Johanna G. Barry

Listening effort and fatigue: what exactly are we measuring? A British Society of Audiology Cognition in Hearing Special Interest Group 'white paper'.

Abstract Objective: There is growing interest in the concepts of listening effort and fatigue associated with hearing loss. However, the theoretical underpinnings and clinical meaning of these concepts are unclear. This lack of clarity reflects both the relative immaturity of the field and the fact that research studies investigating listening effort and fatigue have used a variety of methodologies including self-report, behavioural, and physiological measures. Design: This discussion paper provides working definitions for listening effort and listening-related fatigue. Using these definitions as a framework, methodologies to assess these constructs are reviewed. Results: Although each technique attempts to characterize the same construct (i.e. the clinical presentation of listening effort and fatigue), different assumptions are often made about the nature of these phenomena and their behavioural and physiological manifestations. Conclusion: We suggest that researchers consider these assumptions when interpreting their data and, where possible, make predictions based on current theoretical knowledge to add to our understanding of the underlying mechanisms of listening effort and listening-related fatigue. Foreword Following recent interest in the cognitive involvement in hearing, the British Society of Audiology (BSA) established a Special Interest Group on Cognition in Hearing in May 2013. In an exploratory group meeting, the ambiguity surrounding listening effort and fatigue was discussed. To address this problem, the group decided to develop a ‘white paper’ on listening effort and fatigue. This is a discussion document followed by an international set of commentaries from leading researchers in the field. An approach was made to the editor of the International Journal of Audiology who agreed to this suggestion. This paper, and the associated commentaries that follow, are the result.

Further defining the language impairment of autism: Is there a specific language impairment subtype?

UNLABELLED Some children with autism demonstrate poor nonword repetition--a deficit considered to be a psycholinguistic marker of specific language impairment (SLI). The present study examined whether there is an SLI subtype among children with autism. We compared the language abilities of children with SLI (n=34, M age=11;10 S.D.=2;3), and children with autism with (Apoor, n=18, M age=10;11 S.D.=3;1) and without (Aapp, n=16, M age=10;8 S.D.=2;7) structural language difficulties. Participants were administered battery of standardized language and memory tests. Although there were some similarities in the language profile of the SLI and Apoor groups, the two groups differed on the tests of oromotor ability and verbal short-term memory and showed a different pattern of errors on the nonword repetition task. These findings providing evidence against the idea of an SLI subtype in autism. Further analyses suggested that the nonword repetition deficits experienced by some children with autism may arise when there is substantial impairment in multiple autistic domains. LEARNING OUTCOMES Readers will be introduced to (a) the current state of behavioral, cognitive and genetic research that has investigated the relation between SLI and autism, and (b) three hypotheses of why there exists similarity in the language characteristics of children with SLI and autism. Readers will then be taken through a detailed comparison of the language and memory abilities of group of children with each diagnosis. A theoretical model that seeks to explain the relation between these two disorders will be discussed.

Heritable risk factors associated with language impairments.

There is a strong genetic contribution to children’s language and literacy impairments. The aim of this study was to determine which aspects of the phenotype are familial by comparing 34 parents of probands with language/literacy impairments and 33 parents of typically developing probands. The parents responded to questionnaires regarding previous history for language/reading impairment and participated in psychometric testing. The psychometric test battery consisted of tests assessing non‐verbal IQ, short‐term memory, articulation, receptive grammar, reading abilities and spelling. Self‐report measures demonstrated a higher prevalence of language and literacy impairments in parents of affected probands (32%) compared with parents of unaffected probands (6%). The two groups of parents differed significantly in their performance on the non‐word repetition, oromotor and digit span tasks. Non‐word repetition gave the best discrimination between the parent groups even when the data from the parents who actually were impaired as ascertained by direct testing or self‐report were removed from the analyses. This suggests that non‐word repetition serves as a marker of a family risk for language impairment. The paper concludes with a discussion of issues associated with ascertainment of specific language impairment (SLI).

Co-localisation of abnormal brain structure and function in specific language impairment

Graphical abstract Highlights ► Compared brain structure and function in SLI, unaffected siblings, and typical peers. ► More grey matter in SLI in the left inferior frontal cortex. ► Less grey matter in SLI in the right caudate nucleus and superior temporal cortex bilaterally. ► Functional activation was examined with an auditory covert naming task. ► Functionally, SLI had reduced activation of the left inferior frontal cortex and the superior temporal cortex bilaterally.

