Acoustic examination of preterm and full-term infant cries: the long-time average spectrum

Noise phenomena in distress cries of term and very preterm infants at term-equivalent age

BACKGROUND AND AIM

To examine whether the noise components in distress cries of term infants differed from very preterm infants whose cries were collected at a comparable "corrected" gestational age.

METHODS

Distress cries were collected from 20 term and 20 preterm infants. The cries were acoustically examined for the occurrence of aperiodic phonatory behavior within and across moments of crying.

RESULTS

The findings indicated no significant differences between term and preterm infants at term age in the occurrence of noise.

CONCLUSIONS

Distress cries of both term and term-equivalent preterm infants appear to contain high instances of phonatory noise. The high arousal associated with distress crying and associated increase in subglottal pressure appeared to influence both term and term-equivalent preterm infants similarly.

A Scientometric Review of Infant Cry and Caregiver Responsiveness: Literature Trends and Research Gaps over 60 Years of Developmental Study

Infant cry is an adaptive signal of distress that elicits timely and mostly appropriate caring behaviors. Caregivers are typically able to decode the meaning of the cry and respond appropriately, but maladaptive caregiver responses are common and, in the worst cases, can lead to harmful events. To tackle the importance of studying cry patterns and caregivers' responses, this review aims to identify key documents and thematic trends in the literature as well as existing research gaps. To do so, we conducted a scientometric review of 723 documents downloaded from Scopus and performed a document co-citation analysis. The most impactful publication was authored by Barr in 1990, which describes typical developmental patterns of infant cry. Six major research thematic clusters emerged from the analysis of the literature. Clusters were renamed "Neonatal Pain Analyzer" (average year of publication = 2002), "Abusive Head Trauma" (average year of publication = 2007), "Oxytocin" (average year of publication = 2009), "Antecedents of Maternal Sensitivity" (average year of publication = 2010), "Neurobiology of Parental Responses" (average year of publication = 2011), and "Hormonal Changes & Cry Responsiveness" (average year of publication = 2016). Research clusters are discussed on the basis of a qualitative inspection of the manuscripts. Current trends in research focus on the neurobiology of caregiver responses and the identification of factors promoting maternal sensitivity. Recent studies have also developed evidence-based strategies for calming crying babies and preventing caregivers' maladaptive responses. From the clusters, two topics conspicuously call for future research: fathers' responsiveness to infant cry and the impact of caregiver relationship quality on cry responsiveness.

Acoustic Cry Characteristics in Preterm Infants and Developmental and Behavioral Outcomes at 2 Years of Age

IMPORTANCE

Acoustic cry characteristics have been associated with severe medical problems in newborns. However, little is known about the utility of neonatal acoustic cry characteristics in the prediction of long-term outcomes of very preterm infants.

OBJECTIVES

To evaluate whether acoustic characteristics of infant cry at neonatal intensive care unit (NICU) discharge are associated with behavioral and developmental outcomes at age 2 years in infants born very preterm.

DESIGN, SETTING, AND PARTICIPANTS

Infants born less than 30 weeks postmenstrual age (PMA) were enrolled from April 2014 through June 2016 as part of a multicenter (9 US university affiliated NICUs) cohort study and followed to adjusted age 2 years. Reported analyses began on September 2021. Data were analyzed from September 2021 to September 2022.

EXPOSURES

The primary exposure was premature birth (<30 weeks PMA).

MAIN OUTCOMES AND MEASURES

Cries were recorded during a neurobehavioral examination administered during the week of NICU discharge. Cry episodes were analyzed using a previously published computerized system to characterize cry acoustics. Year-2 outcomes included the Bayley-III Composite scores, Child Behavior Checklist (CBCL) and the Modified Checklist for Autism in Toddlers (M-CHAT R/F), dichotomized using clinically significant cutoffs (<85 on Bayley Language, Cognitive and/or Motor Composite scores, T-score >63 on the CBCL Internalizing, Externalizing and/or Total Problem Scales and total M-CHAT R/F score >2).

