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Long, H. L. & Hustad, K. C. (2023). Marginal and canonical babbling in ten infants at risk for cerebral palsy. American Journal of Speech Language Pathology, 1-15.

Marginal and canonical babbling in ten infants at risk for cerebral palsy

Purpose: The present study is a preliminary quantification and characterization of the development of marginal and canonical syllable patterns in 10 infants at risk for cerebral palsy (CP).

Method: We calculated marginal and canonical babbling ratios from parent-infant laboratory recordings of 10 infants at two time points, approximately 13 and 16 months of age. The frequency and diversity of labial, coronal, and velar types of marginal and canonical syllables were also examined. Differences across three outcome groups were compared: infants later diagnosed with CP (n = 3, CP Group), risk of CP due to ongoing gross motor delays (n = 4, Risk Group), and current typically developing status with resolved gross motor delays (n = 3, TDx Group). Performance on the Mullen Scales was included for perspective on cognitive development.

Results: Higher marginal syllable ratios were observed in the CP and Risk Groups than the TDx Group. An increasing canonical syllable ratio across the two ages was consistently observed in the TDx Group. The TDx Group produced a greater frequency and diversity of canonical syllable types than the Risk and CP Groups, and of marginal syllable types than the CP Group.

Conclusions: This study offers preliminary support for the possibility that speech motor impairment in infants with CP have the potential to be observed and quantified early in vocal development prior to the expected onset of first words.  Prolonged rates of marginal syllable forms may be suggestive of speech motor impairment; however, additional longitudinal outcome data over a longer time course and a larger sample of infants are needed to provide further support for this possibility.

Long, H. L.*, Drown, L.*, & El Amin, M. (2023). The effect of open access on scholarly and societal metrics of impact in the ASHA Journals. Journal of Speech, Language, and Hearing Research.

*Indicates co-first authorship

The effect of open access on scholarly and societal metrics of impact in the ASHA Journals

Purpose: The present study examined the effect of open access (OA) status on scholarly and societal metrics of impact (citation counts and altmetric scores, respectively) across manuscripts published in the ASHA Journals.

Method: 3,419 manuscripts published in four active ASHA journals were grouped across three access statuses based on their availability to the public: Gold OA, Green OA, and Closed Access. Two linear mixed-effects models tested the effects of OA status on citation counts and altmetric scores of manuscripts.

Results: Both Green OA and Gold OA significantly predicted a 2.70 and 5.21 respective increase in citation counts compared to Closed Access manuscripts (p < .001). Gold OA was estimated to predict a 25.7-point significant increase in altmetric scores (p < .001), but Green OA was only marginally significant (p = 0.68) in predicting a 1.44 increase in altmetric scores relative to Closed Access manuscripts.

Discussion: CSD research that is fully open receives more online attention and overall, more scientific attention than research that is paywalled or available through Green OA methods. Additional research is needed to understand secondary variables affecting these and other scholarly and societal metrics of impact across studies in CSD. Ongoing support and incentives to reduce the inequities of OA publishing are critical for continued scientific advancement.

Long, H. L., Eichorn, N., & Oller, D. K. (2023). A probe study on vocal development in two infants at risk for cerebral palsy. Developmental Neurorehabilitation, 26(1), 44-51. 

A probe study on vocal development in two infants at risk for cerebral palsy.

The present work examined canonical babbling ratios longitudinally as a measure of onset and consolidation of canonical babbling in two infants at risk of cerebral palsy (CP) between 5 and 16 months. Ten typically developing infants were included for comparison at 6, 9, 12, and 16–19 months. Canonical babbling ratios (CBRs) were calculated from 5-min segments, and follow-up diagnostic outcomes were collected between 24 and 33 months. The two infants at risk demonstrated low CBR growth trajectories compared to the typical infant group, and slightly different patterns of consolidation. The two infants at risk were later diagnosed with different levels of CP and speech impairment severity. All infants demonstrated greater variability than expected. Studying canonical babbling and other prelinguistic milestones in this population may inform our perspective of the involvement of the motor system in the vocal domain. Additional implications on the analysis of canonical babbling using all-day home recordings are discussed.

Long, H. L., Ramsay, G., Griebel, U., Bene, E. R., Bowman, D. D., Burkhardt-Reed, M. M., & Oller, D. K. (2022). Perspectives on the origin of language: Infants vocalize most during independent vocal play but produce their most speech-like vocalizations during turn taking. PLoS ONE 17(12), e0279395.

