Music for Reducing Pain in Newborns

Music may have charms to soothe a savage breast*, to distract us from our everyday trials and tribulations and perhaps even numb our emotional distress, but can it reduce physical pain or our perception of it? Is that even a distinction that matters? I think that there is a great deal of plausibility, and some evidence behind claims that music might play a role in mild to moderate pain relief, mostly in adults. But is this apparent benefit a specific effect unique to how music alters human neurophysiology or simply a distraction?

Does the type of music matter? Would music that a patient enjoys work better as an analgesic than music that they find unpleasant or even offensive, perhaps because of physical properties of the sound, such as loudness, dissonance, discord, lyrical content, or even the listener’s feelings** about the source? I can imagine both a connection with music as well as a repulsion by it being factors that play a role in altering pain perception in the face of an acute exposure, with the latter achieving some kind of counterirritant effect.

But even this is complicated. It is difficult, if not impossible, to separate human response to pain from biopsychosocial “wellness”. Listening to music that irritates you could easily exacerbate pain, particularly chronic pain. It might make acute procedural pain worse too. Pain, as they say, is in the brain and numerous factors alter our perception of it in positive and negative ways. Adult patients have cognitive capabilities unavailable to young children that can be both a blessing and a hindrance, and young children have their own host of issues that can complicate the experience and management of pain. Few things are simple when it comes to this issue.

Does the auditory stimulus even need to be music? I think that the human brain is incredibly sensitive to patterns in our sensory input, and music can be a powerful tool in medicine, but could any noise that potentially distracts from a painful experience be helpful? A loud noise that forces a patient to pay attention to it at the same time that a needle is entering their arm just might work. And, to finally come around to the topic of today’s post, what about the potential for reducing pain in newborn patients, whose brains haven’t developed to the point where personal emotional attachments to music could possibly play a role?

We won’t find answers to all of these questions today. We may not find answers to any of these questions today. But we will at least explore the possibility of using music for pain relief in term newborns undergoing a minor procedure likely to cause brief pain, and distress that might last a bit longer, because that is what the authors of the study we’ll dig into looked at.

As a newborn hospitalist who has played a key role in subjecting thousands of young infants to painful procedures over the past 20+ years, I take pain in this population very seriously. Most people who are involved in the care of newborns do. Sadly, this wasn’t always the case.

Though infant pain was widely recognized historically, and attempts (for better or much, much worse) to treat it were commonplace, a belief that infants did not feel pain took hold in the 19th and early 20th centuries. This horrific false track in the care of infants resulted in even open heart surgeries being performed without any pain control into the 1980s. The development of a skepticism, or more accurately a cynical ignorance, of infant pain has numerous origins:

These experiments used pinprick and electric shock, and the results were generally interpreted as evidence of infants’ underdeveloped pain perception, attributed to their lack of brain maturation. Even clear responses to noxious stimuli were often dismissed as reflex responding. Later these experimental findings were used by anesthesiologists to support the lessened use of anesthesia for infants. Based on the reviewed literature, this paper suggests that 4 interrelated causes contributed to the denial of infant pain: the Darwinian view of the child as a lower being, extreme experimental caution, the mechanistic behaviorist perspective, and an increasing emphasis on brain and nervous system development.

https://www.jpain.org/article/S1526-5900%2813%2900025-4/fulltext

It is now beyond any reasonable doubt that newborns experience pain. The newborn’s developing nervous system may even result in an increased sensitivity to pain on average than older children and adults. Pain perception is extremely subjective, however, and any individual response is highly complex and influenced by countless physical and psychological factors. Newborns don’t worry about the future, but they have distress without context, an evolutionary hardwired discomfort when hurt or removed from reassuring care that results in behaviors aimed at reestablishing that care. But it isn’t a competition. Let’s just try to manage pain appropriately in everybody.

It has become increasingly clear that untreated acute and chronic pain during the newborn period can result in immediate adverse physiological changes. There is also growing concern regarding future repercussions. In some cases, for example, pain during the newborn period might increase sensitivity to pain during later childhood and even into the adult years.

It is important to treat pain in all children, but again we will focus more on the newborn population in this post. Even healthy term infants undergo procedures that can cause acute pain. Every child born in the United States, and most other countries as well, has a few drops of blood sent for analysis designed to catch a variety of diseases as early as possible in order to improve outcomes. The newborn screening program began in Massachusetts in the early 1960s with testing for phenylketonuria, or PKU. Each state decides which diseases to screen for, though there is significant overlap, and Massachusetts now uses those drops of blood to screen for more than 30.