RESULTS

Analyzed infants (363 participants) were primarily male (202 participants [55.65%]) and had a mean [SD] gestational age of 27.08 [1.95] weeks). Cross-validated random forest models revealed that cry acoustics were associated with 2-year outcomes. Tests of diagnostic odds ratios (DOR) revealed that infants who exhibited total problem behavior CBCL scores greater than 63 at age 2 years were 3.3 times more likely (95% CI, 1.44-7.49) to be identified as so by random forest model estimates relative to other infants (scores ≤63); this association was robust to adjustment for family-wise type-I error rates and covariate measures. Similar associations were observed for internalizing (DOR, 2.39; 95% CI, 1.04-5.47) and externalizing (DOR, 2.25; 95% CI, 1.12-4.54) scores on the CBCL, clinically significant language (DOR, 1.71; 95% CI, 1.10-2.67) and cognitive (DOR, 1.70; 95% CI, 1.00-2.88) scores on the Bayley-III, and a positive autism screen on the M-CHAT (DOR, 1.91; 95% CI, 1.05-3.44).

CONCLUSIONS AND RELEVANCE

In this cohort study of preterm infants, findings pointed to the potential use of acoustic cry characteristics in the early identification of risk for long-term developmental and behavioral deficits.

Long-term average spectrum measures of consecutive snore sounds from different sources determined by drug-induced sleep endoscopy

STUDY OBJECTIVES

The goal of this study was to investigate the value of the long-term average spectrum in the acoustic analysis of snore sounds arising from different sources in the upper airway.

METHODS

Long-term average spectrum was used to analyze sequences of 10 consecutive snore sounds that had been divided into 2 groups, soft-palate type and lateral-wall type, according to the vibration site generating the snore sounds and the patterns of soft tissue collapse in the upper airway as identified by drug-induced sleep endoscopy. We calculated the first spectral peak, mean spectral energy, high-frequency energy, 0-1 kHz spectral energy, 1-5 kHz spectral energy, and 0-1 kHz/1-5 kHz difference from each group and compared the differences between them.

RESULTS

All parameters except mean spectral energy showed significant differences between the 2 groups. The first spectral peak of less than 265.53 Hz, and the 0-1k/1-5 kHz difference of less than -11.6 dB strongly suggests soft-palate-type snore sounds.

CONCLUSIONS

Long-term average spectrum has potential application for snore sound source identification. We recommend using first spectral peak and a 0-1 kHz/1-5 Hz difference to identify soft-palate-type snore sounds.

CITATION

Peng H, Xu H, Xu Z, Jia R, Yu H. Long-term average spectrum measures of consecutive snore sounds from different sources determined by drug-induced sleep endoscopy. J Clin Sleep Med. 2023;19(1):145-150.

Melody complexity of infants' cry and non-cry vocalisations increases across the first six months

In early infancy, melody provides the most salient prosodic element for language acquisition and there is huge evidence for infants' precocious aptitudes for musical and speech melody perception. Yet, a lack of knowledge remains with respect to melody patterns of infants' vocalisations. In a search for developmental regularities of cry and non-cry vocalisations and for building blocks of prosody (intonation) over the first 6 months of life, more than 67,500 melodies (fundamental frequency contours) of 277 healthy infants from monolingual German families were quantitatively analysed. Based on objective criteria, vocalisations with well-identifiable melodies were grouped into those exhibiting a simple (single-arc) or complex (multiple-arc) melody pattern. Longitudinal analysis using fractional polynomial multi-level mixed effects logistic regression models were applied to these patterns. A significant age (but not sex) dependent developmental pattern towards more complexity was demonstrated in both vocalisation types over the observation period. The theoretical concept of melody development (MD-Model) contends that melody complexification is an important building block on the path towards language. Recognition of this developmental process will considerably improve not only our understanding of early preparatory processes for language acquisition, but most importantly also allow for the creation of clinically robust risk markers for developmental language disorders.

