Cross-Modal Somatosensory Repetition Priming and Speech Processing.

BACKGROUND: Motor speech treatment approaches have been applied in both adults with aphasia and apraxia of speech and children with speech-sound disorders. Identifying links between motor speech intervention techniques and the modes of action (MoA) targeted would improve our understanding of how and why motor speech interventions achieve their effects, along with identifying its effective components. The current study focuses on identifying potential MoAs for a specific motor speech intervention technique. OBJECTIVES: We aim to demonstrate that somatosensory inputs can influence lexical processing, thus providing further evidence that linguistic information stored in the brain and accessed as part of speech perception processes encodes information related to speech production. METHODS: In a cross-modal repetition priming paradigm, we examined whether the processing of external somatosensory priming cues was modulated by both word-level (lexical frequency, low- or high-frequency) and speech sound articulatory features. The study participants were divided into two groups. The first group consisted of twenty-three native English speakers who received somatosensory priming stimulation to their oro-facial structures (either to labial corners or under the jaw). The second group consisted of ten native English speakers who participated in a control study where somatosensory priming stimulation was applied to their right or left forehead as a control condition. RESULTS: The results showed significant somatosensory priming effects for the low-frequency words, where the congruent somatosensory condition yielded significantly shorter reaction times and numerically higher phoneme accuracy scores when compared to the incongruent somatosensory condition. Data from the control study did not reveal any systematic priming effects from forehead stimulation (non-speech related site), other than a general (and expected) tendency for longer reaction times with low-frequency words. CONCLUSIONS: These findings provide further support for the notion that speech production information is represented in the mental lexicon and can be accessed through exogenous Speech-Language Pathologist driven somatosensory inputs related to place of articulation.

PROMPT intervention for children with severe speech motor delay: a randomized control trial.

BACKGROUND: Currently, there is limited information on the intervention efficacy for children with speech motor delay (SMD). This randomized control trial (RCT) study examined the effectiveness of Prompts for Restructuring Oral Muscular Phonetic Targets (PROMPT) intervention to improve the outcomes in children with SMD. We hypothesized that children with SMD receiving PROMPT intervention would improve more in the measured outcomes than those waitlisted and receiving home training. METHODS: Using a two-arm, parallel group, RCT, 49 children with SMD were allocated to either an intervention group (N = 24) that received 45 min of PROMPT intervention two times a week for 10 weeks or were waitlisted for the same duration and received only home training instructions (N = 25). Outcome measures for speech motor control, articulation, speech intelligibility (word and sentence levels), and functional communication were assessed at baseline and at a 10-week follow-up. RESULTS: PROMPT intervention was associated with notable improvements in speech motor control, speech articulation, and word-level speech intelligibility. Intervention allocation yielded weak improvements in sentence-level speech intelligibility and functional communication. CONCLUSIONS: PROMPT intervention is a clinically effective intervention approach for children with SMD. IMPACT: Currently, there is limited information on the intervention efficacy for children with SMD. We report on the findings of a phase III intervention efficacy study on children with SMD using an RCT design. PROMPT intervention is a clinically effective intervention approach for children with SMD. Results of the study will be fundamental to the delivery of effective services for this population. These findings may facilitate the development of an evidence-based care pathway for children with severe speech sound disorders.

Investigating intervention dose frequency for children with speech sound disorders and motor speech involvement.

