How effective is neurofeedback? A new study reopens the debate.
Insomnia is both prevalent and understudied. Most people will, at least once in their life, struggle getting to sleep or staying asleep; for some, this is a lifelong battle.
In fact, an estimated 50-70 million Americans have sleep or wakefulness disorders.
Despite the widespread nature of insomnia, little research has been carried out on methods to ease insomnia, aside from pharmaceutical interventions.
However, one treatment type - neurofeedback - has shown promise in some studies. Neurofeedback allows a patient to view their brainwaves in real-time, most commonly using electroencephalography (EEG).
Each time the individual produces the desired brain activity, they receive positive feedback - auditory or visual cues, or tokens - and negative feedback for undesired brain activity.
In the case of insomnia, the intervention aims to minimize hyperarousal, so if the patient manages to reduce this state as it occurs, they receive positive feedback. In basic terms, it presumes that by rewarding a behavior, it is more likely to recur naturally.
Neurofeedback has been studied for its usefulness in a range of conditions including ADHD, depression, schizophrenia, and epilepsy. However, much of the research looking at neurofeedback and insomnia has not been replicated since its initial investigation in the 1980s.
A recent study, published in the journal Brain, set out to fill this gap by replicating earlier studies and uncovering whether neurofeedback really could have a positive impact on insomnia. According to the authors, they conducted "the first rigorously controlled study on the efficacy of NFT [neurofeedback training] for insomnia since the promising findings obtained in pioneering studies" in the 1970s and 1980s.
Re-testing neurofeedback in insomnia
In total, the study involved 25 participants with primary insomnia (difficulty sleeping that is not related to an underlying condition). Because neurofeedback has rarely been pitted against placebo interventions, the team used a double-blind, placebo-controlled protocol.
Each participant spent 8 nights in the laboratory and had 12 neurofeedback sessions and 12 placebo-feedback sessions spread across 4 weeks. The team measured EEG changes, sleep, and quality of life. All participants underwent both real and placebo sessions.
Participants' sleep-wake cycles were assessed during their laboratory stays, and they also completed sleep diaries and actigraphy (a wearable device that measures rest and activity throughout the day) across the duration of the study.
Once the data were analyzed, the researchers found that placebo-feedback was just as effective as neurofeedback for subjective measures of sleep complaints. Importantly, these improvements were not mirrored in objective EEG measures of sleep quality.
In other words, the experimental procedure, whether real or sham, improved the participants' perceptions of their insomnia without generating any measurable improvements in their condition.
Neurofeedback no more powerful than placebo
The placebo effect is a mysterious and powerful phenomenon. Although the ways in which it exerts its effects are not fully understood, there are a number of factors assumed to be involved. In this case, trusting the experimenters, the experience of receiving care, and empathy from the researchers all probably played a part in improving the perception of their own condition.
As far as neurofeedback and insomnia are concerned, the researchers conclude that it is no more powerful than placebo.
"Given our results, one has to question how much of published neurofeedback effects are due to simple expectations on the side of the participants or, in other words, unspecific placebo effects."
Manuel Schabus, lead author
Although the results are specific to the use of sensorimotor-rhythm neurofeedback in treating insomnia, and the sample size is small, the findings are likely to open a wider debate around the effectiveness of neurofeedback in general and the power of placebo to improve well-being.
While other studies have garnered positive results from neurofeedback, the use of a placebo intervention has often been lacking. If nothing else, it will spur neurofeedback's adherents to conduct more meticulous research.