Video and audio processing in paediatrics: a review

OBJECTIVE

Video and sound acquisition and processing technologies have seen great improvements in recent decades, with many applications in the biomedical area. The aim of this paper is to review the overall state of the art of advances within these topics in paediatrics and to evaluate their potential application for monitoring in the neonatal intensive care unit (NICU).

APPROACH

For this purpose, more than 150 papers dealing with video and audio processing were reviewed. For both topics, clinical applications are described according to the considered cohorts-full-term newborns, infants and toddlers or preterm newborns. Then, processing methods are presented, in terms of data acquisition, feature extraction and characterization.

MAIN RESULTS

The paper first focuses on the exploitation of video recordings; these began to be automatically processed in the 2000s and we show that they have mainly been used to characterize infant motion. Other applications, including respiration and heart rate estimation and facial analysis, are also presented. Audio processing is then reviewed, with a focus on the analysis of crying. The first studies in this field focused on induced-pain cries and the newest ones deal with spontaneous cries; the analyses are mainly based on frequency features. Then, some papers dealing with non-cry signals are also discussed.

SIGNIFICANCE

Finally, we show that even if recent improvements in digital video and signal processing allow for increased automation of processing, the context of the NICU makes a fully automated analysis of long recordings problematic. A few proposals for overcoming some of the limitations are given.

Urban Congolese Refugees in Kenya: The Contingencies of Coping and Resilience in a Context Marked by Structural Vulnerability

The global increase in refugee migration to urban areas creates challenges pertaining to the promotion of refugee health, broadly conceived. Despite considerable attention to trauma and forced migration, there is relatively little focus on how refugees cope with stressful situations, and on the determinants that facilitate and undermine resilience. This article examines how urban Congolese refugees in Kenya promote psychosocial well-being in the context of structural vulnerability. This article is based on interviews ( N = 55) and ethnographic participant observation with Congolese refugees over a period of 8 months in Nairobi in 2014. Primary stressors related to scarcity of material resources, political and personal insecurity, and emotional stress. Congolese refugees mitigated stressors by (a) relying on faith in God's plan and trust in religious community, (b) establishing borrowing networks, and (c) compartmentalizing the past and present. This research has broader implications for the promotion of urban refugees' psychosocial health and resilience in countries of first asylum.

A flexible analysis tool for the quantitative acoustic assessment of infant cry

PURPOSE

In this article, the authors describe and validate the performance of a modern acoustic analyzer specifically designed for infant cry analysis.

METHOD

Utilizing known algorithms, the authors developed a method to extract acoustic parameters describing infant cries from standard digital audio files. They used a frame rate of 25 ms with a frame advance of 12.5 ms. Cepstral-based acoustic analysis proceeded in 2 phases, computing frame-level data and then organizing and summarizing this information within cry utterances. Using signal detection methods, the authors evaluated the accuracy of the automated system to determine voicing and to detect fundamental frequency (F 0) as compared to voiced segments and pitch periods manually coded from spectrogram displays.

RESULTS

The system detected F 0 with 88% to 95% accuracy, depending on tolerances set at 10 to 20 Hz. Receiver operating characteristic analyses demonstrated very high accuracy at detecting voicing characteristics in the cry samples.

CONCLUSIONS

This article describes an automated infant cry analyzer with high accuracy to detect important acoustic features of cry. A unique and important aspect of this work is the rigorous testing of the system's accuracy as compared to ground-truth manual coding. The resulting system has implications for basic and applied research on infant cry development.

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.

Infant Crying: Pattern of Weeping, Recognition of Emotion and Affective Reactions in Observers

This study has three objectives: a) to describe the main differences in the crying patterns produced by the three affective states most closely related to crying: fear, anger and pain; b) to study the adults' accuracy in the recognition of the affective states related to the infant's crying, and c) to analyze the emotional reaction that infant crying elicits in the observers. Results reveal that the main differences appear in the ocular activity and in the pattern of weeping. The infants maintain their eyes open during the crying produced by fear and anger, but in the case of crying provoked by painful stimuli, the eyes remain closed almost all the time. In regard to the pattern of weeping, the crying gradually increase in the case of anger, but the weeping reaches its maximum intensity practically from the beginning in the case of pain and fear. In spite of these differences, it is not easy to know the cause that produces crying in infants, especially in the case of fear or anger. Although observers can't recognize the cause of crying, the emotional reaction is greater when the baby cries in pain than when the baby cries because of fear or anger.

