Book Review: Manuela Filippa,Pierre Kuhn,& Björn Westrup. Early vocal contact and preterm infant brain development: Bridging the gaps between research and practice

Over the last few decades, the field of early years development through music has created an emerging research interest. The neonatal stage more specifically, including both the premature and the full-term sides of the postdelivery period, has reached to accommodate new ways of studying behavior and growth, while new research methods allow for a more detailed and thorough understanding of its context and processes through the sound domain. Consequently, an expanded discussion has gained relevant momentum based on the available findings, which in line asks for a solid understanding of the field’s background and practice techniques in context. Early Vocal Contact and Preterm Infant Brain Development, by Manuela Filippa, Pierre Kuhn, and Björn Westrup (editors), is an excellent resource for learning, understanding, and expanding the interdisciplinary working lines between the neonatal development and music-sound domains. The book encompasses knowledge that ranges from the basic in utero mother–fetus sound-based interactions, up to clinical interventions, bringing into play epigenetics and early family bonding, to name just a few.

For the most part, this book provides thorough coverage of topics related to technical and practical issues, and despite the multi-author format, it mostly achieves an easy-going reading style, quite accessible to a wide research-oriented yet not so specialized audience. All contributors make a great effort to initially provide fundamentals on their specific topic of discussion while further expanding toward new developments and knowledge by employing research studies and paradigms that made an impact on their field.

Following a consistent presentation structure, the book showcases a collection of 17 contributions, being effectively organized in five “umbrella” parts: (I) The Maternal Voice: A Link Between Fetal and Neonatal Period; (II) The NICU Acoustic Environment and the Preterm Infant’s Auditory System Development; (III) The Early Vocal Contact in the NICU; (IV) Family-Centered Music Therapy Experiences in the NICU; and (V) Early Family-Based Interventions in the NICU.

More specifically, Part I (Chapters 1–5) deals with communicative musicality over the last few decades through research observations and videos. For example, in Chapter 1, one of the studies showcases a 2-month premature girl and her father sharing affectionate moments as she is trying to respond to her father’s care, with gestures and facial expressions, during skin-to-skin contact (SSC; van Rees & de Leeuw, 1993). The authors of this study conclude that the prosodic features of the parental voice activate the infant’s interest in trying to communicate, highlighting this interaction. The second chapter brings to the fore the prenatal auditory experience of the fetus. Three studies carried out between 2013 and 2015 using the same ultrasound unit (DiPietro et al., 2013; Marx & Nagy, 2015; Voegtline, Costigan, Pater, & DiPietro, 2013) demonstrate that maternal voice is dominant among the sounds a fetus can perceive. It is interesting to discover that capturing an infant’s attention is more efficient when using a human voice compared to artificial sound (Vouloumanos & Werker, 2007) and even more efficient in sustaining attention and regulating emotions when singing compared to speaking (Corbeil, Trehub, & Peretz, 2016). The third chapter goes more in depth into the prenatal experience, demonstrating that language learning starts in the womb. German and French infants cry with a different pitch contour, which correlates to their mother language (Mampe, Friederici, Christophe, & Wermke, 2009). When it comes to communication, Chapter 4 showcases that infants are sensitive to social partners from birth, therefore producing sounds seeking out their partner’s attention—“protoconversation” (Lavelli & Fogel, 2013; Trevarthen, 1977, 1993). The content discussed stresses the significance of the ecological niche for the former’s development. In the last chapter of this part, Didier Grandjean talks a lot about the importance of understanding how the dyadic relationship of infant–parent is influenced by vocalizations, pointing out the impact of the emotions and the perception of them by specific areas of the human brain.

The second part of the book (Chapter 6) starts with Philbin’s analysis, debating soundscapes and the infant’s auditory system from gestation to the first weeks of life based on animal and human studies. The author stresses the fact that, despite previous research showing mother’s intrauterine heartbeat sound to be prominent (Bench, 1968; Grimwade, Walker, & Wood, 1970; Salk, 1960, 1962), later studies (Abrams & Gerhardt, 2000; Armitage, Baldwin, & Vince, 1980; Richards et al., 1992) employing more accurate measuring methods (e.g., vibroacoustic stimulation) conclude the mother’s voice signal to be more significant and prominent than her heartbeat sounds. By the same token, Philbin deals with the hearing conditions and measurements in the neonatal intensive care unit (NICU), calling for attention toward the need for SSC, which not only raises the mother’s voice signal level but also avoids masking and distraction in a noisy NICU acoustic environment. Continuing, Chapter 7 investigates the auditory sensitivity of preterm infants, providing a detailed description of the anatomical and functional development of the fetus’ auditory system. What has been briefly mentioned previously about infants’ preference on human voice over the artificial sound (Chapter 3) is now illuminated by a study measuring preterm infants’ heart and respiratory rates in an NICU. The authors showcase how the noisy and high-frequency sounds atypical of the environment of the NICUs may harm preterms’ well-being, further interfering with their neurodevelopment (Anand & Scalzo, 2000; Philbin, Lickliter, & Graven, 2000). This chapter ends by providing suggestions over a recommended acoustic environment.

