Working memory training for adult hearing aid users: study protocol for a double-blind randomized active controlled trial

Cogmed Training Does Not Generalize to Real-World Benefits for Adult Hearing Aid Users: Results of a Blinded, Active-Controlled Randomized Trial

Objectives:

Performance on working memory tasks is positively associated with speech-in-noise perception performance, particularly where auditory inputs are degraded. It is suggested that interventions designed to improve working memory capacity may improve domain-general working memory performance for people with hearing loss, to benefit their real-world listening. We examined whether a 5-week training program that primarily targets the storage component of working memory (Cogmed RM, adaptive) could improve cognition, speech-in-noise perception and self-reported hearing in a randomized controlled trial of adult hearing aid users with mild to moderate hearing loss, compared with an active control (Cogmed RM, nonadaptive) group of adults from the same population.

Design:

A preregistered randomized controlled trial of 57 adult hearing aid users (n = 27 experimental, n = 30 active control), recruited from a dedicated database of research volunteers, examined on-task learning and generalized improvements in measures of trained and untrained cognition, untrained speech-in-noise perception and self-reported hearing abilities, pre- to post-training. Participants and the outcome assessor were both blinded to intervention allocation. Retention of training-related improvements was examined at a 6-month follow-up assessment.

Results:

Per-protocol analyses showed improvements in trained tasks (Cogmed Index Improvement) that transferred to improvements in a trained working memory task tested outside of the training software (Backward Digit Span) and a small improvement in self-reported hearing ability (Glasgow Hearing Aid Benefit Profile, Initial Disability subscale). Both of these improvements were maintained 6-month post-training. There was no transfer of learning shown to untrained measures of cognition (working memory or attention), speech-in-noise perception, or self-reported hearing in everyday life. An assessment of individual differences showed that participants with better baseline working memory performance achieved greater learning on the trained tasks. Post-training performance for untrained outcomes was largely predicted by individuals’ pretraining performance on those measures.

Conclusions:

Despite significant on-task learning, generalized improvements of working memory training in this trial were limited to (a) improvements for a trained working memory task tested outside of the training software and (b) a small improvement in self-reported hearing ability for those in the experimental group, compared with active controls. We found no evidence to suggest that training which primarily targets storage aspects of working memory can result in domain-general improvements that benefit everyday communication for adult hearing aid users. These findings are consistent with a significant body of evidence showing that Cogmed training only improves performance for tasks that resemble Cogmed training. Future research should focus on the benefits of interventions that enhance cognition in the context in which it is employed within everyday communication, such as training that targets dynamic aspects of cognitive control important for successful speech-in-noise perception.

Evidence-Based Interventions for Adult Aural Rehabilitation: That Was Then, This Is Now

More than a decade after Arthur Boothroyd published "Adult Aural Rehabilitation: What Is It and Does It Work?," the four cornerstones of adult aural rehabilitation are re-examined in terms of research that we and others in the field have undertaken. The focus is on novel advances in high-quality research relating to interventions to support self-management for hearing aids and other listening devices (sensory management), knowledge and skill (instruction), auditory and cognitive training (perceptual training), and motivational engagement (counseling). Much of this new research has a theoretical underpinning (e.g., behavior change theory) to better guide the development and evaluation of interventions, with a focus on self-management and patient-centered approaches. New and emerging technologies that support e- and m-health delivery of interventions provide greater personalization and interactivity to promote self-management of hearing loss. Looking to the future, there remains a requirement for a set of relevant and appropriate outcome measures to evaluate the effectiveness of interventions trialed in clinical studies. There is a continuing need for high-quality evidence, underpinned by contemporary theory, to increase the likelihood that translational adult aural rehabilitation research that aims to benefit patients will be applied in future clinical practice.

Interventions to improve hearing aid use in adult auditory rehabilitation

BACKGROUND

Acquired adult-onset hearing loss is a common long-term condition for which the most common intervention is hearing aid fitting. However, up to 40% of people fitted with a hearing aid either fail to use it or may not gain optimal benefit from it. This is an update of a review first published in The Cochrane Library in 2014.

OBJECTIVES

To assess the long-term effectiveness of interventions to promote the use of hearing aids in adults with acquired hearing loss fitted with at least one hearing aid.

SEARCH METHODS

The Cochrane ENT Information Specialist searched the Cochrane ENT Trials Register; Central Register of Controlled Trials (CENTRAL 2016, Issue 5); PubMed; EMBASE; CINAHL; Web of Science; ClinicalTrials.gov; ICTRP and additional sources for published and unpublished trials. The date of the search was 13 June 2016.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) of interventions designed to improve or promote hearing aid use in adults with acquired hearing loss compared with usual care or another intervention. We excluded interventions that compared hearing aid technology. We classified interventions according to the 'chronic care model' (CCM). The primary outcomes were hearing aid use (measured as adherence or daily hours of use) and adverse effects (inappropriate advice or clinical practice, or patient complaints). Secondary patient-reported outcomes included quality of life, hearing handicap, hearing aid benefit and communication. Outcomes were measured over the short ( 12 to < 52 weeks) and long term (one year plus).