Atypical cry acoustics in 6-month-old infants at risk for autism spectrum disorder

This study examined differences in acoustic characteristics of infant cries in a sample of babies at risk for autism and a low-risk comparison group. Cry samples derived from vocal recordings of 6-month-old infants at risk for autism spectrum disorder (ASD; n = 21) and low-risk infants (n = 18) were subjected to acoustic analyses using analysis software designed for this purpose. Cries were categorized as either pain-related or non-pain-related based on videotape coding. At-risk infants produced pain-related cries with higher and more variable fundamental frequency (F (0) ) than low-risk infants. At-risk infants later classified with ASD at 36 months had among the highest F (0) values for both types of cries and produced cries that were more poorly phonated than those of nonautistic infants, reflecting cries that were less likely to be produced in a voiced mode. These results provide preliminary evidence that disruptions in cry acoustics may be part of an atypical vocal signature of autism in early life.

Acoustic estimates of respiration in the pain cries of newborns

OBJECTIVE

The purpose of the present study was to examine the temporal features of pain-elicited crying demonstrated by healthy full term infants to estimate (1) the respiratory rate during cry and (2) the inspiratory and expiratory phase composition of the cry respiratory cycle.

PATIENTS AND METHODS

The pain-elicited cries of 12 newborn infants were recorded within the first 2 weeks following birth. A complete crying episode was analyzed for each infant and acoustically measured for the number and duration of inspiratory and expiratory cry components. These components were then used to estimate the respiratory rate of infant crying, as well as the inspiratory and expiratory phase composition of the cry respiratory cycles.

RESULTS

Acoustic analysis revealed that the average rate of crying was 57 breaths min⁻¹ with the inspiratory phase contributing 27% to the overall respiratory cycle. However, considerable variability was found across infants with distinct patterns of respiration associated with high versus low respiratory rates.

CONCLUSIONS

The respiratory patterns associated with pain cries is highly variable and may be associated with variations in stress-arousal, strength of emotional expression, and overall fitness. This study supports the notion that the respiratory activity surrounding newborn infant crying is unique to the type of cry sampled.

Abnormal speech spectrum and increased pitch variability in young autistic children

Children with autism spectrum disorder (ASD) who can speak often exhibit abnormal voice quality and speech prosody, but the exact nature and underlying mechanisms of these abnormalities, as well as their diagnostic power are currently unknown. Here we quantified speech abnormalities in terms of the properties of the long-term average spectrum (LTAS) and pitch variability in speech samples of 83 children (41 with ASD, 42 controls) ages 4-6.5 years, recorded while they named a sequence of daily life pictures for 60 s. We found a significant difference in the group's average spectra, with ASD spectra being shallower and exhibiting less harmonic structure. Contrary to the common impression of monotonic speech in autism, the ASD children had a significantly larger pitch range and variability across time. A measure of this variability, optimally tuned for the sample, yielded 86% success (90% specificity, 80% sensitivity) in classifying ASD in the sample. These results indicate that speech abnormalities in ASD are reflected in its spectral content and pitch variability. This variability could imply abnormal processing of auditory feedback or elevated noise and instability in the mechanisms that control pitch. The current results are a first step toward developing speech spectrum-based bio-markers for early diagnosis of ASD.

Acoustic characteristics of crying in infantile laryngomalacia

The purpose of this study was to add to the extant data base of acoustic cry studies by profiling the condition of laryngomalacia. We hypothesized that the acoustic characteristics of crying produced by an infant with laryngomalacia would differ compared to previously reported cry data for normal infants. An entire episode of crying was audio recorded and acoustically analyzed for the occurrence of expiratory and inspiratory cry segments, as well as the long-time average spectral (LTAS) characteristics. Results obtained for the infant were found to be considerably different from what has been previously reported for normal infants. The overall duration of the infant's crying episode was longer, with proportionately fewer expiratory phonations and more inspiratory phonations compared to normal infants. The LTAS results were reflective of aperiodic components in the glottal source spectrum. Collectively, the infant's unusual crying aspects were not limited solely to those acoustic features resulting from a prolapse of supraglottic soft tissue, and therefore provide new insight into the vocal fold vibratory behavior characterizing infantile laryngomalacia.