We obtain blood for the newborn screen with a heel stick. This involves a poke through the skin on the side of the heel using a lancet, and then milking the heel with repetitive pressure along the foot in order to collect enough blood to saturate four marked circles on the newborn screen card that will be sent to the state lab for analysis. Though I have definitely seen infants sleep through a heel stick, without some kind of pain control intervention they will typically have a startle reaction with an immediate cry that is sustained until they are consoled.

As with an older child or adult who is stuck with a needle and able to communicate their experience, newborns absolutely feel sudden but brief pain during a heel stick. They then experience distress as a result, though it is from reflexive neural functioning rather than an emotional response such as fear or anxiety, which doesn’t mean it should be discounted. This video demonstrates proper technique for the procedure as well as how failure to consider infant pain can result in obvious discomfort.

When it comes to pain control for brief procedures like a heel stick, the focus has largely been on non-pharmaceutical interventions. This can involve the use of a pacifier, a snug swaddle, or being held tight by a caregiver. A baby can even nurse or take a bottle during the procedure. One very effective approach to procedure pain in newborns involves the use of sucrose, typically given as a few drops on the pacifier or directly into the infant’s mouth. We don’t know with certainty how sucrose reduces the pain response in infants, but most experts will say “Something, something, something, endogenous opioids.”

But what about music? Could music be used to reduce pain in newborns undergoing a heel stick or similar procedure associated with a needle poke such as venipuncture or an intramuscular injection? Could it be a helpful adjunct to sucrose? In a study published last year in Pediatric Research, the official publication of the American Pediatric Society, the European Society for Pediatric Research, and the Society for Pediatric Research, researchers set out to “assess the effectiveness of recorded music in a meticulously controlled setting as an adjuvant to the standard of care oral sucrose to relieve acute pain in term newborns undergoing heel pricks in a community hospital newborn nursery.”

In the study, 100 healthy term newborns undergoing a heel stick were randomized to a music exposure or control group. Both also received .5 cc of 24% sucrose 2 minutes prior to the procedure but the treatment group was exposed to recorded music from 20 minutes before the procedure until 5 minutes after completion. The music used in the treatment group was an instrumental lullaby, “Deep Sleep”, from an album named Bedtime Mozart: Classical Lullabies for Babies***.

As you can probably imagine, determining the amount of pain experienced by a newborn is not easy. It certainly isn’t objective, although we have certain tools that attempt to achieve that fantasy. Obviously we can’t ask a baby to give a numerical pain assessment or to point at the face on a chart with the pained expression that best matches their feelings. An outside observer must observe baby behavior and convert what they see to a score.

In this study, trained assessors used the neonatal infant pain scale (NIPS) to evaluate facial expression, crying, breathing patterns, limb movements, and arousal. In general, NIPS scores have good interrater reliability and internal consistency, but it is still a subjective assessment that could easily be influenced by bias, such as in a study where the person assessing an infants pain knew if they were in the treatment group. It also does not include an physiological input, such as heart rate, blood pressure, or specific respiratory rate parameters, because it was designed for ease of widespread use.

This is the breakdown of NIPS scoring:

As you can see, there are several opportunities in scoring a baby that could swing to a 0 or 1 because of unconscious bias, or even unfamiliarity with normal baby behaviors. I am very personally very familiar with the use of such scoring systems, particularly for assessing the degree of potential withdrawal after prenatal exposure to opioid medications, and I have lost count of how often a score changes meaningfully depending on who is doing the unblinded assessment. I’m not arguing that use of such tools are worthless, you just need to understand their limitations.

In this particular study, blinding was attempted. I’m not confident that it was always successful, but I have no definitive evidence to the contrary. Each baby, regardless of whether or not they were exposed to music, had smartphone speakers placed near their head. The pain assessor would enter the room wearing active noise-cancelling headphones that were also playing a random song. The nurse caring for the baby, and who would be charged with performing the heel stick, was not blinded in any fashion.

Noise cancelling headphones are not magic. They generally reduce incoming decibels, most effectively from lower frequency sounds, by up to 30 decibels. They are less effective with midrange and high frequency sounds. Classical music is generally going to be in the midrange of frequencies. The study actually did track the decibel level of the music that babies in the treatment group were exposed to, with a goal of keeping it below 45 decibels but allowing max transient volume of up to 60 decibels, which is at the level of normal conversation. So the noise cancelling headphones alone would likely not completely block out the music and preserve blinding.

