Less is more: latent learning is maximized by shorter training sessions in auditory perceptual learning

The Effect of Religious-Spiritual Education and Care on the Quality of Life of Iranian Women: A Systematic Review and Meta-Analysis

So far, several preliminary studies have been conducted on the effect of religious-spiritual education and care on the quality of life of women in different parts of Iran. Therefore, the current study aims to explore the effect of religious-spiritual education and care on the quality of life of Iranian women through systematic review and meta-analysis. Databases searched for studies related to the research objective include SID, MagIran, Embase, PubMed, Scopus, WoS, and Google Scholar. The search was performed using keywords linked to and validated with MeSH/Emtree with no time limit until April 2022. The I2 index was used to calculate the heterogeneity of the studies and the random effects model was used to combine the data and perform the meta-analysis. Finally, 14 articles with a sample size of 295 intervention group and 288 control group were included in the meta-analysis. The mean score of the quality of life after the intervention showed a significant increase of 1.87 ± 0.29 (95% confidence interval) per unit (P < 0.001). Meta-regression results showed that with the increasing year of study and age, the standardized mean difference decreased and with increasing the number of intervention sessions, this difference increased (P < 0.05). The results of this study show that religious-spiritual education and care significantly increase the quality of life of Iranian women. Therefore, it seems that the use of religious-spiritual education and care can be part of the program to increase the quality of life of women.

Multi-session training in the evening schedule exhibits enhanced speech learning

Speech learning can be influenced by a variety of factors. A growing body of literature suggests a significant influence of sleep on speech learning, i.e., those trained in the evening outperform those trained in the morning most probably due to consolidation of learning that happens during the sleep for the evening group. Since, learning, in general, may be a process that spans multiple sessions, in the current exploratory study, we aimed at investigating the effect of a multi-session training paradigm on the learning performance of the morning vs evening group. We compared young adults who were trained in the morning (8-10 am; n = 16) with those who were trained in the evening (6-8 pm; n = 16) on a Hindi dental-retroflex pseudoword-picture association training paradigm. Overall, we found that the evening group learned to a larger extent both for the identification (on trained items) and discrimination (on untrained items) tasks. The current findings, even with a multi-session paradigm, are consistent with the previous findings that support enhanced performance by training in the evening. These findings may have clinical implications toward scheduling of speech therapy.

Improving Perceptual Speech Ratings: The Effects of Auditory Training on Judgments of Dysarthric Speech

PURPOSE

Auditory training has been shown to reduce rater variability in perceptual voice assessment. Because rater variability is also a central issue in the auditory-perceptual assessment of dysarthria, this study sought to determine if training produces a meaningful change in rater reliability, criterion validity, and scaling magnitude of four features: overall speech impairment, articulatory imprecision, monotony, and slow rate.

METHOD

Forty-four nonexperts randomized to training and nontraining listener groups completed a pretest and posttest. Only the former group underwent auditory training between pre- and posttests. For both testing and training, listeners rated samples from speakers with amyotrophic lateral sclerosis (ALS), speakers with Parkinson's disease (PD), and neurologically healthy control speakers using separate visual analog scales (VASs) for each of the four features. Intraclass correlation coefficients were used to compare inter- and intrarater reliability between pre- and posttest for both listener groups. For criterion validity, severity ratings from the two nonexpert listener groups were compared to those of two experienced listeners for all four features. To determine changes in scaling magnitude, raw VAS scores for each feature were compared from pre- to posttest within the two nonexpert listener groups. Scaling changes were also compared between the two listener groups for the pre- and posttest conditions.

RESULTS AND CONCLUSIONS

In the training group, a meaningful improvement in interrater reliability was observed for some features in all three speaker groups, but not in the nontraining group. In contrast, for intrarater reliability, in the nontraining group, a meaningful improvement was observed for many features in all three speaker groups, but only for PD monotony and slow rate in the training group. All ratings from the nonexpert listeners were valid except for monotony. Raw VAS scores did not meaningfully change from pre- to posttest for any of the features, but there was a trend toward lower scores posttraining, mainly for the ALS samples. Modifications to the auditory training paradigm to further improve reliability and validity, along with future goals for optimizing training, are discussed.

Individual Differences in Auditory Training Benefits for Hearing Aid Users

The present study aimed to examine whether individual differences in baseline speech perception could serve as predictors for the effectiveness and generalization of auditory training (AT) to non-trained tasks. Twelve adults, aged 60-75 years with bilateral hearing loss, completed a two-month, home-based, computerized AT program, involving sessions four times per week. Training tasks included the identification of vowel frontal, height, manner of articulation, point of articulation, voicing, and open-set consonant-vowel-consonant (CVC) words. Non-trained speech perception tests were conducted one month before AT, prior to training, after one and two months of training, and during a two-month follow-up. The results showed that one month of AT improved performance in most trained tasks, with generalization observed in the CVC words test and HeBio sentences with speech-shaped noise (SSN). No evidence of spontaneous learning or added benefit from an extra month of training was found. Most importantly, baseline speech perception predicted improvements in both training and post-training generalization tasks. This emphasizes the significance of adopting an individualized approach when determining the potential effectiveness of AT, applicable in both clinical and research contexts.

A webinar series to educate applicants about the UK academic foundation programme: a longitudinal cross-sectional study

BACKGROUND

The UK academic foundation programme (AFP) is a competitive programme for medical graduates and forms the initial stage of the integrated clinical academic pathway. The application is complex and targeted education is beneficial. As online technologies improve, virtual medical education is becoming more common. Currently, webinar education, particularly that of webinar series, are poorly evidenced. An online course was created to investigate the acceptability and effectiveness of webinars for medical education.

METHODS

A six-part, one-hour sessional webinar course was developed following a focus group with academic foundation doctors. A pre- and post-course cross-sectional questionnaire study evaluated participant demographics, webinar opinion and self-rated understanding of the AFP via Google Form (Google, USA). Where applicable a five-point Likert scale (1-Strongly disagree to 5-strongly agree) was utilised and analysis using non-parametric paired statistical analysis.

RESULTS

Medical students (n=303) from 35 UK universities completed the pre-course questionnaire. Most students had not received targeted education on the AFP. They rated webinars useful for education (mean=4.2 s.d. 0.7). After the course, participants (n=66) expressed it was significantly convenient (mean=4.7), effective (mean=4.7) and suitably interactive (mean=4.4) (p<0.001 compared to neutral). Participants preferred short sessions over multiple days to the concept of a full-day event (mean=4.6 vs 3.1, p<0.001). Paired analysis of participants completing both forms (n=47) demonstrates a significant increase in self-rated understanding of AFP content, portfolio building, application process, acute clinical scenarios, interview technique and overall confidence in acquiring an AFP post (p<0.001). Follow-up identified 43 participants who completed the course were successful in their AFP application. This represents 7.8% of all successful AFP applicants in 2021.

