Validation of a Parent Report Tool for Monitoring Early Vocal Stages in Infants

An examination of the association between infant non-nutritive suck and developmental outcomes at 12 months

OBJECTIVE

To determine the association between infant non-nutritive suck (NNS) dynamics at 3 months and developmental outcomes at 12 months of age in full-term infants. We hypothesized that infants with more mature NNS at 3 months, as evidence by shorter burst duration, fewer cycles per burst, cycles per minute, higher amplitude, and more bursts, would have higher (better) scores on the developmental outcomes at 12 months.

METHODS

This was a prospective study that utilized objective and self-report measures. A five-minute NNS sample was collected from 67 infants (54% male) at 3 months of age (average age 2.99 (0.27) months). At 12 months (average age 11.91 (0.26) months), the Development Profile-3 was administered through caregiver interview.

RESULTS

Infant NNS burst duration, cycles per burst, and cycles per minute were significantly negatively associated with the Development Profile-3 cognitive domain and general scores at 12 months. This is consistent with our hypothesis that infants who have more efficient NNS (fewer bursts and cycles) at 3 months would have higher (better) scores on the Development Profile-3 at 12 months.

CONCLUSIONS

Findings from this work complement emerging research linking infant NNS with subsequent neurodevelopmental outcomes. This is the first time that these associations have been examined using a quantitative and physiologic-based measure of NNS. These results seem to indicate that specific NNS metrics, which demonstrate maturation of this complex skill, may be useful predictors of neurodevelopment later in life.

Vocal Characteristics of Infants at Risk for Speech Motor Involvement: A Scoping Review

PURPOSE

The purpose of this scoping review was to (a) summarize methodological characteristics of studies examining vocal characteristics of infants at high risk for neurological speech motor involvement and (b) report the state of the high-quality evidence on vocal characteristic trends of infants diagnosed or at high risk for cerebral palsy (CP).

METHOD

The PRISMA (Preferred Reporting Items of Systematic Reviews and Meta-Analyses) extension for scoping reviews was followed for reporting our review. Studies measured prelinguistic vocal characteristics of infants under 24 months with birth risk or genetic conditions known to commonly present with speech motor involvement. Fifty-five studies met criteria for Part 1. Eleven studies met criteria for synthesis in Part 2.

RESULTS

A smaller percentage of studies examined infants with or at risk for CP compared to studies examining genetic conditions such as Down syndrome. The median year of publication was 1999, with a median sample size of nine participants. Most studies were conducted in laboratory settings and used human coding of vocalizations produced during caregiver-child interactions. Substantial methodological differences were noted across all studies. A small number of high-quality studies of infants with or at risk for CP revealed high rates of marginal babbling, low rates of canonical babbling, and limited consonant diversity under 24 months. Mixed findings were noted across studies of general birth risk factors.

CONCLUSIONS

There is limited evidence available to support the early detection of speech motor involvement. Large methodological differences currently impact the ability to synthesize findings across studies. There is a critical need to conduct longitudinal research with larger sample sizes and advanced, modern technologies to detect vocal precursors of speech impairment to support the accurate diagnosis and prognosis of speech development in infants with CP and other clinical populations.

Clinical utilisation of the Infant Monitor of vocal Production (IMP) for early identification of communication impairment in young infants at-risk of cerebral palsy: a prospective cohort study

AIM

To report prospective longitudinal data of early vocaliszations of infants identified "at-risk" of cerebral palsy (CP) for early identification of communication impairment.

METHOD

This case-control longitudinal prospective cohort study reports on the assessment of 36 infants, 18 identified as at-risk of CP at the time of enrolment and 18 typically developing (TD) children, at three time points: 6 months, 9 months and 12 months of age, Data were obtained through criterion and norm referenced assessments of vocaliszation behaviors.

RESULTS

Early vocal behaviors of infants identified as at-risk of CP did not differ from their age matched peers at 6 months of age, however, significant group differences emerged at 9 and 12 months when pre-canonical and canonical babble typically emerge. Generalized linear mixed models analysis showed that the rate of development of early language ability and more complex speech-related vocal behaviors was slower for infants at risk of CP when compared to TD infants, with over 75% of infants with CP showing below normal vocal production and impaired language by 12 months of age.

INTERPRETATION

Our data suggest characteristics of infant vocalizations associated with pre-canonical and canonical babbling provide a strong evidence base for predicting communication outcomes in infants at risk of CP.

Evaluation of Parent-Researcher Agreement on the Vocal Development Landmarks Interview

Purpose Parent report was compared to judgments made by a trained researcher to determine the utility of the Vocal Development Landmarks Interview (VDLI) for monitoring development of vocal behaviors in very young children. Method Parents of 40 typically developing children, ages 6-21 months, provided full-day naturalistic audio recordings of their children's vocalizations after completing the VDLI. Six 5-min segments of highly voluble periods were selected from each recording and were analyzed, coded, and scored by the researcher. These data were then compared to the parents' VDLI responses. Parent-researcher agreement was examined using two methods and a generalized linear mixed model. Patterns of disagreement were explored descriptively to gain insights regarding potential sources of parent-researcher differences. Finally, developmental patterns in the researcher-observed vocal behaviors were examined as a function of children's age. Results No significant differences in parent-researcher agreement were found for the Canonical and Word subscales of the VDLI; however, significant differences in agreement were found for the Precanonical subscale. Mean percentages of agreement were high overall for both scoring methods evaluated. Additionally, the researcher's categorization and quantification of vocal behaviors for each age group aligned well with developmental trajectories found in the literature. Conclusion Results provide further support for use of parent report to assess early vocal development and use of the VDLI as a clinical measure of vocal development in infants and toddlers ages 6-21 months.

