Brain electrophysiological development in premature infants

Background. Improvements in postnatal care provided in neonatal intensive care units have resulted in increasing survive percentage of children born at the limits of viability. A large number of premature infants experienced major impairment and/or minor neurodevelopmental disabilities, such as cognitive, psychiatric and motor disorders. The etiology of these developmental deficits still remains not completely understood, but they may be the result of neonatal brain injury as well of interruption of the normal process of brain maturation that occurs during the last trimester of pregnancy, a critical period of prenatal ontogenesis. Prediction of the outcome of individual preterm infants is difficult. Although a premature infant may be asymptomatic for abnormal clinical signs, he may exhibit subtle alterations in brain activity which often remain unrecognized. A neurophysiologic evaluation of brain activity in the third trimester of gestation would probably be of great benefit for early detection of pathological processes or subclinical alterations. Electroencephalogram and cortical auditory evoked potentials turned out to be simple and useful techniques in evaluation of brain maturation. Aims. We conducted cross-sectional and longitudinal investigations at early crucial phases of development (35 and 40 weeks post-conception) in order to identify differences in cerebral activity between premature infants born at different gestational ages and full-term neonates, using electroencephalogram (EEG) at rest and cortical auditory evoked potentials (CAEP). We further aimed to correlate the neonatal data with later neurodevelopment. Methods. The research is divided into three studies: Study 1: EEG spectral activity was recorded at 35 post-conception weeks in 40 premature infants and compared between groups of infants born at different gestational age (“extremely low gestational age”, ELGA: 23–27+6, ‘‘very low gestational age’’, VLGA: 28–31+6 and “low gestational age”, LGA: 34-35). The results were correlated with behavioral developmental scores obtained at 12 months corrected age from 20 infants. Study 2: a subgroup of 10 infants of Study 1 repeated the EEG recording at 40 post-conception age. EEG spectral activity of this subgroup was compared longitudinally and further the activity recorded at 40 GA were compared with those of a group of 10 full-term infants. Study 3: CAEP were recorded in active sleep at 35 post-conception weeks in response to an auditory stimulation in 36 premature infants and compared between groups of infants born at different gestational age (ELGA, VLGA, LGA). The results were correlated with behavioral developmental scores obtained at 12 months corrected age from 20 infants. Methodology Study 1 and 2. Electrical brain activity was recorded for 40 minutes on 5 bipolar channels. Data were transformed into the frequency domain using a Fast Fourier Transform algorithm. Frequency spectrum was divided into the following bands: δ (0.5-4 Hz, comprising δ1 0.5-1 Hz and δ2 1-4 Hz), θ (4-8 Hz), α (8-13 Hz) and β (13-20 Hz). Statistical analysis were performed on absolute and relative power values only on central sites (C3-C4, C3-T3, C4-T4). Methodology Study 3. 1000 Hz (paradigm 1) and 500 Hz (paradigm 2) auditory stimulations were performed on continuous EEG recording. Design consisted of 300 tones for each paradigm. Inter-stimulus interval randomly varied between 600 and 900 ms; 12 monopolar channels were recorded, referenced to the bilateral linked ear lobes. 600 ms epochs were divided for statistical analysis in time windows of 100 ms. Statistical analysis were performed only on central sites (Fz, Cz). Results. Study 1. On C3-C4, relative spectral power values differed significantly between ELGA and LGA groups. Infants born at lower gestational ages had a higher amount of power in the δ and a lower amount of α and β spectral power. The preliminary data on those infants attaining 12 months of corrected age showed that higher amount of δ and a lower amount of β and α resulted associated with poor relational skills and personal self autonomies. Study 2. At 40 post-conception age, premature infants showed on C3-C4 a decrease in δ activity and a mild, not significant, increase in higher frequencies; no significant differences in spectral power values were found with full-term neonates. Study 3. In response to 1000 Hz tones no waveforms became evident on Fz in ELGA infants, while LGA presented a wide and slow positive response; the groups differed significantly. VLGA’s grand average waveform resembled that of LGA group, but characterized by a high variability. Responses to 500 Hz resulted highly variable and not reliable. Conclusions. We found early subtle brain electrical alterations in premature infants experiencing different developmental pathways, suggesting a different cortical organization; these differences seem to be associated with later development. The potential of neurophysiological methodologies is to provide a useful indicator of good prognosis or poor developmental outcomes