Perspectives on the origin of language: Infants vocalize most during independent vocal play but produce their most speech-like vocalizations during turn taking

A growing body of research emphasizes both endogenous and social motivations in human vocal development. Our own efforts seek to establish an evolutionary and developmental perspective on the existence and usage of speech-like vocalizations (“protophones”) in the first year of life. We evaluated the relative occurrence of protophones in 40 typically developing infants across the second-half year based on longitudinal all-day recordings. Infants showed strong endogenous motivation to vocalize, producing vastly more protophones during independent vocal exploration and play than during vocal turn taking. Both periods of vocal play and periods of turn-taking corresponded to elevated levels of the most advanced protophones (canonical babbling) relative to periods without vocal play or without turn-taking. Notably, periods of turn taking showed even more canonical babbling than periods of vocal play. We conclude that endogenous motivation drives infants’ tendencies to explore and display a great number of speech-like vocalizations, but that social interaction drives the production of the most speech-like forms. The results inform our previously published proposal that the human infant has been naturally selected to explore protophone production and that the exploratory inclination in our hominin ancestors formed a foundation for language.

El Amin, M., Borders, J. C., Long, H. L., Keller, M. A., & Kearney, E. (2022). Open science practices in communication sciences and disorders: A survey. Journal of Speech, Language, and Hearing Research.

Open science practices in communication sciences and disorders: A survey

Purpose: Open science is a collection of practices that seek to improve the accessibility, transparency, and replicability of science. Although these practices have garnered interest in related fields, it remains unclear whether open science practices have been adopted in the field of communication sciences and disorders (CSD). This study aimed to survey the knowledge, implementation, and perceived benefits and barriers of open science practices in CSD.

Method: An online survey was disseminated to researchers in the United States actively engaged in CSD research. Four-core open science practices were examined: preregistration, self-archiving, gold open access, and open data. Data were analyzed using descriptive statistics and regression models.

Results: Two hundred twenty-two participants met the inclusion criteria. Most participants were doctoral students (38%) or assistant professors (24%) at R1 institutions (58%). Participants reported low knowledge of preregistration and gold open access. There was, however, a high level of desire to learn more for all practices. Implementation of open science practices was also low, most notably for preregistration, gold open access, and open data (< 25%). Predictors of knowledge and participation, as well as perceived barriers to implementation, are discussed.

Conclusion: Although participation in open science appears low in the field of CSD, participants expressed a strong desire to learn more in order to engage in these practices in the future.

Long, H. L., Mahr, T. J., Natzke, P., Rathouz, P. J., & Hustad, K. C. (2022). Longitudinal change in speech classification between 4 and 10 years in children with cerebral palsy, Developmental Medicine & Child Neurology, 64(9), 1096-1105.  

Longitudinal change in speech classification between 4 and 10 years in children with cerebral palsy

Aim: To examine speech impairment severity classification over time in a longitudinal cohort of children with cerebral palsy (CP).

Method: A total of 101 children (58 males, 43 females) between the ages of 4 and 10 years with CP participated in this longitudinal study. Speech severity was rated using the Viking Speech Scale (VSS), a four-level classification rating scale, at 4, 6, 8, and 10 years (age 4 years: mean = 52 months [3 SD]; age 6 years: mean = 75 months [2 SD]; age 8 years: mean = 100 months [4 SD]; age 10 years: mean = 125 months [5 SD]). We used Bayesian mixed-effects ordinal logistic regression to model (1) the extent to which speech severity changed over time and (2) patterns of change across age groups and classification rating group levels. 

Results: VSS ratings decreased (speech severity became less severe) between 4 and 10 years of age. Children who were first classified in VSS levels I, II, or III at age 4 years had a high probability of staying at, or improving to, VSS level I by 10 years. Children who were first classified in VSS level IV at 4 years had a high probability of remaining in VSS level IV at 10 years. 

Interpretation: Early speech performance is highly predictive of later childhood speech abilities. Children with any level of speech impairment at age 4 years should be receiving speech therapy. Those with more severe speech impairments should be introduced to augmentative and alternative communication as soon as possible.

Koopmans, C., Sakash, A., Soriano, J., Long, H. L., & Hustad, K. C. (2021). Functional communication abilities in youth with cerebral palsy: Association with impairment profiles and school-based therapy goals. Language, Speech, and Hearing Services in Schools, 53(1), 88-103.

