April A. Benasich

Maturation of auditory evoked potentials from 6 to 48 months: prediction to 3 and 4 year language and cognitive abilities.

OBJECTIVE To investigate the maturation of long-latency auditory evoked potentials (LLAEP) from 6 to 48 months in infants with a family history of language impairment (FH+) and control infants (FH-). METHODS LLAEPs of seventeen FH+ infants were compared to 28 FH- infants at 6, 9, 12, 16, 24, 36 and 48 months. Participants received a passive oddball paradigm using fast- and slow-rate non-linguistic auditory stimuli and at 36 and 48 months completed a battery of standardized language and cognitive tests. RESULTS Overall, the morphology of LLAEP responses differed for fast- versus slow-rate stimuli. Significant age-related changes in latency and amplitude were observed. Group differences, favoring FH- infants, in the rate of maturation of LLAEPs were found. Responses to fast-rate stimuli predicted language abilities at 36 and 48 months of age. CONCLUSIONS The development of LLAEP in FH+ children is modulated by differences in the rate of maturation as well as variations in temporal processing abilities. SIGNIFICANCE These findings provide evidence for the role of non-linguistic auditory processes in early language development and illustrate the utility of using a perceptual-processing skills model to further our understanding of the precursors of language development and impairment.

Understanding language and cognitive deficits in very low birth weight children.

Very-low-birth-weight infants are at much higher risk for cognitive and language delays but the nature of such deficits is not clearly understood. Given increasing rates of prematurity and infants born very-low-birth-weight, examination of mechanisms that underlie poorer developmental outcome is essential. We investigated language and cognitive abilities in very-low and normal birth-weight infants to determine whether performance differences were due to poorer global cognitive performance or to deficits in specific processing abilities. Thirty-two very-low and 32 normal birth-weight infants received visual and auditory-visual habituation recognition-memory tasks, and standardized language and cognitive assessments. Very-low-birth-weight infants performed more poorly on visual and auditory-visual habituation tasks and scored lower than controls on cognitive and language measures. These findings suggest that differences in language abilities in very-low-birth-weight children may be part of a global deficit that impacts many areas of cognitive functioning rather than a specific impairment in rapid auditory processing.

How do mothers benefit from early intervention programs

Extant reviews of early childhood intervention programs for the disadvantaged focus on the benefits that accrue to the children. Programs also may influence the parents (typically the mother), as most programs provide services to the mother as well as the child. In this article, the efficacy of a particular set of programs is reviewed. Early interventions that are educationally oriented, that are at least six months in duration, that begin prior to age 3, and that serve disadvantaged families were reviewed. Of the 27 programs, 11 offered regular, substantive, center-based programming (mode = 40 hr/week; M = 25.7 hr/week), and 16 offered home visits and/or center-based programs on a less frequent basis. Maternal benefits are reviewed for maternal employment and education, fertility, mother-infant interaction, home environment, maternal mental health and self-esteem, and maternal attitudes and knowledge about childrearing. The programs had the most impact on maternal employment and education, on subsequent fertility, and on mother-infant interaction. Implications of these findings for programs for poor families are considered.

Early cognitive and language skills are linked to resting frontal gamma power across the first 3 years

High-frequency cortical activity in humans and animals has been linked to a wide variety of higher cognitive processes. This research suggests that specific changes in neuronal synchrony occur during cognitive processing, distinguished by emergence of fast oscillations in the gamma frequency range. To determine whether the development of high-frequency brain oscillations can be related to the development of cognitive abilities, we studied the power spectra of resting EEG in children 16, 24 and 36 months of age. Individual differences in the distribution of frontal gamma power during rest were highly correlated with concurrent language and cognitive skills at all ages. Gamma power was also associated with attention measures; children who were observed as having better inhibitory control and more mature attention shifting abilities had higher gamma power density functions. We included a group of children with a family history of language impairment (FH+) and thus at higher risk for language disorders. FH+ children, as a group, showed consistently lower gamma over frontal regions than the well-matched FH- controls with no such family history (FH-). We suggest that the emergence of high-frequency neural synchrony may be critical for cognitive and linguistic development, and that children at risk for language impairments may lag in this process.

Pediatric neuroimaging in early childhood and infancy: challenges and practical guidelines

Structural and functional magnetic resonance imaging (fMRI) has been used increasingly to investigate typical and atypical brain development. However, in contrast to studies in school‐aged children and adults, MRI research in young pediatric age groups is less common. Practical and technical challenges occur when imaging infants and children, which presents clinicians and research teams with a unique set of problems. These include procedural difficulties (e.g., participant anxiety or movement restrictions), technical obstacles (e.g., availability of child‐appropriate equipment or pediatric MR head coils), and the challenge of choosing the most appropriate analysis methods for pediatric imaging data. Here, we summarize and review pediatric imaging and analysis tools and present neuroimaging protocols for young nonsedated children and infants, including guidelines and procedures that have been successfully implemented in research protocols across several research sites.