BACKGROUND: Treatment outcome data for children with severe speech sound disorders with motor speech involvement (SSD-MSI) are derived from Phase I clinical research studies. These studies have demonstrated positive improvements in speech production. Currently there is no research examining the optimal treatment dose frequency for this population. The results of this study, which is the first of its kind, will inform the delivery of effective services for this population. AIMS: To investigate optimal treatment dose frequency for the Motor Speech Treatment Protocol (MSTP) for children with SSD-MSI. METHODS & PROCEDURES: A total of 48 children (aged 43-47 months) with SSD-MSI participated in the study. Participants received 45-min MSTP intervention sessions either once per week (lower dose frequency) or twice per week (higher dose frequency) for a 10-week period. Blinded outcome assessments were carried out at pre- and post-intervention. OUTCOMES & RESULTS: Treatment-related change was assessed at body structures, functions and activities participation level as per the World Health Organization's International Classification of Functioning framework: Children and Youth Version (ICF-CY) framework WHO (2007). These measures are related to articulation, functional communication and speech intelligibility. One-way analysis of variance (ANOVA) revealed that for all variables the baseline scores were not statistically different (p > 0.05) between the two dose-frequency groups. Overall, there was a significant main effect of Time (pre-post) across all variables (p < 0.01). However, repeated-measures ANOVA did not result in any statistical interactions (Time × Dose frequency) for any of the variables tested (p > 0.05). Only marginal clinical advantages (< 4% change in intelligibility) were noted with the 10 extra sessions. CONCLUSIONS & IMPLICATIONS: Overall, the MSTP intervention approach in conjunction with home practice led to significant positive changes for all measures in children with SSD-MSI. No statistical differences between high- and low-dose-frequency groups were observed for any of the variables. Clinical effects were examined using effect sizes, as well as changes in articulation, speech intelligibility and functional communication; these differed marginally between the two dose frequencies. This suggests limited benefits of 10 additional sessions per block. Thus, it is recommended that caregivers, speech-language therapists and policy-makers perform a cost-benefit analysis before determining the dose frequency, when considering additional sessions per block.

Does emotion matter? The role of alexithymia in violent recidivism: A systematic literature review.

BACKGROUND: Several variables have been evidenced for their association with violent reoffending. Resultant interventions have been suggested, yet the rate of recidivism remains high. Alexithymia, characterised by deficits in emotion processing and verbal expression, might interact with these other risk factors to affect outcomes. AIM: Our goal was to examine the role of alexithymia as a possible moderator of risk factors for violent offender recidivism. Our hypothesis was that, albeit with other risk factors, alexithymia increases the risk of violent reoffending. METHOD: We conducted a systematic literature review, using terms for alexithymia and violent offending and their intersection. RESULTS: (a) No study that directly tests the role of alexithymia in conjunction with other potential risk factors for recidivism and actual violent recidivism was uncovered. (b) Primarily alexithymia researchers and primarily researchers into violence have separately found several clinical features in common between aspects of alexithymia and violence, such as impulsivity (total n = 24 studies). (c) Other researchers have established a relationship between alexithymia and both dynamic and static risk factors for violent recidivism (n = 16 studies). CONCLUSION: Alexithymia may be a possible moderator of risk of violent offence recidivism. Supplementing offenders' rehabilitation efforts with assessments of alexithymia may assist in designing individually tailored interventions to promote desistance among violent offenders.

Coupling dynamics in speech gestures: amplitude and rate influences.

Speech is a complex oral motor function that involves multiple articulators that need to be coordinated in space and time at relatively high movement speeds. How this is accomplished remains an important and largely unresolved empirical question. From a coordination dynamics perspective, coordination involves the assembly of coordinative units that are characterized by inherently stable coupling patterns that act as attractor states for task-specific actions. In the motor control literature, one particular model formulated by Haken et al. (Biol Cybern 51(5):347-356, 1985) or HKB has received considerable attention in the way it can account for changes in the nature and stability of specific coordination patterns between limbs or between limbs and external stimuli. In this model (and related versions), movement amplitude is considered a critical factor in the formation of these patterns. Several studies have demonstrated its role for bimanual coordination and similar types of tasks, but for speech motor control such studies are lacking. The current study describes a systematic approach to evaluate the impact of movement amplitude and movement duration on coordination stability in the production of bilabial and tongue body gestures for specific vowel-consonant-vowel strings. The vowel combinations that were used induced a natural contrast in movement amplitude at three speaking rate conditions (slow, habitual, fast). Data were collected on ten young adults using electromagnetic articulography, recording movement data from lips and tongue with high temporal and spatial precision. The results showed that with small movement amplitudes there is a decrease in coordination stability, independent from movement duration. These findings were found to be robust across all individuals and are interpreted as further evidence that principles of coupling dynamics operate in the oral motor control system similar to other motor systems and can be explained in terms of coupling mechanisms between neural oscillators (organized in networks) and effector systems. The relevance of these findings for understanding motor control issues in people with speech disorders is discussed as well.