Long-term average spectral characteristics of Cantonese alaryngeal speech

OBJECTIVE

In Hong Kong, esophageal (SE), tracheoesophageal (TE), electrolaryngeal (EL), and pneumatic artificial laryngeal (PA) speech are commonly used by laryngectomees as a means to regain verbal communication after total laryngectomy. While SE and TE speech has been studied to some extent, little is known regarding the EL and PA sound quality. The present study examined the sound quality associated with SE, TE, EL, and PA speech, and compared with that associated with laryngeal (NL) speech by using long-term average speech spectra (LTAS).

METHODS

Continuous speech samples of reading a 136-word passage were obtained from NL, SE, TE, EL, and PA speakers of Cantonese. The alaryngeal speakers were all superior speakers selected from the New Voice Club of Hong Kong, which is a self-help organization for the laryngectomees in Hong Kong. TE speakers were fitted with Provox valve, and EL speakers used Servox-type electrolarynx. Speech samples were digitized at 20kHz and 16bits/sample by using Praat, based on which LTAS contours were developed. First spectral peak (FSP), mean spectral energy (MSE), and spectral tilt (ST) derived from the LTAS contours associated with different speaker groups were compared.

RESULTS

Data revealed all speakers generally exhibited similar LTA contours. However, PA speakers exhibited the lowest average FSP value and the greatest average MSE value. NL phonation was associated with a significantly greater ST value than alaryngeal speech of Cantonese.

CONCLUSION

The differences in FSP, MSE, and ST values in different speaker groups may be related to the different sound sources being used by the laryngectomees, and the difference in the way the sound source is coupled with the vocal tract system.

High-resolution cry analysis in preterm newborn infants

Infant monitoring is a common procedure in clinical practice in neonatal critical care units. A number of vital functions are monitored, such as heart beat, breathing, blood flow, etc. Specifically, preterm and/or low-birth-weight infants often present respiratory problems that require monitoring. These may range from insufficient ventilation to apnoea. One of the most common events that may affect the respiratory flow is crying, a physiological action made by the infant to communicate and draw attention, but, for a preterm infant, this action requires great effort, which may cause distress and even may have an adverse impact on blood oxygenation. Acoustic analysis of newborn infant cry is thus of importance, since it is related to other basic neuro-physiological parameters. Being easy to perform, cheap and completely non-invasive, it can be successfully applied in many circumstances. The newborn infant cry is characterised by very high fundamental frequency (F(0)) and resonance frequency (RFs) values, with abrupt changes and voiced/unvoiced features of very short duration in a single utterance. To deal with such signals, a new user-friendly software tool has been developed, that allows robust tracking of main acoustic parameters on very short and time-varying signal frames. The software developed provides the user with a high-resolution picture of the cry signal characteristics.

The effect of positioning on infant cries: implications for sudden infant death syndrome

OBJECTIVE

A definitive cause for sudden infant death syndrome (SIDS) has not yet been identified, but some theories point to laryngeal or respiratory causes, in addition to theories of reduced arousal or reduced autonomic response. The occurrence of SIDS has dropped since the movement to place newborns to sleep in the supine position; however, some research has found a respiratory disadvantage for infants in this position. The current paper studied acoustic characteristics of infant pain cries to determine the potential differences related to prone versus supine positioning.

METHODS

Fifty-one newborn infant cries were recorded during and following a blood draw screening procedure, with infants placed either in the supine or prone position. All infants were healthy, full-term infants. Complete crying episodes were audio-recorded, and results were based on compositional analysis and long-time average spectrum analysis across each crying episode.