Neonatal Cortical Auditory Evoked Potentials Are Affected by Clinical Conditions Occurring in Early Prematurity

Purpose: Cortical auditory evoked potentials may serve as an early indicator of developmental problems in the auditory cortex. The aim of the study was to determine the effect on neonatal cortical auditory processing of clinical conditions occurring in early prematurity. Methods: Sixty-seven preterm infants born at 29 weeks mean gestational age (range, 23\u201334 weeks) were recorded at a mean postconception age of 35 weeks, before discharge from the third level neonatal intensive care unit. The average of 330 responses to standard 1000 Hz pure tones delivered in an oddball paradigm was recorded at frontal location. Data of 45 of 67 recruited premature infants were available for analysis. Mean amplitudes calculated from the data points of 30 milliseconds centered on P1 and N2 peaks in the waveforms of each subject were measured. The effect of perinatal clinical factors on cortical auditory evoked responses was evaluated. Results: The amplitude of P1 component was significantly lower in infants with bronco-pulmonary dysplasia (P \ubc 0.004) and retinopathy of prematurity (P \ubc 0.03). The multivariate analysis, done to evaluate the relative weight of gestational age and bronco-pulmonary dysplasia and/or retinopathy of prematurity on cortical auditory evoked potentials components, showed an effect of clinical factors on P1 (P \ubc 0.005) and of gestational age on N2 (P \ubc 0.02). Conclusions: Cortical auditory processing seems to be influenced by clinical conditions complicating extremely preterm birth

Cartographies of autonomy : tensions and constructions in the field of mental health

O termo autonomia, apesar de associado ao protagonismo do usu-ário em seu tratamento, carece de uma definição clara e consoante dentro do campo psicossocial. Assim, a presente pesquisa se propôs a cartografar uma experiência de trabalho na saúde mental a partir dos encontros com a autonomia, suas diferentes facetas e sua rela-ção indissociável com o cuidado em liberdade. A reflexão, oriunda do diário de anotações produzido durante o contexto da pandemia, demonstrou que a autonomia perpassa o processo de produção de cuidado e incide em todos os seus agentes, seja na construção do plano terapêutico, na relação dos profissionais com o próprio saber e na influência da instituição sobre a enunciação dos sujeitos. Conclui-se que a autonomia é construída e produzida na relação com o outro, sendo elemento imprescindível ao usuários e também aos profissionais que dela necessitam para a realização de um trabalho inventivo e implicado.The term autonomy, despite being associated with the role of the patient in his treatment, lacks a clear and consonant definition with-in the psychosocial field. Thus, this research aimed to map a work experience in mental health based on encounters with autonomy, its different facets and its inseparable relationship with care in freedom. The reflection, derived from the diary of notes produced during the context of the pandemic, demonstrated that autonomy permeates the process of producing care and affects all its agents, whether in the construction of the therapeutic plan, in the relationship of professionals with their own knowledge and in the influence of the institution on the enunciation of the subjects. It is concluded that autonomy is built and produced in the relationship with the other, being an essential element for patients and for professionals who need it to carry out inventive and involved work.La autonomía, a pesar de estar asociada al rol del usuario en su tratamiento, carece de una definición clara y consonante dentro del campo psicosocial. Así, esta investigación tuvo como objetivo mapear una experiencia laboral en salud mental a partir del encuentro con la autonomía, sus diferentes facetas y su relación inseparable con el cuidado en libertad. La reflexión, derivada del diario de notas producidas durante el contexto de la pandemia, demostró que la autonomía impregna el proceso de producir cuidados y afecta a todos sus agentes, ya sea en la construcción del plan terapéutico, en la relación de los profesionales con su propio conocimiento y la influencia de la institución en la enunciación de los sujetos. Se concluye que la autonomía se construye en la relación con el otro, siendo un elemento imprescindible para los usuarios y profesionales que lo necesitan para realizar un trabajo inventivo e implicado