Melody of Vocants: Fixed Pattern or Shaped by Hearing?

INTRODUCTION: Vocants as infants' first vocalic utterances are produced laryngeally while the vocal tract is maintained in a neutral position. These "primitive" sounds have sometimes been described as largely innate and, therefore, as sounding alike in both healthy and hearing-impaired young infants. OBJECTIVE: The objective of this study is to compare melody features of vocants, recorded during face-to-face interaction, between infants (N = 8) with profound congenital sensorineural hearing loss (HI group) and age-matched (N = 18) controls (CO) group. The question was as follows: does a lack of auditory feedback have a noticeable effect on melodic features of vocants? METHODS: The cooing database totalled 6,998 vocalizations (HI: N = 2,847; CO: N = 4,151), all of which had been recorded during the observation period of 60-181 days of age. Identification of the vocants (N = 1,148) was based on broadband spectrograms (KAY-CSL) and auditory impressions. Fundamental frequency (F0) analyses were performed (PRAAT) and the pattern of the F0 contour (melody) analysed using specific in-lab software (CDAP, pw-project). Generalized mixed linear models were used to perform group comparisons. RESULTS: There was a clear predominance of a simple rising-falling pattern (single melody arcs) in vocants of both groups. Nonetheless, significantly more complex contours, particularly, double-arc structures, were found in vocants of the CO group. Moreover, vocants of the HI group were shorter than those uttered by the CO group, while the mean F0 did not significantly differ. CONCLUSION: Vocants are characterized by both, innate features, found in HI and CO groups, and features that additionally require a functioning auditory system. Even at an early pre-linguistic stage, somatosensory sensations cannot compensate for a lack of auditory feedback. Vocants might be relevant in the early diagnosis of hearing disorders and assessments of the effectiveness of, or adjustments required to, hearing aids.

Fundamental Frequency Contour (Melody) of Infant Vocalizations across the First Year.

INTRODUCTION: The fundamental frequency contour (melody) of cry and non-cry utterances becomes more complex with age. However, there is a lack of longitudinal analyses of melody development during the first year of life. OBJECTIVE: The aim of the study was to longitudinally analyze melody development in typical vocalization types across the first 12 months of life. The aim was twofold: (1) to answer the question whether melody becomes more complex in all vocalization types with age and (2) to characterize complex patterns in more detail. METHODS: Repeatedly recorded vocalizations (n = 10,988) of 10 healthy infants (6 female) over their first year of life were analyzed using frequency spectrograms and fundamental frequency (f0) analyses (PRAAT). Melody complexity analysis was performed using specific in-lab software (CDAP, pw-project) in a final subset of 9,237 utterances that contained noise-free, undisturbed contours. Generalized mixed linear models were used to analyze age and vocalization type effects on melody complexity. RESULTS: The vocalization repertoire showed a higher proportion of complex melodies from the second month onward. The age effect was significant, but no difference was found in melody complexity between cry and non-cry vocalizations across the first 6 months. From month 7-12, there was a further significant increase in complex structures only in canonical babbling not in marginal babbling. Melody segmentations by laryngeal constrictions prevailed among complex shapes. CONCLUSION: The study demonstrated the regularity of melody development in different vocalization types throughout the first year of life. In terms of prosodic features of infant sounds, melody contour is of primary importance, and further studies are required that also include infants at risk for language development.

Preliminary evaluation of pre-speech and neurodevelopmental measures in 7-11-week-old infants with isolated oral clefts.

BACKGROUND: The purpose of this research study was to evaluate the earliest markers of vocal functioning and neurological development in infants with isolated oral cleft of the lip and/or palate (iCL/P). METHODS: Participants were recruited through advertisements and clinic visits at a local mid-western university. A total of eight participants (four unaffected and four with iCL/P), ranging in age from 7.29 to 11.57 weeks, were enrolled and completed demographic and pre-speech measures. A subset of six males (four unaffected and two with iCL/P) successfully completed a structural magnetic resonance imaging scan. RESULTS: Patterns of disrupted vocal control and reduced myelinated white matter were found in participants with iCL/P. CONCLUSIONS: The findings of this study provide a foundation from which to build further research on the neuronal development of infants with oral clefts: the need to evaluate measures of cortical development, inclusion of information on anesthesia exposure and airway obstruction, and suggestions for avoiding identified pitfalls/blocks to obtaining data are discussed. IMPACT: Research in children with isolated oral clefts has demonstrated higher rates of learning disorders connected to subtle differences in brain structure. There is no work evaluating the potential impact of exposure to anesthesia on development. This is the first known attempt to evaluate brain structure and function in infants with isolated oral clefts before exposure to anesthesia. Potential trends of early vocal issues and structural brain differences (less myelinated white matter) were identified in infants with isolated oral clefts compared to unaffected controls. Differences in brain structure and function in infants with isolated oral clefts may be present before surgery.

