Newborn & Infant Nursing Reviews 15 (2015) 46–48
Contents lists available at ScienceDirect
Newborn & Infant Nursing Reviews journal homepage: www.nainr.com
Neonatal Therapy Column National Association of Neonatal Therapists (NANT)
Implementation of the NTrainer System into Clinical Practice Targeting Neurodevelopment of Pre-oral Skills and Parental Involvement☆ Angela Soos, OTR/L ⁎, Alicia Hamman, OTR/L 1 The Ohio State University Wexner Medical Center- NICU, Acute Rehabilitative Services, 410 W 10th Ave 539 Doan Hall, Columbus, Ohio 43210
a r t i c l e
i n f o
Keywords: neonatal therapy NTrainer neonatal feeding
a b s t r a c t The initiation of early oral motor assessments by neonatal occupational therapists (OT) and the implementation of an NTrainer system to help facilitate feeding progression in the premature infant population was incorporated into practice by the Ohio State University Wexner Medical Center (OSUWMC) who partnered with Nationwide Children’s Hospital, Columbus, Ohio. OSUWMC did not have a set protocol to use with infants prior to beginning oral feeds and studies have found that providing oral motor stimulation in a consistent manner accelerates transition time to oral feeds. Anecdotally, through observation, repeated experience and data recorded by the NTrainer, the NICU team as a whole noted that infants who received early oral motor assessments by the neonatal OT and NTrainer therapy demonstrated a more mature NNS pattern, improved suck strength, and a decreased hypersensitivity to oral motor intervention, overall positively affecting the neurodevelopment of the preterm infant. These combined therapies also resulted in the development of a standard feeding guideline that begins at 29 weeks gestational age (GA). © 2015 Elsevier Inc. All rights reserved.
Introduction Susan Ludwig, OTR/L, Column Editor Neonatal Therapists are an essential part of the NICU team. A Neonatal Therapist is an occupational therapist, physical therapist or speech language pathologist who delivers holistic direct patient care and consultative services to premature and medically complex infants in a Neonatal Intensive Care Unit (NICU). Using an integrated, neuroprotective, family-centered model, neonatal therapists provide highly specialized and individualized therapeutic interventions in the NICU. These interventions support optimal long-term development, prevent adverse sequelae, and nurture the infant-family dyad. Neonatal therapists also provide education to the family and NICU team. 1 This column features contributions to quality improvement, research, safety and clinical practice made by and/or in collaboration with neonatal therapists. President and Founder National Association of Neonatal Therapists (NANT)
☆ National Association of Neonatal Therapists (NANT), (President, Susan Ludwig, OTR/L) P.O. Box 531790, Cincinnati, OH 45253–1790 ⁎ Corresponding author at: 410 W. 10th Ave Columbus, Ohio 43210. Tel.: +1 614 293 8492. E-mail addresses: [email protected] (A. Soos), [email protected] (A. Hamman), [email protected] (S. Ludwig). URL: http://www.neonataltherapists.com (S. Ludwig). 1 410 W. 10th Ave Columbus, Ohio 43210. http://dx.doi.org/10.1053/j.nainr.2015.04.012 1527-3369/© 2015 Elsevier Inc. All rights reserved.
