The effect of listening to lullaby music on physiologic response and weight gain of premature infants

Abstract

Objectives: The environment plays a key role in survival and brain development for premature infants. Recent interest lends consideration to non pharmacological interventions as a beneficial alternative. This study seeks to investigate the effect of lullaby music on the physiological response and weight gain of premature infants in Mashhad, Iran.
Method: In this study, 44 very low birth weight infants ⩽ 34 weeks of gestational age that were admitted to the Neonatal Intensive Care Unit (NICU) of Imamreza Hospital in Mashhad, Iran were enrolled. Infants were randomly assigned to one of two groups: the Music group and the Control group. Lullaby music was played through earphones for the Music group. This continued for 8 days at 20 minutes per day. The Control group received routine auditory stimulation. Neonates in the two groups were in stable condition and kept in their isolettes. Infants were monitored for 40 minutes; 10 minutes baseline, 20 minutes into the intervention and 10 minutes post intervention. Data measures were heart rate, respiration rate, oxygen saturation and body weight.
Result: The two groups differed significantly in the respiratory rate (p= 0.01) and oxygen saturation (p= 0.001). There were no significant differences in the heart rate (p= 0.24) and weight gain (p= 0.093) between the two groups.
Conclusion: Preterm infants respond to lullaby music as evidenced by the changes in their respiratory rates and oxygen saturations. Although this study did not demonstrate an improvement in weight gain, further studies are recommended to examine the effect of music on other growth and developmental aspects

Full text

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Journal of Neonatal-Perinatal Medicine 3 (2010) 1–5 1
DOI 10.3233/NPM-2010-0101
IOS Press
The effect of listening to lullaby music on
physiologic response and weight gain of
premature infants1
a b,∗c d
a
aMedical School, Neonatal Research Center, Mashhad University of Medical Science, and NICU of Emamreza
Hospital, Mashhad, Iran
bFaculty of Nursing and Midwifery, Neonatal Research Center, Mashhad University of Medical Science, Mashhad,
Iran
cFaculty of Nursing and Midwifery, Mashhad University of Medical Science, Mashhad, Iran
d
Received 18 June 2009
Revised 12 August 2009
Accepted 20 October 2009
Abstract.Objectives: The environment plays a key role in survival and brain development for premature infants. Recent interest
lends consideration to non pharmacological interventions as a beneficial alternative. This study seeks to investigate the effect of
lullaby music on the physiological response and weight gain of premature infants in Mashhad, Iran.
Method: In this study, 44 very low birth weight infants 34 weeks of gestational age that were admitted to the Neonatal Intensive
Care Unit (NICU) of Imamreza Hospital in Mashhad, Iran were enrolled. Infants were randomly assigned to one of two groups:
the Music group and the Control group. Lullaby music was played through earphones for the Music group. This continued for 8
days at 20 minutes per day. The Control group received routine auditory stimulation. Neonates in the two groups were in stable
condition and kept in their isolettes. Infants were monitored for 40 minutes; 10 minutes baseline, 20 minutes into the intervention
and 10 minutes post intervention. Data measures were heart rate, respiration rate, oxygen saturation and body weight.
Result: The two groups differed significantly in the respiratory rate (p=0.01) and oxygen saturation (p=0.001). There were
no significant differences in the heart rate (p=0.24) and weight gain (p=0.093) between the two groups.
Conclusion: Preterm infants respond to lullaby music as evidenced by the changes in their respiratory rates and oxygen saturations.
Although this study did not demonstrate an improvement in weight gain, further studies are recommended to examine the effect
of music on other growth and developmental aspects.
Keywords: Lullaby music, physiologic response, weight gain, preterm infants
1This study has been funded by Mashhad University of Medical
Science.
∗Corresponding author: Amiri Rana, Neonatal Research Center,
NICU, Emamreza Hospital, Mashhad, Iran. Tel.: +98 5112709006;
Mobile: +98 9153065625; E-mail: amirir1@mums.ac.ir.
1. Introduction
The neonatal period is the most vulnerable period
of human life, so it should be given careful considera-
tion [1]. The incidence of premature birth varies from
6–15% and is related to geographic and demographic
status [2]. Approximately 9% of all births are admit-
1934-5798/10/$27.50 2010 – IOS Press and the authors. All rights reserved
Biostatistics department, Mashhad University of Mghkvhujhjvubiljknm ;',;,'edical Science, Mashhad, Iran
Ahmadshah Farhat RanaAmiri Sohaila Karbandi Habibollah Esmaily
Ashraf Mohammadzadeh