Playing music through the noise-cancelling headphones would definitely decrease the likelihood of hearing the lullaby played for half (roughly) the babies in the study, but I’m still not confident that blinding wasn’t compromised in some cases. The nurse caring for the babies being unblinded is a weakness. They easily could have provided unintentional clues to the pain assessor. They also might have interacted differently with babies depending on what group they were in. Finally, wearing headphones that cancel noise and that are playing loud music themselves might interfere with the ability to properly score a baby on the NIPS, though that would apply to all babies equally.

Babies in the study were not allowed to have a pacifier during the heel sticks, which is unfortunate. The authors state that this was in order to reduce other sensory inputs and assess the pure effect of music, but I’m skeptical of the rationale. Infants were also not allowed to be cuddled by caregivers during the study period. So essentially these babies were denied proven pain reduction interventions in order to see if an unproven intervention works, and I’m left quite curious as to the wording of the parental consent form.

NIPS scores were documented 5 minutes before each heel stick, at the time of the heel stick, and at 1 minute intervals for 5 minutes after completion. Their primary outcome measure was the NIPS score 5 minutes after the heel stick, and they considered a reduction of 3 points to be clinically meaningful, which I think is quite reasonable.

When the dust settled, mean and median NIPS scores were found to be lower in the treatment group at all time intervals except for 3 minutes after the heel stick. That’s odd and the authors had no explanation. I would chalk it up to random noise. It is also odd that babies who were in the treatment group had lower NIPS scores at baseline 5 minutes prior to the heel stick, with control group babies being found to have mild pain (average score between 2 and 3). The authors chalk it up to the early exposure to the lullaby, but that is an answer to the wrong question.

Why were babies who were not listening to music in pain? Even if it’s only “mild pain”, why would these healthy term infants who per the guidelines of the study had not had any previous painful procedures performed on them not also have a score of 0-1? The answer is, of course, because these pain scoring systems are imperfect. And, perhaps, the pain assessor had an inkling as to which babies were in the treatment group and which weren’t. It certainly call into question any results moving forward.

The difference between median NIPS scores, as opposed to mean scores, was determined to be statistically significant at the time of the heel stick and at each minute (except for the 3rd) through 5 minutes after the painful procedure. They claim that there was a clinically meaningful difference at each check (again, except for minute 3 for some reason), but I’m not so sure. It definitely at least appears that way at minute 0 and 1, but I think for most babies at minutes 3-5 that likely wasn’t the case.

There are others potential problems with the study methodology, and the authors discuss them to their credit. They did not account for when each baby had most recently been fed or snuggled by a caregiver. Being fed just prior to being taken for a quick but painful procedure, for example, could absolutely alter a babies reactivity. They also admit that measuring objective physiologic responses to the heel stick, such as heart rate, would have been helpful in better assessing infant pain. Finally, they acknowledge that recording babies during the study period and having multiple pain assessors watch muted videos to determine pain scores would have reduced the potential for bias.

Conclusion: Don’t Throw the Mozart Out With the Questionable Methodology

I don’t think that this study proves that exposing newborns to music reduces their pain or distress. It might. It might also improve the mood of caregivers, which is a good outcome as well. And there is no obvious downside to music for babies at any point, provided it isn’t too loud and that it isn’t used (ever again) in place of interventions that are proven safe and effective.

This study absolutely shouldn’t be used to support claims of a specific effect from a specific composer or even genre of music. I would recommend choosing something that the people caring for the baby enjoy. Well, I would actually recommend “Folk Song” by The Sundays. But that’s just me, and only if you want to have a cool baby that has great taste in music.

*Yes, I used that correctly. In the original 1697 tragedy The Mourning Bride by playwright William Congreve, a grieving Almeria opens the play with the oft misquoted line: “”Music hath charms to soothe the savage breast. To soften rocks, or bend the knotted oak.”

**Would a Taylor Swift song relieve or worsen the pain felt by someone having a boil lanced who believes that she is part of a deep state operation attempting to keep Trump from winning a second term in the White House?

***Because the album has the name Mozart attached to it, and there is a history of nonsense associated with that name and infant development, the news reports of the study heavily focused on it. The authors of the study even issued a correction with an updated version clarifying that the music on the album was not necessarily composed by Mozart and that they make no claims of specif benefits from a particular composer. They don’t even claim that only music is potentially beneficial, proposing that using a recording of a parent’s voice might be equally effective.