NCH NICU at OSUWMC The Nationwide Children’s Hospital (NCH) operates the NICU at The Ohio State University Wexner Medical Center (OSUWMC) as a satellite facility within OSUWMC maternity unit. The NCH NICU at OSUWMC works in close partnership to deliver fully integrated quality of care of mom and baby. OSUWMC is a birthing hospital with an average of 4000 births per year and has a specialty focus on high-risk obstetrics. Because of this, the hospital also offers a 49-bed level IIIb NICU to provide care for fragile newborns. The NICU can support infants born at ≥24 weeks gestation and can provide advanced respiratory support including high frequency oscillating ventilation (HFOV) and inhaled nitric oxide (iNO). Some of the neonatal medical diagnoses that are treated include prematurity, respiratory distress, meconium aspiration syndrome (MAS), persistent pulmonary hypertension (PPHN), infants of diabetic mothers (IDM), neonatal narcotic abstinence syndrome (NAS), and various genetic/ chromosomal abnormalities. The NICU also serves as a stabilization center for infants born with complications that require specialty services or surgical intervention due to its close proximity to Nationwide Children’s Hospital. Pre-oral Therapeutic Interventions The standard therapeutic intervention for pre oral development has been up for much debate for the past several years. Oral motor stimulation seems to be the target of change for these fragile newborns. Various practices include tactile stimulation to infant’s lips, cheeks, mouth and tongue as well as non nutritive sucking at breast and/or pacifier with
A. Soos, A. Hamman / Newborn & Infant Nursing Reviews 15 (2015) 46–48
or without taste trials. Prior to the use of the NTrainer as a pre oral motor standard of practice, OSUWMC did not have a set protocol to use with infants prior to beginning oral feeds. Overall, studies have found that providing oral motor stimulation in a consistent manner accelerates transition time to oral feeds.2 Implementation of NTrainer In December 2012, a collaborative decision to implement the NTrainer system to help facilitate feeding progression in the premature infant population was made by hospital management, the NICU medical director, the NICU nurse managers, the occupational and physical therapy group, and the rehabilitation department. Innara Health (Shawnee, KS) provided staff education on the neurologic and scientific evidence supporting the NTrainer System. At first, the nursing staff was hesitant in accepting this new technology; however, within the first year, they began to see the benefits and embraced this therapeutic intervention. They are currently helping to identify eligible infants and working closely with the therapy team. A multi-disciplinary team including a neonatologist, neonatal nurse practitioners (NNP), nurses, and occupational therapists (OT) was formed to develop a standardized feeding approach across the spectrum of an infant’s hospitalization. Prior to the NTrainer System, there was minimal OT involvement in the NICU and no standard feeding approach. With this collaborative team, occupational therapy services were brought into the NICU as full-time staff to provide early oral motor assessment and intervention via the NTrainer System, which resulted in the development of a standard feeding guideline that begins at 29 weeks gestational age (GA). The primary goal of the guideline is to facilitate a developmentally supportive, safe and efficient transition to independent oral feeding in the preterm infant. The guidelines are instituted on admission to the NICU and depend on gestational age and medical status. Stage One Infants 29–31 weeks GA who have been deemed medically stable [extubated, off vasopressor support, and able to be offered a pacifier for non-nutritive sucking (NNS) opportunities] begin stage one of the feeding guideline. This includes introducing positive oral motor experiences such as therapeutic tasting of breast milk or formula via pacifier “dips” and providing NNS opportunities on a quiet pacifier or at the breast during gavage feedings. The goal is to provide at least one session a day for 7–14 days. Stage Two Stage two begins with infants at 31–33 weeks GA who have been deemed medically stable (extubated, off nCPAP, weaning caffeine, and tolerating full enteral feedings). This stage involves the implementation of NTrainer therapy and the transition from NNS to nutritive suck. NTrainer therapy is administered three times a day for approximately 10 days, but the number of days is adjusted depending on infant response and readiness for oral feeding. The goal of NTrainer therapy is to improve the quality and consistency of NNS by stimulating motor neurons to strengthen central pathways that regulate suck and ororhythmic activity. Ideally, therapy is administered during gavage feedings so that the infant begins to link sucking with satiation. To evaluate response to therapy, daily NTrainer assessments are obtained and provide visual data about NNS characteristics. As the infant begins to demonstrate more coordinated, rhythmic sucking bursts and increased suction strength, NTrainer therapy is tapered and oral feedings are gradually introduced. It is well known throughout the literature that infants begin practicing the suck/swallow/breathe pattern around 15 weeks gestation. 3 However, Barlow, Finan, Lee & Chu (2008), have stated
47