CONCLUSIONS

This study evidences an accessible and effective webinar series for AFP education. Comprehensive webinar courses for similar topics and demographics may provide valuable utility in the provision of future medical education.

TRIAL REGISTRATION

Ethics requirements were waived for this study by Bristol University Ethics Committee. All participants in this study consented for anonymous use of their data. As such the trial is not registered.

Slowed reaction times in cognitive fatigue are not attributable to declines in motor preparation

Cognitive fatigue (CF) can result from sustained mental effort, is characterized by subjective feelings of exhaustion and cognitive performance deficits, and is associated with slowed simple reaction time (RT). This study determined whether declines in motor preparation underlie this RT effect. Motor preparation level was indexed using simple RT and the StartReact effect, wherein a prepared movement is involuntarily triggered at short latency by a startling acoustic stimulus (SAS). It was predicted that if decreased motor preparation underlies CF-associated RT increases, then an attenuated StartReact effect would be observed following cognitive task completion. Subjective fatigue assessment and a simple RT task were performed before and after a cognitively fatiguing task or non-fatiguing control intervention. On 25% of RT trials, a SAS replaced the go-signal to assess the StartReact effect. CF inducement was verified by significant declines in cognitive performance (p = 0.003), along with increases in subjective CF (p < 0.001) and control RT (p = 0.018) following the cognitive fatigue intervention, but not the control intervention. No significant pre-to-post-test changes in SAS RT were observed, indicating that RT increases resulting from CF are not substantially associated with declines in motor preparation, and instead may be attributable to other stages of processing during a simple RT task.

Rapid but specific perceptual learning partially explains individual differences in the recognition of challenging speech

Perceptual learning for speech, defined as long-lasting changes in speech recognition following exposure or practice occurs under many challenging listening conditions. However, this learning is also highly specific to the conditions in which it occurred, such that its function in adult speech recognition is not clear. We used a time-compressed speech task to assess learning following either brief exposure (rapid learning) or additional training (training-induced learning). Both types of learning were robust and long-lasting. Individual differences in rapid learning explained unique variance in recognizing natural-fast speech and speech-in-noise with no additional contribution for training-induced learning (Experiment 1). Rapid learning was stimulus specific (Experiment 2), as in previous studies on training-induced learning. We suggest that rapid learning is key for understanding the role of perceptual learning in online speech recognition whereas longer training could provide additional opportunities to consolidate and stabilize learning.

Effect of Hearing Rehabilitation Therapy Program in Hearing Aids Users: A Prospective Randomized Controlled Study

Objectives

Despite sufficient hearing gains, many patients with hearing loss have difficulty using hearing aids due to poor word recognition ability. This study was performed to introduce our hearing rehabilitation therapy (HRT) program for hearing aid users and to evaluate its effect on hearing improvement.

Methods

In this prospective randomized case-control study, 37 participants with moderate or moderate-severe sensorineural hearing loss who had used bilateral hearing aids for more than 3 months with sufficient functional hearing gain were enrolled in this study. Nineteen participants were randomly assigned to the control group (CG) and 18 patients were assigned to participate in our HRT program once a week for 8 consecutive weeks (hearing rehabilitation therapy group [HRTG]). Their hearing results and questionnaire scores for hearing handicap and hearing aid outcomes were prospectively collected and compared between the two groups.

Results

After completing 8 weeks of the HRT program, the HRTG showed a significantly greater improvement in scores for consonant-only and consonant-vowel sound perception than the CG (P<0.05). In addition, the HRTG showed a significant improvement in hearing ability as measured by two questionnaires (P<0.05), while no differences were observed in the CG. However, word and sentence recognition test results did not show significant differences between the two groups.

Conclusion

Even after short-term HRT, patients had subjectively better hearing outcomes and improved phoneme perception ability; this provides scientific evidence regarding a possible positive role for HRT programs in hearing aid users. Further validation in a larger population through a long-term follow-up study is needed.

Audiovisual training rapidly reduces potentially hazardous perceptual errors caused by earplugs

Our ears capture sound from all directions but do not encode directional information explicitly. Instead, subtle acoustic features associated with unique sound source locations must be learned through experience. Surprisingly, aspects of this mapping process remain highly plastic throughout adulthood: Adult human listeners can accommodate acutely modified acoustic inputs ("new ears") over a period of a few weeks to recover near-normal sound localization, and this process can be accelerated with explicit training. Here we evaluated the extent of such plasticity given only transient exposure to distorted inputs. Distortions were produced via earplugs, which severely degrade sound localization performance, constraining their usability in real-world settings that require accurate directional hearing. Localization was measured over a period of ten weeks. Provision of feedback via simple paired auditory and visual stimuli led to a rapid decrease in the occurrence of large errors (responses >|±30°| from target) despite only once-weekly exposure to the altered inputs. Moreover, training effects generalized to untrained sound source locations. Lesser but qualitatively similar improvements were observed in a group of subjects that did not receive explicit feedback. In total, data demonstrate that even transient exposure to altered spatial acoustic information is sufficient for meaningful perceptual improvement (i.e., chronic exposure is not required), offering insight on the nature and time course of perceptual learning in the context of spatial hearing. Data also suggest that the large and potentially hazardous errors in localization caused by earplugs can be mitigated with appropriate training, offering a practical means to increase their usability.

Amateur singing benefits speech perception in aging under certain conditions of practice: behavioural and neurobiological mechanisms

Limited evidence has shown that practising musical activities in aging, such as choral singing, could lessen age-related speech perception in noise (SPiN) difficulties. However, the robustness and underlying mechanism of action of this phenomenon remain unclear. In this study, we used surface-based morphometry combined with a moderated mediation analytic approach to examine whether singing-related plasticity in auditory and dorsal speech stream regions is associated with better SPiN capabilities. 36 choral singers and 36 non-singers aged 20-87 years underwent cognitive, auditory, and SPiN assessments. Our results provide important new insights into experience-dependent plasticity by revealing that, under certain conditions of practice, amateur choral singing is associated with age-dependent structural plasticity within auditory and dorsal speech regions, which is associated with better SPiN performance in aging. Specifically, the conditions of practice that were associated with benefits on SPiN included frequent weekly practice at home, several hours of weekly group singing practice, singing in multiple languages, and having received formal singing training. These results suggest that amateur choral singing is associated with improved SPiN through a dual mechanism involving auditory processing and auditory-motor integration and may be dose dependent, with more intense singing associated with greater benefit. Our results, thus, reveal that the relationship between singing practice and SPiN is complex, and underscore the importance of considering singing practice behaviours in understanding the effects of musical activities on the brain-behaviour relationship.