Musical Intervals in Infants' Spontaneous Crying over the First 4 Months of Life.

INTRODUCTION: Perception and memorizing of melody and rhythm start about the third trimester of gestation. Infants have astonishing musical predispositions, and melody contour is most salient for them. OBJECTIVE: To longitudinally analyse melody contour of spontaneous crying of healthy infants and to identify melodic intervals. The aim was 3-fold: (1) to answer the question whether spontaneous crying of healthy infants regularly exhibits melodic intervals across the observation period, (2) to investigate whether interval events become more complex with age and (3) to analyse interval size distribution. METHODS: Weekly cry recordings of 12 healthy infants (6 females) over the first 4 months of life were analysed (6,130 cry utterances) using frequency spectrograms and pitch analyses (PRAAT). A preselection of utterances containing a well-identifiable, noise-free and undisturbed melodic contour was applied to identify and measure melodic intervals in the final subset of 3,114 utterances. Age-dependent frequency of occurrence of melodic intervals was statistically analysed using generalized estimating equations. RESULTS: 85.3% of all preselected melody contours (n = 3,114) either contained single rising or falling melodic intervals or complex events as combinations of both. In total 6,814 melodic intervals were measured. A significant increase in interval occurrence was found characterized by a non-linear age effect (3 developmental phases). Complex events were found to significantly increase linearly with age. In both calculations, no sex effect was found. Interval size distribution showed a maximum of the minor second as the prevailing musical interval in infants' crying over the first 4 months of life. CONCLUSION: Melodic intervals seem to be a regular phenomenon of spontaneous crying of healthy infants. They are suggested to be a further candidate for developing an early risk marker of vocal control in infants. Subsequent studies are needed to compare healthy infants and infants at risk for respiratory-laryngeal dysfunction to investigate the diagnostic value of the occurrence of melodic intervals and their age-depending complexification.

From melody to words: The role of sex hormones in early language development.

Contribution to Special Issue on Fast effects of steroids. Human infants are the most proficient of the few vocal learner species. Sharing similar principles in terms of the generation and modification of complex sounds, cross-vocal learner comparisons are a suitable strategy when it comes to better understanding the evolution and mechanisms of auditory-vocal learning in human infants. This approach will also help us to understand sex differences in relation to vocal development towards language, the underlying brain mechanisms thereof and sex-specific hormonal effects. Although we are still far from being capable of discovering the "fast effects of steroids" in human infants, we have identified that peripheral hormones (blood serum) are important regulators of vocal behaviour towards language during a transitory hormone surge ("mini-puberty") that is comparable in its extent to puberty. This new area of research in human infants provides a promising opportunity to not only better understand early language acquisition from an ontogenetic and phylogenetic perspective, but to also identify reliable clinical risk-markers in infants for the development of later language disorders.

Does shape affect function? Articulatory skills in babbling of infants with deformational plagiocephaly.

PURPOSE: The purpose of this study was to quantitatively analyse pre-speech/early language skills in healthy full-term infants with moderate or severe deformational plagiocephaly (DP) and in infants without any skull asymmetry. METHODS: At 6 and 12 months, 51 children with DP (41 moderate, 10 severe cases) were studied, along with 15 infants serving as control. Deformational plagiocephaly (DP) was objectively determined based on cranial vault asymmetry (CVA) using 3D stereophotogrammetry (3dMDhead System® and Analytics 4.0, Cranioform®). Articulatory skills in babbling were assessed using the articulatory skill (ART-index) and mean syllable number (MSN). At 12 months, standardized parental questionnaires were used to evaluate early language outcomes. RESULTS: Overall, 3546 vocalizations were studied. Statistical tests did not reveal any significant differences of the ART-index between the three groups (ANOVA, F[2,63] = 0.24, p = 0.24). MSN likewise did not differ between the three shape groups (Kruskal-Wallis, p = 0.84). Among the children assigned to the at-risk group for language outcomes at 12 months were seven members of the symmetrical shape group (vs. seven assigned to the normally developing group), nine of the moderate DP group (vs. 27), and one of the severe DP group (vs. six). Fisher's exact test was used to analyse whether helmet therapy in the moderate DP group affected the results by influencing language outcomes, but did not reveal any significant influence (p = 0.712). CONCLUSIONS: The results of this study do not support arguments suggesting that DP is a cognitive risk condition. The suggestion that a direct neurophysiological relationship exists between a DP condition and a cognitive developmental delay remains controversial.