Developmental Functional Modules in Infant Vocalizations

Purpose Developmental functional modules (DFMs) are biological modules that are defined by their structural (morphological), functional, or developmental elements, and, in some cases, all three of these. This review article considers the hypothesis that vocal development in the first year of life can be understood in large part with respect to DFMs that characterize the speech production system. Method Literature is reviewed on relevant embryology, orofacial reflexes, craniofacial muscle properties, stages of vocal development, and related topics to identity candidates for DFMs. Results The following DFMs are identified and described: laryngeal, pharyngo-laryngeal, mandibular, velopharyngeal, labial complex, and lingual complex. These DFMs and their submodules, considered along with phenomena such as rhythmic movements, account for several well-documented features of vocal development in the first year of life. The proposed DFMs, rooted in embryologic, histologic, and kinematic properties, serve as low-dimensional control variables for the developing vocal tract. Each DFM is semi-autonomous but interacts with other DFMs to produce patterns of vocal behavior. Discussion Considered in relation to contemporary profiles and models of vocal development in the first year of life, DFMs have interpretive and explanatory value. DFMs complement other approaches in the study of infant vocalizations and are grounded in biology.

Früherkennung von Entwicklungsstörungen: Kanonisches Lallen (k)‌ein diagnostischer Marker‍(!)?

Zusammenfassung. Theoretischer Hintergrund: Forschungsergebnisse zum frühen Spracherwerb bei Kindern mit spät erkannten Entwicklungsstörungen sind inkonsistent und angesichts unterschiedlicher Forschungsparadigmen und Definitionen nur bedingt vergleichbar. Fragestellung: Ziel dieser Übersichtsarbeit ist es, das Potenzial früher verbaler Fähigkeiten, vor allem des kanonischen Lallens, als Marker zur Früherkennung von Autismus-Spektrum-Störung, Rett-Syndrom und Fragilem-X-Syndrom zu beschreiben. Methode: Übersichtsarbeit über retrospektive und prospektive Studien zu frühen verbalen Fähigkeiten in der Prodromalphase dieser Störungsbilder. Ergebnisse: Einige Kinder mit spät erkannten Entwicklungsstörungen erwerben das kanonische Lallen nach dem kritischen Zeitfenster von 6 bis 10 Monaten und/oder haben oft qualitative Veränderungen in ihren Lautäußerungen. Diskussion und Schlussfolgerung: Eine abweichende Entwicklung des kanonischen Lallens kann auf spätere atypische Entwicklung hinweisen. Als funktioneller Marker für die spezifische Früherkennung von Entwicklungsstörungen scheint dieser Erwerbsmeilenstein jedoch nicht geeignet. Linguistische und signalbasierte Detailanalysen frühkindlicher Vokalisationen könnten zukünftig einen entscheidenden Beitrag hierzu leisten.

Cross-cultural adaptation and psychometric assessment of a Persian version of Proctor's developmental vocal assessment protocol: Description of Persian infant vocal development

OBJECTIVES

With increasing recognition of the importance of pre-linguistic vocalization, and early intervention for children, proper protocols play an important role in documenting infants' progress and effects of early interventional programs. This study aimed to translate Proctor's Developmental Vocal Assessment Protocol into Persian, make cultural adaptations, assess Persian version of Developmental Vocal Assessment Protocol (P-DVAP)'s validity, internal consistency, and reliability, and provide a general perspective toward Persian infants' vocal behaviors.

METHODS

This study was mainly conducted in reference to Beaton's guidelines included translation, synthesis, back-translation, expert committee review, & pretesting. Ten well-experienced speech and language therapists contributed in expert committee review. Mothers of 202 infants were interviewed by experienced speech and language therapists.

RESULTS

Expert committee pointed out some difficulties that parents might have responding to P-DVAP. Such difficulties were sorted out in the P-DVAP applied for psychometric analysis. The Content Validity Index and Content Validity Ratio of P-DVAP were above 0.9. In test-retest reliability, Kappa coefficient was 0.6 and as the measure of inter item consistency, Kuder-Richardson-20 for each stage ranged from 0.1 to 0.5. Parents of typical infants reported variations in crying, vegetative sounds, laughing, prosody changes, babbling, approximants of meaningful words, and consonant-vowel structures as the most common vocal behaviors. The number of vocal behaviors reported for preterm infants after corrected gestational age was fewer than those of typical full-term infants.

CONCLUSION

The P-DVAP is a comprehensive, reliable, valid, simple and clear protocol for clinical evaluation of Persian infants' vocal behaviors.