Acta Pædiatrica ISSN 0803-5253
EDITORIAL
DOI:10.1111/apa.12766
Maternal singing for preterm infants during kangaroo care comforts both the mother and baby Preterm birth is a major health problem worldwide. Major advances have been made in neonatal intensive care over the last few decades, resulting in increased survival rates of preterm infants and a reduction in major neuromotor impairments. However, there is now a greater awareness of the high risk of adverse brain development among children who are born very immature, together with the subsequent cognitive and behavioural problems. In particular, children who are born extremely preterm have language delay and abnormal auditory event related potentials (1). One of the factors that may contribute to the risk of adverse brain development in preterm infants is maternal separation while they are in the neonatal intensive care unit. The contact between the mother and her offspring is essential for all mammals. Research in rodents has shown that early maternal contact, which takes the form of sensory stimulation through licking behaviour, has an impact on the infant’s brain systems, enabling them to manage stress and enhance their social adaptation mechanisms include fine tuning of the hypothalamus–pituitary–adrenal axis and epigenetic modifications (2). On the other hand, prolonged physical separation between mothers and infants exerts lifelong negative effects on the offspring and is also known to cause maternal stress, anxiety and depression (3). Kangaroo care was developed in Bogota, Columbia, to enable preterm infants to maintain body temperature through skin-to-skin contact with the parent’s body (4) and in the last few decades, it has been introduced to many neonatal units worldwide. The technique has been associated with better autonomic functioning, sleep, reduced pain response, improved mother–infant interaction and maternal mood in early infancy, as reviewed by Flacking et al. (5). Studies on the long-lasting effects on children0 s brain development are scarce, but a recent report indicated that 10-year-old children who were born preterm and received kangaroo care during the neonatal period showed attenuated stress responses and better sleep and executive function (6). The mother’s voice provides another important source of sensory stimulation for the foetus and child. For example, quail chicks that were not allowed to hear their mother’s call during late prenatal development, because of other noise, did not recognise their mother’s voice when they hatched. Similarly, the preterm infant who is cared for in a neonatal intensive care unit, and is often exposed to elevated sound levels, loses significant contact with his or her mother’s voice. It has been suggested that disrupting
exposure to the maternal voice in preterm infants adversely affects a baby’s brain development. For example, neonates born preterm were less able to discriminate between a stranger’s voice and their own mother’s voice (7), and it was suggested that subsequent language development may be negatively affected. Music therapy interventions in neonatal intensive care have previously focused on the effects of recorded music. These showed significant benefits when it came to measures of heart rate, behaviour state, oxygen saturation, sucking/ feeding ability and length of hospital stay, as reported in a recent meta-analysis by Standley. This stated that live music therapy provided the greatest benefits, but pointed out that the live music studies focused mainly on music therapists singing, not mothers. Studies on the effects of maternal singing during neonatal intensive care are scarce, but a novel Italian report showed that when mothers sang to their preterm infants and talked to them it had positive effects on their autonomic stability (8). Recent music therapy research has focussed its interest on infant directed singing (9), which is a natural way to sing interactively to an infant and ideally performed by a parent. The underlying assumption is that interactive singing has an emotional component that enhances bonding, autonomic stability and brain development. During kangaroo care, skin-to-skin contact with the preterm infant provides multisensory stimulation, including emotional, tactile, visual and auditory stimuli. It is actually possible that maternal singing is transmitted better during skin-to skin care, because the vibrations in the mother’s thorax contribute to the sensory experience. However, there has been a lack of studies on this combination. In the current issue of Acta Paedicatrica, Arnon et al. (10) present a unique and well-designed study on the effect of maternal singing during kangaroo care in a neonatal intensive care unit. They hypothesised that this combination would ameliorate autonomic stability and maternal anxiety and compared the results with the effects of kangaroo care on its own. This study included 86 stable preterm infants, with a postmenstrual age of 32–36 weeks, and their mothers. The prospective, randomised intervention featured a cross-over, repeated measures design, so that each mother–infant dyad acted as their own control. Two sessions were performed over 2 days, starting with kangaroo care on its own for 10 min, followed by either maternal singing and kangaroo care or just kangaroo care for 20 min. The sessions ended with another 10 min of just kangaroo care.