Functional communication abilities in students with cerebral palsy:  Association with impairment profiles and school-based therapy goals

Aim. The aim of this study was to examine the relationship between functional communication skills, underlying speech, language, and cognitive impairments, and school-based speech pathology services in students with cerebral palsy (CP).  

Method. Thirty-five participants with CP who had active Individualized Education Programs (IEPs) were classified according to the Communication Function Classification System (CFCS). Participants completed laboratory assessments of speech, receptive language, executive functioning, and non-verbal cognition. Each participant’s speech and language IEP goals were coded into treatment units, then categorized into seven, mutually exclusive target goal areas. Non-parametric analyses were employed to examine differences among CFCS groups in the number of deficit areas and the number of goal areas from the IEP. Descriptive analyses were used to evaluate the extent to which deficit areas and goal areas in the IEP co-occurred by CFCS level. 

Results. Those in more involved CFCS levels demonstrated more severe speech, receptive language, and cognitive impairments.  However, there were no significant differences in the number of deficit areas across CFCS group.  Regardless of CFCS level, there were no differences in the number of treatment goals specified in the IEP.  Literacy was the only goal area addressed across all CFCS levels.  Those in the most involved CFCS levels had AAC goals, but those with more moderate restrictions on functional communication who also had markedly reduced speech intelligibility did not typically have speech or AAC goals.   

Interpretation. Individuals with CP across CFCS levels demonstrate variability in their underlying deficit profiles, suggesting that measures of both functional communication and of underlying deficits are necessary to provide a complete picture of communication needs. Literacy goals were common across all CFCS levels, but AAC goals were limited to the most severely involved individuals, suggesting that continuing education may be necessary to support SLPs in developing treatments involving the integration of AAC and speech to foster functional communication at school.

Gipson, T. T., Ramsay, G., Ellison, E. E., Bene, E. R., Long, H. L., & Oller, D. K. (2021). Early vocal development in tuberous sclerosis complex. Pediatric Neurology, 125, 48-52.

Early vocal development in tuberous sclerosis complex

Objective: Our goal was to assess for the first time early vocalizations as precursors to speech in audio-video recordings of infants with tuberous sclerosis complex (TSC). 

Methods: We randomly selected 40 infants with TSC from the TSC Autism Center of Excellence Research Network data set. Using human observers, we analyzed 74 audio-video recordings within a flexible software-based coding environment. During the recordings, infants were engaged in developmental testing. We determined syllables per minute (volubility), the number of consonant-vowel combinations, such as ‘ba’ (canonical babbling), and the canonical babbling ratio (canonical syllables/total syllables) and compared the data with 2 groups of typically developing (TD) infants. One comparison group's data had come from a laboratory setting, while the other's had come from all-day Language Environment Analysis recordings at home.

Results: Compared with TD infants in laboratory and all-day Language Environment Analysis recordings, entry into the canonical babbling stage was delayed in the majority of infants with TSC, and the canonical babbling ratio was low (TD mean - 0.346, SE - 0.19; TSC mean - 0.117, SE - 0.023)). Volubility level in infants with TSC was less than half that of TD infants (TD mean - 9.82, SE - 5.78; TSC mean - 3.99, SE -  2.16).

Conclusions: Entry into the canonical stage and other precursors of speech development were delayed in infants with TSC and may signal poor language and developmental outcomes. Future studies are planned to assess prediction of language and developmental outcomes using these measures in a larger sample and in more precisely comparable recording circumstances. 

Burkhardt-Reed, M. M., Long, H. L., Bowman, D. D., Bene, E. R., & Oller, D. K. (2021). The origin of language and relative roles of voice and gesture in early communication development. Infant Behavior and Development, 65, 101648. 

The origin of language and the relative roles of voice and gesture in early communication development

Both vocalization and gesture are universal modes of communication and fundamental features of language development. The gestural origins theory proposes that language evolved out of early gestural use. However, evidence reported here suggests vocalization is much more prominent in early human communication than gesture is. To our knowledge no prior research has investigated the rates of emergence of both gesture and vocalization across the first year in human infants. We evaluated the rates of gestures and speech-like vocalizations (protophones) in 10 infants at 4, 7, and 11 months of age using parent-infant laboratory recordings. We found that infant protophones outnumbered gestures substantially at all three ages, ranging from >35 times more protophones than gestures at 3 months, to >2.5 times more protophones than gestures at 11 months. The results suggest vocalization, not gesture, is the predominant mode of communication in human infants in the first year.