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ted to the Neonatal Intensive Care Unit (NICU), 7.7%
of births are low birth weight (LBW) and 1.5% very
low birth weight (VLBW) [3]. The major challenges
preterm infants face is weight gain and lung develop-
ment. Medical therapy such as assisted ventilation,
antenatal steroids and surfactant replacement therapy
have been increasingly effective in reducing mortali-
ty [4]. The environment provided to premature infants
is important, not only fortheir survivalbut also for their
development.
The nursing environment can be unpredictable and
over stimulating exceeding the tolerance level of pre-
mature infants [5]. The environmental noise in the
NICU contributes to increased stress, decreased sleep
times with subsequent behavioral and physiological
disturbances [6,7]. The source of noise may arise from
crying infants, talking staff, ringing telephones, and
alarming equipment which can peak to 80–90 db even
insidean isolette. Recordedlullabymusic isintroduced
into this environment as a more predictable and sta-
ble source of stimulation which masks intermittent and
unpredictable sounds, thereby causing the amount of
stress experienced by the infant to decrease [5]. Lulla-
bies are an appropriate sedative music selection for in-
fants because they contain lyrical predictable and ton-
ic oriented melodies of around 8 bars in length with
a steady rhythm of 60–80 beats /minute [8]. Audito-
ry capability is an early, discriminative ability of a fe-
tus. At 30–35 weeks the fetus hears and responds to
maternal sounds; and it is also capable of distinguish-
ing it from other sounds [9]. Some studies indicated
favorable auditory stimulations as effective for weight
gain and respiratory functions. Weight gain may be re-
sultant of an increased sleep period, decreased caloric
expenditure and regulated respiratory function [6,10–
13]. Increasing oxygen saturation (Spo2) without ex-
cessive O2therapy is an important in order to avoid
oxygen related complications [14]. In this study we
aimed to investigate the effect of lullaby music on the
physiological responses and weight gain of premature
infants.
2. Patients and methods
This study was a randomized, controlled trial con-
sisting of a Control group who received no music in-
tervention and a Music group that was exposed to lul-
laby music. The study was conducted in the NICU
at Imam Reza Hospital in Mashhad, Iran from July
2006 to February 2007. Criteria for inclusion in this
study were: adjusted gestational age 34 weeks; birth
weight between 1000–1500 grams; post natal age of
4 days; and clinically stable neonates (not supported
by ventilator assistance or oxygen therapy). Exclud-
ing criteria were: diagnosed hearing impairment; con-
genital anomalies; maternal drug addiction; and use of
oxygen. Sample size was calculated by considering
the mean and standard deviation (SD) of previous stud-
ies [5,10]. Sample sized was calculated for all vari-
ables including SPO2, heart rate (HR), respiratory rate
(RR) and weight gain and a sample of 40 infants (20
in each group) was considered adequate. All infants
were checked for hearing loss by auto acoustic emis-
sion (OAE) before entering the study. Infants were
randomly assigned to one of two groups. Infants in
the Control group received routine NICU nursing care.
Infants in the Music group received routine NICU care
as well as 20 minutes of music intervention every day
for 8 days. The music was commercially recorded lul-
labies sung by Iranian female vocalists; played by an
MP3player at 60–65 db inside the isolette. The decibel
levels were tested at the subject’s ear using a sound
level meter and the volume level on headphones was
then adjusted and covered to avoid accidental unsafe
changes in volume. Each subject was breast or bottle
fed and their diapers were changed within half an hour
before the intervention. Infants in the two groups were
evaluated and observed for 40 minutes every day for
8 days. The data collection was divided into 40 one
minute time samples. Heart rates and oxygen satura-
tion levels as displayed on the pulse oximeter record-
ed every minute. Respiratory rate was recorded every
5 minutes and weight gain was measured daily by a
digital weight scale. Neonates were evaluated during
3 phases: 10 minute baseline, 20 minute intervention
and 10 minute post intervention. During the second
observation the selected music was played via head-
phones for the music group and during the post obser-
vation period music was discontinued and the infant
was observed by the researcher.
3. Statistical analysis
The anthropometric data are presented as means ±
SD. For quantitative variables, comparisons between
the groups were performed by using independent t-
tests, and within the groups the paired t-test was used.
Categorical variables were analyzed using the chi-
squaretest andtheFisherexact test. If therewas no nor-
mal distribution non-parametrictests, such as the Mann
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Table 1
Characteristics of preterm neonates in two groups
Variable Music group Control group P– value
Mean ±SD Mean ±SD
(n=22) (n=22)
Birth weight (g) 1279 ±172 1298 ±133 0.36
Gestational age (week) 30.5 ±1.7 30.5 ±1.7 0.96
Birth head circumference (cm) 28.7 ±1.2 27.7 ±1.5 0.008
Caloric intake before intervention 84.6 ±23.6 83.1 ±24.3 0.83
Caloric intake after intervention 117.6 ±21.4 117.1 ±30 0.95
Phototherapy (hours) 78 ±2.56 72 ±1.72 0.47
O2therapy (lit/min) 5.1 ±1.8 4.2 ±2.1 0.058
Start feeding (day) 2.5 ±1.4 2.8 ±1.3 0.29
Sex (male) N (%) 12 (54) 11 (48) 0.36
Whitney test, were used. To control for confounders,
general linear model regression was used. The cut- off
level for significance was chosen at p<0.05. Changes
from baseline were calculated (mean ±SD) for HR,
RR and SPO2during the second phase (intervention)
and the third phase (post intervention). The two groups
were compared during the music period and post ob-
servation for any change from the baseline period for
every day and means for a total of 8 days.
4. Results
A total of 44 preterm infants were studied (Music
n=22 and Control n=22). As shown in Table 1 the
two groups did not differ in demographic and clinical
characteristics. For the duration of the intervention, the
changes in SPO2in the intervention period were high-
er in the Music group than in the Control group (p=
0.001). Post intervention, the changes in the Music
group was still significant when compared to the Con-
trol group (p=0.019) (Table 2). When compared to
the Control group, more stable SPO2(less fluctuation)
was observed in the Music group at Days 7 and 8 (p=
0.05 and p=0.022 respectively) (Fig. 1).
Throughout the entire study, changes in the RR dur-
ing the second phase (intervention) were different be-
tween the two groups (p=0.017). During the third
phase (post intervention), changes in the RR were not
different between the two groups (p=0.94) (Table 2).
Respiratory rate decreased in the Control group be-
tween Day 1 and Day 4, followed by an increase after
Day 4. In the music group RR increased in Day 2, 3
and 6; it decreased in Day 4 and 5; and it remained
steady in Day 7 and 8 (Fig. 1).
Throughout the entire study, changes in the HR in
the second (intervention) and third phase (post inter-
vention) did not differ between the two groups (p=
0.24 and p=0.32 respectively) (Table 2), (Fig. 1).
Daily weight gain did not differ between the Music
and Control groups (36.79 ±31.83 and 18.63 ±39.05
respectively, p=0.093), (Fig. 1). In the linear model
regression, after controlling for variables such as birth
weight, gestational age, caloric intake before and after
intervention, phototherapy, start feeding and sex, the
difference between the groups remained significant.
5. Discussion
In this study, we demonstrated that SOP 2and RR in-
creased in the Music, but HR and daily weight gain did
not change between the two groups. The SPO 2and RR
areimportant and effectivevariableson neonates. Most
neonates in the NICU suffer from respiratory compli-
cations and they have apnea or low SPO2. If an inter-
vention can affect SPO2and RR, it is a considerable
point to take into account when caring for neonates.
Weight is a challenging issue among pre term infants
and an effective intervention for it is important. Al-
though, in this study, there was no difference in daily
weight gain between the two groups, further studies
are needed to confirm the lack of change (p=0.093).
Previous studies have shown harp music to be an effec-
tive intervention on weight gain and salivary cortisol
of neonates. Their methods were very similar to this
study but it was a pilot study and they studied only
8 neonates during 3 days. Their results showed that
weight gain differed between the harp music group and
the control group (p<0.05). Music may enhance
weight gain by decreasing activity and caloric expendi-
ture [15]. In 1991, Collin and Kuck [11] observed that
just one 10-minute music presentation significantly in-
creased SPO2among preterm infants (gestational age
of 24–37 weeks) who were in an agitated state. Chou
and Wang [13] also found exposure to lullaby music
caused increased SPO2in infants during tracheal suc-
A Farhat et al. / The effect of listening to lullaby music on physiologic response and weight gain of premature infants 3

