Sudden infant death syndrome: cry characteristics.

OBJECTIVE: To acoustically evaluate the cries of SIDS infants and compare these cry features to a group of healthy term (HT) infants, as well as previously published results for SIDS infants. METHODS: Pain-induced crying episodes were collected from four infants during the first weeks of life that later died of SIDS. Temporal and spectral features of each crying episode were characterized based on measures of cry duration, cry fundamental frequency (F0), and cry formant frequencies (F1 and F2). RESULTS: The SIDS infants were found to produce cries with longer duration compared to HT infants. The cries of SIDS infants also differed from HT infants in regard to the absolute difference in F2-F1 frequency. CONCLUSIONS: The acoustic features considered in the present study support the contention that the cries of SIDS infants are reflective of atypical respiratory-laryngeal control. Although research of this nature is rare, there is evidence to suggest an acoustic profile of crying that is specific to SIDS.

Perspective on racial/ethnic birth weight.

OBJECTIVE: Comprehensive birth weight analyses of single primiparous infants of Samoan, Caucasian, Chinese, Filipino, Hawaiian/Part Hawaiian, Japanese racial ethnic groups. Sampling of intrauterine growth designed to reflect antecedent intra- and extra-environmental factors and insure uniform racial-ethnic data for any later genetic and phenotypic birth weight modeling. STUDY DESIGN: Based upon predetermined relevant gestational age criteria, 121, 197 single primiparous infants birth weight records analyzed. The racial-ethnic basic research paradigms also specified parental diallelic crosses representing intra-and inter-ethnic racial ancestry. Hypotheses tested: 1) the mean birth weight of single primiparous infants of Samoan parentage will be significantly larger than the mean birth weight of similar single primiparous infants of Caucasian, Chinese, Filipino, Hawaiian/Part Hawaiian, and Japanese parentage; 2) mean birth weight of single primiparous infants of only Samoan intra-parentage will be significantly larger t han the mean birth weights of single primiparous infants of only Caucasian, Chinese, Filipino, Hawaiian/Part Hawaiian, and Japanese parentage and 3) mean birth weight of single primiparous infants Samoan mothers and non-Samoan fathers will be significantly larger than single primiparous infants of Caucasian, Chinese, Filipino, Hawaiian/Part Hawaiian, and Japanese mothers and non-Caucasian, non-Chinese, non-Filipino, non-Hawaii/Part Hawaiian and non-Japanese father. CONCLUSION: Two of three proposed associated hypotheses adopted: namely, that the mean birth weight of single primiparous infants of one, primary Samoan maternal parentage, and two, of only Samoan maternal and paternal parentage, will be significantly larger than their comparative counterparts. Hypotheses 3 based on Samoan mothers and non-Samoan fathers is tenable, but questionable relative to Caucasian parental background. Research highlights importance of control for potentially confounding variables and assets inherent in independent racial-ethnic cohort investigations.

Cry features in siblings of SIDS.

AIM: To examine the acoustic features of crying demonstrated by infants whose older sibling died of sudden infant death syndrome (SIDS) and compare these features to a nonrisk group of infants. METHODS: Pain-induced crying episodes were collected from a group of healthy term (HT) infants and siblings of SIDS infants. One complete crying episode was obtained from each infant and analyzed acoustically with regard to durational and spectral features. RESULTS: The cries of SIDS siblings were found to be significantly higher in pitch and reflected hyperadductory vocal fold vibratory behaviour compared to the HT group. There were no group differences with regard to durational features of crying. CONCLUSIONS: The laryngeal behaviour of infant crying, as inferred via acoustic analyses, differs between HT infants and siblings of SIDS infants. Accordingly, acoustic features of infant crying may serve as an additional diagnostic marker in the identification of children who may be at risk for SIDS.

Cry analysis in infants resuscitated for apnea of infancy.