The development of speech production following cochlear implantation

Conversational speech samples were analysed over a six-year period postoperatively for nine profoundly deaf children implanted with the Cochlear Limited 22-electrode cochlear implant between ages 2-5 years. Four years post-implant, at least 90% of all syllables produced by each child were intelligible, although only one of the children (who had suffered a progressive hearing loss) had over 10% intelligible syllables prior to implantation. Over the 6-year period, the mean number of intelligible words per utterance increased from 0.15 to 4.2 and the mean number of syllables (counting both intelligible and unintelligible syllables) increased from 1.7 to 5.2, indicating an increase in complexity as well as intelligibility. The speech samples were transcribed phonetically and percentage correct analyses were conducted on the transcripts. These analyses showed a steady improvement in the percentage of correctly produced monophthongs, diphthongs and consonants. There was a corresponding rise in the percentage of words that were produced without phonetic errors. Following six years of implantation, the speech acquisition process was incomplete, although there was no evidence to suggest a plateau in performance.

Is auditory discrimination mature by middle childhood? A study using time-frequency analysis of mismatch responses from 7 years to adulthood

Behavioural and electrophysiological studies give differing impressions of when auditory discrimination is mature. Ability to discriminate frequency and speech contrasts reaches adult levels only around 12 years of age, yet an electrophysiological index of auditory discrimination, the mismatch negativity (MMN), is reported to be as large in children as in adults. Auditory ERPs were measured in 30 children (7 to 12 years), 23 teenagers (13 to 16 years) and 32 adults (35 to 56 years) in an oddball paradigm with tone or syllable stimuli. For each stimulus type, a standard stimulus (1000 Hz tone or syllable [ba]) occurred on 70% of trials, and one of two deviants (1030 or 1200 Hz tone, or syllables [da] or [bi]) equiprobably on the remaining trials. For the traditional MMN interval of 100–250 ms post-onset, size of mismatch responses increased with age, whereas the opposite trend was seen for an interval from 300 to 550 ms post-onset, corresponding to the late discriminative negativity (LDN). Time-frequency analysis of single trials revealed that the MMN resulted from phase-synchronization of oscillations in the theta (4–7 Hz) range, with greater synchronization in adults than children. Furthermore, the amount of synchronization was significantly correlated with frequency discrimination threshold. These results show that neurophysiological processes underlying auditory discrimination continue to develop through childhood and adolescence. Previous reports of adult-like MMN amplitudes in children may be artefactual results of using peak measurements when comparing groups that differ in variance.

Tone discrimination in Cantonese-speaking children using a cochlear implant

Most tone perception tests for Cantonese-speaking cochlear implant users have been based on tone identification tasks which require significant cognitive development to be successfully completed. Results from such tests suggest that cochlear implant child users are performing at about chance level and may not be receiving much information about pitch using the implant. This paper reports on the ability of cochlear implant child users to discriminate pitch variations in Cantonese by using an experimental procedure based on play audiometry. As part of the study, the usefulness of higher rates of electrode stimulation for aiding tone discrimination is also examined. Cochlear implant users are shown to derive sufficient information about pitch to discriminate most tone contrasts relatively successfully, with performance being most variable for contrasts involving tones clustered in the lower register of the speakers fundamental frequency range. Contrary to hypothesis, higher electrode stimulation rates are not found to offer significant benefits for aiding pitch discrimination.

Lower-Frequency Event-Related Desynchronization: A Signature of Late Mismatch Responses to Sounds, Which Is Reduced or Absent in Children with Specific Language Impairment

Poor discrimination of nonlinguistic sounds has been implicated in language-learning problems in children, but research evidence has been inconsistent. This study included 32 participants with specific language impairment (SLI) and 32 typically developing controls aged 7–16 years. Frequency discrimination thresholds were estimated in a task where participants had to distinguish a higher-frequency tone from a 1000 Hz tone. Neurophysiological responses were assessed in an oddball paradigm. Stimuli were either 1030 or 1200 Hz pure tones (deviants) presented in a series of standard 1000 Hz tones, or syllables (deviant [da] or [bi] in a series of standard /ba/). On the behavioral task, children (7- to 11-year-olds) had high thresholds, regardless of language status, but teenagers (12–16 years) with SLI had higher thresholds than their controls. Conventional analysis of electrophysiological responses showed no difference between groups for the mismatch negativity (MMN), but the late discriminative negativity (LDN) was reduced in amplitude for smaller deviants in participants with SLI. Time–frequency analysis revealed that, whereas the MMN reflected enhanced intertrial coherence in the theta frequency band, the LDN corresponded to a period of event-related desynchronization extending across a wide low-frequency band including delta, theta, and alpha. This manifested as a drop in power in those frequencies, which was marked in the controls but reduced or absent in children with SLI across all stimulus types. This provides compelling evidence for a low-level auditory perceptual impairment in SLI that affects a processing stage after initial detection of a sound change.

