A Cohort Study of Relations Among Caregiver-Infant Co-Occupation and Reciprocity.

Co-occupation is the mutual engagement of two people in a shared occupation. Recent research has investigated co-occupational activities during sensitive periods to inform clinical practice. However, there remains a dearth of applied research to bridge gaps between research and practice within salient co-occupational relationships between caregivers and infants. The study applied co-occupational constructs of physicality, emotionality, and intentionality within caregiver-infant dyads across infancy. These constructs were examined in relation to caregiver-infant reciprocity in other domains (i.e., language, motor, and affective) to determine the overlapping features of reciprocal co-occupation with established aspects of reciprocity. Results suggest that as infants transitioned into toddlerhood and became more mobile and intentional in behavior, there were observable changes in caregiver-infant reciprocity. Caregiver utterances, affect, touch, and co-occupation were significantly related within and across time, highlighting the need for more studies to disentangle these relations in reference to infant development.

Classification of Infant Vocalizations by Untrained Listeners.

Purpose To better enable communication among researchers, clinicians, and caregivers, we aimed to assess how untrained listeners classify early infant vocalization types in comparison to terms currently used by researchers and clinicians. Method Listeners were caregivers with no prior formal education in speech and language development. A 1st group of listeners reported on clinician/researcher-classified vowel, squeal, growl, raspberry, whisper, laugh, and cry vocalizations obtained from archived video/audio recordings of 10 infants from 4 through 12 months of age. A list of commonly used terms was generated based on listener responses and the standard research terminology. A 2nd group of listeners was presented with the same vocalizations and asked to select terms from the list that they thought best described the sounds. Results Classifications of the vocalizations by listeners largely overlapped with published categorical descriptors and yielded additional insight into alternate terms commonly used. The biggest discrepancies were found for the vowel category. Conclusion Prior research has shown that caregivers are accurate in identifying canonical babbling, a major prelinguistic vocalization milestone occurring at about 6-7 months of age. This indicates that caregivers are also well attuned to even earlier emerging vocalization types. This supports the value of continuing basic and clinical research on the vocal types infants produce in the 1st months of life and on their potential diagnostic utility, and may also help improve communication between speech-language pathologists and families.

Utterance Duration as It Relates to Communicative Variables in Infant Vocal Development.

Purpose: We aimed to provide novel information on utterance duration as it relates to vocal type, facial affect, gaze direction, and age in the prelinguistic/early linguistic infant. Method: Infant utterances were analyzed from longitudinal recordings of 15 infants at 8, 10, 12, 14, and 16 months of age. Utterance durations were measured and coded for vocal type (i.e., squeal, growl, raspberry, vowel, cry, laugh), facial affect (i.e., positive, negative, neutral), and gaze direction (i.e., to person, to mirror, or not directed). Results: Of the 18,236 utterances analyzed, durations were typically shortest at 14 months of age and longest at 16 months of age. Statistically significant changes were observed in utterance durations across age for all variables of interest. Conclusion: Despite variation in duration of infant utterances, developmental patterns were observed. For these infants, utterance durations appear to become more consolidated later in development, after the 1st year of life. Indeed, 12 months is often noted as the typical age of onset for 1st words and might possibly be a point in time when utterance durations begin to show patterns across communicative variables.

Phonological working memory in developmental stuttering: Potential insights from the neurobiology of language and cognition.

The current review examines how neurobiological models of language and cognition could shed light on the role of phonological working memory (PWM) in developmental stuttering (DS). Toward that aim, we review Baddeley's influential multicomponent model of PWM and evidence for load-dependent differences between children and adults who stutter and typically fluent speakers in nonword repetition and dual-task paradigms. We suggest that, while nonword repetition and dual-task findings implicate processes related to PWM, it is unclear from behavioral studies alone what mechanisms are involved. To address how PWM could be related to speech output in DS, a third section reviews neurobiological models of language proposing that PWM is an emergent property of cyclic sensory and motor buffers in the dorsal stream critical for speech production. We propose that anomalous sensorimotor timing could potentially interrupt both fluent speech in DS and the emergent properties of PWM. To further address the role of attention and executive function in PWM and DS, we also review neurobiological models proposing that prefrontal cortex (PFC) and basal ganglia (BG) function to facilitate working memory under distracting conditions and neuroimaging evidence implicating the PFC and BG in stuttering. Finally, we argue that cognitive-behavioral differences in nonword repetition and dual-tasks are consistent with the involvement of neurocognitive networks related to executive function and sensorimotor integration in PWM. We suggest progress in understanding the relationship between stuttering and PWM may be accomplished using high-temporal resolution electromagnetic experimental approaches.

Differing Roles of the Face and Voice in Early Human Communication: Roots of Language in Multimodal Expression.

Seeking roots of language, we probed infant facial expressions and vocalizations. Both have roles in language, but the voice plays an especially flexible role, expressing a variety of functions and affect conditions with the same vocal categories-a word can be produced with many different affective flavors. This requirement of language is seen in very early infant vocalizations. We examined the extent to which affect is transmitted by early vocal categories termed "protophones" (squeals, vowel-like sounds, and growls) and by their co-occurring facial expressions, and similarly the extent to which vocal type is transmitted by the voice and co-occurring facial expressions. Our coder agreement data suggest infant affect during protophones was most reliably transmitted by the face (judged in video-only), while vocal type was transmitted most reliably by the voice (judged in audio-only). Voice alone transmitted negative affect more reliably than neutral or positive affect, suggesting infant protophones may be used especially to call for attention when the infant is in distress. By contrast, the face alone provided no significant information about protophone categories. Indeed coders in VID could scarcely recognize the difference between silence and voice when coding protophones in VID. The results suggest that partial decoupling of communicative roles for face and voice occurs even in the first months of life. Affect in infancy appears to be transmitted in a way that audio and video aspects are flexibly interwoven, as in mature language.

The Reciprocity Team: Development of an Interprofessional Research Collaboration.

The purpose of this article is to articulate and provide detail about an interprofessional research collaboration at a public university in a rural area of western United States. This interprofessional research collaboration was organized to explore infant and maternal reciprocity. As a part of the organization and process portion of the collaborative effort, the authors identify the unique attributes of their collaboration. Additionally, barriers to collaborative research are presented, with opportunities and recommendations made to support existing and future interprofessional collaborative efforts for basic science scholars, clinicians, and educators in health-related professions.