DATA COLLECTION AND ANALYSIS

We used the standard methodological procedures expected by Cochrane.

MAIN RESULTS

We included 37 studies involving a total of 4129 participants. Risk of bias across the included studies was variable. We judged the GRADE quality of evidence to be very low or low for the primary outcomes where data were available.The majority of participants were over 65 years of age with mild to moderate adult-onset hearing loss. There was a mix of new and experienced hearing aid users. Six of the studies (287 participants) assessed long-term outcomes.All 37 studies tested interventions that could be classified using the CCM as self-management support (ways to help someone to manage their hearing loss and hearing aid(s) better by giving information, practice and experience at listening/communicating or by asking people to practise tasks at home) and/or delivery system design interventions (just changing how the service was delivered). Self-management support interventions We found no studies that investigated the effect of these interventions on adherence, adverse effects or hearing aid benefit. Two studies reported daily hours of hearing aid use but we were unable to combine these in a meta-analysis. There was no evidence of a statistically significant effect on quality of life over the medium term. Self-management support reduced short- to medium-term hearing handicap (two studies, 87 participants; mean difference (MD) -12.80, 95% confidence interval (CI) -23.11 to -2.48 (0 to 100 scale)) and increased the use of verbal communication strategies in the short to medium term (one study, 52 participants; MD 0.72, 95% CI 0.21 to 1.23 (0 to 5 scale)). The clinical significance of these statistical findings is uncertain. It is likely that the outcomes were clinically significant for some, but not all, participants. Our confidence in the quality of this evidence was very low. No self-management support studies reported long-term outcomes. Delivery system design interventionsThese interventions did not significantly affect adherence or daily hours of hearing aid use in the short to medium term, or adverse effects in the long term. We found no studies that investigated the effect of these interventions on quality of life. There was no evidence of a statistically or clinically significant effect on hearing handicap, hearing aid benefit or the use of verbal communication strategies in the short to medium term. Our confidence in the quality of this evidence was low or very low. Long-term outcome measurement was rare. Combined self-management support/delivery system design interventionsOne combined intervention showed evidence of a statistically significant effect on adherence in the short term (one study, 167 participants, risk ratio (RR) 1.06, 95% CI 1.00 to 1.12). However, there was no evidence of a statistically or clinically significant effect on daily hours of hearing aid use over the long term, or the short to medium term. No studies of this type investigated adverse effects. There was no evidence of an effect on quality of life over the long term, or short to medium term. These combined interventions reduced hearing handicap in the short to medium term (15 studies, 728 participants; standardised mean difference (SMD) -0.26, 95% CI -0.48 to -0.04). This represents a small-moderate effect size but there is no evidence of a statistically significant effect over the long term. There was evidence of a statistically, but not clinically, significant effect on long-term hearing aid benefit (two studies, 69 participants, MD 0.30, 95% CI 0.02 to 0.58 (1 to 5 scale)), but no evidence of an effect over the short to medium term. There was evidence of a statistically, but not clinically, significant effect on the use of verbal communication strategies in the short term (four studies, 223 participants, MD 0.45, 95% CI 0.15 to 0.74 (0 to 5 scale)), but not the long term. Our confidence in the quality of this evidence was low or very low.We found no studies that assessed the effect of other CCM interventions (decision support, the clinical information system, community resources or health system changes).

AUTHORS' CONCLUSIONS

There is some low to very low quality evidence to support the use of self-management support and complex interventions combining self-management support and delivery system design in adult auditory rehabilitation. However, effect sizes are small. The range of interventions that have been tested is relatively limited. Future research should prioritise: long-term outcome assessment; development of a core outcome set for adult auditory rehabilitation; and study designs and outcome measures that are powered to detect incremental effects of rehabilitative healthcare system changes.