Effectiveness of Computer-Based Auditory Training for Adult Cochlear Implant Users: A Randomized Crossover Study

The aim of this study was to assess whether a computer-based speech-in-noise auditory training (AT) program would lead to short- and long-term changes in trained and untrained measures of listening, cognition, and quality of life. A secondary aim was to assess whether directly training the underlying cognitive abilities required for speech perception in noise, using a computer-based visual training (VT) program without the auditory component, would elicit comparable outcomes as the AT program. A randomized crossover study with repeated measures was conducted with 26 adult cochlear implant users. Participants completed either 6 weeks of speech perception in noise training followed by 6 weeks of masked text recognition training, or vice versa. Outcome measures were administered twice before each training program, as well as twice after the completion of each program. The test battery was designed to evaluate whether training led to improvements in listening abilities, cognitive abilities, or quality of life. Mixed-effects models were conducted to analyze whether changes occurred on the trained tasks and on untrained outcome measures after training. Statistically significant improvements were shown for verbal recognition performance during both training programs, in particular for consonants in words, and during the first 2 weeks of training. This on-task learning, however, did not lead to clear improvements in outcomes measured beyond the training programs. This suggests that experienced cochlear implant users may not show transfer of on-task learning to untrained tasks after computer-based auditory and visual training programs such as the ones used in this study.

Test-retest Reliability of the qReading Method in Normally Sighted Young Adults

SIGNIFICANCE

We recently developed a novel Bayesian adaptive method, qReading, to measure reading function. The qReading method has both the efficiency and excellent test-retest reliability in normally sighted young adults to make it an excellent candidate for future studies of its value in diagnosis and longitudinal evaluation of treatment and/or rehabilitation outcomes.

PURPOSE

A novel Bayesian adaptive method, qReading, was recently developed to measure reading function. Here we performed a systematic assessment of the test-retest reliability of the qReading method.

METHODS

The variability of five repeated measurements of the reading curve was examined in two settings: within session and between sessions. For the within-session design, we considered two subpopulations: naive observers and experienced observers. All observers were normally sighted young adults. For each set of data, in addition to examining the intrinsic precision of the qReading method (the half width of the credible interval of the posterior distribution of the estimated performance), we computed four metrics to assess repeatability: standard deviation, Bland-Altman coefficient of repeatability, correlation coefficient, and Fractional Rank Precision.

RESULTS

Extrinsic factors such as observer, time interval between repeated measures, and observer experience all contribute to the variation across measurements. Nevertheless, the four metrics consistently show that the variability across five repeated measurements is small for each set of data. This is true even without taking learning effects into account (standard deviations, ≤0.092 log10 units; Bland-Altman coefficient of repeatability, ≤0.15 (log10)2 units; correlation coefficient, ≥0.91; and Fractional Rank Precision, ≥0.81).

CONCLUSIONS

The qReading method has excellent test-retest reliability in normally sighted young adults.

Practice Makes Transfer Imperfect: Evidence From Auditory Learning

BACKGROUND

Evidence from motor and visual studies suggests that the ability to generalize learning gains to untrained conditions decreases as the training progresses. This decrease in generalization was suggested to reflect a shift from higher to lower levels of neuronal representations of the task following prolonged training. In the auditory modality, however, the few studies that tested the influence of prolonging training on generalization ability showed no decrease and sometimes even an increase in generalization.

OBJECTIVE

To test the impact of extending training in a basic psychoacoustic task on the ability to generalize the gains attained in training to untrained conditions.

DESIGN

Eighty-two young adults participated in two experiments that differed in the specific training regimen. In both experiments, training was conducted using a difference limen for frequency (DLF) task with an adaptive forced-choice procedure, for either a single- or nine-session training. Following training, generalization to the untrained ear and to an untrained frequency was assessed.

RESULTS

(a) Training induced significant learning (i.e., smaller DLF thresholds) following a single session of training, and more so following nine training sessions; (b) results from the combined data from both experiments showed that the ability to generalize the learning gains to the untrained ear and frequency was limited after the extended DLF training; (c) larger improvements under the trained condition resulted in smaller generalization to the untrained conditions.

CONCLUSIONS

The findings of increased specificity with training in the auditory modality support the notion that gradual changes, both quantitative and qualitative, occur in the neural representations of an auditory task during its acquisition. These findings suggest common underlying mechanisms in basic skill learning across different modalities.

Feature-based attention enables robust, long-lasting location transfer in human perceptual learning

Visual perceptual learning (VPL) is typically specific to the trained location and feature. However, the degree of specificity depends upon particular training protocols. Manipulating covert spatial attention during training facilitates learning transfer to other locations. Here we investigated whether feature-based attention (FBA), which enhances the representation of particular features throughout the visual field, facilitates VPL transfer, and how long such an effect would last. To do so, we implemented a novel task in which observers discriminated a stimulus orientation relative to two reference angles presented simultaneously before each block. We found that training with FBA enabled remarkable location transfer, reminiscent of its global effect across the visual field, but preserved orientation specificity in VPL. Critically, both the perceptual improvement and location transfer persisted after 1 year. Our results reveal robust, long-lasting benefits induced by FBA in VPL, and have translational implications for improving generalization of training protocols in visual rehabilitation.

Effects of daily training amount on visual motion perceptual learning

Perceptual learning has been widely used to study the plasticity of the visual system in adults. Owing to the belief that practice makes perfect, perceptual learning protocols usually require subjects to practice a task thousands of times over days, even weeks. However, we know very little about the relationship between training amount and behavioral improvement. Here, four groups of subjects underwent motion direction discrimination training over 8 days with 40, 120, 360, or 1080 trials per day. Surprisingly, different daily training amounts induced similar improvement across the four groups, and the similarity lasted for at least 2 weeks. Moreover, the group with 40 training trials per day showed more learning transfer from the trained direction to the untrained directions than the group with 1080 training trials per day immediately after training and 2 weeks later. These findings suggest that perceptual learning of motion direction discrimination is not always dependent on the daily training amount and less training leads to more transfer.

Improving older adults' understanding of challenging speech: Auditory training, rapid adaptation and perceptual learning

The literature surrounding auditory perceptual learning and auditory training for challenging speech signals in older adult listeners is highly varied, in terms of both study methodology and reported outcomes. In this review, we discuss some of the pertinent features of listener, stimulus, and training protocol. Literature regarding the elicitation of auditory perceptual learning for time-compressed speech, non-native speech, and noise-vocoded speech is reviewed, as are auditory training protocols designed to improve speech-in-noise recognition. The literature is synthesized to establish some over-arching findings for the aging population, including an intact capacity for auditory perceptual learning, but a limited transfer of learning to untrained stimuli.

