Sure music helps some people sleep, but what about people with real sleep disorders?
We have seen that music before bed improves sleep quality for people with sleep troubles. Even when multiple scientific experiments are combined: music is shown to improve sleep in a large enough way that it is recommended by sleep scientists as a tool for doctors and nurses. So far however, we have only seen that music is effective for people with poor sleep quality, but what about people with clinical insomnia?
Is music really effective in improving sleep quality for people with diagnosed sleep disorders? The answer is, according to the latest scientific research: yes.
Researchers have found that listening to soothing music before sleep improved sleep quality in people with clinical insomnia.
More then that, the people who listened to music before bed spent more time in REM sleep.
REM sleep is the sleep stage named for the sleeper’s Rapid Eye Movements, and is thought to be critical for restfulness and memory. For instance, people who have their REM sleep interrupted have cognitive troubles the next day.
Chang, E. T., Lai, H. L., Chen, P. W., Hsieh, Y. M., & Lee, L. H. (2012). The effects of music on the sleep quality of adults with chronic insomnia using evidence from polysomnographic and self-reported analysis: a randomized control trial. International journal of nursing studies, 49(8), 921–930.
The insomnia rate in the general population is approximately 29%, depending on the diagnostic criteria used (Morin et al., 2006; Ohayon, 2002); this widespread difficulty sleeping is recognized as an increasing health concern (Bartlett et al., 2008; Nomura et al., 2010). Insomnia involves trouble falling asleep, non-restful sleep, and interrupted or incomplete sleep. Insomnia affects the waking hours too, leading to daytime drowsiness, increased visits to the doctor, and decreased quality of life (Leger et al., 1999).
Psychopharmacological intervention, or the use of drugs that alter the functioning of the brain, is the most common treatment for insomnia. However these drugs can have serious side effects “including daytime residual effects, tolerance, dependence, altered sleep stages, and rebound insomnia (DeMartinis et al., 2009)” and
“An increase in drug consumption increases the risk of work accidents and absenteeism (Walsh, 2004) and poor self-esteem and lower efficiency (Leger et al., 2006), resulting in decreased productivity (Leger, 2000; Walsh, 2004), daytime sleepiness (Glass et al., 2005), and impaired driving abilities (Verster et al., 2006) at a substantial cost to both the individual and society (Wade, 2011).“
With the health risks of insomnia, combined with the risks associated with the most common treatment, the cost is immense. In terms of financial cost: “direct medical costs of insomnia are estimated to be $13.9 billion annually in the United States (Martin et al., 2004). Treatment related costs were approximately $2 billion of the total direct costs associated with insomnia (Martin et al., 2004; Kryger, 2006).”.
Researchers who study sleep have called for further investigation into non-pharmacological interventions, specifically methods of improving sleep that focus on the connection between consciousness and physiology (Kozasa et al., 2010). In this vain, music is one of the most commonly used tools to improve sleep (Morin et al., 2006).
In systematic meta-analyses, music has been shown to decrease anxiety and stress (Nilsson, 2011). Music has been shown to improve sleep quality for older folks and college students alike, and in meta-analyses the effect holds up (Lai and Good, 2005; Harmat et al., 2008). Overall, a solid body of research indicates that “soothing music reduces anxiety (Lai et al., 2008a; Nilsson, 2010, 2011)” as well as decreasing “stress, and cortisol levels (Lai and Li, 2011; Ventura et al., 2012), though the consequences on sleep architecture remain unclear.” In accordance with these findings, researchers have also shown that a high percentage of adults (sometimes half the population surveyed) listen to music to aid sleep. Additionally, people with insomnia are more likely to listen to music before sleep, compared to non-insomniacs.
While other studies have shown that music improves sleep quality, these studies tend to have small sample sizes, and tended to use subjective self-report measures of sleep quality.
This study was a randomized controlled trial using polysomnography. People who suffered from chronic insomnia, but who were otherwise healthy, were recruited to volunteer for the experiment; they had to have a score of >5 on the PSQI for at least a month, and be between twenty and sixty years of age. To control for other variables, participants could not be part of the study if they had a history of substance abuse, neurological problems, or had recently been pregnant. Participants were quizzed before the study began to screen for other possible mitigating factors like medication use. None were found. On the day of the study, prior to participation, volunteers were given a medical check up. Statistical analysis was used to determine the minimum sample size, and this criteria was met. Overall there were 25 people in each experimental condition (n=50).
Participants in the music intervention condition were told to bring sedative music of their own choosing into the laboratory, where they would be sleeping under observation. If they did not bring music, the following options were provided:”Spring Rural Field, Woman under the Moon (Chinese music), Going Home (Czech music), Destiny, Heart Lotus (Taiwanese music), and Memory.” Memory was composed by the researchers, and there is an excerpt from it in Figure 2 of the article. Participants listened to this music for 45 minutes. The supplied music was selected specifically to be sedative: “all the tracks had tempos ranging from 60 to 85 beats/min (slow), minor tonalities, smooth melodies, and no dramatic change in volume or rhythm to achieve a relaxing effect (Nilsson, 2010).”
Insomnia was measured by the Pittsburgh Sleep Quality Index (PSQI) (Buysse et al., 1989). This was the same measure used in the Harmat et al., (2008) study which found that for students, music improves sleep quality on every relevant dimension of the PSQI. It is a common, clinically validated, nineteen question self-report measure of multiple dimensions of sleep quality, with sumable scores that give a global indication of sleep quality.