ª2014 Foundation Acta Pædiatrica. Published by John Wiley & Sons Ltd 2014 103, pp. 995–996
995
Editorial
Editorial
Mothers were instructed to sing using a repetitive, soothing tone, softly, simply and with slow tempo. The researchers provided a sound analyser and asked the mothers to keep the sound between 60 and 70 decibels and to include lullabies, preferably the ones that they sang during pregnancy. The heart rates, oxygen saturation and respiratory rates were recorded for the mother and child and the child’s behavioural state and the mother’s anxiety were assessed. The authors reported that when they compared maternal singing and kangaroo care with just kangaroo care, they were unable to demonstrate additive effects on mean heart rate, respiratory rate, oxygen saturation or behavioural state. This is not unexpected as kangaroo care on its own has clear effects (5). On the other hand, heart rate variability changed, with a decreased low frequency/high frequency ratio, and this indicated increased autonomic stability and a calming effect during kangaroo care with maternal singing, compared with kangaroo care alone. The study design controlled for some possible confounders, including body temperature and the infant’s head position. Finally, direct evaluation of the mothers showed that they felt less anxiety after maternal singing, as demonstrated by lower scores on the State Trait Anxiety Inventory scale, a well-validated score of anxiety. This study adds an important new perspective on the use of kangaroo care, which is now a standard initiative in many units caring for preterm infants. Singing during skinto-skin care seems to be a natural way to deliver music to the infant for many mothers. If the mother also benefits from her own singing, it is not far-fetched to believe that her relief transmits to the child. On the other hand, some mothers will not feel at all comfortable singing to their child in the neonatal unit and, in this study, 15 of the 116 mother–infant dyads refused to take part. Although mothers should be encouraged to sing lullabies to their children, this study underscores that it must be done with great respect for the mother’s own attitude towards singing. Maternal singing for preterm infants during kangaroo care may comfort most mothers and babies. But what about fathers? They commonly perform kangaroo care with positive effects on active fatherhood. A recent brain imaging report underscored the common neural basis of maternal and paternal care, showing that childcare experiences also led to morphological changes in the father0 s brain (11). Future studies are needed to elucidate whether paternal singing is also beneficial for the infant and the father. This study by Arnon et al. was performed well and shows meaningful immediate advantages for the preterm infant
996
and the singing parent. The major question is whether encouraging parents to sing lullabies during skin-to-skin care during infancy improves long-term neurodevelopment, with a particular emphasis on the effects on language development. This needs to be evaluated in future studies.
Ulrika Aden ([email protected]) Department of Woman and Child Health, Neonatology Unit, Karolinska Institutet, Stockholm, Sweden
References 1. Hovel H, Partanen E, Huotilainen M, Lindgren M, Rosen I, Fellman V. Auditory event-related potentials at preschool age in children born very preterm. Clin Neurophysiol 2014; 125: 449–56. 2. Zhang TY, Labonte B, Wen XL, Turecki G, Meaney MJ. Epigenetic mechanisms for the early environmental regulation of hippocampal glucocorticoid receptor gene expression in rodents and humans. Neuropsychopharmacology 2013; 38: 111–23. 3. Miles MS, Holditch-Davis D, Schwartz TA, Scher M. Depressive symptoms in mothers of prematurely born infants. J Dev Behav Pediatr 2007; 28: 36–44. 4. Charpak N, Figueroa Z, Ruiz JG. Kangaroo mother care. Lancet 1998; 351: 914. 5. Flacking R, Lehtonen L, Thomson G, Axelin A, Ahlqvist S, Moran VH et al. Closeness and separation in neonatal intensive care. Acta Paediatr 2012; 101: 1032–7. 6. Feldman R, Rosenthal Z, Eidelman AI. Maternal-preterm skin-to-skin contact enhances child physiologic organization and cognitive control across the first 10 years of life. Biol Psychiatry 2014; 75: 56–64. 7. Krueger C. Exposure to maternal voice in preterm infants: a review. Adv Neonatal Care 2010; 10: 13–8; quiz 9-20. 8. Standley J. Music therapy research in the NICU: an updated meta-analysis. Neonatal Netw 2012; 31: 311–6. 9. Filippa M, Devouche E, Arioni C, Imberty M, Gratier M. Live maternal speech and singing have beneficial effects on hospitalized preterm infants. Acta Paediatr 2013; 102: 1017– 20. 10. Arnon S, Diamant C, Bauer S, Regev R, Sirota G, Litmanovitz I. Maternal singing during kangaroo care led to autonomic stability in preterm infants and reduced maternal anxiety. Acta Paediatr 2014; 103: 1039–44. 11. Abraham E, Hendler T, Shapira-Lichter I, Kanat-Maymon Y, Zagoory-Sharon O, Feldman R. Father’s brain is sensitive to childcare experiences. Proc Natl Acad Sci USA 2014; 111: 9792–7.
