Prevention of Neurological Sequelae in Preterm Infants.

BACKGROUND: Preterm birth is one of the world's critical health problems, with an incidence of 5% to 18% of living newborns according to various countries. White matter injuries due to preoligodendrocytes deficits cause hypomyelination in children born preterm. Preterm infants also have multiple neurodevelopmental sequelae due to prenatal and perinatal risk factors for brain damage. The purpose of this work was to explore the effects of the brain risk factors and MRI volumes and abnormalities on the posterior motor and cognitive development at 3 years of age. METHODS: A total of 166 preterm infants were examined before 4 months and clinical and MRI evaluations were performed. MRI showed abnormal findings in 89% of the infants. Parents of all infants were invited to receive the Katona neurohabilitation treatment. The parents of 128 infants accepted and received Katona's neurohabilitation treatment. The remaining 38 infants did not receive treatment for a variety of reasons. At the three-year follow-up, Bayley's II Mental Developmental Index (MDI) and the Psychomotor Developmental Index (PDI) were compared between treated and untreated subjects. RESULTS: The treated children had higher values of both indices than the untreated. Linear regression showed that the antecedents of placenta disorders and sepsis as well as volumes of the corpus callosum and of the left lateral ventricle significantly predicted both MDI and PDI, while Apgar < 7 and volume of the right lateral ventricle predicted the PDI. CONCLUSIONS: (1) The results indicate that preterm infants who received Katona's neurohabilitation procedure exhibited significantly better outcomes at 3 years of age compared to those who did not receive the treatment. (2) The presence of sepsis and the volumes of the corpus callosum and lateral ventricles at 3-4 months were significant predictors of the outcome at 3 years of age.

EEG effective connectivity during the first year of life mirrors brain synaptogenesis, myelination, and early right hemisphere predominance.

INTRODUCTION: The maturation of electroencephalogram (EEG) effective connectivity in healthy infants during the first year of life is described. METHODS: Participants: A cross-sectional sample of 125 healthy at-term infants, from 0 to 12 months of age, underwent EEG in a state of quiet sleep. PROCEDURES: The EEG primary currents at the source were described with the sLoreta method. An unmixing algorithm was applied to reduce the leakage, and the isolated effective coherence, a direct and directed measurement of information flow, was calculated. RESULTS AND DISCUSSION: Initially, the highest indices of connectivity are at the subcortical nuclei, continuing to the parietal lobe, predominantly the right hemisphere, then expanding to temporal, occipital, and finally the frontal areas, which is consistent with the myelination process. Age-related connectivity changes were mostly long-range and bilateral. Connections increased with age, mainly in the right hemisphere, while they mainly decreased in the left hemisphere. Increased connectivity from 20 to 30 Hz, mostly at the right hemisphere. These findings were consistent with right hemisphere predominance during the first three years of life. Theta and alpha connections showed the greatest changes with age. Strong connectivity was found between the parietal, temporal, and occipital regions to the frontal lobes, responsible for executive functions and consistent with behavioral development during the first year. The thalamus exchanges information bidirectionally with all cortical regions and frequency bands. CONCLUSIONS: The maturation of EEG connectivity during the first year in healthy infants is very consistent with synaptogenesis, reductions in synaptogenesis, myelination, and functional and behavioral development.

Early detection and treatment of attention deficits in preterm and at term infants with risk factors for brain damage.

Cognitive deficits in infants born preterm and infants at term with risk factors for brain damage are a common outcome. Attention deficits in preterm infants are related to the development of attention-deficit/hyperactivity disorder (ADHD), and therefore, there is a need for earlier evaluations and treatment procedures that are implemented before the presence of signs of ADHD. METHODS: We studied preterm (74%) and term infants with the Infant Scale of Selective Attention (ISSA, Escala de Evaluación de la Atención Selectiva (EEAS), in Spanish). This scale evaluates both visual- and auditory-orienting attention. Two groups participated, one with attention deficits (n = 26) and another with regular performance (n = 36). An early attention-stimulation program (EASP) was implemented in the infant group with attention deficits from three to eight months of age. All infants underwent magnetic resonance imaging (MRI), and visual and auditory evoked responses were assessed. RESULTS: All infants had prenatal and perinatal risk factors for brain damage and abnormal MRI findings, and the majority had abnormalities compatible with white matter injury. However, there were four infants with porencephalic cysts; 3 of them were in the treated group. At the beginning of the treatment, ISSA values showed differences between groups. These differences persisted for five months in the visual test and up to the sixth month in the auditory evaluation. Afterward, there were no significant differences, indicating that infants with attention deficits had satisfactorily responded to the treatment. CONCLUSIONS: The ISSA is helpful for the early evaluation of visual and auditory attention. Infants with attention deficits react well enough after six months of EASP.