Participants slept in a hospital, where two way communication with the researchers was available. The environmental conditions were carefully controlled: “All the participants slept in dim, sound-attenuated, air-conditioned, temperature-and light-controlled single bedrooms. The temperature in the bedrooms ranged from 24 C to 27 C depending on the participants’ requests. The background noise levels in the sleep laboratory during the nights were measured at approximately 30–35 dB by decibel meter“. Controlling these conditions across participants was intended to decrease the likelihood that any observed effect of music intervention could be due to unaccounted-for environmental influence.
Polysomnography, as the word indicates, is the use of multiple objective (or physiological and non self-report) instruments to measure sleep related changes. Researchers used electroencephalography, which measures changes in electrical activity in different parts of the brain and then graphes them. Electromyography, which measures changes in electrical activity in muscle tissues via electrodes, was also used. Finally, electrooculography, which uses pairs of electrodes around the eyes to measure electrical potential changes as a way of detecting eye movements, was also utilized. “Sleep recordings were visually scored in 30 s intervals by a qualified technician according to standard criteria (Iber et al., 2007).” Scoring was done blindly, meaning that the scorer was unaware of any of the participant’s demographics as well as being ignorant of their experimental group or condition.
“The following objective clinical sleep measures were defined as minutes of total sleep time (TST), sleep efficiency (SE; %; total sleep time/total recording time), sleep onset latency (SOL), wake after sleep onset (WASO), number of awakenings, percentage of time in stages 1, 2, 3, 4, and rapid eye movement (REM) sleep, and arousal index (number of electroencephalographic arousals per hour of sleep)”
Upon waking, participants filled out a thorough questionnaire which asked about sleep quality, sleep time, time taken to fall asleep, number of times woken, general restedness ect.
To measure perceived characteristics of the music, participants indicate the likeability, sleepiness, and relaxedness of the music using a visual analogue scale, which entailed sliding a bar along a spectrum spanning from ‘not at all’ to ‘very much’. Past studies have indicated that this kind of visual report is more accurate than other scales when it comes to conveying subjective experience (Gift, 1989). “The music was rated by the subjects in the music group in the morning for three consecutive days. The test–retest reliability of the VAS scale for music evaluation has been established (Lai et al., 2008b).”
Objective Results: Polysomnographic evidence indicates that insomniacs who listened to music before sleep spent less time in stage 2 of the sleep cycle, and more time in REM sleep, compared to the control group. “REM sleep is especially vital to psychological and emotional well-being”
Subjective Results: Participants who listened to music before sleep reported higher overall daytime restedness ratings, compared to the control group.
This is the first major study to use clinically acceptable methodology (randomized, controlled, statistically tested, over time) as well as subjective (PSQI) and objective (polysomnographic) measures to test the usefulness of music for improving sleep quality. This study is given even more weight based on the fact that it was done with a clinically sleep-deprived population. Sample size, participant characteristics, music selection, and music enjoyability all vary between studies, so there are no completely methodologically comparable studies. This substantially limits the confirmatory power of this study. However, meta-analysis and controlled randomized trials with similar results do exist in support of these results.
“The findings of this study contribute to existing knowledge of the effectiveness of music as a therapy to improve the sleep quality of insomniac adults. Listening to soothing music at nocturnal sleep time improved the rested rating scores, shortened stage 2 sleep, and prolonged REM sleep.”
While there is still some controversy about the function of REM sleep among psychologists and neuroscientists, useful information is available. REM sleep is when dreams are believed to happen. The brain goes through a period of complex widespread communication that connects the brainstem (pons) to the midbrain (thalamus) to the most recently developed outer layer of the brain (the neocortex). REM sleep is believed to be necessary for healthy development. Infants spend substantial larger portions of their sleeping time in REM sleep. REM sleep is also believed to be needed to maintain basic well being, laboratory rats, deprived of REM sleep, die substantially sooner than normal. When humans have their REM sleep interrupted, the next uninterrupted night is spent ‘catching up’ on REM sleep, meaning we go into REM faster and stay in REM longer. This sleep stage is also implicated in adult learning. Adults who were deprived of REM sleep after learning a mental skill ended up being worse at remembering that skill the next day, compared to those who got enough REM sleep. Depriving people of other forms of non-REM sleep did not have the same memory impairing effect. Overall, REM is of vital importance to our well being and intelligence. The finding that listening to music before sleep can induce more time spent in REM sleep is exciting and potentially a major health benefit of listening to music before bed, particularly since this effect was observed in a population with clinically significant insomnia.
This study, as stated before, meets the basic criteria for a clinically useful experiment. Proper controls and statistical measures were employed. It would be more useful to have a study that had a longer longitudinal range, spanning more than three days.
This is the first study of it’s kind to use polysomnography, so these results cannot be confirmed by a large body of similar research. That being said, the basic findings are in accordance with previous studies (i.e. Harmat et al., 2008).
This Study was not done in the United States, and thus some of the measures were unfamiliar, although they all appeared to be commonly in use, based on empirical evidence, and already validated. The author is prolifically published in multiple journals. The journal itself is an international nursing journal, published by a reputable publishing company. The journal has a good impact factor, which is a score that indicates the rate at which studies published in the journal are cited. All this lends institutional credibility to this experiment.