ª2014 Foundation Acta Pædiatrica. Published by John Wiley & Sons Ltd 2014 103, pp. 995–996
EDITORIAL
DOI:10.1111/apa.12766
Maternal singing for preterm infants during kangaroo care comforts both the mother and baby Preterm birth is a major health problem worldwide. Major advances have been made in neonatal intensive care over the last few decades, resulting in increased survival rates of preterm infants and a reduction in major neuromotor impairments. However, there is now a greater awareness of the high risk of adverse brain development among children who are born very immature, together with the subsequent cognitive and behavioural problems. In particular, children who are born extremely preterm have language delay and abnormal auditory event related potentials (1). One of the factors that may contribute to the risk of adverse brain development in preterm infants is maternal separation while they are in the neonatal intensive care unit. The contact between the mother and her offspring is essential for all mammals. Research in rodents has shown that early maternal contact, which takes the form of sensory stimulation through licking behaviour, has an impact on the infant’s brain systems, enabling them to manage stress and enhance their social adaptation mechanisms include fine tuning of the hypothalamus–pituitary–adrenal axis and epigenetic modifications (2). On the other hand, prolonged physical separation between mothers and infants exerts lifelong negative effects on the offspring and is also known to cause maternal stress, anxiety and depression (3). Kangaroo care was developed in Bogota, Columbia, to enable preterm infants to maintain body temperature through skin-to-skin contact with the parent’s body (4) and in the last few decades, it has been introduced to many neonatal units worldwide. The technique has been associated with better autonomic functioning, sleep, reduced pain response, improved mother–infant interaction and maternal mood in early infancy, as reviewed by Flacking et al. (5). Studies on the long-lasting effects on children0 s brain development are scarce, but a recent report indicated that 10-year-old children who were born preterm and received kangaroo care during the neonatal period showed attenuated stress responses and better sleep and executive function (6). The mother’s voice provides another important source of sensory stimulation for the foetus and child. For example, quail chicks that were not allowed to hear their mother’s call during late prenatal development, because of other noise, did not recognise their mother’s voice when they hatched. Similarly, the preterm infant who is cared for in a neonatal intensive care unit, and is often exposed to elevated sound levels, loses significant contact with his or her mother’s voice. It has been suggested that disrupting
exposure to the maternal voice in preterm infants adversely affects a baby’s brain development. For example, neonates born preterm were less able to discriminate between a stranger’s voice and their own mother’s voice (7), and it was suggested that subsequent language development may be negatively affected. Music therapy interventions in neonatal intensive care have previously focused on the effects of recorded music. These showed significant benefits when it came to measures of heart rate, behaviour state, oxygen saturation, sucking/ feeding ability and length of hospital stay, as reported in a recent meta-analysis by Standley. This stated that live music therapy provided the greatest benefits, but pointed out that the live music studies focused mainly on music therapists singing, not mothers. Studies on the effects of maternal singing during neonatal intensive care are scarce, but a novel Italian report showed that when mothers sang to their preterm infants and talked to them it had positive effects on their autonomic stability (8). Recent music therapy research has focussed its interest on infant directed singing (9), which is a natural way to sing interactively to an infant and ideally performed by a parent. The underlying assumption is that interactive singing has an emotional component that enhances bonding, autonomic stability and brain development. During kangaroo care, skin-to-skin contact with the preterm infant provides multisensory stimulation, including emotional, tactile, visual and auditory stimuli. It is actually possible that maternal singing is transmitted better during skin-to skin care, because the vibrations in the mother’s thorax contribute to the sensory experience. However, there has been a lack of studies on this combination. In the current issue of Acta Paedicatrica, Arnon et al. (10) present a unique and well-designed study on the effect of maternal singing during kangaroo care in a neonatal intensive care unit. They hypothesised that this combination would ameliorate autonomic stability and maternal anxiety and compared the results with the effects of kangaroo care on its own. This study included 86 stable preterm infants, with a postmenstrual age of 32–36 weeks, and their mothers. The prospective, randomised intervention featured a cross-over, repeated measures design, so that each mother–infant dyad acted as their own control. Two sessions were performed over 2 days, starting with kangaroo care on its own for 10 min, followed by either maternal singing and kangaroo care or just kangaroo care for 20 min. The sessions ended with another 10 min of just kangaroo care.
