Normative longitudinal EEG recordings during sleep stage II in the first year of age.

The electroencephalogram (EEG) is a fundamental diagnostic procedure that explores brain function. This manuscript describes the characteristics of a sample of healthy at-term infants. One hundred and three (103) infants from Mexico between 15 days and 12.5 months of age were recorded during physiological sleep. Referential EEG recordings were obtained using linked ear lobes as reference. The amplifier gain was 10,000, the bandwidth was set between 0.3 and 30 Hz, and the sample rate was 200 Hz. Sample windows of 2.56 s were marked for later quantitative analysis. To our knowledge, this is the first dataset of normal infants during the first year of age.

The impact of nutritive and non-nutritive sweeteners on the central nervous system: preliminary study.

BACKGROUND: Human consumption of food and beverages containing added nutritive or non-nutritive sweeteners has increased worldwide. OBJECTIVE: The present study evaluated the possible impact of frequent sweetener consumption on human CNS activity and functions through neuropsychological testing and EEG/qEEG analysis. METHODS: A sample of 23 women and 16 men, aged 18-35, with a body mass index between 18 and 24.9 kg/m2 was evaluated. Participants underwent a 1-week washout period in which food with added sugars or sweeteners was restricted from their diet. Initial assessment of cognitive functions was performed with a validated neuropsychological test and EEG/qEEG analysis, prior to supplementation. Sucrose, sucralose, or steviol glycosides, in commercially available presentations, were randomly assigned to three experimental groups of 13 participants each. Sweeteners were supplemented in fixed amounts, daily, for six weeks. After supplementation, neurological tests were repeated and the initial and final results were compared. RESULTS: The results show no significant changes between final and initial measures in the steviol glycosides group. However, a significant decrease in encoding memory was found in the sucrose group in the final evaluation. Strikingly, the sucralose group showed a significant decrease in overall memory, encoding memory, and executive functions after supplementation. Furthermore, qEEG analysis showed an increase in theta wave absolute and relative power at the final evaluation in the same group. CONCLUSION: These data show that frequent consumption of specific sweeteners is accompanied by measurable changes in EEG/qEEG activity and neuropsychological test performance in humans.

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.

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.

Two Different Populations within the Healthy Elderly: Lack of Conflict Detection in Those at Risk of Cognitive Decline.

During healthy aging, inhibitory processing is affected at the sensorial, perceptual, and cognitive levels. The assessment of event-related potentials (ERPs) during the Stroop task has been used to study age-related decline in the efficiency of inhibitory processes. Studies using ERPs have found that the P300 amplitude increases and the N500 amplitude is attenuated in healthy elderly adults compared to those in young adults. On the other hand, it has been reported that theta excess in resting EEG with eyes closed is a good predictor of cognitive decline during aging 7 years later, while a normal EEG increases the probability of not developing cognitive decline. The behavioral and ERP responses during a Counting-Stroop task were compared between 22 healthy elderly subjects with normal EEG (Normal-EEG group) and 22 healthy elderly subjects with an excess of EEG theta activity (Theta-EEG group). Behaviorally, the Normal-EEG group showed a higher behavioral interference effect than the Theta-EEG group. ERP patterns were different between the groups, and two facts are highlighted: (a) the P300 amplitude was higher in the Theta-EEG group, with both groups showing a P300 effect in almost all electrodes, and (b) the Theta-EEG group did not show an N500 effect. These results suggest that the diminishment in inhibitory control observed in the Theta-EEG group may be compensated by different processes in earlier stages, which would allow them to perform the task with similar efficiency to that of participants with a normal EEG. This study is the first to show that healthy elderly subjects with an excess of theta EEG activity not only are at risk of developing cognitive decline but already have a cognitive impairment.

Neurofeedback in Learning Disabled Children: Visual versus Auditory Reinforcement.

Children with learning disabilities (LD) frequently have an EEG characterized by an excess of theta and a deficit of alpha activities. NFB using an auditory stimulus as reinforcer has proven to be a useful tool to treat LD children by positively reinforcing decreases of the theta/alpha ratio. The aim of the present study was to optimize the NFB procedure by comparing the efficacy of visual (with eyes open) versus auditory (with eyes closed) reinforcers. Twenty LD children with an abnormally high theta/alpha ratio were randomly assigned to the Auditory or the Visual group, where a 500 Hz tone or a visual stimulus (a white square), respectively, was used as a positive reinforcer when the value of the theta/alpha ratio was reduced. Both groups had signs consistent with EEG maturation, but only the Auditory Group showed behavioral/cognitive improvements. In conclusion, the auditory reinforcer was more efficacious in reducing the theta/alpha ratio, and it improved the cognitive abilities more than the visual reinforcer.