Neurocognitive factors in sensory restoration of early deafness: a connectome model

Progress in biomedical technology (cochlear, vestibular, and retinal implants) has led to remarkable success in neurosensory restoration, particularly in the auditory system. However, outcomes vary considerably, even after accounting for comorbidity-for example, after cochlear implantation, some deaf children develop spoken language skills approaching those of their hearing peers, whereas other children fail to do so. Here, we review evidence that auditory deprivation has widespread effects on brain development, affecting the capacity to process information beyond the auditory system. After sensory loss and deafness, the brain's effective connectivity is altered within the auditory system, between sensory systems, and between the auditory system and centres serving higher order neurocognitive functions. As a result, congenital sensory loss could be thought of as a connectome disease, with interindividual variability in the brain's adaptation to sensory loss underpinning much of the observed variation in outcome of cochlear implantation. Different executive functions, sequential processing, and concept formation are at particular risk in deaf children. A battery of clinical tests can allow early identification of neurocognitive risk factors. Intervention strategies that address these impairments with a personalised approach, taking interindividual variations into account, will further improve outcomes.

Working Memory Training and Speech in Noise Comprehension in Older Adults

Understanding speech in the presence of background sound can be challenging for older adults. Speech comprehension in noise appears to depend on working memory and executive-control processes (e.g., Heald and Nusbaum, 2014), and their augmentation through training may have rehabilitative potential for age-related hearing loss. We examined the efficacy of adaptive working-memory training (Cogmed; Klingberg et al., 2002) in 24 older adults, assessing generalization to other working-memory tasks (near-transfer) and to other cognitive domains (far-transfer) using a cognitive test battery, including the Reading Span test, sensitive to working memory (e.g., Daneman and Carpenter, 1980). We also assessed far transfer to speech-in-noise performance, including a closed-set sentence task (Kidd et al., 2008). To examine the effect of cognitive training on benefit obtained from semantic context, we also assessed transfer to open-set sentences; half were semantically coherent (high-context) and half were semantically anomalous (low-context). Subjects completed 25 sessions (0.5–1 h each; 5 sessions/week) of both adaptive working memory training and placebo training over 10 weeks in a crossover design. Subjects' scores on the adaptive working-memory training tasks improved as a result of training. However, training did not transfer to other working memory tasks, nor to tasks recruiting other cognitive domains. We did not observe any training-related improvement in speech-in-noise performance. Measures of working memory correlated with the intelligibility of low-context, but not high-context, sentences, suggesting that sentence context may reduce the load on working memory. The Reading Span test significantly correlated only with a test of visual episodic memory, suggesting that the Reading Span test is not a pure-test of working memory, as is commonly assumed.

How Does Auditory Training Work? Joined-Up Thinking and Listening

Auditory training aims to compensate for degradation in the auditory signal and is offered as an intervention to help alleviate the most common complaint in people with hearing loss, understanding speech in a background noise. Yet there remain many unanswered questions. This article reviews some of the key pieces of evidence that assess the evidence for whether, and how, auditory training benefits adults with hearing loss. The evidence supports that improvements occur on the trained task; however, transfer of that learning to generalized real-world benefit is much less robust. For more than a decade, there has been an increasing awareness of the role that cognition plays in listening. But more recently in the auditory training literature, there has been an increased focus on assessing how cognitive performance relevant for listening may improve with training. We argue that this is specifically the case for measures that index executive processes, such as monitoring, attention switching, and updating of working memory, all of which are required for successful listening and communication in challenging or adverse listening conditions. We propose combined auditory-cognitive training approaches, where training interventions develop cognition embedded within auditory tasks, which are most likely to offer generalized benefits to the real-world listening abilities of people with hearing loss.

Computer and Internet Interventions to Optimize Listening and Learning for People With Hearing Loss: Accessibility, Use, and Adherence

PURPOSE

The aim of this research forum article was to examine accessibility, use, and adherence to computerized and online interventions for people with hearing loss.

METHOD

Four intervention studies of people with hearing loss were examined: 2 auditory training studies, 1 working memory training study, and 1 study of multimedia educational support.

RESULTS

A small proportion (approximately 15%) of participants had never used a computer, which may be a barrier to the accessibility of computer and Internet-based interventions. Computer competence was not a factor in intervention use or adherence. Computer skills and Internet access influenced participant preference for the delivery method of the multimedia educational support program.

CONCLUSIONS

It is important to be aware of current barriers to computer and Internet-delivered interventions for people with hearing loss. However, there is a clear need to develop and future-proof hearing-related applications for online delivery.

Language Outcomes in Children With Unilateral Hearing Loss: A Review

Unilateral hearing loss (UHL) in children is only recently beginning to be widely appreciated as having a negative impact. We now understand that simply having one normal-hearing ear may not be sufficient for typical child development, and leads to impairments in speech and language outcomes. Unfortunately, UHL is not a rare problem among children in the United States, and is present among more than 1 out of every 10 of adolescents in this country. How UHL specifically affects development of speech and language, however, is currently not well understood. While we know that children with UHL are more likely than their normal-hearing siblings to have speech therapy and individualized education plans at school, we do not yet understand the mechanism through which UHL causes speech and language problems. The objective of this review is to describe what is currently known about the impact of UHL on speech and language development in children. Furthermore, we discuss some of the potential pathways through which the impact of unilateral hearing loss on speech and language might be mediated.