Children's and adults' perception of questions and statements from terminal fundamental frequency contours.

The present study compared children's and adults' identification and discrimination of declarative questions and statements on the basis of terminal cues alone. Children (8-11 years, n = 41) and adults (n = 21) judged utterances as statements or questions from sentences with natural statement and question endings and with manipulated endings that featured intermediate fundamental frequency (F0) values. The same adults and a different sample of children (n = 22) were also tested on their discrimination of the utterances. Children's judgments shifted more gradually across categories than those of adults, but their category boundaries were comparable. In the discrimination task, adults found cross-boundary comparisons more salient than within-boundary comparisons. Adults' performance on the identification and discrimination tasks is consistent with but not definitive regarding categorical perception of statements and questions. Children, by contrast, discriminated the cross-boundary comparisons no better than other comparisons. The findings indicate age-related sharpening in the perception of statements and questions based on terminal F0 cues and the gradual emergence of distinct perceptual categories.

Imitation of Non-Speech Oral Gestures by 8-Month-Old Infants.

This study investigates the oral gestures of 8-month-old infants in response to audiovisual presentation of lip and tongue smacks. Infants exhibited more lip gestures than tongue gestures following adult lip smacks and more tongue gestures than lip gestures following adult tongue smacks. The findings, which are consistent with predictions from Articulatory Phonology, imply that 8-month-old infants are capable of producing goal-directed oral gestures by matching the articulatory organ of an adult model.

Effects of age on speech and voice quality ratings.

The quality of communication may be affected by listeners' perception of talkers' characteristics. This study examined if there were effects of talker and listener age on the perception of speech and voice qualities. Younger and older listeners judged younger and older talkers' gender and age, then rated speech samples on pleasantness, naturalness, clarity, ease of understanding, loudness, and the talker's suitability to be an audiobook reader. For the same talkers, listeners also rated voice samples on pleasantness, roughness, and power. Younger and older talkers were perceived to be similar on most qualities except age. Younger and older listeners rated talkers similarly, except that younger listeners perceived younger voices to be more pleasant and less rough than older voices. For vowel samples, younger listeners were more accurate than older listeners at age estimation, while older listeners were more accurate than younger listeners at gender identification, suggesting that younger and older listeners differ in their evaluation of specific talker characteristics. Thus, the perception of quality was generally more affected by the age of the listener than the age of the talker, and age-related differences between listeners depended on whether voice or speech samples were used and the rating being made.

Children's identification of questions from rising terminal pitch.

Young children are slow to master conventional intonation patterns in their yes/no questions, which may stem from imperfect understanding of the links between terminal pitch contours and pragmatic intentions. In Experiment 1, five- to ten-year-old children and adults were required to judge utterances as questions or statements on the basis of intonation alone. Children eight years of age or younger performed above chance levels but less accurately than adult listeners. To ascertain whether the verbal content of utterances interfered with young children's attention to the relevant acoustic cues, low-pass filtered versions of the same utterances were presented to children and adults in Experiment 2. Low-pass filtering reduced performance comparably for all age groups, perhaps because such filtering reduced the salience of critical pitch cues. Young children's difficulty in differentiating declarative questions from statements is not attributable to basic perceptual difficulties but rather to absent or unstable intonation categories.

Visual speech gestures modulate efferent auditory system.

Visual and auditory systems interact at both cortical and subcortical levels. Studies suggest a highly context-specific cross-modal modulation of the auditory system by the visual system. The present study builds on this work by sampling data from 17 young healthy adults to test whether visual speech stimuli evoke different responses in the auditory efferent system compared to visual non-speech stimuli. The descending cortical influences on medial olivocochlear (MOC) activity were indirectly assessed by examining the effects of contralateral suppression of transient-evoked otoacoustic emissions (TEOAEs) at 1, 2, 3 and 4 kHz under three conditions: (a) in the absence of any contralateral noise (Baseline), (b) contralateral noise + observing facial speech gestures related to productions of vowels /a/ and /u/ and (c) contralateral noise + observing facial non-speech gestures related to smiling and frowning. The results are based on 7 individuals whose data met strict recording criteria and indicated a significant difference in TEOAE suppression between observing speech gestures relative to the non-speech gestures, but only at the 1 kHz frequency. These results suggest that observing a speech gesture compared to a non-speech gesture may trigger a difference in MOC activity, possibly to enhance peripheral neural encoding. If such findings can be reproduced in future research, sensory perception models and theories positing the downstream convergence of unisensory streams of information in the cortex may need to be revised.