OBJECTIVE: The purpose of the present study was to examine the acoustic features of crying demonstrated by infants who experienced apnea of infancy (AOI) and compare these features to a non-AOI group of infants. Based on past physiological descriptions of AOI, three predictions in regard to the influence of AOI on acoustic cry features were proposed: (1) the rate of crying would be significantly faster among infants with AOI, (2) the latency of crying onset would be significantly longer among infants with AOI and (3) the F(0) characterizing an overall episode of crying would be significantly lower among infants with AOI. PATIENTS AND METHODS: Pain-induced crying episodes were collected from a group of healthy term infants (HT) and those with AOI. One complete crying episode was obtained from each infant and analyzed acoustically with regard to durational and spectral features of the cry. RESULTS: Infants comprising the AOI group were found to demonstrate a significantly longer cry latency and lower F(0) compared to HT infants. CONCLUSIONS: The acoustic cry features measured for the AOI infants are discussed with regard to past reports of poor arousal and decreased muscle tone. A model of AOI crying is proposed whereby the autonomic nervous system and associated pathways are slower to interpret pain stimulus compared to HT infants.

Samoan parental ethnicity and infant birth-weight in Hawai'i.

OBJECTIVE: Comparative study of racial-ethnic (RE) gestational age (GA) mean birth-weight (MBW) differences for 1968-1994. STUDY DESIGN: Descriptive statistical analyses of 314,633 State of Hawai'i live birth certificates: birthweights of 500-5000 grams, gestational ages 24-42 weeks, and recorded Caucasian, Chinese, Filipino, Hawaiian, Japanese, Samoan, and Other RE parentage. Multiple regression analyses of single infant birth records were performed to adjust birth-weight for selected covariates and assess the independent effects of maternal and paternal RE on MBW. RESULTS: Samoans consistently displayed significantly the largest MBW whether based on single or mixed RE parentage. After covariate adjustment MBW significantly related to Samoan maternal RE followed by Samoan paternal RE. CONCLUSION: A consistent trajectory of larger MBWs across GA span of 24-42 weeks is associated with the Samoan group. Results support the importance of maternal role in determining birth-weight. Additional data for analysis of birth size and cord blood levels of insulin growth factor and research on genetic and epigenetic questions are warranted.

Factors that influence use of a home cardiorespiratory monitor for infants: the collaborative home infant monitoring evaluation.

BACKGROUND: As part of the Collaborative Home Infant Monitoring Evaluation, a home monitor was developed to record breathing, heart rate, other physiologic variables, and the time the monitor was used. OBJECTIVE: To determine the frequency of monitor use, factors that influence use, and validity of a model developed to predict use. DESIGN: We developed a model to predict monitor use using multiple linear regression analysis; we then tested the validity of this model to predict adherence for the first week of monitoring and for the subsequent 4-week period (weeks 2-5). SETTING: Clinical research centers in Chicago, Ill; Cleveland, Ohio; Honolulu, Hawaii; Los Angeles, Calif; and Toledo, Ohio. Patients Preterm infants, infants younger than 1 month with a history of autopsy-confirmed sudden infant death syndrome in a sibling, and infants with an idiopathic apparent life-threatening event were divided into 2 cohorts based on enrollment date. Main Outcome Measure Mean hours of monitor use per week. RESULTS: In cohort 1, the variables available before monitoring were only weakly associated with total hours of monitor use in weeks 2 to 5 (total model r(2) = 0.08). However, when hours of monitor use in week 1 were included as a variable to predict monitor use in weeks 2 to 5, the r(2) increased to 0.64 for hours of monitor use per week. CONCLUSIONS: Our data show that monitor use in the first week was the most important variable for predicting subsequent monitor use. The study suggests that a major focus of home monitoring should be adherence in the first week, although it remains to be tested whether this adherence can be altered.

Ontogeny of arousal.

Ontogeny of arousal data constitute a vital supplement to the sparse literature on spontaneous neuronal activity. These data demonstrate that measurable infant spontaneous arousals (SAs) with an inherent oscillatory entrainment occur six times more in active sleep than in quiet sleep of the same duration and are identifiable as a human neurobiologic function. These SAs are not significantly associated with race or ethnicity, gender, total hours spent sleeping, percent time spent in active or quiet sleep, preterm status, history of a life-threatening event, having had a sibling who died of sudden infant death syndrome (SIDS), or having had a mother who smoked during this pregnancy. As measurable neurophysiologic events, SAs establish parameters for research at molecular and molar levels focusing on several critical areas: (1) the neuronal control of SA related to neurotransmitters, (2) as a significant antecedent factor in clinical cardiorespiratory events occurring in infants at high epidemiologic risk for SIDS; (3) as a regulatory biologic factor underlying temperament and executive cognitive functioning, and (4) morbidity and mortality effects possibly related to therapeutic interventions that alter SA levels.

