Biomedical subjects

M S Scher

Publications and source records attributed to M S Scher.

At least 37 records · Page 2Linked to original sources

PubMed1996

Normal electrographic-polysomnographic patterns in preterm and fullterm infants.

Maturational changes occur in electroencephalogram (EEG)-sleep patterns for the neonate from preterm to fullterm postconceptional age. Electrical maturity of the neonatal brain is correlated within 1 to 2 weeks of other criteria for gestational maturity. Proper recording techniques of EEG-sleep studies in neonates will ensure accurate documentation of both cerebral and noncerebral parameters. Before 36 weeks postconceptional age (PCA), recognition of specific electrographic patterns are used to identify neonates of different PCAs. Following 36 weeks PCA, concordance between cerebral and noncerebral physiological behaviors are more predictable of neonatal EEG-sleep segments; this phenomena is independent of intrauterine or extrauterine development. Computer-assisted analyses of EEG sleep complement visual inspection by better characterizing relationships among EEG-sleep behaviors. Such analyses have documented group differences between preterm and fullterm infants of comparable postconceptional ages, suggesting adaptation of brain function to conditions of prematurity. Recognition of neonatal EEG-sleep patterns facilitate both an understanding of functional brain ontogeny and a recognition of pattern disturbances that underlie pathological or stressful conditions.

Brain↗

PubMed1996

Computer classification of sleep in preterm and full-term neonates at similar postconceptional term ages.

A classification strategy of neonatal sleep is being developed by comparing visually scored minutes of 21 channels of electroencephalographic (EEG)/polygraphic recordings with the corresponding values for each physiological signal derived from either visual or computer analyses. Continuous 3-hour sleep studies on 54 preterm and full-term neonates at similar postconceptional term ages were acquired under environmentally controlled conditions using a computerized monitoring system. An on-line event marker program recorded behavioral observations. One of three EEG sleep states was assigned to each of 8,995 minutes by traditional visual analysis criteria. EEG spectral values, spectral and nonspectral cardiorespiratory calculations and behaviorally observed movements, arousals and rapid eye movement counts were submitted for discriminant analysis. Based on the total minutes known for each of three states (i.e. active, quiet and awake), linear combinations of all specified digitized parameters were formed into an arithmetic algorithm by use of discriminant analysis, which served as the basis of a state assignment for each minute. Fifty percent of the data were arbitrarily used as the training set to derive the state classification model. The remaining fifty percent of the data were used as the cross-validation "test sample" to determine the accuracy of the classification when compared to the visually analyzed score for each corresponding minute. Thirteen out of 32 physiological measures best predicted state of both preterm and full-term neonatal groups. For both groups, the correct classification for active sleep was 90.3%, quiet sleep was 97.4%, awake was 97% and the overall accuracy was 93.3%. However, the order of significance for specific variables differed between these two neonatal groups. Differences in the order of variables that predict sleep states between preterm and full-term infants may reflect adaptation of brain function of the preterm infant to prematurity and/or prolonged extrauterine experience.

Child, Preschool↗

PubMed1995

A longitudinal study of prenatal marijuana use. Effects on sleep and arousal at age 3 years.

OBJECTIVE: To test the hypothesis that sleep disruptions would be evident in 3-year-old children with a history of prenatal marijuana exposure. DESIGN: A prospective study using stratified random sampling beginning in the fourth month of pregnancy. Marijuana and other substance use were assessed by interviews at multiple time points. Offspring were followed up through age 3 years with multidomain assessments at fixed time points, including electroencephalographic sleep studies in the newborn period and at age 3 years. SETTING: Primary care, prenatal clinic at a university hospital. SUBJECTS: The sample included 18 children with prenatal marijuana exposure (mean [+/- SD] age, 39.0 +/- 4.4 months) and 20 control children (mean [+/- SD] age, 39.7 +/- 4.4 months). The two groups were similar in relationship to maternal age, race, income, education, or maternal use of alcohol, nicotine, and other substances in the first trimester. MAIN OUTCOME MEASURE: Sleep variables from polysomnographic recordings at age 3 years. RESULTS: Children with prenatal marijuana exposure showed more nocturnal arousals (mean [+/- SD], 8.2 +/- 5.3 vs 3.2 +/- 4.6; P < .003), more awake time after sleep onset (mean [+/- SD], 27.4 +/- 20.0 vs 13.7 +/- 12.4 min; P < .03), and lower sleep efficiency (mean [+/- SD], 91.0 +/- 3.8 vs 94.4 +/- 2.1; P < .03) than did control children. CONCLUSION: Prenatal marijuana exposure was associated with disturbed nocturnal sleep at age 3 years.