RESULTS

Spectral analysis revealed acoustic differences related to infant positioning, and acoustic analysis also revealed that there were no respiratory differences between supine-positioned and prone-positioned infants. Overall, the acoustic differences suggest decreased arousal and/or a decreased response to pain for healthy infants recorded in the prone position.

CONCLUSIONS

As decreased arousal and prone positioning have been seen as possible causative factors for SIDS, the current results are seen as a successful step in evaluating the possibility of using acoustic analysis of infant cries as a means of evaluating SIDS risk for healthy infants.

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.

Vibratory regime classification of infant phonation

Infant phonation is highly variable in many respects, including the basic vibratory patterns by which the vocal tissues create acoustic signals. Previous studies have identified the regular occurrence of nonmodal phonation types in normal infant phonation. The glottis is like many oscillating systems that, because of nonlinear relationships among the elements, may vibrate in ways representing the deterministic patterns classified theoretically within the mathematical framework of nonlinear dynamics. The infant's preverbal vocal explorations present such a variety of phonations that it may be possible to find effectively all the classes of vibration predicted by nonlinear dynamic theory. The current report defines acoustic criteria for an important subset of such vibratory regimes, and demonstrates that analysts can be trained to reliably use these criteria for a classification that includes all instances of infant phonation in the recorded corpora. The method is thus internally comprehensive in the sense that all phonations are classified, but it is not exhaustive in the sense that all vocal qualities are thereby represented. Using the methods thus developed, this study also demonstrates that the distributions of these phonation types vary significantly across sessions of recording in the first year of life, suggesting developmental changes. The method of regime classification is thus capable of tracking changes that may be indicative of maturation of the mechanism, the learning of categories of phonatory control, and the possibly varying use of vocalizations across social contexts.

Acoustic quality of cry in very-low-birth-weight infants at the age of 1 1/2 years

BACKGROUND

Infant cry characteristics reflect the integrity of the central nervous system. Previous studies have shown that preterm infants and infants with neurological conditions have different cry characteristics such as fundamental frequency compared to healthy full-term infants. Cry characteristics of preterm infants after the first year of life have not been studied.

AIMS

The aim of this study was to assess the quality of cry in 1 1/2-year-old very-low-birth-weight infants (VLBWI, < or =1500 g at birth). STUDY SUBJECTS AND DESIGN: Study groups included 21 VLBWI and 25 healthy full-term controls. Thirty seconds of pain cry after vaccination was recorded at well-baby clinics. The first cry utterance was acoustically analyzed using Praat software. The quality of cry was compared between the groups. In addition, the association of cry quality to patient characteristics, to developmental outcome, and to findings in brain imaging studies of the VLBWI was studied.

RESULTS

The cry response was elicited in 20 of the 21 VLBWI and in 20 out of 25 full-term infants. VLBWI had higher minimum fundamental frequency and fourth formant values. Patient characteristics that were associated with cry quality were 5-min Apgar scores, the occurrence of bronchopulmonary dysplasia, Bayley Psychomotor Index scores at 12 months, and current weight and head circumference.

CONCLUSIONS

Differences found between the study groups were not explained primarily by brain pathology or by patient characteristics, so it seems that prematurity has an impact on cry quality still at the age of 1 1/2 years.

Neonatal pain analyzer: development and validation

We developed a pain analyzer (ABC analyzer) to perform automatic acoustic analysis of neonatal crying and to provide an objective estimate of neonatal pain. The ABC analyzer uses a validated pain scale (ABC scale) based on three acoustic parameters: pitch frequency, normalized RMS amplitude, and presence of a characteristic frequency- and amplitude-modulated crying feature, defined as "siren cry". Here we assessed the reliability of the analyzer. We enrolled 57 healthy neonates. Each baby was recorded with a video camera during heel prick. Pain intensity was evaluated using a validated scale [Douleur Aigue du Nouveau-Né (DAN) scale] and the analyzer and the two scores were compared. We found a statistically significant concordance between the DAN score and ABC analyzer score (p < 0.0001). The ABC analyser is a novel approach to cry analysis that should now have its properties carefully evaluated in a series of studies, just as is necessary in the development of any other pain measurement tool.