Lessons Learned in Teaching Battlefield (Ear) Acupuncture to Emergency Medicine Clinicians

Background: Acupuncture, in general, is being proclaimed as an alternative analgesic amid the opioid crisis, and along with this, within emergency departments (EDs) there is a specific interest in a form of ear acupuncture called Battlefield Acupuncture (BFA). It is expected that BFA will be used more widely in emergency medicine as it is easy to learn and can be applied both promptly and easily. Teaching programs will be required to sustain this increased demand and upskill emergency clinicians in this skill. Objectives: This article provides experiences and recommendations, based on faculty experiences from teaching BFA in Australia to ED clinicians combined with formal participant feedback. Main Points: BFA courses were adjusted to suit ED doctors and nurses, along with their unique case mix and associated challenging environment. The content of the BFA courses included evidence, pain indications, contraindications, application, safety, mechanism of action, and how to negotiate barriers of credentialing. Workshops used the latest and most effective teaching methods that encompassed problem-based learning, infotainment, simulation, "four stage skills teaching," and "teaching on the run." Conclusion: It is hoped that the experiences gained, and lessons learned in educating this new frontier of BFA to emergency clinicians will assist others in teaching BFA and its related techniques as a viable analgesic alternative in emergency medicine.

The Use of Auditory-Perceptual Training as a Research Method: A Summary Review

OBJECTIVE

The purpose of this descriptive review was to document the current state of training to perform auditory-perceptual analysis as reported in the voice literature.

METHODS

A review of the literature was performed.

RESULTS

Thirty-six articles were included in the review. The theoretical basis of training, specific training methods employed, duration of training, stimuli used to train, vocal qualities trained, and the type of listeners used are reported.

CONCLUSION

There is wide variation to training procedures used in research including auditory-perceptual evaluation of voice quality. In order to begin to discover how to best train listeners for research and clinical settings, attention to the training methods used in research is necessary. Further, these training methods must be explicitly acknowledged and described to allow for adequate evaluation of research findings, comparison across studies, and to determine for which populations results might be applicable. The conceptual framework outlined in this study is a starting point to review voice quality research and to design future studies for which auditory-perceptual evaluation is taught to listeners.

Auditory Training for Adult Cochlear Implant Users: A Survey and Cost Analysis Study

OBJECTIVES

The aims of this study were as follows: (a) to describe audiologists' practices toward auditory training (AT) for adult cochlear implant (CI) users with a postlingual hearing loss; and (b) to assess the cost of different AT methods for clients and service providers in comparison with no AT delivery.

DESIGN

A survey was distributed to approximately 230 Australian CI audiologists to investigate the range, magnitude, and rationale of AT practices adopted as part of rehabilitation services with adult CI users. The cost of these different AT practices was then estimated from the perspectives of both clients and service providers, and compared against no AT delivery.

RESULTS

Seventy-eight audiologists responded to at least one section of the survey (16% to 33% response rate), of which 85.5% reported that they viewed AT as a necessary component of rehabilitation. Home-based and face-to-face were the methods most frequently adopted to deliver AT. Methods used during training, such as stimuli type, feedback, and encouragement for training adherence, varied across respondents. The cost analysis indicated that home-based training resulted in the lowest program costs, whereas face-to-face AT (when delivered independently from routine appointments) was the method with highest cost for clients and service providers.

CONCLUSIONS

The type of AT, recommended frequency of sessions, and overall duration of programs varied widely across respondents. Costs incurred by clients depended mainly on whether the AT was home-based or clinician-led (i.e., face-to-face, group-based), program fees, and travel arrangements made by clients, as well as clinicians' wages and the method chosen to deliver AT.

Effects of stimulus repetition and training schedule on the perceptual learning of time-compressed speech and its transfer

Perceptual learning can facilitate the recognition of hard-to-perceive (e.g., time-compressed or spectrally-degraded) speech. Although the learning induced by training with time-compressed speech is robust, previous findings suggest that intensive training yields learning that is partially specific to the items encountered during practice. Here, we asked whether three parameters of the training procedure - the overall number of training trials (training intensity), how these trials are distributed across sessions, and the number of semantically different items encountered during training (set size) - influence learning and transfer. Different groups of participants (69 normal-hearing young adults; nine to 11 participants/group) completed different training protocols (or served as an untrained control group) and tested on the recognition of time-compressed sentences taken from the training set (learning), new time-compressed sentences presented by the trained talker (semantic transfer), and time-compressed sentences taken from the training set but presented by a different talker (acoustic transfer). Compared to untrained listeners, all training protocols yielded both learning and transfer. More intense training resulted in greater item-specific learning and greater acoustic transfer than less intense training with the same number of training sessions. Training on a smaller set size (i.e., greater token repetition during training) also resulted in greater acoustic transfer, whereas distributing practice over a number of sessions improved semantic transfer. Together, these data suggest that whereas practice on a small set that results in stimulus repetition during training is not harmful for learning, distributed training can support transfer to new stimuli, perhaps because it provides multiple opportunities to consolidate learning.

Does training with amplitude modulated tones affect tone-vocoded speech perception?

Temporal-envelope cues are essential for successful speech perception. We asked here whether training on stimuli containing temporal-envelope cues without speech content can improve the perception of spectrally-degraded (vocoded) speech in which the temporal-envelope (but not the temporal fine structure) is mainly preserved. Two groups of listeners were trained on different amplitude-modulation (AM) based tasks, either AM detection or AM-rate discrimination (21 blocks of 60 trials during two days, 1260 trials; frequency range: 4Hz, 8Hz, and 16Hz), while an additional control group did not undertake any training. Consonant identification in vocoded vowel-consonant-vowel stimuli was tested before and after training on the AM tasks (or at an equivalent time interval for the control group). Following training, only the trained groups showed a significant improvement in the perception of vocoded speech, but the improvement did not significantly differ from that observed for controls. Thus, we do not find convincing evidence that this amount of training with temporal-envelope cues without speech content provide significant benefit for vocoded speech intelligibility. Alternative training regimens using vocoded speech along the linguistic hierarchy should be explored.

Short-term effects of sound localization training in virtual reality

Head-related transfer functions (HRTFs) capture the direction-dependant way that sound interacts with the head and torso. In virtual audio systems, which aim to emulate these effects, non-individualized, generic HRTFs are typically used leading to an inaccurate perception of virtual sound location. Training has the potential to exploit the brain's ability to adapt to these unfamiliar cues. In this study, three virtual sound localization training paradigms were evaluated; one provided simple visual positional confirmation of sound source location, a second introduced game design elements ("gamification") and a final version additionally utilized head-tracking to provide listeners with experience of relative sound source motion ("active listening"). The results demonstrate a significant effect of training after a small number of short (12-minute) training sessions, which is retained across multiple days. Gamification alone had no significant effect on the efficacy of the training, but active listening resulted in a significantly greater improvements in localization accuracy. In general, improvements in virtual sound localization following training generalized to a second set of non-individualized HRTFs, although some HRTF-specific changes were observed in polar angle judgement for the active listening group. The implications of this on the putative mechanisms of the adaptation process are discussed.

