Jonathan L. Preston

The relationship between phonological and auditory processing and brain organization in beginning readers

We employed brain-behavior analyses to explore the relationship between performance on tasks measuring phonological awareness, pseudoword decoding, and rapid auditory processing (all predictors of reading (dis)ability) and brain organization for print and speech in beginning readers. For print-related activation, we observed a shared set of skill-correlated regions, including left hemisphere temporoparietal and occipitotemporal sites, as well as inferior frontal, visual, visual attention, and subcortical components. For speech-related activation, shared variance among reading skill measures was most prominently correlated with activation in left hemisphere inferior frontal gyrus and precuneus. Implications for brain-based models of literacy acquisition are discussed.

Glutamate and Choline Levels Predict Individual Differences in Reading Ability in Emergent Readers

Reading disability is a brain-based difficulty in acquiring fluent reading skills that affects significant numbers of children. Although neuroanatomical and neurofunctional networks involved in typical and atypical reading are increasingly well characterized, the underlying neurochemical bases of individual differences in reading development are virtually unknown. The current study is the first to examine neurochemistry in children during the critical period in which the neurocircuits that support skilled reading are still developing. In a longitudinal pediatric sample of emergent readers whose reading indicators range on a continuum from impaired to superior, we examined the relationship between individual differences in reading and reading-related skills and concentrations of neurometabolites measured using magnetic resonance spectroscopy. Both continuous and group analyses revealed that choline and glutamate concentrations were negatively correlated with reading and related linguistic measures in phonology and vocabulary (such that higher concentrations were associated with poorer performance). Correlations with behavioral scores obtained 24 months later reveal stability for the relationship between glutamate and reading performance. Implications for neurodevelopmental models of reading and reading disability are discussed, including possible links of choline and glutamate to white matter anomalies and hyperexcitability. These findings point to new directions for research on gene-brain-behavior pathways in human studies of reading disability.

Ultrasound Visual Feedback Treatment and Practice Variability for Residual Speech Sound Errors

PURPOSE The goals were to (a) test the efficacy of a motor-learning-based treatment that includes ultrasound visual feedback for individuals with residual speech sound errors and (b) explore whether the addition of prosodic cueing facilitates speech sound learning. METHOD A multiple-baseline, single-subject design was used, replicated across 8 participants. For each participant, 1 sound context was treated with ultrasound plus prosodic cueing for 7 sessions, and another sound context was treated with ultrasound but without prosodic cueing for 7 sessions. Sessions included ultrasound visual feedback as well as non-ultrasound treatment. Word-level probes assessing untreated words were used to evaluate retention and generalization. RESULTS For most participants, increases in accuracy of target sound contexts at the word level were observed with the treatment program regardless of whether prosodic cueing was included. Generalization between onset singletons and clusters was observed, as was generalization to sentence-level accuracy. There was evidence of retention during posttreatment probes, including at a 2-month follow-up. CONCLUSION A motor-based treatment program that includes ultrasound visual feedback can facilitate learning of speech sounds in individuals with residual speech sound errors.

Ultrasound visual feedback for acquired apraxia of speech: A case report

Background: Individuals with acquired apraxia of speech (AOS) can lose precision of articulatory movements, including the ability to achieve correct production of specific sounds or sound sequences. Novel treatment approaches should be explored to enhance treatment outcomes. Aims: To evaluate the clinical feasibility of ultrasound visual feedback of the tongue for addressing errors on rhotics in a patient with AOS. Ultrasound visual feedback was used to provide knowledge of performance to the participant. Methods & Procedures: A multiple baseline single case report is presented to evaluate a treatment programme that uses visual feedback of the participant’s tongue from real-time ultrasound images. A blocked practice schedule was implemented during 12 one-hour therapy sessions; 30 minutes involved ultrasound visual feedback (10 minutes of pre-practice and 20 minutes of practice) and 20 minutes involved non-ultrasound practice. Cues were provided to modify tongue shape to achieve perceptually accurate production of rhotics, along with practice trials with increasing levels of phonetic complexity. The feedback type (verbal knowledge of performance and knowledge of results) and feedback frequency (number of trials with feedback) were structured to adhere to principles of motor learning. Outcomes & Results: The participant demonstrated moderate evidence of acquisition of prevocalic rhotics and strong evidence of acquisition of postvocalic rhotics during treatment. There was evidence of retention and generalisation only for postvocalic rhotics. An untreated context was probed regularly and showed no evidence of improvement. Conclusion: The results provide preliminary support for the feasibility of this treatment approach for improving speech accuracy in adults with acquired AOS. The improvements in stimulability for the treated sound sequences could be used to foster further motor learning.