Panel A Panel B
Panel C Panel D
Fig. 1. Comparison between the Music group (solid lines) and Control group (dashed lines) during the duration of the study. The graphs
illustrate the changes in SPO2(Panel A), respiratory rate (Panel B), heart rate (Panel C), and weight gain (Panel D). Data are expressed in means.
Significant differences are observed in SPO2(P =0.001) and respiratory rate (P=0.017).
tioning. Caine [10] also observed that music can af-
fect weight gain, caloric expenditure and hospital stay.
Coleman and Pratt [16] observed that music decreased
heart rate, increased oxygen saturation, reduced dis-
tressed behaviors and increased weight gain. Other
studies [6,12] obtained the same results. Lullaby mu-
sic may be useful because of its effect on the nervous
canter (limbic and autonomic) thus decreasing stress,
andinducing comfort and relaxation. Whenrespiratory
rates are regulated, oxygenation improves [17,18].
In their study, Cassidy and Standley [12] observed
preterm infants responded music on the first day in-
creased. However this response gradually decreased
because of habitation. Our findings do not support this;
in our study, response to the music fluctuated but we
did not see a decreased response in the following days.
Standley and Moore compared baseline, interven-
tionand post observation periodsandfound that lullaby
music increases SPO2. However after interrupting the
music, physiological responses decreased below base-
line. In our study there was a difference between the
2 groups; during the third phase (post-intervention),
SPO2remained high so even after the lullaby music
was interrupted the effect of music remained steady. In
our study, we did not observe a significant difference
in weight gain between the two groups (p=0.093),
(Table 3). However, we speculate that if lullaby music
was presented more frequently (2–3 times) each day
or the duration of the study period was increased (8+
days) then a significant difference would plausibly oc-
cur. This is the first study in Iran that evaluated the
effect of lullaby music on preterm infants and more
research is needed.
Acknowledgement
The authors would like to thank Research Vice
Chancellor of Mashhad Science University for fund-
ing this study. Additionally, we would like to thank
Mr. Farifteh (Music Training Professional), the Pejvak
Hearing Center and Miss Sedighee (data collection).
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Financial disclosure
The authors do not have any financial interest to
disclose.
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