“neuronal circuits are shaped by experience during critical periods of early post-natal life and may remain in a waiting state until appropriate sensory input is provided.” 3 The NTrainer provides that sensory input by “centrally generating oral motor patterns produced by, which can be entrained to an applied oral cutaneous stimulus, which serves to induce synchronous patterned neural activity along trigeminal primary afferents and lemniscal pathways.”4 Stage Three Stage three is the last stage and involves the implementation of nutritive suck and cue-based feedings. This begins at approximately 33 weeks GA and/or when stage two criteria have been met. During this stage, the infant receives a readiness score that is assessed at each feeding (gavage or oral) based on level of alertness and oro-motor reflexes/infant cues. Once oral feedings are initiated, a quality score is determined based on the infant’s performance and physiologic stability. The score is a strong indicator of oral feeding advancement. The goal of stage three is to provide staff and families with a patient-based, objective plan of care to safely, systematically, and efficiently progress to full oral feedings, which ultimately result in earlier discharges and decreased lengths of stays (LOS). Clinical Observations Related to NTrainer Use and Feeding Guideline Infants Anecdotally, through observation, repeated experience and data recorded by the NTrainer, the NICU team as a whole noted that infants who received NTrainer therapy demonstrated a more mature NNS pattern, improved suck strength, and a decreased hypersensitivity to oral motor intervention overall positively affecting the neurodevelopment of the preterm infant. They frequently show an earlier appearance of pre-feeding cues during care times, such as bringing their hands to their faces and/or mouths; rooting; and eagerly sucking on their hands, fingers or pacifiers, all of which assist in the transition to oral feeding. In addition, improvement in physiologic stability during handling with less bradycardia and desaturation events associated with feeding was documented, as well as improved state transition/duration and increased social interaction. Finally, referrals and transfers for more invasive feeding studies have decreased since the NTrainer has been implemented. “The NTrainer has proved to be a unique therapy that we have integrated into our daily cares. Our OTs and PTs have shown parents how to use this therapy with their infant. It has helped parents bond with their baby in a special way that a parent of a 31–33 weeker hasn't experienced. Typically the infant is more alert or develops this alertness during their NTrainer session, which allows the parent to interact via positive stimuli. When an infant who has completed the NTrainer sessions begins to breast/bottle feed, they seem to have learned how to pause at the breast or bottle. In addition, they are showing more signs of readiness for oral attempts. When these infants who have been exposed to the NTrainer follow a cue-based feeding guideline, they have been more successful at achieving full oral feedings.” [Lauren Rufener, RN]
Parents One major benefit of the NTrainer is the opportunity to encourage and support parent involvement. During NTrainer therapy sessions, the therapist can provide bedside education on oral feeding readiness and help parents identify their infant’s specific feeding cues. Parents can hold their infant during therapy and practice placing their infant
48
A. Soos, A. Hamman / Newborn & Infant Nursing Reviews 15 (2015) 46–48
in appropriate feeding positions. These early opportunities increase self-confidence and empower parents to participate in the care of their infant as members of the multi-disciplinary team. Parents can also learn how to read the daily assessment and gauge their infant’s response to therapy. As their infant makes the transition from gavage to independent oral feeding, parents use the information they learned during NTrainer sessions to respond appropriately to their infant’s feeding signals, thereby increasing safe and successful long-term feeding experiences. “I feel that the NTrainer helped prepare my babies for bottle feeding in several ways. When it came time to actually bottle feed, they both seemed to know what to do. I think it also helped with their stamina because the NTrainer encouraged them to be actively engaged. It was great to see the assessment from day to day and see the improvements in coordination. Another piece I found invaluable was the time spent with the PT or OT because they provided me with invaluable education regarding stress signals and what to look for successful signs of feeding. When it came time to bottle feed, my babies seemed ready to suck and I could see their coordination improving each day.” [Christina Dalzell, NICU parent]
Future Outlook Given the positive experiences of using the NTrainer, OSUWMC hopes to target other populations for NTrainer assessment and therapy. Though it will require additional staff and equipment, the NICU staff is exploring expansion of the eligible patient population to include infants on nasal continuous airway pressure (nCPAP) and neonatal abstinence syndrome (NAS) exposure as a means to provide a pre-oral stimulation for introductory breastfeeding experiences. In addition, it will prove beneficial to conduct a randomized controlled trial comparing infants receiving NTrainer therapy versus infants receiving traditional nonnutritive suck experiences to assess amount of time to full oral feeds and/or changes in length of stay. References 1. National Association of Neonatal Nurses (NANT). http://neonataltherapists.com/faq. [Accessed April 2, 2015]. 2. Fucile S, Gisel E, Lau C. Oral stimulation accelerates the transition from tube to oral feeding in preterm infants. J Pediatr. 2002;14:230-6. 3. Brenton S, Steinwender S. Timing introduction and transition to oral feeding in preterm infants: current trends and practice. Newborn Infant Nurs Rev. 2008;8:153-9. 4. Barlow SM, Finan DS, Lee J, Chu S. Synthetic orocutaneous stimulation entrains preterm infants with feeding difficulties to suck. J Perinatol. 2008;28:541-8.
