Relationships between behavior, brainstem and cortical encoding of seen and heard speech in musicians and non-musicians

from Hearing Research

Musicians have a variety of perceptual and cortical specializations compared to non-musicians. Recent studies have shown that potentials evoked from primarily brainstem structures are enhanced in musicians, compared to non-musicians. Specifically, musicians have more robust representations of pitch periodicity and faster neural timing to sound onset when listening to sounds or both listening to and viewing a speaker. However, it is not known whether musician-related enhancements at the subcortical level are correlated with specializations in the cortex. Does musical training shape the auditory system in a coordinated manner or in disparate ways at cortical and subcortical levels? To answer this question, we recorded simultaneous brainstem and cortical evoked responses in musician and non-musician subjects. Brainstem response periodicity was related to early cortical response timing across all subjects, and this relationship was stronger in musicians. Peaks of the brainstem response evoked by sound onset and timbre cues were also related to cortical timing. Neurophysiological measures at both levels correlated with musical skill scores across all subjects. In addition, brainstem and cortical measures correlated with the age musicians began their training and the years of musical practice. Taken together, these data imply that neural representations of pitch, timing and timbre cues and cortical response timing are shaped in a coordinated manner, and indicate corticofugal modulation of subcortical afferent circuitry.

Structural Asymmetries in the Infant Language and Sensori-Motor Networks

from Cerebral Cortex

Both language capacity and strongly lateralized hand preference are among the most intriguing particularities of the human species. They are associated in the adult brain with functional and anatomical hemispheric asymmetries in the speech perception–production network and in the sensori-motor system. Only studies in early life can help us to understand how such asymmetries arise during brain development, and to which point structural left–right differences are the source or the consequence of functional lateralization. In this study, we aimed to provide new in vivo structural markers of hemispheric asymmetries in infants from 1 to 4 months of age, with diffusion tensor imaging. We used 3 complementary analysis methods based on local diffusion indices and spatial localizations of tracts. After a prospective approach over the whole brain, we demonstrated early leftward asymmetries in the arcuate fasciculus and in the cortico-spinal tract. These results suggest that the early macroscopic geometry, microscopic organization, and maturation of these white matter bundles are related to the development of later functional lateralization.

A pilot study into the effect of vocal exercises and singing on dysarthric speech

from Neurorehabilitation

This pilot study aimed to investigate the effects of vocal exercises and singing on intelligibility and speech naturalness for subjects with acquired dysarthria following traumatic brain injury or stroke. A multiple case study design was used, involving pre, mid, and post-treatment assessments of intelligibility, rate, naturalness, and pause time for four subjects with dysarthria. Each subject participated in 24 individual music therapy sessions over eight weeks involving oral motor respiratory exercises, rhythmic and melodic articulation exercises, rhythmic speech cuing, vocal intonation therapy, and therapeutic singing using familiar songs. Results were measured using a standardized dysarthric speech assessment – the Sentence Intelligibility Test, waveform analysis, and ratings of speech naturalness. Statistically significant improvements in functional speech intelligibility were achieved but improvements in rate of speech were not significant. Speech naturalness improved post-treatment and a reduction in the number and length of pauses was verified via waveform analysis. Preliminary findings suggest that a program of vocal exercises and singing may facilitate more normative speech production for people with acquired dysarthria and support the need for further research in this area.

Rapid Neural Adaptation to Sound Level Statistics

from the Journal of Neuroscience

Auditory neurons must represent accurately a wide range of sound levels using firing rates that vary over a far narrower range of levels. Recently, we demonstrated that this “dynamic range problem” is lessened by neural adaptation, whereby neurons adjust their input–output functions for sound level according to the prevailing distribution of levels. These adjustments in input–output functions increase the accuracy with which levels around those occurring most commonly are coded by the neural population. Here, we examine how quickly this adaptation occurs. We recorded from single neurons in the auditory midbrain during a stimulus that switched repeatedly between two distributions of sound levels differing in mean level. The high-resolution analysis afforded by this stimulus showed that a prominent component of the adaptation occurs rapidly, with an average time constant across neurons of 160 ms after an increase in mean level, much faster than our previous experiments were able to assess. This time course appears to be independent of both the timescale over which sound levels varied and that over which sound level distributions varied, but is related to neural characteristic frequency. We find that adaptation to an increase in mean level occurs more rapidly than to a decrease. Finally, we observe an additional, slow adaptation in some neurons, which occurs over a timescale of tens of seconds. Our findings provide constraints in the search for mechanisms underlying adaptation to sound level. They also have functional implications for the role of adaptation in the representation of natural sounds.