[Electroencephalographic and neurodevelopmental disorders in severe congenital heart disease: A follow-up study]. / Alteraciones electroencefalográficas y del neurodesarrollo en cardiopatías congénitas severas. Estudio de seguimiento.

Congenital heart defects are the most common malformations at birth. Due to the fact that the developmental windows at early stages close rapidly, the aim of this study was to determine the impact of congenital heart defects on the central nervous system at short and medium terms after applying traditional and quantitative electroencephalography techniques and a test of neurodevelopment. Twenty-one patients (8-27 months, x = 14.8) with severe congenital heart defects who had been studied previously, and a control group of 19 healthy children (8-29 months, x = 14.6) were included. In all of them traditional electroencephalography, quantitative electroencephalography, and a test of neurodevelopment were performed. The results between groups (control vs. congenital heart defects) and between congenital heart defects (previous vs. present) were compared. In the second evaluation, congenital heart defect children maintained abnormal quantitative and traditional electroencephalography recordings. Comparing quantitative electroencephalography among congenital heart defects (previous vs. present) and between controls and congenital heart defects, significant differences of theta band activity in frontal, central, and temporal leads were found (p < 0.05). Upon assessing neurodevelopment, 86% of the previously studied congenital heart defect cases kept the same diagnosis of abnormality, of which mild-to-moderate hypotone was the most frequently observed. As hypothesized, congenital heart defect diseases have a very important impact on central nervous system function as determined by neurodevelopmental testing and traditional and quantitative electroencephalography recordings. The alterations observed persisted throughout the period studied.

[Incidence of congenital heart disease and factors associated with mortality in children born in two Hospitals in the State of Mexico]. / Incidencia de las cardiopatías congénitas y los factores asociados a la letalidad en niños nacidos en dos hospitales del Estado de México.

We studied the incidence, survival, and risk factors for mortality in a cohort of infants for a period of five years, born in two hospitals, one a second-level General Hospital, the second a tertiary perinatal hospital, both in the City of Toluca. The analysis of survival was performed with the Kaplan-Meier method, and Cox regression was used to estimate the risk of death according to different factors. We found an overall incidence of 7.4 per 1,000 live births; in preterm infants, the rate was 35.6 per 1,000, and in term newborns it was 3.68 per 1,000. The most common heart disease was the ductus arteriosus in the overall group and in preterm infants; in term newborns the most common was the atrial septal defect. The specific mortality was 18.64%, follow-up was 579 days, where we found, according to Kaplan-Meier, survival of an average of 437.92 days, with 95% confidence intervals of 393.25 to 482.6 days, with a standard error of 22.79 days; the cumulative probability of survival was 0.741, with a standard error of 0.44. In Cox regression, two variables had a high hazard ratio (HR): these were the presence or absence of cyanosis and the hospital where they were treated as newborns.

[Electroencephalographic and neurodevelopmental disorders in toddlers with severe congenital heart diseases. Preliminary study]. / Alteraciones electroencefalográficas y del neurodesarrollo en niños portadores de cardiopatías congénitas severas. Estudio preliminar.

UNLABELLED: Within the field of pediatric heart disease, congenital cardiopathology is the most important issue due to the fact that in these patients a delay of neurodevelopment is the most frequent morbidity. The major aim of this work was to determine the impact of severe congenital cardiopathology (SCC) on the central nervous system (CNS) through the study of the electroencephalogram (EEG) and the assessment of neurodevelopment. POPULATION AND METHODS: Children under 3 years old, 41 of them presenting SCC and 15 healthy controls (C) were studied. Conventional EEG recording and assessment of neurodevelopment were performed. RESULTS: In twenty children presenting SCC (48.8%) the EEG was found abnormal (paroxysmal of spikes and sharp waves). Forty of them (97.6%) presented neurodevelopmental alterations, including hypotonia and a delay in gross motor skills. When comparing EEG between SCC and C children, odds ratio was 13.33 (1.602-111) and comparing neurodevelopment delay, it was 35 (3.769-235). Both were statistically significant (p ≤ 0.00039 and p ≤ 0.00038, respectively). CONCLUSIONS: A high percentage of children suffering from SCC exhibited EEG patterns with abnormal epileptic-like activity although without clinical manifestation of seizures. These children also showed delay features in different areas of neurodevelopmental. The assessment of new born carrying some type of severe cardiopathology indicated that they were under high risk of suffering from CNS altered development.