Contents lists available at ScienceDirect
Newborn & Infant Nursing Reviews journal homepage: www.nainr.com
Neonatal Therapy Column National Association of Neonatal Therapists (NANT)
Implementation of the NTrainer System into Clinical Practice Targeting Neurodevelopment of Pre-oral Skills and Parental Involvement☆ Angela Soos, OTR/L ⁎, Alicia Hamman, OTR/L 1 The Ohio State University Wexner Medical Center- NICU, Acute Rehabilitative Services, 410 W 10th Ave 539 Doan Hall, Columbus, Ohio 43210
a r t i c l e
i n f o
Keywords: neonatal therapy NTrainer neonatal feeding
a b s t r a c t The initiation of early oral motor assessments by neonatal occupational therapists (OT) and the implementation of an NTrainer system to help facilitate feeding progression in the premature infant population was incorporated into practice by the Ohio State University Wexner Medical Center (OSUWMC) who partnered with Nationwide Children’s Hospital, Columbus, Ohio. OSUWMC did not have a set protocol to use with infants prior to beginning oral feeds and studies have found that providing oral motor stimulation in a consistent manner accelerates transition time to oral feeds. Anecdotally, through observation, repeated experience and data recorded by the NTrainer, the NICU team as a whole noted that infants who received early oral motor assessments by the neonatal OT and NTrainer therapy demonstrated a more mature NNS pattern, improved suck strength, and a decreased hypersensitivity to oral motor intervention, overall positively affecting the neurodevelopment of the preterm infant. These combined therapies also resulted in the development of a standard feeding guideline that begins at 29 weeks gestational age (GA). © 2015 Elsevier Inc. All rights reserved.
Introduction Susan Ludwig, OTR/L, Column Editor Neonatal Therapists are an essential part of the NICU team. A Neonatal Therapist is an occupational therapist, physical therapist or speech language pathologist who delivers holistic direct patient care and consultative services to premature and medically complex infants in a Neonatal Intensive Care Unit (NICU). Using an integrated, neuroprotective, family-centered model, neonatal therapists provide highly specialized and individualized therapeutic interventions in the NICU. These interventions support optimal long-term development, prevent adverse sequelae, and nurture the infant-family dyad. Neonatal therapists also provide education to the family and NICU team. 1 This column features contributions to quality improvement, research, safety and clinical practice made by and/or in collaboration with neonatal therapists. President and Founder National Association of Neonatal Therapists (NANT)
☆ National Association of Neonatal Therapists (NANT), (President, Susan Ludwig, OTR/L) P.O. Box 531790, Cincinnati, OH 45253–1790 ⁎ Corresponding author at: 410 W. 10th Ave Columbus, Ohio 43210. Tel.: +1 614 293 8492. E-mail addresses: [email protected] (A. Soos), [email protected] (A. Hamman), [email protected] (S. Ludwig). URL: http://www.neonataltherapists.com (S. Ludwig). 1 410 W. 10th Ave Columbus, Ohio 43210. http://dx.doi.org/10.1053/j.nainr.2015.04.012 1527-3369/© 2015 Elsevier Inc. All rights reserved.
