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.

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.

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.

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.

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.