Diagnostic criteria for the Zappella variant of Rett syndrome (the preserved speech variant)

from Brain and Development

The preserved speech variant is the milder form of Rett syndrome: affected girls show the same stages of this condition and by the second half of the first decade are making slow progress in manual and verbal abilities. They walk without help, and may be able to make simple drawings and write a few words. Most of them can speak in sentences. Autistic behavior can often be observed. We previously described several cases in the pre-molecular era and subsequently reported a survey of 12 cases with MECP2 mutations. Seventeen new patients with the preserved speech variant and a proven MECP2 mutation have been clinically evaluated. Additional clinical data of our previously described cases are reported. These 29 preserved speech variant cases were compared with 129 classic Rett patients using a clinical severity score system including 22 different signs. There was both statistical and clinical evidence of the existence of this variant. On the basis of their abilities these girls can be distinguished as low-, intermediate- and high-functioning. Girls of the last two groups show a greater homogeneity: they speak in sentences, use their hands more easily, have normal somatic features, mild neurovegetative abnormalities, with autistic behavior in 76%, epilepsy in 30%, while girls of the first group are closer to classic Rett syndrome. The majority of patients carries either missense mutations (especially the p.R133C change) or late truncating mutations in the MECP2 gene. These results confirm the existence of this variant of Rett syndrome (Zappella variant), a clear example of progress of manual and verbal abilities, and not of a “preserved speech” and suggest corresponding diagnostic criteria.

Transcribing disordered speech: By target or by production?

from Clinical Linguistics and Phonetics

The ability to transcribe disordered speech is a vital tool for speech-language pathologists, as accurate description of a client’s speech output is needed for both diagnosis and effective intervention. Clients in the speech clinic often use sounds that are not part of the target sound system and which may, in some cases, be sounds not found in natural language at all. While the IPA provides a wide range of symbols that can be used in clinical transcription, the extended IPA (extIPA) may also be needed to transcribe atypical sounds never or rarely encountered in natural language. When using the IPA and extIPA transcribers aim to show the client’s productions, irrespective of the intended target. An alternative tradition of clinical transcription has grown up in the US: the symbols suggested by Shriberg and Kent (SK). In many cases, these symbols are designed to show the intended target with a diacritic illustrating in which way the realization differs from the target. In this article possible confusions that may occur if the SK system is used are discussed, together with problems that may occur when SK and IPA are used together.

Visuomotor tracking abilities of speakers with apraxia of speech or conduction aphasia

from Brain and Language

This investigation examined the visuomotor tracking abilities of persons with apraxia of speech (AOS) or conduction aphasia (CA). In addition, tracking performance was correlated with perceptual judgments of speech accuracy. Five individuals with AOS and four with CA served as participants, as well as an equal number of healthy controls matched by age and gender. Participants tracked predictable (sinusoidal) and unpredictable signals using jaw and lip movements transduced with strain gauges. Tracking performance in participants with AOS was poorest for predictable signals, with decreased kinematic measures of cross-correlation and gain ratio and increased target-tracker difference. In contrast, tracking of the unpredictable signal by participants with AOS was performed as well as for other groups (e.g. participants with CA, healthy controls). Performance of the subjects with AOS on the predictable tracking task was found to strongly correlate with perceptual judgments of speech. These findings suggest that motor control capabilities are impaired in AOS, but not in CA. Results suggest that AOS has its basis in motor programming deficits, not impaired motor execution.

Using Individual Growth and Development Indicators to Measure Early Language and Literacy

from Infants and Young Children

Learning to read is founded on the acquisition of oral language, phonological processing, print awareness, knowledge, and comprehension skills acquired before school entry. Practitioners who work with very young children have limited means of knowing whether interventions in these areas are helping children make progress toward important language and early literacy outcomes. As a result, reporting of child outcomes in these areas is usually insufficient at the program, state, and national levels. Child performance measures are needed that are easy and repeatable so that estimates of child growth can be obtained and used to inform intervention decisions. Individual Growth and Development Indicators are emerging as a robust approach to assessment particularly well suited to these challenges. This article describes 5 Individual Growth and Development Indicators for measuring progress in young children’s early language and literacy. A brief overview of theoretical and empirical background information is provided demonstrating the reliability, validity, and feasibility of this approach for measuring growth in these critical areas of child development. Examples illustrate how these measures are used in early intervention programs for evaluating the progress of children as well as for program evaluation.

Updating Hearing Screening Practices in Early Childhood Settings

fromfInfants and Young Children

Each day in the life of a young child with an undetected hearing loss is a day without full access to language. When hearing loss goes undetected, the resulting language deficits can become overwhelming obstacles to literacy, educational achievement, socialization, and school readiness. Several programs, such as Head Start, Early and Periodic Screening, Diagnosis and Treatment, and Part C of the Individuals with Disabilities Education Act, are responsible for providing hearing screening to many young children nationwide. These programs have typically had to rely on subjective hearing screening methods. Otoacoustic emissions technology, used widely in hospital-based newborn screening programs, is beginning to be recognized as a more practical and effective alternative when screening children from birth to 3 years of age. Successful otoacoustic emissions screening in early childhood settings is dependent on consultation from an experienced pediatric audiologist, selection of appropriate equipment, adherence to an appropriate screening and follow-up protocol, and access to training and follow-up technical assistance. When these elements are present, children with a wide range of hearing health conditions can be identified in a timely manner.