Cardiorespiratory events detected by home memory monitoring and one-year neurodevelopmental outcome.

OBJECTIVE: To determine if infants with cardiorespiratory events detected by home memory monitoring during early infancy have decreased neurodevelopmental performance. STUDY DESIGN: Infants (n = 256) enrolled in the Collaborative Home Infant Monitoring Evaluation also completed the Bayley Scales of Infant Development II at 92 weeks' postconceptional age. Infants were classified as having 0, 1 to 4, or 5+ cardiorespiratory events. Events were defined as apnea >or=20 seconds or heart rate <60 to 80 bpm or <50 to 60 bpm, for >or=5 to 15 seconds, depending on age. RESULTS: For term infants, having 0, 1 to 4, and 5+ cardiorespiratory events was associated with unadjusted mean Mental Developmental Index (MDI) values (+/-SD) of 103.6 (10.6), 104.2 (10.7), and 97.7 (10.9), respectively, and mean Psychomotor Developmental Index (PDI) values of 109.5 (16.6), 105.8 (16.5), and 100.2 (17.4). For preterm infants, having 0, 1 to 4, and 5+ cardiorespiratory events was associated with unadjusted mean MDI values of 100.4 (10.3), 96.8 (11.5), and 95.8 (10.6), respectively, and mean PDI values of 91.7 (19.2), 93.8 (15.5), and 94.4 (17.7). The adjusted difference in mean MDI scores with 5+ events compared with 0 events was 5.6 points lower in term infants ( P = .03) and 4.9 points lower in preterm infants ( P = .04). CONCLUSIONS: Having 5+ conventional events is associated with lower adjusted mean differences in MDI in term and preterm infants.

Infant polysomnography: reliability and validity of infant arousal assessment.

Infant arousal scoring based on the Atlas Task Force definition of transient EEG arousal was evaluated to determine (1). whether transient arousals can be identified and assessed reliably in infants and (2). whether arousal and no-arousal epochs scored previously by trained raters can be validated reliably by independent sleep experts. Phase I for inter- and intrarater reliability scoring was based on two datasets of sleep epochs selected randomly from nocturnal polysomnograms of healthy full-term, preterm, idiopathic apparent life-threatening event cases, and siblings of Sudden Infant Death Syndrome infants of 35 to 64 weeks postconceptional age. After training, test set 1 reliability was assessed and discrepancies identified. After retraining, test set 2 was scored by the same raters to determine interrater reliability. Later, three raters from the trained group rescored test set 2 to assess inter- and intrarater reliabilities. Interrater and intrarater reliability kappa's, with 95% confidence intervals, ranged from substantial to almost perfect levels of agreement. Interrater reliabilities for spontaneous arousals were initially moderate and then substantial. During the validation phase, 315 previously scored epochs were presented to four sleep experts to rate as containing arousal or no-arousal events. Interrater expert agreements were diverse and considered as noninterpretable. Concordance in sleep experts' agreements, based on identification of the previously sampled arousal and no-arousal epochs, was used as a secondary evaluative technique. Results showed agreement by two or more experts on 86% of the Collaborative Home Infant Monitoring Evaluation Study arousal scored events. Conversely, only 1% of the Collaborative Home Infant Monitoring Evaluation Study-scored no-arousal epochs were rated as an arousal. In summary, this study presents an empirically tested model with procedures and criteria for attaining improved reliability in transient EEG arousal assessments in infants using the modified Atlas Task Force standards. With training based on specific criteria, substantial inter- and intrarater agreement in identifying infant arousals was demonstrated. Corroborative validation results were too disparate for meaningful interpretation. Alternate evaluation based on concordance agreements supports reliance on infant EEG criteria for assessment. Results mandate additional confirmatory validation studies with specific training on infant EEG arousal assessment criteria.