NCH NICU at OSUWMC The Nationwide Children’s Hospital (NCH) operates the NICU at The Ohio State University Wexner Medical Center (OSUWMC) as a satellite facility within OSUWMC maternity unit. The NCH NICU at OSUWMC works in close partnership to deliver fully integrated quality of care of mom and baby. OSUWMC is a birthing hospital with an average of 4000 births per year and has a specialty focus on high-risk obstetrics. Because of this, the hospital also offers a 49-bed level IIIb NICU to provide care for fragile newborns. The NICU can support infants born at ≥24 weeks gestation and can provide advanced respiratory support including high frequency oscillating ventilation (HFOV) and inhaled nitric oxide (iNO). Some of the neonatal medical diagnoses that are treated include prematurity, respiratory distress, meconium aspiration syndrome (MAS), persistent pulmonary hypertension (PPHN), infants of diabetic mothers (IDM), neonatal narcotic abstinence syndrome (NAS), and various genetic/ chromosomal abnormalities. The NICU also serves as a stabilization center for infants born with complications that require specialty services or surgical intervention due to its close proximity to Nationwide Children’s Hospital. Pre-oral Therapeutic Interventions The standard therapeutic intervention for pre oral development has been up for much debate for the past several years. Oral motor stimulation seems to be the target of change for these fragile newborns. Various practices include tactile stimulation to infant’s lips, cheeks, mouth and tongue as well as non nutritive sucking at breast and/or pacifier with
A. Soos, A. Hamman / Newborn & Infant Nursing Reviews 15 (2015) 46–48
or without taste trials. Prior to the use of the NTrainer as a pre oral motor standard of practice, OSUWMC did not have a set protocol to use with infants prior to beginning oral feeds. Overall, studies have found that providing oral motor stimulation in a consistent manner accelerates transition time to oral feeds.2 Implementation of NTrainer In December 2012, a collaborative decision to implement the NTrainer system to help facilitate feeding progression in the premature infant population was made by hospital management, the NICU medical director, the NICU nurse managers, the occupational and physical therapy group, and the rehabilitation department. Innara Health (Shawnee, KS) provided staff education on the neurologic and scientific evidence supporting the NTrainer System. At first, the nursing staff was hesitant in accepting this new technology; however, within the first year, they began to see the benefits and embraced this therapeutic intervention. They are currently helping to identify eligible infants and working closely with the therapy team. A multi-disciplinary team including a neonatologist, neonatal nurse practitioners (NNP), nurses, and occupational therapists (OT) was formed to develop a standardized feeding approach across the spectrum of an infant’s hospitalization. Prior to the NTrainer System, there was minimal OT involvement in the NICU and no standard feeding approach. With this collaborative team, occupational therapy services were brought into the NICU as full-time staff to provide early oral motor assessment and intervention via the NTrainer System, which resulted in the development of a standard feeding guideline that begins at 29 weeks gestational age (GA). The primary goal of the guideline is to facilitate a developmentally supportive, safe and efficient transition to independent oral feeding in the preterm infant. The guidelines are instituted on admission to the NICU and depend on gestational age and medical status. Stage One Infants 29–31 weeks GA who have been deemed medically stable [extubated, off vasopressor support, and able to be offered a pacifier for non-nutritive sucking (NNS) opportunities] begin stage one of the feeding guideline. This includes introducing positive oral motor experiences such as therapeutic tasting of breast milk or formula via pacifier “dips” and providing NNS opportunities on a quiet pacifier or at the breast during gavage feedings. The goal is to provide at least one session a day for 7–14 days. Stage Two Stage two begins with infants at 31–33 weeks GA who have been deemed medically stable (extubated, off nCPAP, weaning caffeine, and tolerating full enteral feedings). This stage involves the implementation of NTrainer therapy and the transition from NNS to nutritive suck. NTrainer therapy is administered three times a day for approximately 10 days, but the number of days is adjusted depending on infant response and readiness for oral feeding. The goal of NTrainer therapy is to improve the quality and consistency of NNS by stimulating motor neurons to strengthen central pathways that regulate suck and ororhythmic activity. Ideally, therapy is administered during gavage feedings so that the infant begins to link sucking with satiation. To evaluate response to therapy, daily NTrainer assessments are obtained and provide visual data about NNS characteristics. As the infant begins to demonstrate more coordinated, rhythmic sucking bursts and increased suction strength, NTrainer therapy is tapered and oral feedings are gradually introduced. It is well known throughout the literature that infants begin practicing the suck/swallow/breathe pattern around 15 weeks gestation. 3 However, Barlow, Finan, Lee & Chu (2008), have stated
47