Deficient brainstem encoding of pitch in children with Autism Spectrum Disorders

from Clinical Neurophysiology

Abstract
Objective
Deficient prosody is a hallmark of the pragmatic (socially contextualized) language impairment in Autism Spectrum Disorders (ASD). Prosody communicates emotion and intention and is conveyed through acoustic cues such as pitch contour. Thus, the objective of this study was to examine the subcortical representations of prosodic speech in children with ASD.

Methods
Using passively evoked brainstem responses to speech syllables with descending and ascending pitch contours, we examined sensory encoding of pitch in children with ASD who had normal intelligence and hearing and were age-matched with typically developing (TD) control children.

Results
We found that some children on the autism spectrum show deficient pitch tracking (evidenced by increased Frequency and Slope Errors and reduced phase locking) compared with TD children.

Conclusions
This is the first demonstration of subcortical involvement in prosody encoding deficits in this population of children.

Significance
Our findings may have implications for diagnostic and remediation strategies in a subset of children with ASD and open up an avenue for future investigations.

Occupational voice complaints and objective acoustic measurements—do they correlate?

from Logopedics Phoniatrics Vocology

To enable the development of appropriate diagnostics and treatment for occupational voice disorders, this study addresses connections between subjective voice complaints and objective observations. The subjects of this study were 24 female customer advisors, who mainly use the telephone during their working hours. During one working day, at four different times, speech samples covering 20 minutes of telephone conversation by the customer service advisors (CSAs) were recorded. In addition, the CSAs filled in a questionnaire (visual analogue scale) concerning their voice problems. To represent the vocal symptoms three variables were used: vocal fatigue, hoarseness and a general sum-variable. A 5-minute sample was taken from recordings for further analyses. This included fundamental frequency, sound pressure level, alpha ratio (the ratio between the spectral energy below and above 1000 Hz) and number of vocal fold vibrations. In the objective acoustic measurements, it was found that fundamental frequency (F0) rose significantly during the working day. Also the self-reported voice symptoms increased significantly during the working day. However, correlations between vocal symptoms and acoustic measures were not found.

Developmental Links of Very Early Phonological and Language Skills to Second Grade Reading Outcomes

from the Journal of Learning Disabilities

The authors examined second grade reading accuracy and fluency and their associations via letter knowledge to phonological and language predictors assessed at 3.5, 4.5, and 5.5 years in children in the Jyväskylä Longitudinal Study of Dyslexia. Structural equation modeling showed that a developmentally highly stable factor (early phonological and language processing [EPLP]) behind key dyslexia predictors (i.e., phonological awareness, short-term memory, rapid naming, vocabulary, and pseudoword repetition) could already be identified at 3.5 years. EPLP was significantly associated with reading and spelling accuracy and by age with letter knowledge. However, EPLP had only a minor link with reading fluency, which was additionally explained by early letter knowledge. The results show that reading accuracy is well predicted by early phonological and language skills. Variation in fluent reading skills is not well explained by early skills, suggesting factors other than phonological core skills. Future research is suggested to explore the factors behind the development of fast and accurate decoding skills.

Interventions for Reading Difficulties

from the Journal of Learning Disabilities

This article explores whether struggling readers from different primary language backgrounds differ in response to phonologically based remediation. Following random assignment to one of three reading interventions or to a special education reading control program, reading and reading-related outcomes of 166 struggling readers were assessed before, during, and following 105 intervention hours. Struggling readers met criteria for reading disability, were below average in oral language and verbal skills, and varied in English as a first language (EFL) versus English-language learner (ELL) status. The research-based interventions proved superior to the special education control on both reading outcomes and rate of growth. No differences were revealed for children of EFL or ELL status in intervention outcomes or growth during intervention. Oral language abilities at entry were highly predictive of final outcomes and of reading growth during intervention, with greater language impairment being associated with greater growth.

Conceptual and Perceptual Similarity Between Encoding and Retrieval Contexts and Recognition Memory Context Effects in Older and Younger Adults

from the Journals of Gerontology Series B: Psychological Sciences and Social Sciences

We examined the hypothesis that older adults’ deficits in contextual memory result from difficulties in contending with partial encoding-to-retrieval changes in the context. We measured effects of contextual change and constancy on recognition memory for words, in older and younger adults. We assessed the ability to adjust to partial contextual changes by manipulating encoding–retrieval context similarity: identical, new and unrelated, conceptually similar, or perceptually similar. For both older and younger adults, identical and conceptually similar contexts benefited recognition of target words, whereas perceptually similar contexts did not. Older adults did not make more false alarms. In contrast, older adults’ direct recognition of contextual stimuli was at chance. These results indicate that retrieval processes, rather than encoding or rigidity in the use of contextual cues, are implicated in older adults’ difficulties in memory for contextual information.

New Research Claims Link Between Diabetes And Hearing Loss

from Medical News Today.com

New research claims that adults with diabetes are twice as likely to have impaired hearing as people without the condition.