The third (III) part of this book concentrates on early vocal contact (EVC) in the NICU, focusing on the maternal voice but without excluding fathers and other caregivers (Chapter 8). Manuela Filippa, one of the editors and principal authors of this book, cites a couple of vignette cases that deal with imitations and efforts of communication between the infant and the parent. Taking into consideration the fact that EVC is contributing to preterm infants’ physiological stability (Filippa et al., 2017), she is encouraging parents to start talking and singing to their infants, preferably in a position of physical closeness to build a unique companionship with them. Chapter 9 is underlying the importance of EVC and its potentially beneficial role to the infant’s health when stress and sleep are concerned. The authors encourage further research in the same direction while describing in detail the neurological, relational, and stress risks of the vulnerable preterm infants. They investigate how vital the process of the two sleep cycles (quiet and active) and the five behavioral states (Prechtl, 1974) are, throwing ample light on procedures that reduce detrimental environmental sounds in this context. According to Chapter 10, due to preterm infants’ increased risk of language and communication impairments (Barre, Morgan, Doyle, & Anderson, 2011), the necessity to investigate related environmental factors is brought to the fore, suggesting that auditory stimuli deprivation and early maternal separation could be significant factors leading to relevant delays. On this topic, an interesting comparison is taking place, matching a table of several studies on typical and optimal sound NICU environments. The eleventh chapter’s most substantial part concentrates on the bioecology of the newborn. Different infant microsystems (i.e., micro-, meso-, macro-, exo-system) are discussed according to Bronfenbrenner’s ecological theory, while existing alterations of these infant microsystems in the NICU explained. A selection of studies is further presented on this topic, expanding on music therapy practices through recorded (i.e., instrumental or maternal) (Dearn & Shoemark, 2014; Krueger, 2010; Shoemark, Hanson-Abromeit, & Stewart, 2015) and live (Loewy et al., 2016) music. According to the authors of these studies, research is further in need while promoting modern NICUs’ mother–infant communication and contact.

The analysis of EVC in the NICU leads to the fourth (IV) part of this book. Starting with the twelfth chapter, this outlines the role of the music therapist attempting to encourage and give opportunities to the parents to sing in three phases (i.e., anticipatory, cautious interplay, and active parenting), while empowering singing in the NICU, Chapter 13 illustrates how family-centered intervention in the NICU can eliminate parents’ hesitations. For this reason, several approaches, such as “Kangaroo Care” and “Creative and Clinical music therapy”, are investigated, while Friederike Haslbeck and Pernilla Hugoson present two music therapy case vignettes (Sweden and Switzerland) concluding that family-centered music therapy with SSC stimulates communication and creates the first foundations of the parent–infant relationship and bonding.

The beginning of the fifth (V) and last part of this book in Chapter 14 introduces the reader to a selection of studies that measure parental brain activity using functional magnetic resonance imaging (fMRI). These studies employ infant stimuli to measure parenting sensitivity through behaviors such as fear and joy, emotion regulation and response, empathy, and reflective function, as well as exposure to stress. The book authors suggest that although these studies have significantly contributed to a better understanding of the parenting framework, six critical unanswered questions remain, stressing the need for more research on the subject (Chapter 14). Chapter 15, on the contrary, focuses on emotional infant–mother communication through a theory called Family Nurture Intervention (FNI). FNI aims to be a therapeutic method during which senses enhance the exchange and connection of emotions, seeking calmness through mutual bonding. The authors of this chapter compare a standard NICU with an FNI-inclusive NICU, showcasing remarkably beneficial results for both mother and infant. In that matter, a few more theories are analyzed, including the “Calming Cycle Theory” and the “Four Questions of Tinbergen (causation, ontogeny, function, and evolution)”, as well as the Pavlovian theory of co-conditioning. In the book’s penultimate chapter (Chapter 16), the mechanism of DNA methylation is investigated in animals as well as in humans, investigating and explaining on that very base how EVC and caring interventions in the NICU could eliminate stress when a dyadic harmony (Theorell, 2014) is present. According to the authors of this chapter, this process may create positive correlations to favorable DNA modifications, which as a fact debates and highlights the utmost importance of epigenetics in the NICU (Maddalena, 2013; Provenzi & Barello, 2015; Samra, McGrath, Wehbe, & Clapper, 2012). Finally, the last chapter (17) aims to extend the book’s content, evaluating family-based interventions and developmental care programs. The authors suggest more relevant research interventions to focus on the maternal voice itself while not forgetting other holistic approaches favoring vocal, optical, and behavioral stimuli communication for the infant–parent dyad.

Reading all the above, we have concluded that this book achieves its goal of informing the reader at a significant level on many fundamental concepts related to its field, offering an efficient and valuable battery of scientific evidence through the variation of its contributions. However, it is also our opinion that not all of the book’s parts equally correspond to the assigned title. While indeed some of the parts directly cover the “brain development” field as suggested, in the end, we understood that most of them showcase a deep link and interest to the maternal voice-NICU system at a behavioral–psychological level rather the biological one, as someone would expect from the book title. This fact builds a quite disorienting flow of expectations which are left somehow half-met toward the completion of the reading. Perhaps omitting the word “brain” from the title or including more neuroimaging studies in the book would have brought a better alignment between its content and title. In addition, we would like to see some more case studies being included, fulfilling further the communication need for action and field research in the specific domain.

Overall, the book reads very well as we have already suggested at the beginning of our review, and we certainly believe that it justifiably raises curiosity and thirst to learn more in this specific field of the newborn’s EVC and development. The synthesis of this book makes an excellent tool for advancing interdisciplinary studies, as well as a great addition to any library dealing with the frontiers of research in the early years development field.