Easy-to-hard effects in perceptual learning depend upon the degree to which initial trials are "easy"

Starting perceptual training at easy levels before progressing to difficult levels generally produces better learning outcomes than constantly difficult training does. However, little is known about how "easy" these initial levels should be in order to yield easy-to-hard effects. We compared five levels of initial training block difficulty varying from very easy to hard in two auditory-discrimination learning tasks-a frequency modulation rate discrimination (Experiment 1) and a frequency range discrimination (Experiment 2). The degree of difficulty was based on individualized pretraining ~71% correct discrimination thresholds. Both experiments revealed a sweet spot for easy-to-hard effects. Conditions where initial blocks were either too easy or too difficult produced less benefit than did blocks of intermediate difficulty. Results challenge assumptions that sequencing effects in learning are related to attentional spotlighting of task-relevant dimensions. Rather, they support incremental learning models that account for easy-to-hard effects. Further, the results have implications for how perceptual training regimens should be designed to maximize the benefits of rehabilitative perceptual training.

Tactile angle discriminability improvement: roles of training time intervals and different types of training tasks

Perceptual learning, which is not limited to sensory modalities such as vision and touch, emerges within a training session and between training sessions and is accompanied by the remodeling of neural connections in the cortex. However, limited knowledge exists regarding perceptual learning between training sessions. Although tactile studies have paid attention to between-session learning effects, there have been few studies asking fundamental questions regarding whether the time interval between training sessions affects tactile perceptual learning and generalization across tactile tasks. We investigated the effects of different training time intervals on the consecutive performance of a tactile angle discrimination (AD) task and a tactile orientation discrimination (OD) task training on tactile angle discriminability. The results indicated that in the short-interval training group, AD task performance significantly improved in the early stage of learning and nearly plateaued in the later stage, whereas in the long-interval training group, significant improvement was delayed and then also nearly plateaued in the later stage; additionally, improved OD task performance resulted in improved AD task performance. These findings suggest that training time interval affects the early stage of learning but not the later stage and that generalization occurs between different types of tactile tasks.

NEW & NOTEWORTHY Perceptual learning, which constitutes important foundations of complicated cognitive processes, is learning better perception skills. We demonstrate that training time interval can affect the early stage of learning but not the later stage. Moreover, a tactile orientation discrimination training task can also improve tactile angle discrimination performance. These findings may expand the characteristics of between-session learning and help understand the mechanism of the generalization across tactile tasks.

Change deafness can be reduced, but not eliminated, using brief training interventions

Research on change deafness indicates there are substantial limitations to listeners' perception of which objects are present in complex auditory scenes, an ability that is important for many everyday situations. Experiment 1 examined the extent to which change deafness could be reduced by training with performance feedback compared to no training. Experiment 2 compared the efficacy of training with detailed feedback that identified the change and provided performance feedback on each trial, training without feedback, and no training. We further examined the timescale over which improvement unfolded by examining performance using an immediate post-test and a second post-test 12 h later. We were able to reduce, but not eliminate, change deafness for all groups, and determined that the practice content strongly impacted bias and response strategy. Training with simple performance feedback reduced change deafness but increased bias and false alarm rates, while providing a more detailed feedback improved change detection without affecting bias. Together, these findings suggest that change deafness can be reduced if a relatively small amount of practice is completed. When bias did not impede performance during the first post-test, the majority of the learning following training occurred immediately, suggesting that fast within-session learning primarily supported improvement on the task.

Auditory and Cognitive Training for Cognition in Adults With Hearing Loss: A Systematic Review and Meta-Analysis

This systematic review and meta-analysis examined the efficacy of auditory training and cognitive training to improve cognitive function in adults with hearing loss. A literature search of academic databases (e.g., MEDLINE, Scopus) and gray literature (e.g., OpenGrey) identified relevant articles published up to January 25, 2018. Randomized controlled trials (RCTs) or repeated measures designs were included. Outcome effects were computed as Hedge’s g and pooled using random-effects meta-analysis (PROSPERO: CRD42017076680). Nine studies, five auditory training, and four cognitive training met the inclusion criteria. Following auditory training, the pooled effect was small and statistically significant for both working memory (g = 0.21; 95% CI [0.05, 0.36]) and overall cognition (g = 0.19; 95% CI [0.07, 0.31]). Following cognitive training, the pooled effect for working memory was small and statistically significant (g = 0.34; 95% CI [0.16, 0.53]), and the pooled effect for overall cognition was large and significant (g = 1.03; 95% CI [0.41, 1.66]). However, this was dependent on the classification of training approach. Sensitivity analyses revealed no statistical difference between the effectiveness of auditory and cognitive training for improving cognition upon removal of a study that used a combined auditory–cognitive approach, which showed a very large effect. Overall certainty in the estimation of effect was “low” for auditory training and “very low” for cognitive training. High-quality RCTs are needed to determine which training stimuli will provide optimal conditions to improve cognition in adults with hearing loss.

Auditory temporal perceptual learning and transfer in Chinese-speaking children with developmental dyslexia

Perceptual learning refers to the improvement of perceptual performance as a function of training. Recent studies found that auditory perceptual learning may improve phonological skills in individuals with developmental dyslexia in alphabetic writing system. However, whether auditory perceptual learning could also benefit the reading skills of those learning the Chinese logographic writing system is, as yet, unknown. The current study aimed to investigate the remediation effect of auditory temporal perceptual learning on Mandarin-speaking school children with developmental dyslexia. Thirty children with dyslexia were screened from a large pool of students in 3th-5th grades. They completed a series of pretests and then were assigned to either a non-training control group or a training group. The training group worked on a pure tone duration discrimination task for 7 sessions over 2 weeks with thirty minutes per session. Post-tests immediately after training and a follow-up test 2 months later were conducted. Analyses revealed a significant training effect in the training group relative to non-training group, as well as near transfer to the temporal interval discrimination task and far transfer to phonological awareness, character recognition and reading fluency. Importantly, the training effect and all the transfer effects were stable at the 2-month follow-up session. Further analyses found that a significant correlation between character recognition performance and learning rate mainly existed in the slow learning phase, the consolidation stage of perceptual learning, and this effect was modulated by an individuals' executive function. These findings indicate that adaptive auditory temporal perceptual learning can lead to learning and transfer effects on reading performance, and shed further light on the potential role of basic perceptual learning in the remediation and prevention of developmental dyslexia.

Is the Role of External Feedback in Auditory Skill Learning Age Dependent?

PURPOSE

The purpose of this study is to investigate the role of external feedback in auditory perceptual learning of school-age children as compared with that of adults.

METHOD

Forty-eight children (7-9 years of age) and 64 adults (20-35 years of age) conducted a training session using an auditory frequency discrimination (difference limen for frequency) task, with external feedback (EF) provided for half of them.

RESULTS

Data supported the following findings: (a) Children learned the difference limen for frequency task only when EF was provided. (b) The ability of the children to benefit from EF was associated with better cognitive skills. (c) Adults showed significant learning whether EF was provided or not. (d) In children, within-session learning following training was dependent on the provision of feedback, whereas between-sessions learning occurred irrespective of feedback.

