Expert urges caution as evidence for sonic sleep aids remains mixed, with music showing the strongest support

Sound-based sleep tools are marketed as simple, low-risk methods to improve rest, but how strong is the evidence behind them, and what should healthcare decision-makers know before recommending or covering these products? In this Q&A, Managed Healthcare Executive spoke with Jessica Vazzaz, a doctoral researcher and tutor in psychology at the University of Sussex, about findings from a November study published in Sleep that reviewed the evidence on sonic sleep aids, their limitations and what health plans and providers should consider before treating them as clinical solutions.

MHE: Your analysis found that music has stronger evidence than white noise or bedtime stories. For health plans or health systems, what does that difference really mean in practice?

Vazzaz: From our analysis, music did seem to have the strongest evidence, but it's also worth considering that there was a lot of variance in the quality and quantity of the evidence. So, for example, color noise, like white and pink noise, had a lot of evidence, but the quality was deemed quite poor from two independent systematic reviews. While, for example, for bedtime stories, there's just not that much evidence out there as a standalone treatment just before bed.

I think something to consider, given the fact that there is not that much evidence and that there are wide disparities in evidence, is to think about the underlying causes of the sleep difficulty and the settings as well. So, for example, with white noise, we know that the proposed mechanism of action is blocking noises that might disrupt your sleep. And so this can be effective, for example, in hospital settings, in an ICU where there's a lot of noise that might disrupt people's sleep. While for music or bedtime stories and mindfulness, these are likely to have a lot of different underlying mechanisms. We don't really know much about them yet, but it's possible it’s some sort of relaxation or distraction. And so this could be used in different settings as well.

A good recommendation for now would be just to offer them as a package of tools and have a wide variety of them as well, because it's probably likely to be very dependent on individual differences and preferences as well.

MHE: Many sleep apps are sold as easy, harmless tools, but your paper points out that strong clinical studies are often missing. What problems can happen when these tools are treated as wellness products instead of health interventions?

Vazzaz: I do think that this type of content is really unlikely to cause any direct, significant harm to people listening. But however, the fact that these are branded as “wellness products” rather than as clinical treatment for insomnia, for example, should not exempt them from showing any evidence on their efficacy or on their safety.

While I do understand that they shouldn't be regarded at the same level of standard as medical devices, I think the reality is that a lot of these wellness apps don't have any evidence whatsoever backing their efficacy or their safety, and this can cause some direct and indirect problems to the user. First of all, it might be a waste of money and time, which is not great. And then it might also delay individuals in seeking evidence-based treatment. It might also make people lose trust in digital health interventions in general, which could be a problem in the long run.

MHE: You suggest these tools may help people with mild sleep problems more than those with insomnia. Why is it important for healthcare leaders to think carefully about who these tools are actually meant for?

Vazzaz: I think this is a very important point, and there is a bit of conflicting evidence on this as well, in that some studies suggest that people with higher sleep disturbances benefit more because they have more to gain from them, and other evidence suggests that they should be used for people with milder sleep difficulties.

I think healthcare leaders and healthcare providers should still recommend evidence-based treatment for individuals with clinical insomnia. Cognitive behavioral therapy for insomnia, for example, is quite effective. For individuals with subclinical insomnia or occasional sleep disturbance, the healthcare provider, again, should reflect with the person on the possible causes and the nature of their sleep disturbance, because we know that sleep is impacted by everything. So it might be psychological, but it might be a behavioral or societal influence on your sleep disturbance. And it is very unlikely that this kind of intervention might help every single case.

So I think, yeah, just understanding the root cause, and if the root cause is possibly a target for this type of intervention, will be good.

MHE: Sleep guidelines usually say people should avoid using phones at bedtime, yet most sonic sleep aids are used on phones. How should clinicians and payers think about this contradiction?

Vazzaz: I know a lot of people might be worried about the impact of screens and blue light at that time, but there's kind of mixed evidence about that, and most phones now have filters for it. So I think what I would be more worried about is that the same device you're using to play the sonic sleep aid is a device where you can access your work email, message your friends, or access social media and endless stimulation.

I think both clinicians and especially users should be kind of honest with themselves and try to think, okay, will I resist the urge or the temptation of checking my emails one more time or checking social media? Just be honest with themselves about this. We also know that discipline is a finite resource, and it kind of gets depleted as the day goes on. So that's something to consider as well—that probably just before going to bed, we are tired. We've been working all day, so maybe we are most vulnerable in terms of resisting temptations.

But that being said, there are a lot of different things you can do on your phone, from Do Not Disturb to time limits for apps to external physical devices that you need to scan to unblock the apps. There are a lot of things that can be done in that regard. Something that we suggested in our review as well is that this is speculation, but it might be that this type of content works as a harm minimization strategy—that there are a lot of people who would be on their phones anyway, and this is the least harmful content to consume just before bed, because it is designed to make you relax.

For people who would use their phones anyway, this is somewhat the least terrible thing they can do at that time. I think all these things should be considered on a case-by-case basis, especially for adults. For children and adolescents, it would be a completely different story.

MHE: Before recommending or paying for sonic sleep aids, what kind of evidence should healthcare decision-makers be asking companies to show?

Vazzaz: I think they should ask for very large randomized controlled trials. The effects of these sonic sleep aids are probably modest and kind of dependent on preference and individual differences, as we discussed. So studies will need to recruit a very, very large and diverse sample. Recruiting a very large and diverse sample will also help us run more analyses on who benefits, when, and for what type of sleep disturbance.

We also need to know a bit more about the characteristics of what is the active ingredient of one of these sleep tools. For example, for sleep stories, does the content matter? Does the way it is narrated matter, or the rhythm in which the person speaks? Do they usually go a bit slower? Do they go a bit faster? And how much of this is also influenced by preference and maybe cannot be easily measured and quantified?

Another quite significant limitation of this type of research, and mental health apps and wellness apps in general, is that usually the interventions are measured against a passive control, for example, a waitlist control, and we know that that might inflate findings a bit. So testing them against some sort of credible active control condition will give us better results.

Ultimately, I think we just need research not just to know if these are effective, but for whom and under what circumstances.