Oller, D. K., Ramsay, G., Bene, E., Long, H. L., & Griebel, U. (2021). Protophones, the precursors to speech, dominate the human infant vocal landscape. Philosophical Transactions of the Royal Society B: Biological Sciences, 376(1836), 20200255.

Protophones, the precursors to speech, dominate the human infant vocal landscape

Human infant vocalization is viewed as a critical foundation for vocal learning and language. All apes share distress sounds (shrieks and cries) and laughter. Another vocal type, speech-like sounds, common in human infants, is rare but not absent in other apes. These three vocal types form a basis for especially informative cross-species comparisons. To make such comparisons possible we need empirical research documenting frequency of occurrence of all three. 

The present work provides a comprehensive portrayal of these three vocal types in the human infant from longitudinal research in various circumstances of recording. Recently the predominant vocalizations of the human infant have been shown to be speech-like sounds, or “protophones”, including both canonical and non-canonical babbling. The research shows that protophones outnumber cries by a factor of at least five based on data from random-sampling of all-day recordings across the first year. The present work expands on the prior reports, showing the protophones vastly outnumber both cry and laughter in both all-day and laboratory recordings in various circumstances. The data provide new evidence of the predominance of protophones in the infant vocal landscape and illuminate their role in human vocal learning and the origin of language. 

Long, H. L., Bowman, D. D., Yoo, H., Burkhardt-Reed, M. M., Bene, E. R., & Oller, D. K. (2020). Social and endogenous infant vocalizations. PLoS ONE, 15(8), e0224956. 

Social and endogenous infant vocalizations

Research on infant vocal development has provided notable insights into vocal interaction with caregivers, elucidating growth in foundations for language through parental elicitation and reaction to vocalizations. A role for infant vocalizations produced endogenously, potentially providing raw material for interaction and a basis for growth in the vocal capacity itself, has received less attention. We report that in laboratory recordings of infants and their parents, the bulk of infant speech-like vocalizations, or “protophones”, were directed toward no one and instead appeared to be generated endogenously, mostly in exploration of vocal abilities. The tendency to predominantly produce protophones without directing them to others occurred both during periods when parents were instructed to interact with their infants and during periods when parents were occupied with an interviewer, with the infants in the room. The results emphasize the infant as an agent in vocal learning, even when not interacting socially and suggest an enhanced perspective on foundations for vocal language.

Oller, D. K., Griebel, U., Bowman, D. D., Bene, E. R., Long, H. L., Yoo, H., & Ramsay, G. (2020). Infant boys are more vocal than infant girls. Current Biology, 30, R417-429. 

Infant boys are more vocal than infant girls 

Although it is generally assumed females have a language advantage over males, Oller et al., studying all-day recordings of 100 infants, found that boys in the first year of life produced more speech-like vocalizations than girls and that the effect size was more than four times larger than the commonly reported female language advantage.

Long, H. L., Oller, D. K., & Bowman, D. D. (2019). Reliability of listener judgments of infant vocal imitation. Frontiers in Psychology, 10, 1340. 

Reliability of listener judgments of infant vocal imitation

There are many theories surrounding infant imitation; however, there is no research to our knowledge evaluating the reliability of listener perception of vocal imitation in prelinguistic infants. This paper evaluates intra- and inter-rater judgments on the degree of "imitativeness" in utterances of infants below 12 months of age. 18 listeners were presented audio segments selected from naturalistic recordings to represent in each case a parent vocal model followed by an infant utterance ranging from low to high degrees of imitativeness. The naturalistic data suggested vocal imitation occurred rarely across the first year, but strong intra- and inter-rater correlations were found for judgments of imitativeness. Our results suggest salience of the infant's vocal imitation despite its rare occurrence as well as active perception by listeners of the imitative signal. We discuss infant vocal imitation as a potential signal of well-being as perceived by caregivers.

Other Articles

Pfeiffer, D. L., Long, H. L., & El Amin, M. (2022, September). Access Research Beyond the Paywall: Five Strategies to Read What You Need. ASHA Leader Live.

Access Research Beyond the Paywall: Five Strategies to Read What You Need

Restricted access to journals can make it challenging for clinicians to keep up with new research. Check out these five free, legal ways to read what you need.