Sex hormone influence on human infants' sound characteristics: melody in spontaneous crying.

The specific impact of sex hormones on brain development and acoustic communication is known from animal models. Sex steroid hormones secreted during early development play an essential role in hemispheric organization and the functional lateralization of the brain, e.g. language. In animals, these hormones are well-known regulators of vocal motor behaviour. Here, the association between melody properties of infants' sounds and serum concentrations of sex steroids was investigated. Spontaneous crying was sampled in 18 healthy infants, averaging two samples taken at four and eight weeks, respectively. Blood samples were taken within a day of the crying samples. The fundamental frequency contour (melody) was analysed quantitatively and the infants' frequency modulation skills expressed by a melody complexity index (MCI). These skills provide prosodic primitives for later language. A hierarchical, multiple regression approach revealed a significant, robust relationship between the individual MCIs and the unbound, bioactive fraction of oestradiol at four weeks as well as with the four-to-eight-week difference in androstenedione. No robust relationship was found between the MCI and testosterone. Our findings suggest that oestradiol may have effects on the development and function of the auditory-vocal system in human infants that are as powerful as those in vocal-learning animals.

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.

Cry melody in 2-month-old infants with and without clefts.

OBJECTIVE: To investigate cry melody properties in infants with clefts using objective methods and to identify early differences in cry development in relation to infants without clefts that may indicate special developmental risks. DESIGN: Melody analysis was carried out on cries from the second month of life. The cry properties of infants with a cleft lip and palate (CLP) and infants with a cleft palate only (CP) were quantitatively compared. Both groups were compared to infants without clefts. PARTICIPANTS: Twenty-one infants with nonsyndromic clefts, including 11 infants with CLP and 10 infants with CP, were compared to 50 healthy controls. MAIN OUTCOME MEASURES: Frequency spectrograms and melody diagrams of about 7000 cries were analyzed. For each infant's crying, melodic and rhythmic properties were investigated and expressed by appropriate quantitative indices. Based on previous studies, the degree of melody complexity in an infants' crying was used as an indicator of their present prespeech developmental status. RESULTS: The cleft groups did not significantly differ from each other with respect to their cry melody development. However, both groups were significantly different from the control group, exhibiting a lower proportion of complex cry melodies and a deviation in rhythmicity. No significant correlation to hearing performances was found that could explain the differences. CONCLUSIONS: Infants with clefts differ in their cry development from infants without clefts at 2 months of life. This early difference occurs before the infants undergo any surgical intervention or other treatment.

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.

Cry features of healthy neonates who passed their newborn hearing screening vs. those who did not.

OBJECTIVES: Temporal and fundamental frequency (fo) variations in infant cries provide critical insights into the maturity of vocal control and hearing performances. Earlier research has examined the use of vocalisation properties (in addition to hearing tests) to identify infants at risk of hearing impairment. The aim of this study was to determine whether such an approach could be suitable for neonates. METHODS: To investigate this, we recruited 74 healthy neonates within their first week of life as our participants, assigning them to either a group that passed the ABR-based NHS (PG, N = 36) or a group that did not, but were diagnosed as normally hearing in follow-up check at 3 months of life, a so-called false-positive group (NPG, N = 36). Spontaneously uttered cries (N = 2330) were recorded and analysed quantitatively. The duration, minimum, maximum and mean fo, as well as two variability measures (fo range, fo sigma), were calculated for each cry utterance, averaged for individual neonates, and compared between the groups. RESULTS: A multiple analysis of variance (MANOVA) revealed no significant effects. This confirms that cry features reflecting vocal control do not differ between healthy neonates with normal hearing, irrespective of the outcome of their initial NHS. CONCLUSIONS: Healthy neonates who do not pass the NHS but are normal hearing in the follow-up (false positive cases) have the same cry properties as those with normal hearing who do. This is an essential prerequisite to justify the research strategy of incorporating vocal analysis into NHS to complement ABR measures in identifying hearing-impaired newborns.