The acoustic analysis of tone differentiation as a means for assessing tone production in speakers of Cantonese

This paper reports on a methodology for acoustically analyzing tone production in Cantonese. F0 offset versus F0 onset are plotted for a series of tokens for each of the six tones in the language. These are grouped according to tone type into a set of six ellipses. Qualitative visual observations regarding the degree of differentiation of the ellipses within the tonal space are summarized numerically using two indices, referred to here as Index 1 and Index 2. Index 1 is a ratio of the area of the speakers tonal space and the average of the areas of the ellipses of the three target tones making up the tonal space. Index 2 is a ratio of the average distance between all six tonal ellipses and the average of the sum of the two axes for all six tone ellipses. Using this methodology, tonal differentiation is compared for three groups of speakers; normally hearing adults; normally hearing children aged from 4-6 years; and, prelinguistically deafened cochlear implant users aged from 4-11 years. A potential conundrum regarding how tone production abilities can outstrip tone perception abilities is explained using the data from the acoustic analyses. It is suggested that young children of the age range tested are still learning to normalize for pitch level differences in tone production. Acoustic analysis of the data thus supports results from tone perception studies and suggests that the methodology is suitable for use in studies investigating tone production in both clinical and research contexts.

Psychometric properties of the Tinnitus Functional Index (TFI): Assessment in a UK research volunteer population

Objectives Questionnaires are essential for measuring tinnitus severity and intervention-related change but there is no standard instrument used routinely in research settings. Most tinnitus questionnaires are optimised for measuring severity but not change. However, the Tinnitus Functional Index (TFI) claims to be optimised for both. It has not however been fully validated for research purposes. Here we evaluate the relevant psychometric properties of the TFI, specifically the questionnaire factor structure, reproducibility, validity and responsiveness guided by quality criteria for the measurement properties of health-related questionnaires. Methods The study involved a retrospective analysis of data collected for 294 members of the general public who participated in a randomised controlled trial of a novel tinnitus device (ClinicalTrials.gov Identifier: NCT01541969). Participants completed up to eight commonly used assessment questionnaires including the TFI, Tinnitus Handicap Inventory (THI), Tinnitus Handicap Questionnaire (THQ), a Visual Analogue Scale of loudness (VAS-Loudness), Percentage Annoyance question, the Becks Depression Inventory (BDI), Becks Anxiety Inventory (BAI), and the World Health Organisation Quality of Life-Bref (WHOQOL-BREF). A series of analyses assessed the study objectives. Forty four participants completed the TFI at a second visit (within 7–21 days and before receiving any intervention) providing data for reproducibility assessments. Results The 8-factor structure was not fully confirmed for this general (non-clinical) population. Whilst it was acceptable standalone subscale, the ‘auditory’ factor showed poor loading with the higher order factor ‘functional impact of tinnitus’. Reproducibility assessments for the overall TFI indicate high internal consistency (α = 0.80) and extremely high reliability (ICC: 0.91), whilst agreement was borderline acceptable (93%). Construct validity was demonstrated by high correlations between scores on the TFI and THI (r = 0.82) and THQ (r = 0.82), moderate correlations with VAS-L (r = 0.46), PR-A (r = 0.58), BDI (r = 0.57), BAI (r = 0.39) and WHOQOL (r = −0.48). Floor effects were observed for more than 50% of the items. A smallest detectable change score of 22.4 is proposed for the TFI global score. Conclusion Even though the proposed 8-factor structure was not fully confirmed for this population, the TFI appears to cover multiple symptom domains, and to measure the construct of tinnitus with an excellent reliability in distinguishing between patients. While the TFI may discriminate those whose tinnitus is not a problem, floor effects in many items means it is less appropriate as a measure of change in this subgroup. Further investigation is needed to determine whether these effects are relevant in other populations.