Auditory temporal processing thresholds, habituation, and recognition memory over the 1st year

Abstract Selective impairments have been found in the ability of language impaired (LI) children to process the rapidly changing temporal cues critical to language comprehension and production. Performance on temporal perception and production tasks alone enable correct identification of 98% of LI from normal children. These findings suggest that auditory temporal processing (ATP) deficits might serve as a behavioral “marker” of language impairment and could be useful in early identification. Measures of perceptual-cognitive abilities in infancy such as habituation and recognition memory have been shown to be particularly sensitive to language delays. Specific links have been demonstrated between these measures and language comprehension. We hypothesize that a critical mechanism contributing to “speed of processing,” as measured by rate and amount of habituation and novelty preference on recognition memory tests, may be temporal processing efficiency in infancy. Auditory temporal processing thresholds were examined in two groups of infants from 6 to 10 months of age: infants from families with no known history of LI and infants from families with a positive history of LI. Infants from families with a positive history of LI had significantly lower mean thresholds than control infants. Habituation, ATP thresholds, and recognition memory were found to be significantly associated suggesting that they may be tapping similar processes.

Functional connectivity of the sensorimotor area in naturally sleeping infants

Patterns of cortical functional connectivity in normal infants were examined during natural sleep by observing the time course of very low frequency oscillations. Such oscillations represent fluctuations in blood oxygenation level and cortical blood flow thus allowing computation of neurophysiologic connectivity. Structural and resting-state information were acquired for 11 infants, with a mean age of 12.8 months, using a GE 1.5 T MR scanner. Resting-state data were processed and significant functional connectivity within the sensorimotor area was identified using independent component analysis. Unilateral functional connectivity in the developing sensory-motor cortices was observed. Power spectral analysis showed that slow frequency oscillations dominated the hemodynamic signal at this age, with, on average, a peak frequency for all subjects of 0.02 Hz. Our data suggest that there is more intrahemispheric than interhemispheric connectivity in the sensorimotor area of naturally sleeping infants. This non-invasive imaging technique, developed to allow reliable scanning of normal infants without sedation, enabled computation of neurophysiologic connectivity for the first time in naturally sleeping infants. Such techniques permit elucidation of the role of slow cortical oscillations during early brain development and may reveal critical information regarding the normative development and lateralization of brain networks across time.

Development of structure and function in the infant brain: Implications for cognition, language and social behaviour

Recent advances in cognitive neuroscience have allowed us to begin investigating the development of both structure and function in the infant brain. However, despite the rapid evolution of technology, surprisingly few studies have examined the intersection between brain and behaviour over the first years of life. Even fewer have done so in the context of a particular research question. This paper aims to provide an overview of four domains that have been studied using techniques amenable to elucidating the brain/behaviour interface: language, face processing, object permanence, and joint attention, with particular emphasis on studies focusing on early development. The importance of the unique role of development and the interplay between structure and function is stressed throughout. It is hoped that this review will serve as a catalyst for further thinking about the substantial gaps in our understanding of the relationship between brain and behaviour across development. Further, our aim is to provide ideas about candidate brain areas that are likely to be implicated in particular behaviours or cognitive domains.

Resting frontal gamma power at 16, 24 and 36 months predicts individual differences in language and cognition at 4 and 5 years

Gamma activity has been linked to a variety of different cognitive processes and exists in both transient and persistent forms. Across studies, different brain regions have been suggested to contribute to gamma activity. Multiple studies have shown that the function of gamma oscillations may be related to temporal binding of early sensory information to relevant top-down processes. Given this hypothesis, we expected gamma oscillations to subserve general brain mechanisms that contribute to the development of cognitive and linguistic systems. The present study aims to examine the predictive relations between resting-state cortical gamma power density at a critical point in language and cognitive acquisition (i.e. 16, 24 and 36 months), and cognitive and language output at ages 4 and 5 years. Our findings show that both 24- and 36-month gamma power are significantly correlated with later language scores, notably Non-Word Repetition. Further, 16-, 24- and 36-month gamma were all significantly correlated with 4-year PLS-3 and CELF-P sentence structure scores. Although associations reported here do not reflect a direct cause and effect of early resting gamma power on later language outcomes, capacity to generate higher power in the gamma range at crucial developmental periods may index better modulation of attention and allow easier access to working memory, thus providing an advantage for overall development, particularly in the linguistic domain. Moreover, measuring abilities at times when these abilities are still emergent may allow better prediction of later outcomes.

The effects of early education intervention on maternal employment, public assistance, and health insurance: the infant health and development program.

OBJECTIVES The purpose of this study was to test whether early education intervention influences maternal employment, education, fertility, and receipt of public assistance and health insurance. METHODS The Infant Health and Development Program is a randomized trial of the efficacy of early education on the outcomes of 985 low-birthweight, premature children. Families in eight sites received either pediatric follow-up and referral (follow-up only group) or pediatric services plus early intervention services (intervention group) for the first 3 years of the childs life. RESULTS Mothers in the intervention group were employed more months and returned to the work force earlier than those in the follow-up only group. Fertility and education were not associated with treatment. Mothers who had some college education received more months of public assistance in the intervention group compared with the follow-up only group. Mothers who were employed received more public assistance and public health insurance in the intervention group compared with the follow-up only group, when maternal employment was controlled. CONCLUSIONS Findings are discussed in terms of the recent emphasis on two-generational programs directed to providing health, welfare, and child care services to young children and their families.