Auditory training can improve working memory, attention, and communication in adverse conditions for adults with hearing loss

Auditory training (AT) helps compensate for degradation in the auditory signal. A series of three high-quality training studies are discussed, which include, (i) a randomized controlled trial (RCT) of phoneme discrimination in quiet that trained adults with mild hearing loss (n = 44), (ii) a repeated measures study that trained phoneme discrimination in noise in hearing aid (HA) users (n = 30), and (iii) a double-blind RCT that directly trained working memory (WM) in HA users (n = 57). AT resulted in generalized improvements in measures of self-reported hearing, competing speech, and complex cognitive tasks that all index executive functions. This suggests that for AT related benefits, the development of complex cognitive skills may be more important than the refinement of sensory processing. Furthermore, outcome measures should be sensitive to the functional benefits of AT. For WM training, lack of far-transfer to untrained outcomes suggests no generalized benefits to real-world listening abilities. We propose that combined auditory-cognitive training approaches, where cognitive enhancement is embedded within auditory tasks, are most likely to offer generalized benefits to the real-world listening abilities of adults with hearing loss.

Failing to get the gist of what's being said: background noise impairs higher-order cognitive processing

A dynamic interplay is known to exist between auditory processing and human cognition. For example, prior investigations of speech-in-noise have revealed there is more to learning than just listening: Even if all words within a spoken list are correctly heard in noise, later memory for those words is typically impoverished. These investigations supported a view that there is a "gap" between the intelligibility of speech and memory for that speech. Here, the notion was that this gap between speech intelligibility and memorability is a function of the extent to which the spoken message seizes limited immediate memory resources (e.g., Kjellberg et al., 2008). Accordingly, the more difficult the processing of the spoken message, the less resources are available for elaboration, storage, and recall of that spoken material. However, it was not previously known how increasing that difficulty affected the memory processing of semantically rich spoken material. This investigation showed that noise impairs higher levels of cognitive analysis. A variant of the Deese-Roediger-McDermott procedure that encourages semantic elaborative processes was deployed. On each trial, participants listened to a 36-item list comprising 12 words blocked by each of 3 different themes. Each of those 12 words (e.g., bed, tired, snore…) was associated with a "critical" lure theme word that was not presented (e.g., sleep). Word lists were either presented without noise or at a signal-to-noise ratio of 5 decibels upon an A-weighting. Noise reduced false recall of the critical words, and decreased the semantic clustering of recall. Theoretical and practical implications are discussed.

Benefits of phoneme discrimination training in a randomized controlled trial of 50- to 74-year-olds with mild hearing loss

OBJECTIVES

The aims of this study were to (i) evaluate the efficacy of phoneme discrimination training for hearing and cognitive abilities of adults aged 50 to 74 years with mild sensorineural hearing loss who were not users of hearing aids, and to (ii) determine participant compliance with a self-administered, computer-delivered, home- and game-based auditory training program.

DESIGN

This study was a randomized controlled trial with repeated measures and crossover design. Participants were trained and tested over an 8- to 12-week period. One group (Immediate Training) trained during weeks 1 and 4. A second waitlist group (Delayed Training) did no training during weeks 1 and 4, but then trained during weeks 5 and 8. On-task (phoneme discrimination) and transferable outcome measures (speech perception, cognition, self-report of hearing disability) for both groups were obtained during weeks 0, 4, and 8, and for the Delayed Training group only at week 12.

RESULTS

Robust phoneme discrimination learning was found for both groups, with the largest improvements in threshold shown for those with the poorest initial thresholds. Between weeks 1 and 4, the Immediate Training group showed moderate, significant improvements on self-report of hearing disability, divided attention, and working memory, specifically for conditions or situations that were more complex and therefore more challenging. Training did not result in consistent improvements in speech perception in noise. There was no evidence of any test-retest effects between weeks 1 and 4 for the Delayed Training group. Retention of benefit at 4 weeks post-training was shown for phoneme discrimination, divided attention, working memory, and self-report of hearing disability. Improved divided attention and reduced self-reported hearing difficulties were highly correlated.

CONCLUSIONS

It was observed that phoneme discrimination training benefits some but not all people with mild hearing loss. Evidence presented here, together with that of other studies that used different training stimuli, suggests that auditory training may facilitate cognitive skills that index executive function and the self-perception of hearing difficulty in challenging situations. The development of cognitive skills may be more important than the development of sensory skills for improving communication and speech perception in everyday life. However, improvements were modest. Outcome measures need to be appropriately challenging to be sensitive to the effects of the relatively small amount of training performed.