CONCLUSIONS

EF was found beneficial for auditory skill learning of 7-9-year-old children but not for young adults. The data support the supervised Hebbian model for auditory skill learning, suggesting combined bottom-up internal neural feedback controlled by top-down monitoring. In the case of immature executive functions, EF enhanced auditory skill learning. This study has implications for the design of training protocols in the auditory modality for different age groups, as well as for special populations.

Disruption of Perceptual Learning by a Brief Practice Break

Some forms of associative learning require only a single experience to create a lasting memory [1, 2]. In contrast, perceptual learning often requires extensive practice within a day for performance to improve across days [3, 4]. This suggests that the requisite practice for durable perceptual learning is integrated throughout each day. If the total amount of daily practice is the only important variable, then a practice break within a day should not disrupt across-day improvement. To test this idea, we trained human listeners on an auditory frequency-discrimination task over multiple days and compared the performance of those who engaged in a single continuous practice session each day [4] with those who were given a 30-min break halfway through each practice session. Continuous practice yielded significant perceptual learning [4]. In contrast, practice with a rest break led to no improvement, indicating that the integration process had decayed within 30 min. In a separate experiment, a 30-min practice break also disrupted durable learning on a non-native phonetic classification task. These results suggest that practice trials are integrated up to a learning threshold within a transient memory store before they are sent en masse into a memory that lasts across days. Thus, the oft cited benefits of distributed over massed training [5, 6] may arise from different mechanisms depending on whether the breaks occur before or after a learning threshold has been reached. Trial integration could serve as an early gatekeeper to plasticity, helping to ensure that longer-lasting changes are only made when deemed worthwhile.

Auditory Training for Adults Who Have Hearing Loss: A Comparison of Spaced Versus Massed Practice Schedules

Purpose

The spacing effect in human memory research refers to situations in which people learn items better when they study items in spaced intervals rather than massed intervals. This investigation was conducted to compare the efficacy of meaning-oriented auditory training when administered with a spaced versus massed practice schedule.

Method

Forty-seven adult hearing aid users received 16 hr of auditory training. Participants in a spaced group (mean age = 64.6 years, SD = 14.7) trained twice per week, and participants in a massed group (mean age = 69.6 years, SD = 17.5) trained for 5 consecutive days each week. Participants completed speech perception tests before training, immediately following training, and then 3 months later. In line with transfer appropriate processing theory, tests assessed both trained tasks and an untrained task.

Results

Auditory training improved the speech recognition performance of participants in both groups. Benefits were maintained for 3 months. No effect of practice schedule was found on overall benefits achieved, on retention of benefits, nor on generalizability of benefits to nontrained tasks.

Conclusion

The lack of spacing effect in otherwise effective auditory training suggests that perceptual learning may be subject to different influences than are other types of learning, such as vocabulary learning. Hence, clinicians might have latitude in recommending training schedules to accommodate patients' schedules.

Spacing Repetitions Over Long Timescales: A Review and a Reconsolidation Explanation

Recent accounts of the spacing effect have proposed molecular explanations that explain spacing over short, but not long timescales. In the first half of this paper, we review research on the spacing effect that has employed spaces of 24 h or more across skill-related tasks, language-related tasks and generalization for adults and children. Throughout this review, we distinguish between learning and retention by defining learning (or acquisition) as performance at the end of training and retention as performance after a delay period. Using this distinction, we find age- and task-related differences in the manifestation of the spacing effect over long timescales. In the second half of this paper, we discuss a reconsolidation account of the spacing effect. In particular, we review the evidence that suggests the spacing of repetitions influences the subsequent consolidation and reconsolidation processes; we explain how a reconsolidation account may explain the findings for learning; the inverted-U curve for retention; and compare the reconsolidation account with previous consolidation accounts of the spacing effect.

Evidence and evidence gaps in tinnitus therapy

A nearly endless number of procedures has been tried and in particular sold for the treatment of tinnitus, unfortunately they have not been evaluated appropriately in an evidence-based way. A causal therapy, omitting the tinnitus still does not exist, actually it cannot exist because of the various mechanisms of its origin. However or perhaps because of that, medical interventions appear and reappear like fashion trends that can never be proven by stable and reliable treatment success. This contribution will discuss and acknowledge all current therapeutic procedures and the existing or non-existing evidence will be assessed. Beside external evidence, the term of evidence also encompasses the internal evidence, i.e. the experience of the treating physician and the patient's needs shall be included. While there is no evidence for nearly all direct procedures that intend modulating or stimulating either the cochlea or specific cervical regions such as the auditory cortex, there are therapeutic procedures that are acknowledged in clinical practice and have achieved at least a certain degree of evidence and generate measurable effect sizes. Those are in particular habituation therapy and psychotherapeutic measures, especially if they are combined with concrete measures for improved audio perception (hearing aids, CI, hearing therapies).

The Effect of Short-Term Auditory Training on Speech in Noise Perception and Cortical Auditory Evoked Potentials in Adults with Cochlear Implants

This study investigated whether a short intensive psychophysical auditory training program is associated with speech perception benefits and changes in cortical auditory evoked potentials (CAEPs) in adult cochlear implant (CI) users. Ten adult implant recipients trained approximately 7 hours on psychophysical tasks (Gap-in-Noise Detection, Frequency Discrimination, Spectral Rippled Noise [SRN], Iterated Rippled Noise, Temporal Modulation). Speech performance was assessed before and after training using Lexical Neighborhood Test (LNT) words in quiet and in eight-speaker babble. CAEPs evoked by a natural speech stimulus /baba/ with varying syllable stress were assessed pre- and post-training, in quiet and in noise. SRN psychophysical thresholds showed a significant improvement (78% on average) over the training period, but performance on other psychophysical tasks did not change. LNT scores in noise improved significantly post-training by 11% on average compared with three pretraining baseline measures. N1P2 amplitude changed post-training for /baba/ in quiet (p = 0.005, visit 3 pretraining versus visit 4 post-training). CAEP changes did not correlate with behavioral measures. CI recipients' clinical records indicated a plateau in speech perception performance prior to participation in the study. A short period of intensive psychophysical training produced small but significant gains in speech perception in noise and spectral discrimination ability. There remain questions about the most appropriate type of training and the duration or dosage of training that provides the most robust outcomes for adults with CIs.

Rapid auditory learning of temporal gap detection

The rapid initial phase of training-induced improvement has been shown to reflect a genuine sensory change in perception. Several features of early and rapid learning, such as generalization and stability, remain to be characterized. The present study demonstrated that learning effects from brief training on a temporal gap detection task using spectrally similar narrowband noise markers defining the gap (within-channel task), transfer across ears, however, not across spectrally dissimilar markers (between-channel task). The learning effects associated with brief training on a gap detection task were found to be stable for at least a day. These initial findings have significant implications for characterizing early and rapid learning effects.