Adolescent↗

PubMed1995

Estimation of gestational maturity of preterm infants by five fetal sonographic measurements compared with neonatal EEG and the last menstrual period.

We previously reported no differences in estimates of gestational maturity between a cumulative score based on sonographic/obstetrical measurements and an EEG interpretation for healthy preterm neonates. For the present study, a rank order among 5 fetal sonographic measurements was used to estimate gestational age: head circumference, transcerebellar diameter, biparietal diameter, femur length, and abdominal circumference were compared with an electroencephalographic estimate and an arithmetic estimate of maturity (i.e., the mother's last menstrual period). A fetal sonographic study for each of 13 premature neonates (i.e., born at < 32 weeks estimated gestational age) was followed after birth by a neonatal EEG recording. EEG and sonographic estimates of maturity were assigned without knowledge of other clinical data. The mother's last menstrual period was obtained from the medical record. Principal component analysis determined that 86% of the variance was evenly distributed over the 5 sonographic measurements. Using a regression procedure, 61% of the variance (adjusted r2 = 0.61) was explained by EEG when compared with fetal sonographic estimates. Only 19% (adjusted r2 = 0.19) of the variance was explained by the estimate based on the mother's last menstrual period. Optimal subset selection determined that the rank order for prediction of gestational maturity among the fetal sonographic measurements was as follows: (1) head circumference; (2) transcerebellar diameter; (3) biparietal diameter; (4) femur length; (5) abdominal circumference. Cranial measurements on fetal sonography (i.e., head circumference, transcerebellar diameter, biparietal diameter) compared more closely with EEG estimates than non-cranial measurements (i.e., femur length and abdominal circumference). In conclusion, neonatal EEG estimates of gestational maturity compared more closely with sonographic measurements than estimates based on the time of the last menstrual period. These findings will be useful in situations when dates of conception are unknown or inaccurate, or when intrauterine growth restriction causes discrepancies in growth rates between cranial and non-cranial fetal measurements on sonography.

Brain↗

PubMed1995

Maturational trends of EEG-sleep measures in the healthy preterm neonate.

Five physiologic groupings of 45 EEG-sleep measures were acquired from serial 24-channel EEG-sleep recordings (i.e., sleep architecture, continuity, EEG spectral, phasic, and autonomic measures), utilizing 129 studies on 56 healthy preterm infants from 28 to 43 weeks postconceptional age (PCA) who were neurodevelopmentally normal on follow-up. Regression analyses chose the least number of measures that best reflected maturation. Four of 45 variables (i.e., spectral alpha energy during quiet sleep, total spectral EEG energy, arousal number during active sleep, and percentage of EEG discontinuity) most significantly explained brain maturation in neonates < 36 weeks PCA. Three of 45 variables (i.e., spectral theta and beta energies during active sleep and spectral alpha energy during quiet sleep) were most representative after 36 weeks PCA. Spectral EEG energies were the strongest indicators of maturation compared with other measures, particularly in near-term neonates.

Cardiovascular Physiological Phenomena↗

PubMed1995

Postnatal adaptation of brain function in full-term neonates as assessed by EEG sleep analyses.

Differences in electroencephalographic (EEG) sleep between preterm and full-term neonatal cohorts at matched postconceptional ages have been previously presented by our study group. These differences may have occurred, however, because of postnatal brain adaptation of the full-term infant after a more recent delivery. EEG sleep analyses, therefore, were performed on only the full-term cohort to determine if EEG sleep measures changed over the first three days after birth, which might account for the differences with the preterm group. Twelve full-term infants studied on the first day of life were compared with 17 full-term infants who were studied on days of life 2 and 3. Using multivariate analysis of variance (MANOVA), comparisons were performed among 13 EEG sleep measures. No EEG sleep differences were seen between full-term children born by Cesarean section versus those born by vaginal presentation. No statistical differences were noted between day 1 compared to days 2 and 3 with respect to 10 measures concerning sleep architecture, phasic, continuity, spectral EEG, and autonomic features. In three EEG sleep measures, changes occurred between days 1 and 2-3, but two of the three measures were in a direction that strengthen our claim that differences exist between preterm and full-term cohorts: more body movements and lower percentages of quiet sleep were noted for full-term infants on days 2-3. EEG sleep differences between preterm and full-term infants at matched postconceptional term ages are more likely to be due to conditions associated with prematurity rather than postnatal brain adaptation in the full-term group who experienced a more recent delivery.