The Vocalist in the Crib: the Flexibility of Respiratory Behaviour During Crying in Healthy Neonates.

OBJECTIVE: To evaluate the flexibility of respiratory behavior during spontaneous crying using an objective analysis of temporal measures in healthy neonates. PARTICIPANTS: A total of 1,375 time intervals, comprising breath cycles related to the spontaneous crying of 72 healthy, full-term neonates (35 females) aged between two and four days, were analyzed quantitatively. METHODS: Digital recordings (44 kHz, 16 bit) of cries emitted in a spontaneous, pain-free context were obtained at the University Children's Hospital Wurzburg. The amplitude-by-time representation of PRAAT: doing phonetics by computer (38) was used for the manual segmentation of single breath-cycles involving phonation. Cursors were set in these time intervals to mark the duration of inspiratory (IPh) and expiratory phases (EPh), and double-checks were carried out using auditory analyses. A PRAAT script was used to extract temporal features automatically. The only intervals analyzed were those that contained an expiratory cry utterance embedded within preceding and subsequent inspiratory phonation (IP). Beyond the reliable identification of IPh and EPh, this approach also guaranteed inter-individual and inter-utterance homogenization with respect to inspiratory strength and an unconstructed vocal tract. RESULTS: Despite the physiological constraints of the neonatal respiratory system, a high degree of flexibility in the ratio of IPh/EPh was observed. This ratio changed hyperbolically (r = 0.71) with breath-cycle duration. Descriptive statistics for all the temporal measures are reported as reference values for future studies. CONCLUSION: The existence of respiratory exploration during the spontaneous crying of healthy neonates is supported by quantitative data. From a clinical perspective, the data demonstrate the presence of a high degree of flexibility in the respiratory behavior, particularly neonates' control capability with respect to variable cry durations. These data are discussed in relation to future clinical applications.

Laryngeal Constriction Phenomena in Infant Vocalizations.

Purpose Instances of laryngeal constriction have been noted as a feature of infant vocal development. The purpose of this study was to directly evaluate the developmental occurrence of laryngeal constriction phenomena in infant crying, cooing, and babbling vocalizations. Method The cry and noncry vocalizations of 20 healthy term-born infants between the ages of 1 and 7 months were examined for instances of laryngeal constriction. Approximately 20,000 vocalization samples were acoustically evaluated, applying a combined visual (frequency spectra and melody curves) and auditory analysis; the occurrence of instances of different constriction phenomena was analyzed. Results Laryngeal constrictions were found during the production of cry and noncry vocalizations. The developmental pattern of constrictions for both vocalizations was charac-terized by an increase in constrictions followed by a decrease. During the age period of 3-5 months, when cry and noncry vocalizations were co-occurring, laryngeal constrictions were observed in 14%-22% of both types of vocalizations. An equal percentage of constrictions was found for both vocalizations at 5 months of age. Conclusions The findings confirm that the production of laryngeal constriction is a regularly occurring phenomenon in healthy, normally developing infants' spontaneous crying, cooing, and marginal babbling. The occurrence of constriction in both cry and noncry vocalizations suggests that an infant is exploiting physiological constraints of the sound-generating system for articulatory development during vocal exploration. These results lend support to the notion that the laryngeal articulator is the principal articulator that infants 1st start to control as they test and practice their phonetic production skills from birth through the 1st several months of life.

Inspiratory Phonation in Baby Voice.