Early diagnosis and treatment of infants with prenatal and perinatal risk factors for brain damage at the neurodevelopmental research unit in Mexico.

Prenatal and perinatal risk factors for perinatal brain damage frequently produce brain injuries in preterm and term infants. The early diagnosis and treatment of these infants, in the period of higher brain plasticity, may prevent the neurological and cognitive sequels that accompany these lesions. The Neurodevelopmental Research Unit at the Institute of Neurobiology of the National Autonomous University of Mexico has taken this endeavor. A multidisciplinary approach is followed. Pediatric, neurologic and rehabilitation clinical studies, MRI, EEG, visual and auditory evoked responses, and Bayley II evaluations are carried out initially. Infants are followed up to 8 years, with periodic appointments for evaluation and treatment. Katona's neurohabilitation method is used for initial diagnosis and treatment. Selective visual and auditory attention are explored from 3 months of age. This method was created in the Unit and, if deficiencies are observed, the method also describes the treatment to avoid subsequent alterations of these processes. Deficiencies in the acquisition of language are evaluated from 4 months of age, implementing treatment through instructions to parents on how they should teach their children to speak. This method has also been developed in the Unit and is in its validation process. In the MRI, we pay special attention to subtle and diffuse patterns, due to the high frequency with which they appear in contemporary cohorts at a national and international level. More than 80% of these infants showed abnormal MRI findings that should be taken into consideration. The outcome of children at 8 years old showed that 78%, 76% and 78% of extremely preterm, very preterm and late preterm, respectively, had a normal neurodevelopment. In term infants, only 69% had a normal neurodevelopment; in this group, the majority of infants had very severe brain lesions. Conclusions: It is necessary to evaluate, at an early age, all newborns with prenatal and perinatal risk factors for brain damage. Special attention should be payed to all premature newborns and those newborns who have been discharged from the intensive care unit.

Working Memory in Children with Learning Disorders: An EEG Power Spectrum Analysis.

Learning disorders (LDs) are diagnosed in children whose academic skills of reading, writing or mathematics are impaired and lagging according to their age, schooling and intelligence. Children with LDs experience substantial working memory (WM) deficits, even more pronounced if more than one of the academic skills is affected. We compared the task-related electroencephalogram (EEG) power spectral density of children with LDs (n = 23) with a control group of children with good academic achievement (n = 22), during the performance of a WM task. sLoreta was used to estimate the current distribution at the sources, and 18 brain regions of interest (ROIs) were chosen with an extended version of the eigenvector centrality mapping technique. In this way, we lessened some drawbacks of the traditional EEG at the sensor space by an analysis at the brain-sources level over data-driven selected ROIs. Results: The LD group showed fewer correct responses in the WM task, an overall slower EEG with more delta and theta activity, and less high-frequency gamma activity in posterior areas. We explain these EEG patterns in LD children as indices of an inefficient neural resource management related with a delay in neural maturation.

Long-term therapeutic effects of Katona therapy in moderate-to-severe perinatal brain damage.

AIM: To determine the long-term efficacy of Katona therapy and early rehabilitation of infants with moderate-to-severe perinatal brain damage (PBD). METHODS: Thirty-two participants were recruited (7-16 years) and divided into 3 groups: one Healthy group (n = 11), one group with PBD treated with Katona methodology from 2 months of corrected age, and with long-term follow-up (n = 12), and one group with PBD but without treatment in the first year of life due to late diagnosis of PBD (n = 9). Neuropediatric evaluations, motor evoked potentials (MEPs) and magnetic resonance images (MRI) were made. The PBD groups were matched by severity and topography of lesion. RESULTS: The patients treated with Katona had better motor performance when compared to patients without early treatment (Gross Motor Function Classification System levels; 75% of Katona group were classified in levels I and II and 78% of patients without early treatment were classified in levels III and IV). Furthermore, independent k-means cluster analyses of MRI, MEPs, and neuropediatric evaluations data were performed. Katona and non-treated early groups were classified in the same MRI cluster which is the expected for PBD population patients. However, in MEPs and neuropediatric evaluations clustering, the 67% of Katona group were assigned into Healthy group showing the impact of Katona therapy over the patients treated with it. These results highlight the Katona therapy benefits in early rehabilitation of infants with moderate-to-severe PBD. CONCLUSIONS: Katona therapy and early rehabilitation have an important therapeutic effect in infants with moderate-to-severe PBD by decreasing the severity of motor disability in later stages of life.