Speed and accuracy of rapid speech output by adolescents with residual speech sound errors including rhotics

Children with residual speech sound errors are often underserved clinically, yet there has been a lack of recent research elucidating the specific deficits in this population. Adolescents aged 10–14 with residual speech sound errors (RE) that included rhotics were compared to normally speaking peers on tasks assessing speed and accuracy of speech production. The two groups were evaluated on an oral diadochokinetic task, which required rapid production of the trisyllable /pΛtΛkΛ/, and two rapid naming tasks: monosyllabic letter names and multisyllabic picture names. No significant group differences were observed in the speed of trisyllables on the DDK task, whether examining all attempts or only correct productions. However, the RE group was less accurate and more variable in their production of the trisyllables. In addition, the RE group was slower and phonologically less accurate in rapidly naming multisyllabic pictures, but not in naming letters. A combination of speed and accuracy measures from these tasks revealed relatively little overlap between groups. Results suggest that both speed and accuracy may be impaired in adolescents with RE, although the underlying causal mechanisms require further exploration.

Identification of conductive hearing loss in young infants using tympanometry and wideband reflectance

Objective: The goal of the study was to evaluate the effectiveness of tympanometry and wideband reflectance (WBR) in detecting conductive hearing loss (CHL) in young infants. Methods: Type of hearing loss was determined using auditory brainstem response using air- and bone-conducted tone bursts in 84 ears from 70 infants (median age = 10 weeks). Of these 84 ears, 60 are included in the current analysis: 43 with normal hearing (NH) and 17 with CHL. Tympanometry was measured using probe tone frequencies of 226, 678, and 1000 Hz. Tympanograms were evaluated in two ways: (1) Acoustic middle ear admittance (Ya, in millimhos); and (2) two-category classification (normal/abnormal), as described by Baldwin (2006). Measures of Ya were evaluated in two ways: by admittance-magnitude tympanograms and calculated admittance magnitude from subcomponents (conductance and susceptance). WBR was measured in response to a chirp stimulus after probe calibration. WBR was analyzed into thirteen 1/3 octave bands. Tests for statistical differences for two-category classification were analyzed using Chi-squared and Ya, and WBR were analyzed using repeated-measures analyses of variances. Cohen’s d and likelihood ratios were computed for comparison with statistically significant differences. Results: Ya measured with 678- and 1000 Hz probe tones was significantly different between ears with CHL and NH. Two-category classification of tympanograms using a 1000 Hz probe tone was significantly different between ears with CHL and NH. Neither two-category classification nor Ya was significantly different between ears identified with CHL and NH using a 226 Hz probe tone. WBR was significantly higher in the frequency bands 800 to 2500 Hz and in the frequency band centered at 6300 Hz in infants with CHL. Effect sizes (Cohen’s d) were greater than 2 for several WBR frequency bands and Ya measured with 1000 Hz probe tones. The results were similar for calculations of Ya from admittance-magnitude and subcomponent tympanograms. Positive likelihood ratios for WBR ranged between 8.1 and 38, and those for Ya using 1000 Hz ranged between 12.5 and 32. Conclusions: CHL in young infants can be detected well with WBR or tympanometry using probe frequencies of 678 and 1000 Hz.

