Long-term pain affects one-third of the United Kingdom population and can be very disabling. People experiencing long-term pain often suffer from disturbed sleep because of their pain symptoms, and disturbed sleep can then make their pain symptoms worse. Managing long-term pain is also very costly to the National Health Service. The most common treatment is prescribed medicines, but these do not always work and can have serious side-effects for some patients.

The investigators have been developing an alternative approach for treating long-term pain. This approach uses simple non-invasive tools to promote some kinds of brain activity over others. It involves patients using headphones to listen to some specific sounds, or a headset with lights flashing at particular frequencies. The studies undertaken so far seem to show that doing this can change how the brain responds to pain. It potentially offers an inexpensive yet effective way of reducing pain and improving sleep for patients with long-term pain. There are a few small studies that support this approach and more work is needed. In a recent study the investigators found that these tools can be reliably used in home settings and there were some indications that they improved symptoms. However, sleep was only measured with sleep diary and movement detection, there was no direct measurement of whether the stimulation frequencies were resulting in the desired brainwave changes. Finally, the benefit to symptoms may have been the result of other factors, such as the passage of time or placebo effect.

Therefore this study extends the experiment, adding more accurate sleep monitoring which includes monitoring electrical activity in the brain (EEG), as well as providing rhythmic and non-rhythmic stimulation in a randomised order. The aim is to further test the effect of these home-based tools with individuals with long-term pain, in a more rigorous way. Up to 30 participants with long-term pain and pain-related sleep disturbance will use the tools for 30 minutes at bed time every day for 4 weeks (2 weeks with one type of stimulation, 2 weeks with another type). The changes in participants' pain, sleep, brainwave frequencies, fatigue and mood will be measured.

These findings will inform the planning and design of a future much larger study to test this technology, if this is justified by the results.

Inclusion Criteria:

• Age 18-80 years
• Chronic non-cancer pain (recurring pain ≥ 3 months duration)
• Diagnosis of fibromyalgia, meeting 2016 ACR criteria.
• Having nocturnal pain (NRS 0-10 worst pain ≥ 4)
• Self-reported sleep difficulties (trouble falling asleep, difficulty staying asleep, waking up too early, or waking up unrefreshed) 3 or more nights per week during the past month

Exclusion Criteria:

• Planned intervention during the study period
• Seizure disorder
• Photosensitivity
• Hearing or sight problems causing inability to use hBET
• Cognitive problems or dementia or mental health disorders causing inability to consent
• Night shift worker
• Any known primary sleep disorder including obstructive sleep apnoea, narcolepsy, restless leg syndrome

The stimulation is delivered via a smartphone application. Each participant will receive one of two versions, which are identical apart from the order in which the two types of stimulation are given. The participant and the investigator enrolling participants and conducting questionnaire and interview outcome assessment, will be masked as to which version they are using. The record of which version was allocated to which participant will be held centrally by co-investigators with no direct participant contact, until results are analysed.