Week-by-week changes in sleep EEG in healthy full-term newborns.

Spectral analysis of neonatal sleep is useful for studying brain maturation; however, most studies have analyzed conventional broad bands described for awake adults, so a distinct approach for EEG analysis may disclose new findings. STUDY OBJECTIVES: To extract independent EEG broad bands using principal component analysis (PCA) and describe week-by-week EEG changes in quiet sleep (QS) and active sleep (AS) during the first 5 weeks of postnatal life in healthy, full-term newborns. METHODS: Polysomnography of spontaneous sleep was recorded in 60 newborns in 5 groups at 41, 42, 43, 44, and 45 weeks (n = 12 each) postconceptional age (POST-C). QS and AS stages were identified. Absolute power (AP) for 1 Hz bins between 1 and 30 Hz was subjected to PCA to extract independent broad bands. RESULTS: PCA rendered three independent broad bands distinct from conventional bands. They explained 82.8% of variance: 2-10 Hz, 10-16 Hz, and 17-30 Hz. ANOVAs (group × age × derivations) showed significant higher power at 2-10 Hz with greater age, higher power in QS than AS in all three bands, and significantly higher AP in the left central region, and in the right occipital and temporal areas, in both sleep stages. CONCLUSION: A different method of analyzing sleep EEG generated new information on brain maturation. The Sigma frequencies identified suggest that sleep spindle maturation begins by at least 41 weeks of POST-C age. Interhemispheric asymmetries during sleep suggest earlier development of the central left region and the right occipital and temporal areas.

How to Obtain Reliable Visual Event-related Potentials in Newborns.

The present study discusses the characteristics of visual event-related potentials (VEPs) and outlines methodological steps for obtaining reliable measurements in newborns. Obtaining high-quality, reliable VEPs is crucial for the early detection of abnormal development of the central nervous system in at-risk newborns, and for implementing successful early interventions. Recommendations are based on a previous study which showed that when post-conceptional age, polysomnography-identified sleep stages, and light-emitting diodes (LEDs) googles as the luminous source are controlled, no more than 4 repetitions of VEP averages are required to obtain replicable recordings, variability decreases, and reliable VEPs can be obtained. By controlling for these sources of variability and using statistical analyses, we were able to clearly and reliably identify the amplitude and latency of three main components (NII, PII and NIII) present in 100% of newborns (n = 20) during active sleep. Recording VEPs during awake states, quiet sleep and transitional sleep is not recommended because VEP morphology may differ significantly from one average to the next, leading to the risk of misleading clinical prognoses. Moreover, it is easier to obtain VEPs during active sleep because this state can be clearly and reliably identified at this stage of development, sleep cycles are short enough to allow measurements to be taken in a reasonable time, and the method does not require new o expensive equipment.

Programa de educación para padres sobre estimulación del desarrollo del lenguaje de lactantes prematuros con riesgo de daño cerebral / Parent education programme on stimulation of language development in preterm infants at risk of brain damage

Introducción: La interacción temprana madre-hijo es crítica para el desarrollo adecuado del lactante; sin embargo, la interacción de los padres con los lactantes prematuros presenta una dificultad particular por las circunstancias que acompañan un nacimiento prematuro, como son los factores de riesgo de daño cerebral, y la necesidad de estimulación temprana tanto motora como cognitiva que demandan estos bebés. Se ha observado que los programas educativos tienen efectos positivos en los padres de lactantes prematuros ya que mejoran los resultados de sus hijos en evaluaciones motrices, cognitivas y del lenguaje. Método: En este trabajo se examina el efecto de un programa de educación para padres para estimular el desarrollo de las habilidades comunicativas de los lactantes prematuros. Se examinó cómo cambió la interacción padres-hijo después del programa de intervención. Adicionalmente, se compararon los resultados de las evaluaciones de lenguaje de los niños, hijos de los padres que participaron en el programa de intervención comparados con niños pares, hijos de padres que no participaron en dicho programa. Resultados: El programa contribuyó a cambiar la interacción de los padres con los lactantes y a mejorar los puntajes en las evaluaciones posteriores del lenguaje de sus hijos. Conclusión: Se recomienda la participación de los padres de niños prematuros en programas de educación para padres para estimular el desarrollo del lenguaje de sus hijos