Arousal↗

PubMed1995

Grating acuity and visual field development in infants following perinatal asphyxia.

Grating acuity and visual fields were assessed in 66 children who had had perinatal asphyxia (ASPH). Also tested were 41 healthy preterm children (H-PT). Subjects were tested at birth to one month, and four, nine, 12, 17, 24, 30 and 36 months corrected age. The mean acuity scores of the ASPH group were lower than those of the H-PT group at most test ages, and significantly so at 30 and 36 months. The mean visual field size of the infants in the ASPH group was significantly smaller than that of the H-PT group at nine, 12, 30 and 36 months. No significant effects were found for preterm vs term birth, gestational age at birth, degree of asphyxia and presence of strabismus. However, central nervous system abnormalities (intraventricular haemorrhage and periventricular leukomalacia) were related to deficits in acuity and visual field size.

Asphyxia Neonatorum↗

PubMed1994

Positive temporal sharp waves on EEG recordings of healthy neonates: a benign pattern of dysmaturity in pre-term infants at post-conceptional term ages.

One complete sleep cycle was selected in each of ninety-four 3 h EEG recordings on 52 healthy neonates from 29 to 43 weeks CA (28 pre-term (PT)/24 full-term (FT)); 51 who are neurodevelopmentally normal up to at least 18 months of age. Each recording was reviewed to identify positive temporal sharp waves (PTS). This wave form was compared to another commonly occurring wave form, temporal theta of prematurity (PT theta). 588 PTS and 626 PT theta observations were tabulated in terms of frequency, amplitude, morphology, left:right predominance, and sleep state at 6 post-conceptional age ranges up to term. Mean PTS for FT, PT and pre-term at post-conceptional term age (PTT) infants, respectively, were 1.5 +/- 0.85, 2.8 +/- 2.5, 2.0 +/- 1.6 per sleep cycle. PTS amplitudes (microV) were 59.7 +/- 23.5, 38.2 +/- 17.8, and 51.8 +/- 29.3. The peak incidence of PTS occurs at older post-conceptional ages than PT theta (r = 0.21, P = 0.0001). PTT infants had more PTS (chi 2 = 32.5, P = 0.001) than FT infants. Similar numbers and descriptions of PT theta were noted between neonatal groups at post-conceptional term ages. While pathological PTS waves have been described in FT neonates and infants (Chung and Clancy: Electroenceph. clin. Neurophysiol., 1991, 79: 256-263), benign PTS waves are also present on recordings of healthy pre-term and full-term neonates. PTS are electrographically similar to PT theta, but are more abundant at older post-conceptional ages in pre-term infants than full-term infants.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗

PubMed1994

Physiological significance of sharp wave transients on EEG recordings of healthy pre-term and full-term neonates.

One EEG sleep cycle was selected from each of ninety-four 3 h studies on 52 healthy neonates from 29 to 43 weeks post-conceptional ages (CA) (28 pre-term (PT)/24 full-term infants (FT); 51 are normal up to at least 18 months of age). Each record was reviewed to identify sharp wave transients (SWTs). No spike discharges were noted. 364 SWTs were tabulated in terms of amplitude, morphology, left:right predominance, anatomical site and EEG sleep state. Mean number of SWTs per hour for full-term, pre-term, and pre-term at post-conceptional term age (PTT) infants were 11.7 (+/- 12), 10.0 (+/- 7), and 13 (+/- 10). Mean amplitudes (microV) were 98.8 (+/- 23.2), 84.9 (+/- 38.3), and 99.4 (+/- 28.8) for FT, PT, and PTT infants respectively. FP1, FP2, T4 and C3 accounted for 94%, 83% and 84% of SWT sites for FT, PT and PTT groups, respectively. Biphasic waves were noted more frequently, and triphasic waves almost exclusively in PT infants (chi 2 = 130.8, P = 0.001). Spearman correlations were significant for amplitude of SWTs with CA (and r = 0.45, P = 0.0001). Significant differences (ANOVA) were found, for instance, between SWT frequency with the site and sleep state (R2 = 0.63, P = 0.0001) between SWT amplitude with sleep state and morphology (R2 = 0.59, P = 0.0001). Brain maturation alters the location and morphology of SWTs in healthy neonates. Descriptions of SWTs on EEG recordings of healthy neonates will improve the assessment of encephalopathic recordings of infants studied for clinical reasons.

