EEG repetition and change detection responses in infancy predict adaptive functioning in preschool age: a longitudinal study.

Neurodevelopmental disorders (NDDs) are mostly diagnosed around the age of 4-5 years, which is too late considering that the brain is most susceptive to interventions during the first two years of life. Currently, diagnosis of NDDs is based on observed behaviors and symptoms, but identification of objective biomarkers would allow for earlier screening. In this longitudinal study, we investigated the relationship between repetition and change detection responses measured using an EEG oddball task during the first year of life and at two years of age, and cognitive abilities and adaptive functioning during preschool years (4 years old). Identification of early biomarkers is challenging given that there is a lot of variability in developmental courses among young infants. Therefore, the second aim of this study is to assess whether brain growth is a factor of interindividual variability that influences repetition and change detection responses. To obtain variability in brain growth beyond the normative range, infants with macrocephaly were included in our sample. Thus, 43 normocephalic children and 20 macrocephalic children were tested. Cognitive abilities at preschool age were assessed with the WPPSI-IV and adaptive functioning was measured with the ABAS-II. Time-frequency analyses were conducted on the EEG data. Results indicated that repetition and change detection responses in the first year of life predict adaptive functioning at 4 years of age, independently of head circumference. Moreover, our findings suggested that brain growth explains variability in neural responses mostly in the first years of life, so that macrocephalic children did not display repetition suppression responses, while normocephalic children did. This longitudinal study demonstrates that the first year of life is an important period for the early screening of children at risk of developing NDDs.

Impact of Macrocephaly, as an Isolated Trait, on EEG Signal as Measured by Spectral Power and Multiscale Entropy during the First Year of Life.

Macrocephaly has been associated with neurodevelopmental disorders; however, it has been mainly studied in the context of pathological or high-risk populations and little is known about its impact, as an isolated trait, on brain development in general population. Electroencephalographic (EEG) power spectral density (PSD) and signal complexity have shown to be sensitive to neurodevelopment and its alterations. We aimed to investigate the impact of macrocephaly, as an isolated trait, on EEG signal as measured by PSD and multiscale entropy during the first year of life. We recorded high-density EEG resting-state activity of 74 healthy full-term infants, 50 control (26 girls), and 24 macrocephalic (12 girls) aged between 3 and 11 months. We used linear regression models to assess group and age effects on EEG PSD and signal complexity. Sex and brain volume measures, obtained via a 3D transfontanellar ultrasound, were also included into the models to evaluate their contribution. Our results showed lower PSD of the low alpha (8-10 Hz) frequency band and lower complexity in the macrocephalic group compared to the control group. In addition, we found an increase in low alpha (8.5-10 Hz) PSD and in the complexity index with age. These findings suggest that macrocephaly as an isolated trait has a significant impact on brain activity during the first year of life.

Impact of brain overgrowth on sensorial learning processing during the first year of life.

Macrocephaly is present in about 2-5% of the general population. It can be found as an isolated benign trait or as part of a syndromic condition. Brain overgrowth has been associated with neurodevelopmental disorders such as autism during the first year of life, however, evidence remains inconclusive. Furthermore, most of the studies have involved pathological or high-risk populations, but little is known about the effects of brain overgrowth on neurodevelopment in otherwise neurotypical infants. We investigated the impact of brain overgrowth on basic perceptual learning processes (repetition effects and change detection response) during the first year of life. We recorded high density electroencephalograms (EEG) in 116 full-term healthy infants aged between 3 and 11 months, 35 macrocephalic (14 girls) and 81 normocephalic (39 girls) classified according to the WHO head circumference norms. We used an adapted oddball paradigm, time-frequency analyses, and auditory event-related brain potentials (ERPs) to investigate differences between groups. We show that brain overgrowth has a significant impact on repetition effects and change detection response in the 10-20 Hz frequency band, and in N450 latency, suggesting that these correlates of sensorial learning processes are sensitive to brain overgrowth during the first year of life.

Developmental course of the repetition effect and change detection responses from infancy through childhood: a longitudinal study.