Introduction: Early mother-child interaction is critical for proper infant development; however, the interaction of parents with preterm infants presents a particular difficulty due to the circumstances that accompany premature birth, such as risk factors for brain damage and the early motor and cognitive stimulation that these infants demand. It has been observed that educational programmes have positive effects on the parents of preterm infants as they improve the outcomes of their children in motor, cognitive and language assessments. Method: This paper examines the effect of a parent education programme designed to stimulate the development of the early communicative skills of preterm infants. We examined how the parent-child interaction changed following the intervention programme. In addition, the results of the language evaluations of the children whose parents participated in the intervention programme and those whose parents did not participate were compared. Results: The programme helped to change the interaction of parents with their infants and to improve scores in the children's subsequent language assessments. Conclusion: Parents of premature children are encouraged to participate in parent education programmes to encourage the development of their child's language abilities

Principales efectos de la reserva cognitiva sobre diversas enfermedades: una revisión sistemática / Main effects of cognitive reserve on different disorders: A systematic review

Introducción: Se considera la reserva cognitiva (RC) como la optimización de los recursos cerebrales al emplear redes neuronales y estrategias cognitivas alternativas. Se piensa que la RC es una explicación plausible a un mecanismo potencial que permite al cerebro compensar deficiencias, ya sean causadas por el deterioro cerebral o por el declive funcional. Objetivo: Analizar la información de la literatura científica acerca de los efectos de la RC sobre variables clínicas y cognitivas en pacientes con diversas enfermedades distintas a las demencias. Desarrollo: Se realizó una búsqueda sistemática en las bases PubMed/Medline y ScienceDirect de artículos que evaluaran la influencia de la RC sobre variables clínicas y cognitivas en pacientes con enfermedades distintas a las demencias, incluyendo estudios empíricos con diseño longitudinal/transversal y observacional/cuasiexperimental. Se incluyeron 107 artículos. Resultados: Mayores niveles de RC se relacionan con un menor deterioro cognitivo en una gran variedad de trastornos y con una mejor recuperación en pacientes con enfermedad neurológica, psiquiátrica, infecciosa, cáncer, etc. También hay evidencia sobre el papel de la RC como factor protector para el retraso en el desarrollo de enfermedades neurológicas, neuropsiquiátricas, infecciosas, etc. Limitaciones: Podría existir más bibliografía, pues solo exploramos 2 bases. Conclusión: Una aproximación a la RC podría estar constituida por un conjunto de variables (cognitivas, demográficas, físicas, etc.) que parecen influir de manera importante sobre aspectos cognitivos, clínicos y funcionales de diversas enfermedades. Se subraya la necesidad de investigar a profundidad el papel de la RC en el proceso de recuperación y como factor protector en diferentes dolencias

Introduction: Cognitive reserve (CR) is considered as an optimisation of brain resources by using alternative neural networks and cognitive strategies. It is suggested that CR is a plausible explanation of a potential mechanism that allows the brain to compensate deficiencies caused either by brain damage or functional decline. Objective: To analyse the information from scientific literature about the effects of CR on clinical and cognitive variables of patients affected by disorders other than dementia. Development: A systematic search was conducted in the PubMed/Medline and ScienceDirect databases. A review was performed on articles that assessed the influence of CR in clinical and cognitive variables associated with disorders other than dementia. Empirical, longitudinal/transactional, and observational/quasi-experimental design studies were considered. The study finally included 107 research papers that fulfilled the established criteria. Results: Higher CR levels were associated with lower cognitive impairment in a wide variety of disorders, as well as with a better recovery on neurological, psychiatric or infectious conditions. Moreover, there is evidence on the CR role as a protective factor that could delay the development of neurological, neuropsychiatric, or infectious disorders. Limitations: As only 2 databases were searched, there may be more literature references on CR. Conclusion: CR proxies constitute a set of variables (cognitive, demographic, physical, etc.) that may have a significant influence on cognitive, clinical and functional aspects of different disorders. The need to conduct more research about the role of CR in the recovery process and as a protective factor in different disorders is highlighted