Auditory Discrimination Learning: Role of Working Memory

Perceptual training is generally assumed to improve perception by modifying the encoding or decoding of sensory information. However, this assumption is incompatible with recent demonstrations that transfer of learning can be enhanced by across-trial variation of training stimuli or task. Here we present three lines of evidence from healthy adults in support of the idea that the enhanced transfer of auditory discrimination learning is mediated by working memory (WM). First, the ability to discriminate small differences in tone frequency or duration was correlated with WM measured with a tone n-back task. Second, training frequency discrimination around a variable frequency transferred to and from WM learning, but training around a fixed frequency did not. The transfer of learning in both directions was correlated with a reduction of the influence of stimulus variation in the discrimination task, linking WM and its improvement to across-trial stimulus interaction in auditory discrimination. Third, while WM training transferred broadly to other WM and auditory discrimination tasks, variable-frequency training on duration discrimination did not improve WM, indicating that stimulus variation challenges and trains WM only if the task demands stimulus updating in the varied dimension. The results provide empirical evidence as well as a theoretic framework for interactions between cognitive and sensory plasticity during perceptual experience.

Auditory Training for Central Auditory Processing Disorder

Auditory training (AT) is an important component of rehabilitation for patients with central auditory processing disorder (CAPD). The present article identifies and describes aspects of AT as they relate to applications in this population. A description of the types of auditory processes along with information on relevant AT protocols that can be used to address these specific deficits is included. Characteristics and principles of effective AT procedures also are detailed in light of research that reflects on their value. Finally, research investigating AT in populations who show CAPD or present with auditory complaints is reported. Although efficacy data in this area are still emerging, current findings support the use of AT for treatment of auditory difficulties.

Efficacy of auditory training in elderly subjects

Auditory training (AT) has been used for auditory rehabilitation in elderly individuals and is an effective tool for optimizing speech processing in this population. However, it is necessary to distinguish training-related improvements from placebo and test-retest effects. Thus, we investigated the efficacy of short-term AT [acoustically controlled auditory training (ACAT)] in elderly subjects through behavioral measures and P300. Sixteen elderly individuals with auditory processing disorder (APD) received an initial evaluation (evaluation 1 - E1) consisting of behavioral and electrophysiological tests (P300 evoked by tone burst and speech sounds) to evaluate their auditory processing. The individuals were divided into two groups. The Active Control Group (n = 8) underwent placebo training. The Passive Control Group (n = 8) did not receive any intervention. After 12 weeks, the subjects were revaluated (evaluation 2 - E2). Then, all of the subjects underwent ACAT. Following another 12 weeks (eight training sessions), they underwent the final evaluation (evaluation 3 - E3). There was no significant difference between E1 and E2 in the behavioral test [F(9.6) = 0.06, p = 0.92, λ de Wilks = 0.65)] or P300 [F(8.7) = 2.11, p = 0.17, λ de Wilks = 0.29] (discarding the presence of placebo effects and test-retest). A significant improvement was observed between the pre- and post-ACAT conditions (E2 and E3) for all auditory skills according to the behavioral methods [F(4.27) = 0.18, p = 0.94, λ de Wilks = 0.97]. However, the same result was not observed for P300 in any condition. There was no significant difference between P300 stimuli. The ACAT improved the behavioral performance of the elderly for all auditory skills and was an effective method for hearing rehabilitation.

Acquisition versus consolidation of auditory perceptual learning using mixed-training regimens

Learning is considered to consist of two distinct phases-acquisition and consolidation. Acquisition can be disrupted when short periods of training on more than one task are interleaved, whereas consolidation can be disrupted when a second task is trained after the first has been initiated. Here we investigated the conditions governing the disruption to acquisition and consolidation during mixed-training regimens in which primary and secondary amplitude modulation tasks were either interleaved or presented consecutively. The secondary task differed from the primary task in either task-irrelevant (carrier frequency) or task-relevant (modulation rate) stimulus features while requiring the same perceptual judgment (amplitude modulation depth discrimination), or shared both irrelevant and relevant features but required a different judgment (amplitude modulation rate discrimination). Based on previous literature we predicted that acquisition would be disrupted by varying the task-relevant stimulus feature during training (stimulus interference), and that consolidation would be disrupted by varying the perceptual judgment required (task interference). We found that varying the task-relevant or -irrelevant stimulus features failed to disrupt acquisition but did disrupt consolidation, whereas mixing two tasks requiring a different perceptual judgment but sharing the same stimulus features disrupted both acquisition and consolidation. Thus, a distinction between acquisition and consolidation phases of perceptual learning cannot simply be attributed to (task-relevant) stimulus versus task interference. We propose instead that disruption occurs during acquisition when mixing two tasks requiring a perceptual judgment based on different cues, whereas consolidation is always disrupted regardless of whether different stimulus features or tasks are mixed. The current study not only provides a novel insight into the underlying mechanisms of perceptual learning, but also has practical implications for the optimal design and delivery of training programs that aim to remediate perceptual difficulties.

The effects of stimulus variability on the perceptual learning of speech and non-speech stimuli

Previous studies suggest fundamental differences between the perceptual learning of speech and non-speech stimuli. One major difference is in the way variability in the training set affects learning and its generalization to untrained stimuli: training-set variability appears to facilitate speech learning, while slowing or altogether extinguishing non-speech auditory learning. We asked whether the reason for this apparent difference is a consequence of the very different methodologies used in speech and non-speech studies. We hypothesized that speech and non-speech training would result in a similar pattern of learning if they were trained using the same training regimen. We used a 2 (random vs. blocked pre- and post-testing) × 2 (random vs. blocked training) × 2 (speech vs. non-speech discrimination task) study design, yielding 8 training groups. A further 2 groups acted as untrained controls, tested with either random or blocked stimuli. The speech task required syllable discrimination along 4 minimal-pair continua (e.g., bee-dee), and the non-speech stimuli required duration discrimination around 4 base durations (e.g., 50 ms). Training and testing required listeners to pick the odd-one-out of three stimuli, two of which were the base duration or phoneme continuum endpoint and the third varied adaptively. Training was administered in 9 sessions of 640 trials each, spread over 4–8 weeks. Significant learning was only observed following speech training, with similar learning rates and full generalization regardless of whether training used random or blocked schedules. No learning was observed for duration discrimination with either training regimen. We therefore conclude that the two stimulus classes respond differently to the same training regimen. A reasonable interpretation of the findings is that speech is perceived categorically, enabling learning in either paradigm, while the different base durations are not well-enough differentiated to allow for categorization, resulting in disruption to learning.