Analysis of Variance↗

PubMed1994

Language abilities following prematurity, periventricular brain injury, and cerebral palsy.

This study compares language abilities in three groups of children who were born prematurely: children with bilateral spastic cerebral palsy associated with perinatal injury to the periventricular white matter of the brain; a group with similar brain injury but no motor impairment; and a group of controls with no brain injuries. Six boys in each group were 36 to 39 months of age at the time of the study. All achieved a standard score above 80 on the McCarthy Scales of Children's Abilities at the same age. Language samples, generated during parent-child interaction, were analyzed using the Child Language Data Exchange System. The size and diversity of the lexicon was assessed using types and tokens per minute. Morpho-syntactic skills were assessed using number of grammatical morphemes, mean length of utterance and the Index of Productive Syntax. Verbal productivity was assessed using number of utterances per minute. No significant differences were observed among any of the groups on any measure. Measures of the lexicon and morpho-syntactic skills were highly correlated with the scores on the McCarthy Scales of Children's Abilities. The data demonstrated that specific language impairments were not associated with cerebral palsy or brain injury after prematurity at this early stage of language development. However, individual children within each of the groups had delays in skill attainment that warranted language intervention.

Brain↗

PubMed1994

Rectal temperature changes during sleep state transitions in term and preterm neonates at postconceptional term ages.

Mean rectal temperatures in neonates were investigated during sleep state transitions as assessed by visually analyzed electroencephalographic-polygraphic recordings. Continuous 3-hour studies were obtained on 3 term and 5 preterm infants at postconceptional term ages using a 24-channel computerized monitoring system. In the study, 1,461 min were assigned an EEG state by traditional criteria. Mean rectal temperature measurements were tabulated for each minute of sleep. Data were analyzed both as 1,461 consecutive minutes of sleep, and as 28 complete ultradian neonatal sleep cycles. Exploratory analyses were performed using t tests, Mann-Whitney U tests, and one-way analysis of variance. Decreases in mean rectal temperatures followed a transition from active to quiet sleep for only the term group. The preterm group had higher temperatures at sleep onset than the term group and demonstrated no changes during state transitions. Higher temperatures were maintained in the preterm group during both active and quiet sleep (i.e., 36.7 degrees C versus 36.4 degrees C, P = .02) when 28 complete cycles of sleep were compared and during the transition when 658 min of active sleep were compared to 617 min of quiet sleep. These findings are preliminary; however, the phenomenon of state-dependent changes in mean rectal temperature in neonates based on electroencephalographic sleep is unreported. Higher mean rectal temperatures during active sleep and altered temperature responses during transition to quiet sleep in the preterm infant suggest altered brain function because of the preterm infant's adaptation to the extrauterine experience.

Autonomic Nervous System↗

PubMed1994

Comparisons of EEG spectral and correlation measures between healthy term and preterm infants.