Uso del Inventario de Habilidades Comunicativas de MacArthur-Bates con lactantes en riesgo de daño cerebral / Use of the MacArthur-Bates-Communicative-Inventory with infants at risk of brain damage

Introducción. Existen escasas pruebas conductuales validadas para hispanoparlantes que incluyen dentro de sus normas lactantes normo-oyentes con riesgo de daño cerebral perinatal. Sin medidas conductuales validadas, los clínicos usan pruebas que no están normadas para esta población, como el Inventario de Habilidades Comunicativas MacArthur-Bates (SCDI). Estudios electrofisiológicos han mostrado que las subpruebas comprensión y producción de palabras de dicho inventario tienen un alto poder discriminante en estas poblaciones en riesgo cuando se ajusta la norma de la prueba al percentil 50. Se examinó dicha norma ajustada en la práctica clínica. Método. Diseño de un solo grupo y selección de la muestra semialeatoria. Se seleccionaron 30 niños con factores de riesgo de daño cerebral perinatal de la Unidad de investigación en Neurodesarrollo a los que se les hubiera aplicado el inventario al año de edad y la Escala de Lenguaje Preescolar (PLS-5) entre los 3 y 4 años. Se comparó la proporción de niños identificados con alteraciones en el desarrollo del lenguaje por la PLS-5 entre los 3-4 años con la proporción de niños identificados con riesgo por el SCDI al año de edad usando la norma sin ajustar y la norma ajustada. Resultados. La norma ajustada del SCDI permitió identificar una proporción de niños con riesgo del lenguaje al año de edad similar a la proporción que se identificó con alteraciones entre los 3 y 4 años. Conclusión. Debería considerarse una norma ajustada cuando se examinen poblaciones con riesgo de daño cerebral usando el Inventario SCDI al año de edad

Introduction. There are few validated language test for Spanish speakers that cover normo-listeners infants at risk of brain damage. Without validated behavioural measures, clinicians use test that are not standardised for this population, such as the MacArthur-Bates Communicative Skills Inventory (SCDI). Electrophysiological studies have shown that the comprehension and word production sub-test of such inventory have high discriminatory power in these at-risk populations when the test standard is adjusted to the 50th percentile. This adjusted standard was examined in clinical practice. Methods. Design of a single group and selection of the semi-random sample. We selected 30 infants at risk of brain damage from the Neurodevelopment Research Unit to which the Inventory at one year old and the Preschool Language Scale (PLS-5) were applied between the ages of 3 and 4 years. We compared the proportion of children identified with language developmental impairments by PLS-5 between the ages of 3-4 with the proportion of children identified at risk by SCDI at one year of age using the non-adjusted norm and adjusted norm. Results. The adjusted SCDI standard allowed the identification of a proportion of infants at risk of brain damage and also at risk of language development impairments at one year of age, similar to the proportion that was identified with impairments between 3 and 4 years. Conclusion. An adjusted norm should be considered when examining infants at risk of brain damage using the SCDI Inventory at one year of age

Los padres como promotores del desarrollo de lenguaje de bebés prematuros: propuesta de intervención temprana / Parents as Promoters of Language Development in Premature Babies: a Proposal for Early intervention

Resumen Objetivo: Comparar dos sistemas de puntuación para un test de fluidez verbal con el Modelo de Escalas de Calificación. Método: Se analizaron datos de 289 participantes, de los cuales 92 habían sido diagnosticados con Parkinson. Las puntuaciones se calcularon con dos sistemas de categorización: un procedimiento convencional y otro basado en percentiles. Resultados: Las puntuaciones Rasch procedentes de percentiles dan lugar a categorías adecuadas y medidas fiables; la correlación con las puntuaciones del test Minimental es evidencia de validez concurrente. Tras controlar estadísticamente el efecto de la edad, las medidas Rasch procedentes de percentiles discriminan entre ambos grupos, lo que evidencia validez predictiva. Conclusiones: El análisis de los dos procedimientos permite recomendar el uso de las categorías basadas en percentiles.