Children with speech sound disorder: comparing a non-linguistic auditory approach with a phonological intervention approach to improve phonological skills

This study aimed to compare the effects of a non-linguistic auditory intervention approach with a phonological intervention approach on the phonological skills of children with speech sound disorder (SSD). A total of 17 children, aged 7–12 years, with SSD were randomly allocated to either the non-linguistic auditory temporal intervention group (n = 10, average age 7.7 ± 1.2) or phonological intervention group (n = 7, average age 8.6 ± 1.2). The intervention outcomes included auditory-sensory measures (auditory temporal processing skills) and cognitive measures (attention, short-term memory, speech production, and phonological awareness skills). The auditory approach focused on non-linguistic auditory training (e.g., backward masking and frequency discrimination), whereas the phonological approach focused on speech sound training (e.g., phonological organization and awareness). Both interventions consisted of 12 45-min sessions delivered twice per week, for a total of 9 h. Intra-group analysis demonstrated that the auditory intervention group showed significant gains in both auditory and cognitive measures, whereas no significant gain was observed in the phonological intervention group. No significant improvement on phonological skills was observed in any of the groups. Inter-group analysis demonstrated significant differences between the improvement following training for both groups, with a more pronounced gain for the non-linguistic auditory temporal intervention in one of the visual attention measures and both auditory measures. Therefore, both analyses suggest that although the non-linguistic auditory intervention approach appeared to be the most effective intervention approach, it was not sufficient to promote the enhancement of phonological skills.

Auditory learning through active engagement with sound: biological impact of community music lessons in at-risk children

The young nervous system is primed for sensory learning, facilitating the acquisition of language and communication skills. Social and linguistic impoverishment can limit these learning opportunities, eventually leading to language-related challenges such as poor reading. Music training offers a promising auditory learning strategy by directing attention to meaningful acoustic elements of the soundscape. In light of evidence that music training improves auditory skills and their neural substrates, there are increasing efforts to enact community-based programs to provide music instruction to at-risk children. Harmony Project is a community foundation that has provided free music instruction to over 1000 children from Los Angeles gang-reduction zones over the past decade. We conducted an independent evaluation of biological effects of participating in Harmony Project by following a cohort of children for 1 year. Here we focus on a comparison between students who actively engaged with sound through instrumental music training vs. students who took music appreciation classes. All children began with an introductory music appreciation class, but midway through the year half of the children transitioned to the instrumental training. After the year of training, the children who actively engaged with sound through instrumental music training had faster and more robust neural processing of speech than the children who stayed in the music appreciation class, observed in neural responses to a speech sound /d/. The neurophysiological measures found to be enhanced in the instrumentally-trained children have been previously linked to reading ability, suggesting a gain in neural processes important for literacy stemming from active auditory learning. Despite intrinsic constraints on our study imposed by a community setting, these findings speak to the potential of active engagement with sound (i.e., music-making) to engender experience-dependent neuroplasticity and may inform the development of strategies for auditory learning.

The plastic ear and perceptual relearning in auditory spatial perception

The auditory system of adult listeners has been shown to accommodate to altered spectral cues to sound location which presumably provides the basis for recalibration to changes in the shape of the ear over a life time. Here we review the role of auditory and non-auditory inputs to the perception of sound location and consider a range of recent experiments looking at the role of non-auditory inputs in the process of accommodation to these altered spectral cues. A number of studies have used small ear molds to modify the spectral cues that result in significant degradation in localization performance. Following chronic exposure (10–60 days) performance recovers to some extent and recent work has demonstrated that this occurs for both audio-visual and audio-only regions of space. This begs the questions as to the teacher signal for this remarkable functional plasticity in the adult nervous system. Following a brief review of influence of the motor state in auditory localization, we consider the potential role of auditory-motor learning in the perceptual recalibration of the spectral cues. Several recent studies have considered how multi-modal and sensory-motor feedback might influence accommodation to altered spectral cues produced by ear molds or through virtual auditory space stimulation using non-individualized spectral cues. The work with ear molds demonstrates that a relatively short period of training involving audio-motor feedback (5–10 days) significantly improved both the rate and extent of accommodation to altered spectral cues. This has significant implications not only for the mechanisms by which this complex sensory information is encoded to provide spatial cues but also for adaptive training to altered auditory inputs. The review concludes by considering the implications for rehabilitative training with hearing aids and cochlear prosthesis.

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.

Learning one task by interleaving practice with another task

Perceptual learning is a sustainable improvement in performance on a perceptual task following training. A hallmark of perceptual learning is task specificity - after participants have trained on and learned a particular task, learning rarely transfers to another task, even with identical stimuli. Accordingly, it is assumed that performing a task throughout training is a requirement for learning to occur on that specific task. Thus, interleaving training trials of a target task, with those of another task, should not improve performance on the target task. However, recent findings in audition show that interleaving two tasks during training can facilitate perceptual learning, even when the training on neither task yields learning on its own. Here we examined the role of cross-task training in the visual domain by training 4 groups of human observers for 3 consecutive days on an orientation comparison task (target task) and/or spatial-frequency comparison task (interleaving task). Interleaving small amounts of training on each task, which were ineffective alone, not only enabled learning on the target orientation task, as in audition, but also surpassed the learning attained by training on that task alone for the same total number of trials. This study illustrates that cross-task training in visual perceptual learning can be more effective than single-task training. The results reveal a comparable learning principle across modalities and demonstrate how to optimize training regimens to maximize perceptual learning.

Older adults benefit from music training early in life: biological evidence for long-term training-driven plasticity

Aging results in pervasive declines in nervous system function. In the auditory system, these declines include neural timing delays in response to fast-changing speech elements; this causes older adults to experience difficulty understanding speech, especially in challenging listening environments. These age-related declines are not inevitable, however: older adults with a lifetime of music training do not exhibit neural timing delays. Yet many people play an instrument for a few years without making a lifelong commitment. Here, we examined neural timing in a group of human older adults who had nominal amounts of music training early in life, but who had not played an instrument for decades. We found that a moderate amount (4-14 years) of music training early in life is associated with faster neural timing in response to speech later in life, long after training stopped (>40 years). We suggest that early music training sets the stage for subsequent interactions with sound. These experiences may interact over time to sustain sharpened neural processing in central auditory nuclei well into older age.

Reduction of internal noise in auditory perceptual learning

This paper examines what mechanisms underlie auditory perceptual learning. Fifteen normal hearing adults performed two-alternative, forced choice, pure tone frequency discrimination for four sessions. External variability was introduced by adding a zero-mean Gaussian random variable to the frequency of each tone. Measures of internal noise, encoding efficiency, bias, and inattentiveness were derived using four methods (model fit, classification boundary, psychometric function, and double-pass consistency). The four methods gave convergent estimates of internal noise, which was found to decrease from 4.52 to 2.93 Hz with practice. No group-mean changes in encoding efficiency, bias, or inattentiveness were observed. It is concluded that learned improvements in frequency discrimination primarily reflect a reduction in internal noise. Data from highly experienced listeners and neural networks performing the same task are also reported. These results also indicated that auditory learning represents internal noise reduction, potentially through the re-weighting of frequency-specific channels.