Continuous 12-hour electroencephalography (EEG)-sleep studies were acquired by a computerized monitoring system under environmentally controlled conditions for 2 groups of neonates. Eighteen health preterm infants at a postconceptional term age were matched to 18 term infants. These 2 groups were also matched for gender, race, and socioeconomic class. For the entire 12-hour recording, relative spectral power values (i.e., ratio of specific EEG power in specific frequency band compared to total EEG power) were significantly reduced in the preterm group for theta (P < or = .007), alpha (P < or = .001), and beta (P < or = .018) frequency bands, while delta remained unchanged. Correlations between 91 pairs of EEG channels were also calculated and the preterm infants had significantly higher correlation values in 27 of the 91 pairs of channels (P < .05); 14 interhemispheric, 8 intrahemispheric, and 5 sagittal combinations, while 3 intrahemispheric combinations were higher in the term group. Fewer functional neuronal aggregates generate less oscillatory potential (i.e., lower spectral power) in the theta through beta frequency ranges in the preterm infant, while greater cortical connectivity (i.e., higher correlations) exists in many brain regions by postconceptional term ages in this group. These findings suggest a functional alteration in brain development of the preterm infant as a result of prolonged extrauterine experience and/or prematurity.

Action Potentials↗

PubMed1994

Brain lesions of fetal onset in encephalopathic infants with nonimmune hydrops fetalis.

Nonimmune hydrops fetalis (NIHF) comprised 79% (45/57) of all infants with hydrops fetalis at our institution over a 6-year period. Thirty-seven infants with NIHF were liveborn. One or more electroencephalograms were performed on 40% of liveborn infants (15/37); the majority (87%) were moderately to markedly abnormal, including burst suppression, lack of background, multifocal sharp waves, excessive discontinuity, and disorganization reflecting significant neonatal encephalopathies. Postmortem neuropathologic examinations were performed in 86% of infants with NIHF who died or were stillborn, 81% of whom demonstrated intrauterine brain insults including microcalcifications, cerebral and/or cerebellar hypoplasia, microcephaly, encephalomalacia, cavitary lesions, astrocytosis, polymicrogyria, and severe neuronal loss. Cranial ultrasonography failed to document the diverse pathologic lesions that were later noted on postmortem examination. Ten infants survived the neonatal period, but 6 were neurologically abnormal at the time of discharge. Infants with NIHF are at risk for antepartum brain injury, and electroencephalographic abnormalities reflect in part a fetal brain disorder. A prospective clinical study is needed to fully assess the prevalence, incidence, spectrum of central nervous system involvement, contribution of intrapartum and neonatal stress, and long-term outcome in surviving infants with NIHF.

Brain↗

PubMed1994

Neonatal encephalopathies as classified by EEG-sleep criteria: severity and timing based on clinical/pathologic correlations.

Neonatal encephalopathies can be characterized in functional terms using electroencephalography. Severity of an encephalopathic state can also be estimated by electrographic interpretation independent of the time of disease process onset. Moderately or markedly abnormal electroencephalographic patterns on serial studies are highly correlated with neurologic sequelae in survivors. Electroencephalography is rarely pathognomonic or specific in determining when a condition initially occurred. However, electroencephalographic abnormalities are associated with different clinical situations, and brain lesions documented on neuroimaging or with postmortem neuropathologic examination are observed in infants with certain abnormal electrographic patterns. When interpreted in the context of history, clinical findings, and other laboratory information, the neurophysiologic studies augment the understanding of both the severity and timing of an encephalopathic state.

Brain↗

PubMed1994

Comparative estimates of neonatal gestational maturity by electrographic and fetal ultrasonographic criteria.

We previously reported a high correlation between electrographic and postmortem neuroanatomic (i.e., sulcal-gyral) estimates of maturity in sick preterm neonates who were clinically abnormal because of neonatal medical illnesses. Electroencephalographic studies have not yet been compared with ultrasonographic measurements in healthy fetuses who subsequently had normal neurodevelopmental outcome. Twenty-five EEG recordings on healthy neonates (28-43 weeks postconceptional age) had EEG estimates of gestational maturity without knowledge of obstetric, neonatal, or ultrasonographic criteria. Thirteen recordings from this cohort were obtained on very premature neonates (i.e., < 32 weeks estimated gestational age). Fetal ultrasonographic determinations of gestational maturity for these 13 subjects were also obtained prior to birth. Ultrasonographic estimates were assigned without knowledge of other clinical data. Gestational age estimates based on electroencephalographic analyses were compared with 5 ultrasonographic estimates of gestational age maturity using multivariate regression (i.e., biparietal diameter, abdominal circumference, femur length, transcerebellar diameter, and head circumference), as well as the mother's last menstrual period. No significant differences were detected between the electrographic and obstetric/ultrasonographic estimates of gestational maturity. An electroencephalographer's assessment of gestational age is as accurate as the fetal ultrasonographic estimates in the asymptomatic preterm neonate whose gestational age is < 32 weeks at birth.