Abstract Objective: Two scoring systems for a verbal fluency test were compared using the Rasch Rating Scale Model. Method: The analysis was carried out on 289 participants, 92 of whom had had a Parkinson's disease diagnosis. Scores were calculated with two different category systems: a conventional procedure and a percentile-based one. Results: The percentile-based Rasch scores produce adequate categories and reliable measures, while the correlation with the Mini Mental State Examination evinces concurrent validity. After statistically controlling for age, percentile-based Rasch measures discriminated between both groups, demonstrating predictive validity. Conclusions: The analysis of the two procedures allows for the recommendation of the use of percentile-based categories.

Visual evoked potentials are similar in polysomnographically defined quiet and active sleep in healthy newborns.

Morphology and late components of evoked potentials change depending on wake-sleep stages in adults. Visual Evoked potentials (VEPs) have been frequently studied in newborns to identify abnormal development of visual pathways; however, large variability has been reported and there is uncertainty as to the effect of sleep stages on VEPs in neonates. OBJECTIVE: To describe the characteristics of VEPs in one month old, healthy full-term newborns during active sleep (AS) and quiet sleep (QS), defined by simultaneous polysomnography (PSG). METHODS: VEPs were obtained by monocular LEDs stimulation of each eye during AS and QS, in 20 healthy full-term newborns (gestational age 37-40 weeks) with normal birth weights and normal prenatal Doppler ultrasound indices. Latencies and amplitudes of N2, P2 and N3 components in AS and QS were compared, and their association with absolute power of EEG frequency bands, assessed. RESULTS: There were no significant differences in VEP morphology, latencies and amplitudes between sleep states. Typical wave forms were obtained in all newborns in AS; however, no VEPs could be identified clearly in 3 newborns in QS; QS VEPs were less reliable than in AS: more averaging was required; correlation was significantly lower between the VEP averages; and a larger number of babies needed more than two averages to obtain replicable responses needed for clinical purposes. CONCLUSIONS: These results indicate that changes in amplitude and latency of some VEP components observed in NREM and REM sleep in adults are not yet present in one month old newborns probably due to immaturity of cortical and sleep mechanisms. VEPs are more reliable during AS than QS in newborns. Systematic VEP recording during AS, and polysomnographic control to identify this stage, are highly recommended as methods that can increase there liability of neonatal VEPs.

Improving the efficiency of Auditory Brainstem Responses in newborns, using a 60clicks/s stimulation rate.

Recent evidence suggests that Auditory Brainstem Responses (ABR), in neonates with risk factors for neurological damage, may show auditory brainstem abnormalities, even in patients with normal hearing. To compare the recording and diagnostic accuracy of neonatal Auditory Brainstem Responses (ABR), using 10 and 60clicks/s stimulation rates, two groups of neonates were prospectively studied: 30 healthy full-term neonates, with no peri- or postnatal complications; and 30 high-risk newborns with two or more of the following conditions: hyperbilirubinemia, use of ototoxic drugs, birth weight inferior to 1500g, perinatal sepsis, intraventricular hemorrhage, and/or mechanical ventilation. Correlation between ABR trials, recording duration, and the absolute and interpeak latencies of ABR waves I, III and V, were measured. ROC-curve analysis assessed the diagnostic accuracy of both stimulation rates. The correlations between ABRs trials were significantly higher at 60clicks/s than at 10clicks/s (F(1,116)=14.5, p<0.0002). Recording duration at 60clicks/s was significantly lower (t=20.9, p<0.0001). ROC-curve comparisons showed increased diagnostic accuracy at the stimulation rate of 60clicks/s, for waves I (D=2.04, p=0.04), V (D=2.02, p=0.04), interpeak latencies III-V (D=2.2, p=0.02), and I-V (D=2.86, p=0.004). In neonates, the use of 60clicks/s stimulation rate permits a substantial shortening of the ABR recording, with greater diagnostic accuracy and replicability.

Clinical neuroimaging in the preterm infant: Diagnosis and prognosis.

