The purpose of this study is to investigate the ability of a translational device, Teledyne PeakSleep, to reduce sleep onset latency, reduce time awake after sleep onset and improve restfulness and the subjective benefits of sleep in a patient population with insomnia via transcranial direct current stimulation (tDCS) applied to frontal lobe circuits.

The purpose of this research study is to investigate a new, targeted intervention to improve outcomes for those suffering from insomnia by attempting to enhance the brain rhythms within the frontal lobe implicated in slow wave generation during the transition from wake to sleep. The device applies a pulsed trapezoidal direct current waveform at 0.75 Hz to the frontal areas of the brain immediately prior to attempted sleep onset to facilitate the transition to sleep.

During this cross-over trial, patients will be asked to use a PeakSleep wearable neurotechnology prototype headband, which delivers <14 minutes of frontal tDCS over a 30-minute period, immediately before trying to fall asleep. Using an active stimulation versus sham paradigm, we will compare actigraphy data, physiological data, and subjective sleep measures against a pre-treatment baseline in the same patient.

Participants will complete five in-person visits over the course of the 8-week study. The first visit includes the collection of baseline self-reported data and actigraphy device training. All subsequent visits involve headset training, downloading PeakSleep and actigraphy data, repeating self-reported data measures, and reporting user experience with the device. Participants will not perform any formal sleep study visits and instead provide daily actigraphy data via a FitBit and EEG data when wearing PeakSleep in their own home.

Inclusion Criteria:

• diagnosed with sleep onset insomnia
• Self report insomnia diagnosis (ISI score ≥15)
• 18-70 years old that are Tricare eligible
• No pharmacologic or non-pharmacologic treatment for insomnia in the last 14 days, including over-the-counter medications such as diphenhydramine or cyclobenzaprine not using sedating medications (including over-the-counter) at bedtime in the last 14 days. These can include sedating antihistamines such as diphenhydramine/Benadryl, combination pills such as Tylenol or Advil PM, ZzzQuil. Psychiatric medications such as benzodiazepines (clonazepam/Klonopin, lorazepam/Ativan, diazepam/Valium, alprazolam/Xanax), anti-histamines (hydroxyzine/Atarax/Vistaril), or anti-psychotics (quetiapine/Seroquel).

Exclusion Criteria:

• Neurologic conditions such as seizures or conditions that increase the risk of seizures, including concussions within the last 3 months; moderate or severe traumatic brain injury; stroke; multiple sclerosis; or cognitive impairment with or without the use of prescription medication or requirement for hospitalization.

• Any psychiatric disorder requiring weekly or more frequent clinical monitoring or medication changes in the last 4 weeks.

• History of neurodevelopmental disorder such as attention deficit hyperactivity disorder, learning disability, or developmental delay

• Any inpatient hospitalization, major surgery, or medical procedure within the past 6 months

• Hearing impairments requiring implanted or external devices worn at all times for amplification.

  **Pregnant or believes there is a chance of pregnancy

• Current substance use disorder (addiction) within the past year, not including nicotine Current use of narcotics (opioid based medications for the treatment of pain (OxyContin, Percocet, Vicodin, etc.) with or without a prescription within the last year

• Change in psychotropic (non sleep related) medications within the last 4 weeks (examples include: benzodiazepines, SSRI/SNRIs, bupropion, gabapentin).

• Consuming more than 10 alcoholic beverages per week

• Treatment for drug or alcohol use/abuse within the past 1 year

• Presence of a recently diagnosed or unstable sleep disorder, other than insomnia, with an treatment regimen less than 3 months old

• Any motor coordination deficits that interfere with use of the tES device

• Participants should not have trauma/cuts/rashes to their forehead or behind the ears that would interfere with wearing of the device or cause discomfort for the research subject

• Tattoos on the head

• Non-removable metal above the shoulders, except bridges or fillings, OR implanted devices anywhere in the body (e.g., pacemakers, defibrillators, cochlear implants, brain implants including deep brain stimulators or other implanted devices) presence of an unstable medical condition that significantly contributes to their insomnia (e.g. chronic pain, cough, GERD, sleep apnea) - or diagnosis of an above condition that no longer significantly contribute to insomnia but has not been stable on a treatment regimen for at least 3 months.

any suicidal attempts within the last 12 months.

• Any other condition that the investigator believes would prevent completion of the study or put participant at risk

• Any suicidal ideations or thoughts of self-harm (as measured by the PHQ-9, Item 9) within the last 2 weeks.

  • Note: Pregnancy Safety data for tES use in pregnant women is scarce but is reviewed in: Antal, Andrea, et al. "Low intensity transcranial electric stimulation: safety, ethical, legal regulatory and application guidelines." Clinical neurophysiology 128.9 (2017): 1774-1809. The authors cite two case studies of tES use in pregnant women with no impact or safety risk for the mother or fetus when tES was applied to the head at 2mA and 20-30 min per day. The recommendation by the authors is to verbally enquire as to the pregnancy status of the subjects and only deliver tES when the benefit outweighs risk. Here we propose to completely exclude this population if the questionnaire reveals they are pregnant or are trying to become pregnant. In the event that the patient is untruthful regarding their pregnancy status we view the risk as insignificant given these reported studies and the fact that our dose is <¼ the dose used in them. For this reason we have chosen not to perform a urine test to screen for pregnancy as we view it as an obtrusive and unnecessary step given the risk profile.

The specific individual participant data (IPD) to be shared includes de-identified EEG recordings collected during treatment sessions and responses to sleep diary questions. This data is coded using an alphanumeric identifier unlinked from any personal information. The mapping spreadsheet linking identifiers to participants will be destroyed 120 days after study completion, fully de-identifying the data. Participants consent to future use of their data through an opt-in checkbox and may withdraw consent at any time. Only approved research staff will access the data, stored securely per DoD and USUHS guidelines.

The de-identified individual participant data (IPD) and supporting information will be available starting 120 days after study completion, following destruction of the spreadsheet linking participant identities to study codes. The data will be maintained indefinitely by Dr. Werner for future research use, with no specified end date.

Only research staff listed in the study protocol and approved by the IRB will have access to the IPD and supporting information. They will be able to access de-identified EEG data and sleep diary responses linked only to alphanumeric codes. Access will be through secure, password-protected computers or servers. After de-identification, the data may be shared for future research with qualified investigators upon request and IRB approval, but will remain free of any personal identifiers and only include data necessary for approved analyses.