Treatment intensity and childhood apraxia of speech.

BACKGROUND: Intensive treatment has been repeatedly recommended for the treatment of speech deficits in childhood apraxia of speech (CAS). However, differences in treatment outcomes as a function of treatment intensity have not been systematically studied in this population. AIM: To investigate the effects of treatment intensity on outcome measures related to articulation, functional communication and speech intelligibility for children with CAS undergoing individual motor speech intervention. METHODS & PROCEDURES: A total of 37 children (32-54 months of age) with CAS received 1×/week (lower intensity) or 2×/week (higher intensity) individual motor speech treatment for 10 weeks. Assessments were carried out before and after a 10-week treatment block to study the effects of variations in treatment intensity on the outcome measures. OUTCOMES & RESULTS: The results indicated that only higher intensity treatment (2×/week) led to significantly better outcomes for articulation and functional communication compared with 1×/week (lower intensity) intervention. Further, neither lower nor higher intensity treatment yielded a significant change for speech intelligibility at the word or sentence level. In general, effect sizes for the higher intensity treatment groups were larger for most variables compared with the lower intensity treatment group. CONCLUSIONS & IMPLICATIONS: Overall, the results of the current study may allow for modification of service delivery and facilitate the development of an evidence-based care pathway for children with CAS.

Tongue kinematics in palate relative coordinate spaces for electro-magnetic articulography.

This paper describes a method for constructing a three-dimensional model of the hard palate using electro-magnetic articulography, and defines two algorithms to derive constriction degree and constriction location values from the trajectories of tongue coils using this model. The kinematics of tongue motion that have been transformed into constriction degree and constriction location values are investigated in detail to determine whether this type of representation obeys the constraints theorized to operate over higher level motor control. Results show that palate-relative coordinate spaces decouple mechanical dependencies present in the tongue, while maintaining low-level kinematic properties. They additionally preserve the 1/3 power law for speed and curvature observed across many motor systems. Finally, it is shown that tongue movements in a palate relative coordinate space more closely correspond to their optimal, jerk-minimized trajectories. These results suggest that this type of coordinate space provides a closer match to higher level motor-planning, in line with production models that specify control units in terms of vocal tract constriction parameters.

Decoding kinematic information from beta-band motor rhythms of speech motor cortex: a methodological/analytic approach using concurrent speech movement tracking and magnetoencephalography.

Introduction: Articulography and functional neuroimaging are two major tools for studying the neurobiology of speech production. Until now, however, it has generally not been feasible to use both in the same experimental setup because of technical incompatibilities between the two methodologies. Methods: Here we describe results from a novel articulography system dubbed Magneto-articulography for the Assessment of Speech Kinematics (MASK), which is technically compatible with magnetoencephalography (MEG) brain scanning systems. In the present paper we describe our methodological and analytic approach for extracting brain motor activities related to key kinematic and coordination event parameters derived from time-registered MASK tracking measurements. Data were collected from 10 healthy adults with tracking coils on the tongue, lips, and jaw. Analyses targeted the gestural landmarks of reiterated utterances/ipa/ and /api/, produced at normal and faster rates. Results: The results show that (1) Speech sensorimotor cortex can be reliably located in peri-rolandic regions of the left hemisphere; (2) mu (8-12 Hz) and beta band (13-30 Hz) neuromotor oscillations are present in the speech signals and contain information structures that are independent of those present in higher-frequency bands; and (3) hypotheses concerning the information content of speech motor rhythms can be systematically evaluated with multivariate pattern analytic techniques. Discussion: These results show that MASK provides the capability, for deriving subject-specific articulatory parameters, based on well-established and robust motor control parameters, in the same experimental setup as the MEG brain recordings and in temporal and spatial co-register with the brain data. The analytic approach described here provides new capabilities for testing hypotheses concerning the types of kinematic information that are encoded and processed within specific components of the speech neuromotor system.