Neurobehavioral assessment of children presenting diverse congenital cardiopathologies.

Brain maturation in 1-36 month old children suffering from congenital cardiopathologies was assessed after a study of psychomotor development. The Rogers' test (Rogers et al., Developmental programming for infants and young children. Volume 2. Early intervention developmental profile, Revised edition, ESL/ELT Michigan, Ann Arbor, 1981) was applied to 65 children, of whom 21 presented with simple cardiopathologies (CpS) and 22 with complex cardiopathologies (CpC). All children were matched by age, sex and socioeconomic status to 22 healthy children in a control group (C). Mean differences between the three groups were established by applying the Kruskal-Wallis test, and mean differences between the C and CpS/CpC groups were determined using the Mann-Whitney test. The proportion of cases evaluated as "low" in each group was calculated by applying the Rogers' test, and a test of proportion differences was applied between the C and CpS/CpC groups. CpS children performed similarly to the C, whereas CpC children scored significantly lower than C children on all variables. It is highly likely that the suboptimal psychomotor performance observed in CpC children was due to compromised hemodynamics and related to subclinical immaturity of cerebral development.

Limbic system pathologies associated with deficiencies and excesses of the trace elements iron, zinc, copper, and selenium.

Deficiencies of nutrients such as amino acids, vitamins, lipids, and trace elements during gestation and early infanthood have strong deleterious effects on the development of the limbic system; these effects may be irreversible, even when adequate supplementation is provided at later developmental stages. Recent advances in the neurochemistry of biometals are increasingly establishing the roles of the trace elements iron, copper, zinc, and selenium in a variety of cell functions and are providing insight into the repercussions of deficiencies and excesses of these elements on the development of the central nervous system, especially the limbic system. The limbic system comprises diverse areas with high metabolic demands and differential storage of iron, copper, zinc, and selenium. This review summarizes available evidence suggesting the involvement of these trace elements in pathological disorders of the limbic system.

Screening of neurodevelopmental delays in four communities of Mexico and Cuba.

OBJECTIVE: Nursing personnel applied a computerized evaluation instrument, Neuropediatric Development (NPED), and compared the prevalence of deviations from normal neurodevelopment in four communities of two Latin American countries, Mexico and Cuba. At the same time the feasibility of introducing this tool into Mexican local health centers was assessed. DESIGN AND SAMPLE: The NPED screening tool was applied to 400 children 1-60 months old from two suburban and one urban communities of Mexico and one urban community of Cuba. MEASURES: The NPED instrument was developed at the Neurosciences Centre of Cuba (Santos, & Pérez-Ábalo, 2011; Santos, Pérez-Abalo, & Álvarez, 2007), and explores three neurodevelopmental areas: language/communication, psychomotor, and sensory maturation (hearing/vision). RESULTS: Global (21.5%), language (16.5%), psychomotor (5.8%), and sensory (vision/audition; 2.3%/7%) failures were observed. Among Mexican communities, apart from the hearing test in which the urban community showed a significantly higher percentage of failures (p < .001), there were no other significant differences. When compared, the Cuban community showed a significantly higher proportion of audition failures in relation to the Mexican communities. CONCLUSIONS: The prevalence of deviations from normal neurodevelopment was highly similar between both countries, and the NPED system fulfils the necessary requisites for mass screening to be applied by nursing staff at a primary care level.

Relationship of working memory and EEG to academic performance: a study among high school students.

Some biological and behavioral elements which could explain differences between high and low academic attainment (HA/LA) students were identified. The qEEG of subjects under the 10-20 derivation system was recorded at rest and while completing a 3-back working memory (WM) task. While completing the task LA students showed more theta and total absolute potency at rest, and HA individuals showed more energy in delta and theta frequencies in frontal regions; LA students made a higher number of mistakes while executing the WM task with no differences in reaction time between groups. We conclude that a diminished WM capacity is present in LA students.