OBJECTIVE: This study aimed to evaluate the developmental occurrence of inspiratory phonations (IPs) in the spontaneous cries of healthy infants across the first 10 weeks of life. STUDY DESIGN: This is a populational retrospective study. PARTICIPANTS: The spontaneous crying of 17 healthy infants (10 were male) was retrospectively investigated. MATERIALS AND METHODS: Sound files of spontaneously uttered cries that were repeatedly recorded once per week for across the first 10 weeks of life were retrospectively analyzed. Frequency spectra and waveforms were used to identify the occurrence of IPs and to measure the duration and fundamental frequency (fo) of each instance of IP. RESULTS: A consistent number of IPs were identified across the 10-week period. All infants were observed to produce IPs in their spontaneous cries, although the frequency of occurrence was not consistent across infants. A marked sex difference was observed with female infants producing a higher number of IPs compared to males. The duration and fo of IPs did not differ significantly across the 10 weeks or between sexes. CONCLUSIONS: The production of IPs is a regularly occurring phenomenon in healthy, normally developing infants' spontaneous crying. The proportional difference in the production of IPs between female and male infants, observed for the first time here, is postulated to be linked to sex-based differences (including steroidal hormones) in respiratory anatomy and physiology.

Fundamental Frequency of Crying in Two-month-old Boys and Girls: Do Sex Hormones During Mini-puberty Mediate Differences?

OBJECTIVE: To evaluate whether the puberty-like sex hormone surge during the first months of life (mini-puberty) affects fundamental frequency (fo) in infant crying as one would derive from hormone influences on voice in adults. STUDY DESIGN: Populational prospective study. PARTICIPANTS: Twenty healthy normal-hearing infants (nine boys) were recruited for participation. METHODS: Spontaneously uttered cries were collected from each infant at 8 weeks of age. The cries were acoustically analyzed for mean fo and fo range. The fo properties were correlated to the average serum levels of bioavailable estradiol (E2) (mean E2/sex hormone-binding globulin [SHBG]) and testosterone (T) (mean T/SHBG) across the second month of life. RESULTS: Whereas no significant hormone effect was found for mean fo, a significant negative correlation (r = -0.55) was found between fo range and mean E2/SHBG. No indication for a T influence on fo features was found at this age. Although girls showed a slightly higher mean E2 concentration than boys did, the observed differences in cry fo range were judged to be reflective of an infant's serum concentration of E2 rather than a sex-based difference. CONCLUSION: In the absence of laryngeal size differences between female and male infants, the result was interpreted as indicative of an E2 influence on viscoelastic properties of the vocal folds. In our opinion, the investigation of young infants' vocalizations during the early postnatal surge of sex steroids (mini-puberty) may advance our understanding of the mechanisms mediating average sex differences in vocal development and early communication.

Six month-old infants with deformational plagiocephaly do not differ from unaffected infants with respect to vocal control.

OBJECTIVES: The recommendation of a supine sleeping position led to a significant reduction of SIDS, but increased positional skull deformities (DP). Here, a quantitative analysis of babbling aims to complement previous studies of language-relevant competence based on items of the Bayley-scales that suggested the presence of developmental language delays in DP infants. Measures of fundamental frequency variability as proxies for vocal control are well suited for testing this assumption, since the laryngeal neuro-muscular system matures early and is coupled with brain function while working rapidly in coordinating the structures and mechanisms involved in infant sound production. METHODS: Sixty-six healthy, full-term infants with normal hearing and a monolingual background took part: (1) moderately asymmetrical DP group - N = 41; 21 male; (2) severely asymmetrical DP group - N = 10; 8 male; and (3) controls - N = 15; 5 male (group assignment based on stereophotogrammetric 360° scans). Fundamental frequency (fo) measures were taken as proxies for vocal control skills during babbling. RESULTS: A MANOVA revealed no significant multivariate effect for the shape group, Wilks' λ = 0.86, F(2, 63) = 1.21, p = 0.30, η2 = 0.07 (medium effect-size). The results do not support previous findings based on Bayley scale evaluations that suggested a negative impact of DP on language development during infancy. CONCLUSIONS: A strong link between DP and brain dysfunction affecting vocal control, which would cause deviations in otherwise healthy DP infants, was not observed. Objective long-term studies of sound production are necessary to identify and/or understand the potential consequences of DP on early language development.

Fundamental Frequency Variation in Crying of Mandarin and German Neonates.