ª2014 Foundation Acta Pædiatrica. Published by John Wiley & Sons Ltd 2014 103, pp. 995–996
995
Editorial
Editorial
Mothers were instructed to sing using a repetitive, soothing tone, softly, simply and with slow tempo. The researchers provided a sound analyser and asked the mothers to keep the sound between 60 and 70 decibels and to include lullabies, preferably the ones that they sang during pregnancy. The heart rates, oxygen saturation and respiratory rates were recorded for the mother and child and the child’s behavioural state and the mother’s anxiety were assessed. The authors reported that when they compared maternal singing and kangaroo care with just kangaroo care, they were unable to demonstrate additive effects on mean heart rate, respiratory rate, oxygen saturation or behavioural state. This is not unexpected as kangaroo care on its own has clear effects (5). On the other hand, heart rate variability changed, with a decreased low frequency/high frequency ratio, and this indicated increased autonomic stability and a calming effect during kangaroo care with maternal singing, compared with kangaroo care alone. The study design controlled for some possible confounders, including body temperature and the infant’s head position. Finally, direct evaluation of the mothers showed that they felt less anxiety after maternal singing, as demonstrated by lower scores on the State Trait Anxiety Inventory scale, a well-validated score of anxiety. This study adds an important new perspective on the use of kangaroo care, which is now a standard initiative in many units caring for preterm infants. Singing during skinto-skin care seems to be a natural way to deliver music to the infant for many mothers. If the mother also benefits from her own singing, it is not far-fetched to believe that her relief transmits to the child. On the other hand, some mothers will not feel at all comfortable singing to their child in the neonatal unit and, in this study, 15 of the 116 mother–infant dyads refused to take part. Although mothers should be encouraged to sing lullabies to their children, this study underscores that it must be done with great respect for the mother’s own attitude towards singing. Maternal singing for preterm infants during kangaroo care may comfort most mothers and babies. But what about fathers? They commonly perform kangaroo care with positive effects on active fatherhood. A recent brain imaging report underscored the common neural basis of maternal and paternal care, showing that childcare experiences also led to morphological changes in the father0 s brain (11). Future studies are needed to elucidate whether paternal singing is also beneficial for the infant and the father. This study by Arnon et al. was performed well and shows meaningful immediate advantages for the preterm infant
996
and the singing parent. The major question is whether encouraging parents to sing lullabies during skin-to-skin care during infancy improves long-term neurodevelopment, with a particular emphasis on the effects on language development. This needs to be evaluated in future studies.
Ulrika Aden ([email protected]) Department of Woman and Child Health, Neonatology Unit, Karolinska Institutet, Stockholm, Sweden
References 1. Hovel H, Partanen E, Huotilainen M, Lindgren M, Rosen I, Fellman V. Auditory event-related potentials at preschool age in children born very preterm. Clin Neurophysiol 2014; 125: 449–56. 2. Zhang TY, Labonte B, Wen XL, Turecki G, Meaney MJ. Epigenetic mechanisms for the early environmental regulation of hippocampal glucocorticoid receptor gene expression in rodents and humans. Neuropsychopharmacology 2013; 38: 111–23. 3. Miles MS, Holditch-Davis D, Schwartz TA, Scher M. Depressive symptoms in mothers of prematurely born infants. J Dev Behav Pediatr 2007; 28: 36–44. 4. Charpak N, Figueroa Z, Ruiz JG. Kangaroo mother care. Lancet 1998; 351: 914. 5. Flacking R, Lehtonen L, Thomson G, Axelin A, Ahlqvist S, Moran VH et al. Closeness and separation in neonatal intensive care. Acta Paediatr 2012; 101: 1032–7. 6. Feldman R, Rosenthal Z, Eidelman AI. Maternal-preterm skin-to-skin contact enhances child physiologic organization and cognitive control across the first 10 years of life. Biol Psychiatry 2014; 75: 56–64. 7. Krueger C. Exposure to maternal voice in preterm infants: a review. Adv Neonatal Care 2010; 10: 13–8; quiz 9-20. 8. Standley J. Music therapy research in the NICU: an updated meta-analysis. Neonatal Netw 2012; 31: 311–6. 9. Filippa M, Devouche E, Arioni C, Imberty M, Gratier M. Live maternal speech and singing have beneficial effects on hospitalized preterm infants. Acta Paediatr 2013; 102: 1017– 20. 10. Arnon S, Diamant C, Bauer S, Regev R, Sirota G, Litmanovitz I. Maternal singing during kangaroo care led to autonomic stability in preterm infants and reduced maternal anxiety. Acta Paediatr 2014; 103: 1039–44. 11. Abraham E, Hendler T, Shapira-Lichter I, Kanat-Maymon Y, Zagoory-Sharon O, Feldman R. Father’s brain is sensitive to childcare experiences. Proc Natl Acad Sci USA 2014; 111: 9792–7.
ª2014 Foundation Acta Pædiatrica. Published by John Wiley & Sons Ltd 2014 103, pp. 995–996