Peripheral auditory tuning for vowels.

In this study, 35 young, healthy adults were tested on whether speech-like stimuli evoke a unique response in the auditory efferent system. To this end, descending cortical influences on medial olivocochlear (MOC) activity were indirectly evaluated by studying the effects of contralateral suppression on distortion product otoacoustic emissions (DPOAEs) under four conditions: (a) in the absence of any contralateral noise (Baseline), (b) presence of contralateral broadband noise (Noise Baseline), (c) vowel discrimination-in-noise task (VDN) and (d) tone discrimination-in-noise (TDN) task. A statistically significant release from suppression was evident across all tested DPOAE frequencies (1, 1.5 and 2 kHz) only for the VDN task (p < 0.05), which yielded greater release from suppression than the TDN task. These findings indicate that during active listening in the presence of noise, the MOC activity may be differentially modulated depending on the type of stimulus (vowel vs. tone). Specifically, in the presence of background noise, vowels may show a greater release from suppression in the cochlea than frequency, intensity and duration matched tones.

The effect of phonetic context on speech movements in repetitive speech.

This study examined how, in repetitive speech, articulatory movements differ in degree of variability and movement range depending on articulatory constraints manipulated by phonetic context and type of CVC-CVC word pair. These pairs consisted of words that either differed in onset consonants but shared rhymes, or were identical. Articulatory constraints were manipulated by employing different combinations of vowels and consonants. The word pairs were produced in a repetitive speech task at a normal and fast speaking rate. Articulatory movements were measured with 3D electro-magnetic articulography. As measures of variability, median movement ranges and the coefficient of variation of target and non-target articulators were determined. To assess possible biomechanical constraints, correlation values between target and simultaneous non-target articulators were calculated as well. The results revealed that word pairs with different onsets had larger movement ranges than word pairs with identical onsets. In identical word pairs, the coefficient of variation showed higher values in the second than in the first word. This difference was not present in the alternating onset word pairs. For both types of word pairs, higher speaking rates showed higher correlations between target and non-target articulators than lower speaking rates, suggesting stronger biomechanical constraints for the former condition.

Rate-related kinematic changes in younger and older adults.

AIMS: This study aimed to investigate the effects of speech rate changes on kinematic characteristics and stability of speech movements in younger and older speakers using electromagnetic midsagittal articulography. PATIENTS AND METHODS: Eight young adults and 8 older adults engaged in a series of syllable repetition tasks of /pa/, /sa/ and /ta/ obtained at self-paced slow, habitual and fast speech rates, as well as in a series of metronome-guided speech rates, ranging from 2 to 4 syllables per second. The kinematic parameters duration, amplitude and peak velocity were obtained for opening and closing movements. RESULTS: Older speakers were able to increase speech rate to the same degree or higher compared to younger speakers in both pacing conditions. Kinematic data show that older adults increased duration and decreased peak velocity in closing movements of alveolar constrictions at slower rates more prominently than younger adults. The results on movement stability revealed no differences between age groups. CONCLUSIONS: The results suggest that an age-related difference in speed-accuracy trade-off can be ruled out. Differences in kinematic characteristics point towards the possibility that older adults aimed to facilitate a closed-loop control system to maintain movement stability at slower speech rates.

Predictors of Functional Communication Outcomes in Children With Idiopathic Motor Speech Disorders.

PURPOSE: The purpose of the study was to investigate child- and intervention-level factors that predict improvements in functional communication outcomes in children with motor-based speech sound disorders. METHOD: Eighty-five preschool-age children with childhood apraxia of speech (n = 37) and speech motor delay (n = 48) participated. Multivariable logistic regression models estimated odds ratios and 95% confidence intervals for the association between minimal clinically important difference in the Focus on the Outcomes of Communication Under Six scores and multiple child-level (e.g., age, sex, speech intelligibility, Kaufman Speech Praxis Test diagnostic rating scale) and intervention-level predictors (dose frequency and home practice duration). RESULTS: Overall, 65% of participants demonstrated minimal clinically important difference changes in the functional communication outcomes. Kaufman Speech Praxis Test rating scale was significantly associated with higher odds of noticeable change in functional communication outcomes in children. There is some evidence that delivering the intervention for 2 times per week for 10 weeks provides benefit. CONCLUSION: A rating scale based on task complexity has the potential for serving as a screening tool to triage children for intervention from waitlist and/or determining service delivery for this population.