OBJECTIVES: This study examined whether prenatal exposure to either a tonal or a nontonal maternal language affects fundamental frequency (fo) properties in neonatal crying. STUDY DESIGN: This is a population prospective study. PARTICIPANTS: A total of 102 neonates within the first week of life served as the participants. METHODS: Spontaneously uttered cries (N = 6480) by Chinese (tonal language group) and German neonates (nontonal group) were quantitatively analyzed. For each cry utterance, mean fo and four characteristic variation measures (fo range, fo fluctuation, pitch sigma, and pitch sigma fluctuation) were calculated, averaged for individual neonates, and compared between groups. RESULTS: A multiple analysis of variance highlighted a significant multivariate effect for language group: Wilks λ = .76, F(6, 95) = 4.96, P < .0001, ηp2 = .24. Subsequent univariate analyses revealed significant group differences for fo variation measures, with values higher in the tonal language group. The mean fo did not differ between groups. CONCLUSIONS: Data regarding fo variation in infant cries have been suggested as providing critical insight into the maturity of neurophysiological vocal control. Our findings, alongside with auditive perception studies, further underscore the assumption of an early shaping effect of maternal speech, particularly fo-based features, on cry features of newborns. Further studies are needed to reexamine this observation and to assess its potential diagnostic relevance.

Baby babbling at five months linked to sex hormone levels in early infancy.

Gender-dependent differentiation of the brain at morphological, neurochemical and functional levels of organization have been shown to be primarily controlled by sex differences in gonadal hormone concentrations during pre- and early postnatal development. Indeed, previous studies have reported that pre- and perinatal hormonal environments influence brain development and, consequently, affect sex specific long-term language outcomes. Herein, we investigated whether postnatal surges of estrogen (estradiol) and androgen (testosterone) may predict properties of pre-speech babbling at five months. This study is the first attempt to investigate a possible correlation between sex hormones and infants' articulatory skills during the typical postnatal period of extended hormonal activity known as 'mini-puberty.' A hierarchical, multiple regression approach revealed a significant, robust positive relationship between 4-week concentrations of estradiol and individual articulatory skills. In contrast, testosterone concentrations at five months negatively correlated with articulatory skills at the same age in both boys and girls. Our findings reinforce the assumption of the importance of sex hormones for auditory-vocal development towards language in human infants.

Noisy but effective: crying across the first 3 months of life.

OBJECTIVE: To evaluate the developmental occurrence of subharmonic (SH) and noise (N) phenomena and to quantify their extent in the spontaneous cries of healthy infants across the first 3 months. STUDY DESIGN: Populational prospective study. PARTICIPANTS: Spontaneous elicited cries from 20 infants (10 male) were repeatedly recorded across the first 3 months of life. METHODS: Frequency spectra and waveforms were used to identify the occurrence of SH and N and to measure the percentage of their combined occurrence in overall monthly crying behavior (expressed as a quantitative noise index [NI]). RESULTS: SH and N episodes were prevalent in the cries of young infants during the first 2 months, being present in more than 50% of the recorded cries. A developmental trend was evident in NI with a significant decrease across the 3-month period. A corresponding significant increase in mean duration of single cries was observed during the same period. CONCLUSIONS: SH and phonatory noise are regularly occurring phenomena in healthy infant crying because of the characteristics of pediatric larynx anatomy and neurophysiological control mechanisms underlying cry production. The reduction in NI appears to correspond with the development of an infant's crying complexity. The utility of NI as a metric of cry phonatory behavior should next be validated on infant groups with known or suspected health problems.

Development of the vocal fundamental frequency of spontaneous cries during the first 3 months.

Studies in the field of cry diagnosis have concentrated on the fundamental frequency (F(0)) and related parameters as suitable predictors for an at-risk status of the infant for a CNS dysfunction, mostly reflected in an increased F(0). The high variability of F(0) in infant cries is a limiting factor to develop cry analysis as a non-invasive tool for early diagnosis. As only a few longitudinal studies were carried out, our case study wants to contribute to provide developmental data on fundamental frequency of infant cries with a considerable higher time resolution (shorter recording interval). The fundamental frequency of spontaneous cries of one male infant was analyzed using KAY-CSL 4300 for its daily characteristics during the first 3 months of life. This dense sampling interval (daily recordings) enabled the description of the range of temporary changes of the fundamental frequency during the observation period. The mean fundamental frequency values of cries uttered at single days and of the cries of successive days were relatively variable. In contrast to former studies, no significant decreasing or increasing trend of the mean fundamental frequency of all analyzed cries was found through the first 3 months of life. Only cries shorter than 0.8 s showed an increasing developmental trend of the mean F(0).