Neuronal repetition effect (repetition suppression and repetition enhancement) and change detection responses are fundamental brain responses that have implications in learning and cognitive development in infants and children. Studies have shown altered neuronal repetition and change detection responses in various clinical populations. However, the developmental course of these neuronal responses from infancy through childhood is still unknown. Using an electroencephalography oddball task, we investigate the developmental peculiarities of repetition effect and change detection responses in 43 children that we followed longitudinally from 3 months to 4 years of age. Analyses were conducted on theta (3-5 Hz), alpha (5-10 Hz), and beta (10-30 Hz) time-frequency windows. Results indicated that in the theta time-frequency window, in frontocentral and frontal regions of the brain, repetition and change detection responses followed a U-shaped pattern from 3 months to 4 years of age. Moreover, the change detection response was stronger in young infants compared to older children in frontocentral regions, regardless of the time-frequency window. Our findings add to the evidence of top-down modulation of perceptual systems in infants and children.

Infant repetition effects and change detection: Are they related to adaptive skills?

Repetition effects and change detection response have been proposed as neuro-electrophysiological correlates of fundamental learning processes. As such, they could be a good predictor of brain maturation and cognitive development. We recorded high density EEG in 71 healthy infants (32 females) aged between 3 and 9 months, while they listened to vowel sequences (standard /a/a/a/i/ [80%] and deviant /a/a/a/a/ [20%]). Adaptive skills, a surrogate of cognitive development, were measured via the parent form of the Adaptive Behavior Assessment System Second Edition (ABAS-II). Cortical auditory-evoked potentials (CAEPs) analyses, time-frequency analyses and a statistical approach using linear mixed models (LMMs) and linear regression models were performed. Age and adaptive skills were tested as predictors. Age modulation of repetition effects and change detection response was observed in theta (3-5 Hz), alpha (5-10 Hz) and high gamma (80-90 Hz) oscillations and in all CAEPs. Moreover, adaptive skills modulation of repetition effects was evidenced in theta (3-5 Hz), high gamma oscillations (80-90 Hz), N250/P350 peak-to-peak amplitude and P350 latency. Finally, adaptive skills modulation of change detection response was observed in the N250/P350 peak-to-peak amplitude. Our results confirm that repetition effects and change detection response evolve with age. Moreover, our results suggest that repetition effects and change detection response vary according to adaptive skills displayed by infants during the first year of life, demonstrating their predictive value for neurodevelopment.

Influencias de la edad y de la escolaridad en el examen breve del estado mental (Mini-Mental State Examination) en una población hispano-hablante / Influence of age and education in the Mini Mental State Examination in a Spanish speaking population

Se aplicó el Examen Breve del Estado Mental (Mini-Mental State examination o MMSE) a 430 sujetos neurológicamente intactos entre 16 y 85 años de edad. La muestra se estratificó de acuerdo a la edad en tres grupos: 16-50 años, 51-65 años y 66-89 años y dentro de cada rango de edad se consideraron 4 niveles educativos: nulo (cero a los de estudio), bajo (1-4 años de estudio), medio (5-9 años) y alto (10 o más años de estudio). El nivel de escolaridad mostró un efecto significativo en el puntaje total. Los individuos sanos y funcionalmente independientes con escolaridad nula, obtuvieron puntajes que los clasificaron dentro de un cuadro de demencia severa (promedio = 17.67) mientras que los puntajes de aquellos con escolaridad de 1 a 4 años fueron semejantes a los de demencia leve (promedio = 20.61). Para establecer la especificidad y la sensibilidad del instrumento se estudió una muestra de 40 sujetos con diagnóstico clínico de demencia. Los sujetos fueron comparados por pares con el grupo control de acuerdo a la edad y a la escolaridad. Se utilizó el punto de corte propuesto por Folstein y cols. (1975), de 23/24 puntos y se encontraron bajos niveles de especificidad y sensibilidad en sujetos sin escolaridad y con escolaridad de 1 a 4 años, 50 por ciento y 72.73 por ciento respectivamante. El ajuste del punto de corte en función del desempeño promedio del grupo de sujetos neurológicamente instactos incrementó la especificidad (90 por ciento), pero disminuyó considerablemente la sensibilidad (86.36 por ciento) fueron más altos. En la población hispano-hablante el MMSE puede ser útil para confirmar la presencia de alteraciones cognoscitivas severas en sujetos con más de 5 años de escolaridad, pero no debe considerarse para detectar alteraciones leves. En sujetos de baja escolaridad con el MMSE se obtiene un alto índice de falsos positivos. El MMSE es un instrumento de poca utilidad para el diagnóstico de alteraciones en poblaciones hispano-hablantes sin escolaridad