Age-related changes in talker recognition with reduced spectral cues.

Temporal information provided by cochlear implants enables successful speech perception in quiet, but limited spectral information precludes comparable success in voice perception. Talker identification and speech decoding by young hearing children (5-7 yr), older hearing children (10-12 yr), and hearing adults were examined by means of vocoder simulations of cochlear implant processing. In Experiment 1, listeners heard vocoder simulations of sentences from a man, woman, and girl and were required to identify the talker from a closed set. Younger children identified talkers more poorly than older listeners, but all age groups showed similar benefit from increased spectral information. In Experiment 2, children and adults provided verbatim repetition of vocoded sentences from the same talkers. The youngest children had more difficulty than older listeners, but all age groups showed comparable benefit from increasing spectral resolution. At comparable levels of spectral degradation, performance on the open-set task of speech decoding was considerably more accurate than on the closed-set task of talker identification. Hearing children's ability to identify talkers and decode speech from spectrally degraded material sheds light on the difficulty of these domains for child implant users.

Speech-like and non-speech lip kinematics and coordination in aphasia.

BACKGROUND: In addition to the well-known linguistic processing impairments in aphasia, oro-motor skills and articulatory implementation of speech segments are reported to be compromised to some degree in most types of aphasia. AIMS: This study aimed to identify differences in the characteristics and coordination of lip movements in the production of a bilabial closure gesture between speech-like and non-speech tasks in individuals with aphasia and healthy control subjects. METHODS & PROCEDURES: Upper and lower lip movement data were collected for a speech-like and a non-speech task using an AG 100 EMMA system from five individuals with aphasia and five age- and gender-matched control subjects. Each task was produced at two rate conditions (normal and fast), and in a familiar and a less familiar manner. Single articulator kinematic parameters (peak velocity, amplitude, duration and cyclic spatio-temporal index) and multi-articulator coordination indices (average relative phase and variability of relative phase) were measured to characterize lip movements. OUTCOMES & RESULTS: The results showed that when the two lips had similar task goals (bilabial closure) in speech-like and non-speech task, kinematic and coordination characteristics were not found to be different. However, when changes in rate were imposed on the bilabial gesture, only speech-like task showed functional adaptations, indicated by a greater decrease in amplitude and duration at fast rates. In terms of group differences, individuals with aphasia showed smaller amplitudes and longer movement durations for upper lip, higher spatio-temporal variability for both lips, and higher variability in lip coordination than the control speakers. Rate was an important factor in distinguishing the two groups, and individuals with aphasia were limited in implementing the rate changes. CONCLUSIONS & IMPLICATIONS: The findings support the notion of subtle but robust differences in motor control characteristics between individuals with aphasia and the control participants, even in the context of producing bilabial closing gestures for a relatively simple speech-like task. The findings also highlight the functional differences between speech-like and non-speech tasks, despite a common movement coordination goal for bilabial closure.

Speech Kinematics and Coordination Measured With an MEG-Compatible Speech Tracking System.

Articulography and functional neuroimaging are two major tools for studying the neurobiology of speech production. Until recently, however, it has generally not been possible to use both in the same experimental setup because of technical incompatibilities between the two methodologies. Here we describe results from a novel articulography system dubbed Magneto-articulography for the Assessment of Speech Kinematics (MASK), which we used to derive kinematic profiles of oro-facial movements during speech. MASK was used to characterize speech kinematics in two healthy adults, and the results were compared to measurements from a separate participant with a conventional Electromagnetic Articulography (EMA) system. Analyses targeted the gestural landmarks of reiterated utterances /ipa/, /api/ and /pataka/. The results demonstrate that MASK reliably characterizes key kinematic and movement coordination parameters of speech motor control. Since these parameters are intrinsically registered in time with concurrent magnetoencephalographic (MEG) measurements of neuromotor brain activity, this methodology paves the way for innovative cross-disciplinary studies of the neuromotor control of human speech production, speech development, and speech motor disorders.