The neonate cry after cesarean section and vaginal delivery during the first minutes of life

Although the option for vaginal delivery is most physiological, the achievement of cesarean section is very common in Brazil. The neonate cry represents the beginning of both processes, physiological adaptation and human vocal communication. The cry emission depends on the functioning of respiratory and laryngeal muscles, which are controlled by the nervous system. The acoustic analysis of neonate cry is useful in the assessment of healthy babies and can be used to characterize the signals of diseases through a previously multidisciplinary diagnosis, with immediate medical intervention. The present study compared the acoustic cry characteristics of 30 healthy newborn after a cesarean section and 30 healthy newborn after a vaginal delivery, of both genders, from the exact moment of birth until the first 5 min of life. Using the softwares VOXMETRIA and GRAM, it was possible to analyze the duration, frequency, intensity, occurrence, localization and inspiratory phonation, besides the type of spectrographic tracings. The acoustic cry characteristics of newborns after a C section and a vaginal delivery could evidence not only harmonic, expiratory, acute and strong emissions, but also emissions rich in sounds and varied in types of melody. The differences found can be related to the physiology of birth.

Cry features reflect pain intensity in term newborns: an alarm threshold

The purpose of this study was to assess differences in sound spectra of crying of term newborns in relation to different pain levels. Fifty-seven consecutively born neonates were evaluated during heel-prick performed with different analgesic techniques. Crying was recorded and frequency spectrograms analyzed. A pain score on the DAN (Douleur Aiguë du Nouveau-né) scale was assigned to each baby after the sampling. Three features were considered and correlated with the corresponding DAN scores: 1) whole spectral form; 2) the fundamental frequency of the first cry emitted (F0); and 3) root mean square sound pressure normalized to its maximum. After emission of the first cry, babies with DAN scores >8, but not with DAN scores < or =8 (p < 0.001), showed a pattern ("siren cry") characterized by a sequence of almost identical cries with a period on the order of 1 s. A statistically significant correlation was found between root mean square (r2 = 89%, p < 0.01), F0 (r2 = 32%, p < 0.05), siren cry (r2 = 68.2%, p = 0.02), and DAN score. F0 did not show significant correlation with DAN score in the subset of neonates with DAN scores < or =8 (r2 = 1.4%, p = 0.94), and babies with a DAN score >8 had a significantly higher F0 than those with lower DAN scores (p = 0.016). An alarm threshold exists between high (>8) and low (< or =8) DAN scores: crying has different features in these two groups. When pain exceeds a DAN score of 8, usually a first cry at a high pitch is emitted, followed by the siren cry, with a sound level maintained near its maximum.

Feasibility of using fMRI to study mothers responding to infant cries

While parenting is a universal human behavior, its neuroanatomic basis is currently unknown. Animal data suggest that the cingulate may play an important function in mammalian parenting behavior. For example, in rodents cingulate lesions impair maternal behavior. Here, in an attempt to understand the brain basis of human maternal behavior, we had mothers listen to recorded infant cries and white noise control sounds while they underwent functional MRI (fMRI) of the brain. We hypothesized that mothers would show significantly greater cingulate activity during the cries compared to the control sounds. Of 7 subjects scanned, 4 had fMRI data suitable for analysis. When fMRI data were averaged for these 4 subjects, the anterior cingulate and right medial prefrontal cortex were the only brain regions showing statistically increased activity with the cries compared to white noise control sounds (cluster analysis with one-tailed z-map threshold of P < 0.001 and spatial extent threshold of P < 0.05). These results demonstrate the feasibility of using fMRI to study brain activity in mothers listening to infant cries and that the anterior cingulate may be involved in mothers listening to crying babies. We are currently replicating this study in a larger group of mothers. Future work in this area may help (1) unravel the functional neuroanatomy of the parent-infant bond and (2) examine whether markers of this bond, such as maternal brain response to infant crying, can predict maternal style (i.e., child neglect), offspring temperament, or offspring depression or anxiety.