“neuronal circuits are shaped by experience during critical periods of early post-natal life and may remain in a waiting state until appropriate sensory input is provided.” 3 The NTrainer provides that sensory input by “centrally generating oral motor patterns produced by, which can be entrained to an applied oral cutaneous stimulus, which serves to induce synchronous patterned neural activity along trigeminal primary afferents and lemniscal pathways.”4 Stage Three Stage three is the last stage and involves the implementation of nutritive suck and cue-based feedings. This begins at approximately 33 weeks GA and/or when stage two criteria have been met. During this stage, the infant receives a readiness score that is assessed at each feeding (gavage or oral) based on level of alertness and oro-motor reflexes/infant cues. Once oral feedings are initiated, a quality score is determined based on the infant’s performance and physiologic stability. The score is a strong indicator of oral feeding advancement. The goal of stage three is to provide staff and families with a patient-based, objective plan of care to safely, systematically, and efficiently progress to full oral feedings, which ultimately result in earlier discharges and decreased lengths of stays (LOS). Clinical Observations Related to NTrainer Use and Feeding Guideline Infants Anecdotally, through observation, repeated experience and data recorded by the NTrainer, the NICU team as a whole noted that infants who received NTrainer therapy demonstrated a more mature NNS pattern, improved suck strength, and a decreased hypersensitivity to oral motor intervention overall positively affecting the neurodevelopment of the preterm infant. They frequently show an earlier appearance of pre-feeding cues during care times, such as bringing their hands to their faces and/or mouths; rooting; and eagerly sucking on their hands, fingers or pacifiers, all of which assist in the transition to oral feeding. In addition, improvement in physiologic stability during handling with less bradycardia and desaturation events associated with feeding was documented, as well as improved state transition/duration and increased social interaction. Finally, referrals and transfers for more invasive feeding studies have decreased since the NTrainer has been implemented. “The NTrainer has proved to be a unique therapy that we have integrated into our daily cares. Our OTs and PTs have shown parents how to use this therapy with their infant. It has helped parents bond with their baby in a special way that a parent of a 31–33 weeker hasn't experienced. Typically the infant is more alert or develops this alertness during their NTrainer session, which allows the parent to interact via positive stimuli. When an infant who has completed the NTrainer sessions begins to breast/bottle feed, they seem to have learned how to pause at the breast or bottle. In addition, they are showing more signs of readiness for oral attempts. When these infants who have been exposed to the NTrainer follow a cue-based feeding guideline, they have been more successful at achieving full oral feedings.” [Lauren Rufener, RN]
Parents One major benefit of the NTrainer is the opportunity to encourage and support parent involvement. During NTrainer therapy sessions, the therapist can provide bedside education on oral feeding readiness and help parents identify their infant’s specific feeding cues. Parents can hold their infant during therapy and practice placing their infant
48
A. Soos, A. Hamman / Newborn & Infant Nursing Reviews 15 (2015) 46–48
in appropriate feeding positions. These early opportunities increase self-confidence and empower parents to participate in the care of their infant as members of the multi-disciplinary team. Parents can also learn how to read the daily assessment and gauge their infant’s response to therapy. As their infant makes the transition from gavage to independent oral feeding, parents use the information they learned during NTrainer sessions to respond appropriately to their infant’s feeding signals, thereby increasing safe and successful long-term feeding experiences. “I feel that the NTrainer helped prepare my babies for bottle feeding in several ways. When it came time to actually bottle feed, they both seemed to know what to do. I think it also helped with their stamina because the NTrainer encouraged them to be actively engaged. It was great to see the assessment from day to day and see the improvements in coordination. Another piece I found invaluable was the time spent with the PT or OT because they provided me with invaluable education regarding stress signals and what to look for successful signs of feeding. When it came time to bottle feed, my babies seemed ready to suck and I could see their coordination improving each day.” [Christina Dalzell, NICU parent]
Future Outlook Given the positive experiences of using the NTrainer, OSUWMC hopes to target other populations for NTrainer assessment and therapy. Though it will require additional staff and equipment, the NICU staff is exploring expansion of the eligible patient population to include infants on nasal continuous airway pressure (nCPAP) and neonatal abstinence syndrome (NAS) exposure as a means to provide a pre-oral stimulation for introductory breastfeeding experiences. In addition, it will prove beneficial to conduct a randomized controlled trial comparing infants receiving NTrainer therapy versus infants receiving traditional nonnutritive suck experiences to assess amount of time to full oral feeds and/or changes in length of stay. References 1. National Association of Neonatal Nurses (NANT). http://neonataltherapists.com/faq. [Accessed April 2, 2015]. 2. Fucile S, Gisel E, Lau C. Oral stimulation accelerates the transition from tube to oral feeding in preterm infants. J Pediatr. 2002;14:230-6. 3. Brenton S, Steinwender S. Timing introduction and transition to oral feeding in preterm infants: current trends and practice. Newborn Infant Nurs Rev. 2008;8:153-9. 4. Barlow SM, Finan DS, Lee J, Chu S. Synthetic orocutaneous stimulation entrains preterm infants with feeding difficulties to suck. J Perinatol. 2008;28:541-8.
