of otitis media with effusion: otomicroscopic findings.

A cohort of 946 children who were screened for otitis media with effusion (OME) by serial tympanometry from the age of 2 to 4 years was followed up by otomicroscopy at 7.5 to 8 years of age. At school age, signs of active middle ear disease were present in 2.2% of ears that had been free from OME at preschool age, whereas 12.7% of ears that had suffered from persistent OME and 17.8% of ears that had been treated by a ventilation tube showed signs of active middle ear disease. Otopathologic sequelae (atrophy, tympanosclerosis, atelectasis, and attic retraction) were present in 13.7%, 39.8%, and 87.3% of these ears, respectively. A duration-response effect was found in the association between preschool OME and these sequelae at school age. The high prevalence of otoscopic abnormalities found in this population calls for further follow-up and evaluation of their functional implications.

Maternal blood group in otitis media with effusion.

Risk factors for otitis media with effusion (OME) have proved difficult to apply in selecting persistent cases, or those otherwise requiring intervention. Explanations may include low predictive values of individual factors and the costs of data collection. In this study, profiles on 225 children from conception to age 7 years were compiled from medical and Health Authority records and structured interviews with parents. On the grounds that nearly all cases receiving medical intervention after waiting and onward referral are more than transitory (although many persistent cases will not receive such attention) this was taken as the dependent variable--a marker of persistence. Established risk factors and maternal blood group A were considered singly to predict intervention, then in combination using logistic regression. Maternal blood group A gave a relative risk (RR) for intervention of 2.82. The noted occurrence of an attack of acute otitis media (AOM) before the first birthday gave a RR of 6.13. When these two factors were used together, the RR climbed steeply to 26.77. These findings suggest that further research is justified into the nature of the influence of blood group A on OME, and the use of combinations of risk factors to give enhanced prediction.

Validation of parameters for assessing Obscure Auditory Dysfunction--robustness of determinants of OAD status across samples and test methods.

About 5% of those presenting at an ENT clinic with ear or hearing complaints are found to have normal pure-tone thresholds. Many of this group complain specifically of difficulties understanding speech in background noise. We have termed this complaint 'Obscure Auditory Dysfunction' (OAD). Previous research on OAD (Saunders and Haggard, 1992) on a sample of 50 patients and 50 matched controls showed that 83% of the deviance (binary variance) in membership of group (OAD/control) could be explained by four variables, with three underlying factors. These four variables are performance threshold in noise for speech; discrepancy between this and a self-adjusted signal-to-noise ratio value (i.e. a measure of auditory confidence); dichotic listening performance; and performance on a psychoacoustic test, the threshold for detecting a tone in a spectrally notched noise. This paper reports a study on a further 59 new OAD patients and 64 unmatched controls, using the tests in the form present in the test package, plus certain others. For routine practice, slightly differing implementations of the auditory test techniques were used. Compared to the earlier sample, the new sample had poorer measures of speech reception threshold in noise and they considered themselves more handicapped by their OAD state; however there was no significant difference between the two samples on the other performance variables. Overall, the results demonstrate the robustness of the conclusions reached from the previous study, as the test-variable determinants of OAD status (i.e. case-control differences) were similar. The items on the OAD interview questionnaire which had shown significant differences between OADs and controls were also similar for the two OAD samples, giving a consistent picture of patient profile. These were: difficulties learning to read or write as a child (which relates to dichotic listening scores); adult ear problems; and tinnitus (which relate to the psychoacoustic scores). This necessary replication confirms the validity of the three-factor model of OAD status and the utility of the clinical test package based upon it.