Brain↗

PubMed1994

Comparisons of EEG sleep state-specific spectral values between healthy full-term and preterm infants at comparable postconceptional ages.

Differences in state-specific electroencephalographic (EEG) spectral values are described between groups of preterm and full-term neonates at comparable postconceptional term ages. Eighteen healthy preterm neonates of < or = 32 weeks gestation were selected from an inborn population of a neonatal intensive care unit. Twenty-four-channel recordings were obtained at a full-term age and compared with studies of 22 healthy full-term neonates. The initial three hours of each 12-hour study were recorded on paper from which EEG sleep state scores per minute were visually assessed. Six mean spectral values (i.e. total EEG, electromyogram, delta, theta, alpha and beta energies) were calculated from each corresponding minute of digitized data, which was also assigned one of six EEG sleep states. Each neonatal group displayed statistically significant differences among sleep-state segments for all spectral values. The alpha- and beta-range spectral values of the preterm group, compared to the full-term control group, were lower during all sleep state segments. Spectral values for the theta band were lower during both quiet sleep segments only, whereas spectral values for delta were lower during all sleep stages, except tracé-alternant quiet sleep. Significant differences in EEG spectral values were noted among states of sleep for both preterm and full-term infants of similar postconceptional term ages. These data also suggest differences in central nervous system maturation between neonatal populations. These findings strengthen our previously stated contention that there is a functional alteration in brain development of the preterm infant as reflected in sleep organization that results from a prolonged extrauterine experience and/or prematurity.

Analysis of Variance↗

PubMed1994

A comparison of conventional and matched filtering techniques for rapid eye movement detection of the newborn.

This paper compares an extended conventional filter technique for automated detection and analysis of rapid eye movements (REM) in neonates, using amplitude, synchrony, velocity, and coherence threshold criteria, with a matched filtering technique using the morphology of the REM waveform. Analyses of both simulated and real data were carried out. Automated REM tabulations are compared with visual scoring by a trained observer. Both preterm and fullterm neonates were used to test these methods. Both the advantages and disadvantages of these two techniques are discussed as compared with conventional methods which use only amplitude and synchrony threshold criteria. The major advantage of the extended conventional over the conventional method, as well as the matched filtering over the extended conventional technique, is the increased REM detection rate for ten minute intervals of artifact-free sleep. More accurate methods of automated REM detection that can be applied over extended monitoring periods are still needed.

Computer Simulation↗

PubMed1994

Maturation of phasic and continuity measures during sleep in preterm neonates.

Different physiologic measures during EEG sleep periods in preterm neonates are postulated to change with maturation and reflect functional brain development. Forty-three healthy preterm neonates received 3-h EEG sleep studies in an environmentally controlled setting. Postconceptional ages of neonates at each recording session ranged from 28 to 35 wk. Minute-by-minute analyses of EEG discontinuity, motility, arousals, and REM were performed. Eight phasic events and continuity measures of sleep were tabulated. Data were analyzed using Spearman rank order correlation coefficients. Increases in arousal numbers (p < 0.001) and durations (p < 0.001) were noted with age only during continuous periods of EEG activity (i.e. active sleep). REM also increased with corrected age during indeterminate or transitional sleep (p < 0.002) and decreased during quiet sleep (p < 0.01). Decreases in small body movements per minute (p = 0.02) and large body movements per minute (p < 0.001) occurred only during discontinuous periods of EEG activity (i.e. quiet sleep). Sleep efficiency (p < 0.001), maintenance (p < 0.001), and latency (p = 0.01) also decreased with increasing postconceptional age. Cycle length between two segments of continuous EEG with an intervening period of EEG discontinuity also lengthened with maturation (p < 0.001). These findings are discussed in the context of previously reported differences in phasic and continuity measures noted between preterm and full-term infants at matched full-term postconceptional ages. Changes in phasic and continuity measures with increasing postconceptional ages reflect maturation of specific neuronal processes of the CNS within a rudimentary sleep cycle of the preterm neonate.

Electroencephalography↗