Neural correlates of language and non-language visuospatial processing in adolescents with reading disability

Despite anecdotal evidence of relative visuospatial processing strengths in individuals with reading disability (RD), only a few studies have assessed the presence or the extent of these putative strengths. The current study examined the cognitive and neural bases of visuospatial processing abilities in adolescents with RD relative to typically developing (TD) peers. Using both cognitive tasks and functional magnetic resonance imaging (fMRI) we contrasted printed word recognition with non-language visuospatial processing tasks. Behaviorally, lower reading skill was related to a visuospatial processing advantage (shorter latencies and equivalent accuracy) on a geometric figure processing task, similar to findings shown in two published studies. FMRI analyses revealed key group by task interactions in patterns of cortical and subcortical activation, particularly in frontostriatal networks, and in the distributions of right and left hemisphere activation on the two tasks. The results are discussed in terms of a possible neural tradeoff in visuospatial processing in RD.

Structural brain differences in school-age children with residual speech sound errors

The purpose of the study was to identify structural brain differences in school-age children with residual speech sound errors. Voxel based morphometry was used to compare gray and white matter volumes for 23 children with speech sound errors, ages 8;6-11;11, and 54 typically speaking children matched on age, oral language, and IQ. We hypothesized that regions associated with production and perception of speech sounds would differ between groups. Results indicated greater gray matter volumes for the speech sound error group relative to typically speaking controls in bilateral superior temporal gyrus. There was greater white matter volume in the corpus callosum for the speech sound error group, but less white matter volume in right lateral occipital gyrus. Results may indicate delays in neuronal pruning in critical speech regions or differences in the development of networks for speech perception and production.

The COMT Val/Met polymorphism is associated with reading-related skills and consistent patterns of functional neural activation.

In both children and adults there is large variability in reading skill, with approximately 5-10% of individuals characterized as having reading disability; these individuals struggle to learn to read despite adequate intelligence and opportunity. Although it is well established that a substantial portion of this variability is attributed to the genetic differences between individuals, specifics of the connections between reading and the genome are not understood. This article presents data that suggest that variation in the COMT gene, which has previously been associated with variation in higher-order cognition, is associated with reading and reading-related skills, at the level of both brain and behavior. In particular, we found that the COMT Val/Met polymorphism at rs4680, which results in the substitution of the ancestral Valine (Val) by Methionine (Met), was associated with better performance on a number of critical reading measures and with patterns of functional neural activation that have been linked to better readers. We argue that this polymorphism, known for its broad effects on cognition, may modulate (likely through frontal lobe function) reading skill.

Changes in Transient-evoked Otoacoustic Emissions in the First Month of Life

Objective: Current Joint Committee on Infant Hearing guidelines recommend the use of transient-evoked otoacoustic emissions (TEOAEs) as a screening tool to identify hearing loss for newborns cared for in the well-baby nursery. Newborns who do not pass the TEOAE screen before leaving the hospital are typically rescreened as outpatients by 1 mo of age, at which time, approximately 50 to 70% pass screening criteria. To better understand why many infants are referred at initial screening but pass at the rescreening, more complete knowledge of developmental differences in the TEOAE levels, noise floor, or a combination of both for infants who pass and fail birth screening is needed. In addition, it has been shown that infants with occluding ear-canal debris are more likely to not pass TEOAE screening at the hospital than those without occluding ear-canal debris. This study explores whether changes in TEOAE levels in half-octave frequency bands are related to changes in ear-canal debris over the first month of life. Design: Seventy-nine neonates from a well-baby nursery had their hearing screened before leaving the hospital and again at approximately 1 mo of age. All participants passed the follow-up screening. Overall TEOAE levels and levels in half-octave frequency bands centered at 1.5, 2, 3, and 4 kHz were measured. Judgments of ear-canal debris were made by otoscopy and were rated using one of three categories at both visits. Results: TEOAE levels in infants significantly increased from birth to 1 mo of age across all frequencies tested, regardless of whether they passed or failed the screening at birth. The increase in TEOAE level was frequency dependent, with the greatest increases occurring in the highest frequency bands. No significant correlation between debris change and frequency-specific changes was found for either ear. Infants who failed the screening at birth but who subsequently passed at 1 mo of age had significantly lower TEOAE levels at the rescreening than did infants with passing TEOAE levels at birth. However, pass/fail status at birth was only a weak predictor of TEOAE levels at 1 mo of age. Conclusions: The increase in TEOAE levels during the first month of life is frequency dependent, with greater increases occurring at higher frequencies. Increased TEOAE levels were not associated with changes in ear-canal debris.