Perinatal care advances emerging over the past twenty years have helped to diminish the mortality and severe neurological morbidity of extremely and very preterm neonates (e.g., cystic Periventricular Leukomalacia [c-PVL] and Germinal Matrix Hemorrhage - Intraventricular Hemorrhage [GMH-IVH grade 3-4/4]; 22 to < 32 weeks of gestational age, GA). However, motor and/or cognitive disabilities associated with mild-to-moderate white and gray matter injury are frequently present in this population (e.g., non-cystic Periventricular Leukomalacia [non-cystic PVL], neuronal-axonal injury and GMH-IVH grade 1-2/4). Brain research studies using magnetic resonance imaging (MRI) report that 50% to 80% of extremely and very preterm neonates have diffuse white matter abnormalities (WMA) which correspond to only the minimum grade of severity. Nevertheless, mild-to-moderate diffuse WMA has also been associated with significant affectations of motor and cognitive activities. Due to increased neonatal survival and the intrinsic characteristics of diffuse WMA, there is a growing need to study the brain of the premature infant using non-invasive neuroimaging techniques sensitive to microscopic and/or diffuse lesions. This emerging need has led the scientific community to try to bridge the gap between concepts or ideas from different methodologies and approaches; for instance, neuropathology, neuroimaging and clinical findings. This is evident from the combination of intense pre-clinical and clinicopathologic research along with neonatal neurology and quantitative neuroimaging research. In the following review, we explore literature relating the most frequently observed neuropathological patterns with the recent neuroimaging findings in preterm newborns and infants with perinatal brain injury. Specifically, we focus our discussions on the use of neuroimaging to aid diagnosis, measure morphometric brain damage, and track long-term neurodevelopmental outcomes.

Electroencephalographic characterization of subgroups of children with learning disorders.

Electroencephalographic alterations have been reported in subjects with learning disorders, but there is no consensus on what characterizes their electroencephalogram findings. Our objective was to determine if there were subgroups within a group of scholars with not otherwise specified learning disorders and if they had specific electroencephalographic patterns. Eighty-five subjects (31 female, 8-11 years) who scored low in at least two subscales -reading, writing and arithmetic- of the Infant Neuropsychological Evaluation were included. Electroencephalograms were recorded in 19 leads during rest with eyes closed; absolute power was obtained every 0.39 Hz. Three subgroups were formed according to children's performance: Group 1 (G1, higher scores than Group 2 in reading speed and reading and writing accuracy), Group 2 (G2, better performance than G1 in composition) and Group 3 (G3, lower scores than Groups 1 and 2 in the three subscales). G3 had higher absolute power in frequencies in the delta and theta range at left frontotemporal sites than G1 and G2. G2 had higher absolute power within alpha frequencies than G3 and G1 at the left occipital site. G3 had higher absolute power in frequencies in the beta range than G1 in parietotemporal areas and than G2 in left frontopolar and temporal sites. G1 had higher absolute power within beta frequencies than G2 in the left frontopolar site. G3 had lower gamma absolute power values than the other groups in the left hemisphere, and gamma activity was higher in G1 than in G2 in frontopolar and temporal areas. This group of children with learning disorders is very heterogeneous. Three subgroups were found with different cognitive profiles, as well as a different electroencephalographic pattern. It is important to consider these differences when planning interventions for children with learning disorders.

Characterization of the Sensorimotor Rhythm in 4-Month-Old Infants Born at Term and Premature.

The sensorimotor rhythm (SMR) is an electroencephalographic rhythm associated with motor and cognitive development observed in the central brain regions during wakefulness in the absence of movement, and it reacts contralaterally to generalized and hemibody movements. The purpose of this work was to characterize the SMR of 4-month-old infants, born either healthy at term or prematurely with periventricular leukomalacia (PVL). Two groups of infants were formed: healthy and premature with PVL. Their electroencephalograms (EEGs) were recorded in four conditions: rest, free movement, right-hand grasping and left-hand grasping, in order to explore general reactivity to free movement and contralateral reactivity in hand-grasping conditions. Associations between SMR, and cognitive and motor performance were analyzed. The healthy infants showed a SMR between 5.47 and 7.03 Hz, with clear contralateral reactivity to free movement and right-hand grasping. However, the premature infants with PVL did not show enough electroencephalographic characteristics to evidence the presence of SMR. Poor performance, characteristic of children with PVL, was related to low-frequency SMR, while good performance was associated with a higher frequency rhythm in the left hemisphere. The presence of SMR in the group of healthy infants could be considered a sign of health at this age. Thus, poor SMR evidence in the EEG of infants with PVL is probably a sign of brain immaturity or brain dysfunction. Our results provide data on infant SMR development that is needed to design neurofeedback protocols for infants with PVL.