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Maizie Rodney hears her mother's voice through two speakers in her incubator.
On an early July evening just three weeks after she was born, Maizie Rodney fell asleep to the sound of her mother’s voice reading a story, singing softly and talking about Maizie’s older siblings. “She just sighed and closed her eyes,” said her mother, Tiffany Rodney, with a laugh.
What makes this otherwise ordinary event remarkable is that the soothing sounds of her mother’s voice are delivered to Maizie by a set of small speakers perched in the corners of her isolette in BWH’s NICU. Born at just 26 weeks and five days, and weighing slightly more than two pounds, Maizie is one of the first infants to be enrolled in a study examining the effects of auditory exposure to maternal sounds on brain development of extremely vulnerable newborns.
“We’ve made great progress at preserving the womb environment for premature babies – the incubator does a pretty good job temperature- and humidity-wise,” said Amir Lahav, ScD, PhD, director of the Neonatal Audio Facilitation Program and principal investigator of the study. “What’s missing, unfortunately, is simulation of the auditory environment that these babies otherwise miss out on.”
Lahav aims to fill that gap. Infants enrolled in his study are exposed to 45 minutes of maternal sounds, four times per day, throughout their NICU hospitalization. Each infant receives a personalized soundtrack—consisting of his or her mother’s voice and heartbeat—that is played into the incubator via a specialized micro audio system designed by Lahav. Infants will undergo three MRI brain scans before discharge to determine the effects of soothing maternal sounds.
“We now have the technology and skilled caregivers to ensure that most preemies will survive, but too often they still have neurodevelopmental problems. There is increasing evidence that some of these may be due to the impact of environment on the developing brain,” said Steven Ringer, MD, PhD, chief of the Division of Newborn Medicine. “The potential of this study is enormous because it begins to explore how we might modify the NICU into a more supportive and appropriate environment, retaining some of the positive benefits of the womb.”
Lahav and his research team, which includes Robert Insoft, MD, Elisha Wachman, MD, Jenny Yu, MD, Marianne Moore, RN, Marcia Filip, RN, Emily Stone, BS, and Phil Levin, BS, ultimately plan to enroll 100 premature babies in the study; of these, half will be randomized to hear the maternal sounds intervention.. They will then track the infants’ short- and long-term outcomes, including sensory, cognitive and language development.
Amir Lahav's recording studio is outfitted with a digital stethoscope, microphones and special recording software.
The decision to enroll Maizie in the study was an easy one for Rodney and her husband, Courtney, as they had spent the early months of her pregnancy reading, singing and talking to their daughter. “Since we were already doing the same kinds of things, we were actually super-prepared to do the study,” she said. “We were really excited to be able to do anything to make it closer to being in utero for her.”
Once an infant is enrolled in the study, the mother visits the Lahav Lab’s recording studio to make audio tracks of her heartbeat and voice. Audio technician John Panagiotidis first uses a digital stethoscope to record the mother’s heartbeat. Then, with the help of CCI Research Coordinator Emily Stone, he guides the mother through a series of recordings, capturing three types of vocalization: reading, conversational speaking and singing.
“I sang ‘Bicycle Built for Two,’ which is about a girl named Daisy, but I replaced ‘Daisy’ with ‘Maizie,’ and another song that we made up for her,” said Rodney. “And for the book, I read to her from the summary of The Alchemist, because my husband and I both love it.”
During the recording, Lahav said, mothers are encouraged to close their eyes and imagine they are talking at the bedside of their baby.
“This is a very special moment for many mothers,” Lahav added. “It gives them the opportunity to take an active part in the care of their baby and be present even when they are not physically in the NICU.”
“The only part I was scared about was the singing, because I’m not a singer,” said Rodney as she recalled the recording process. “We saved that part for last, and when it was time, I just kind of said, ‘OK, I’m doing this for her.’”
When the recording is done, Panagiotidis streams the vocal portions over the heartbeat, rotating through the three types of voice recordings and adding 10 minutes of calming instrumental music. The final track is produced at a low frequency that is audible but not harmful to premature infants, and then uploaded onto a small MP3 player installed in a docking station behind the infant’s incubator. To the infant, the voices coming through the two speakers sound faint and muffled, just as noises would be to a baby in the womb.
“This is uncharted territory, and it’s exciting to have an opportunity to evaluate this intervention in a scientific way,” said neonatologist Richard Parad, MD, MPH. “If the study finds that it positively impacts an infant’s neurological developmental outcome, it could affect a portion of our care management that we could modify fairly easy.”
Julianne Mazzawi, MS, RN, NICU assistant nursing director, echoes this sentiment: “It’s great for the parents because it encourages the moms to connect with their babies,” she said. “It’s comforting for the babies in the short-term, and we are hopeful this study will show a positive long-term effect, too.”
“This area of research is still premature,” added Lahav. “But the enormous support we are getting from the hospital leadership, including doctors, nurses, respiratory therapists, biomedical engineers and administrative staff is simply incredible.”