Focused ultrasound stimulation for chronic pain relief

Inclusion Criteria:

* Have self-reported chronic pain of ≥3 months and \<25 years in duration.
* Have an average pain severity of ≥3 on a 0-10 numeric rating scale in the past week.
* Be between 22 to 80 years of age (inclusive) on the day of signing informed consent.
* Be able and willing to undergo a cranial MRI.
* Be willing to use the ATTN201 device during treatment sessions and to attempt use of monitoring devices (Adaptyx Continuous Biomonitor, Epitel REMI EEG, smart watch) during the monitoring period. Participants are informed that continuous wear of monitoring devices is encouraged but partial compliance is expected and acceptable.
* If currently on pain medication, must be at the same stable dose(s) for at least 4 weeks prior to screening and throughout the treatment period.
* Sign the informed consent form, in accordance with local requirements, after the scope and nature of the investigation have been explained to the participant, and before screening assessments.
* Be able to speak, read, and understand English.
* Be able to use a smartphone and the Attune mobile application.
* Possess the ability to respond verbally to questions, follow instructions, and complete study assessments.
* Be able to adhere to the treatment protocol and visit schedules.
* Be judged by the investigator as likely to comply with study procedures and willing to participate in the entirety of the study, including all treatment visits and follow-up assessments through Month 6.
* Be determined by the investigator to be medically stable at baseline as assessed by medical history and non-significant clinical results of a vital signs examination.
* Male participants must ensure a condom is used for all sexual intercourse and follow acceptable methods of contraception for their female partner for the entire duration of the study and for 90 days after the final study visit. Male participants should not father a child or donate sperm during this same period.
* Female participants who are sexually active agree to use two methods of contraception for the duration of the study and for 30 days after the final study visit, or not be of childbearing potential as indicated by one of the following:
* Has reached natural menopause, defined as ≥12 consecutive months of spontaneous amenorrhea without other known cause;
* Has had a hysterectomy;
* Has had bilateral tubal ligation; or
* Has had a bilateral oophorectomy (with or without a hysterectomy) and greater than 6 weeks have passed since the surgery.
* Has a vasectomized male partner whose vasectomy was performed at least 6 months prior to screening, with documented absence of sperm.

Exclusion Criteria:

* Has an unstable or severe medical or psychiatric condition that, in the investigator's judgment, would pose a safety risk to the participant or prevent completion of study procedures. Stable comorbid conditions (e.g., treated depression, anxiety, insomnia) are permitted.
* Has active suicidality or suicide attempt in the last 6 months.
* Has an active, unstable substance use disorder including alcohol use disorder in the past 6 months (except for caffeine and nicotine). Participants on stable medication-assisted treatment (e.g., buprenorphine, methadone, naltrexone) for at least 6 months are eligible.
* Has a history of moderate-to-severe traumatic brain injury, or mild traumatic brain injury within the past 12 months.
* Has any contraindications for completing a brain MRI scan.
* The participant's head does not fit within the MRI head coil (32 or 64 channel) while wearing the MR-compatible device.
* Is pregnant, is attempting to become pregnant, or is nursing.
* Is or has an immediate family member (e.g., spouse, parent/legal guardian, sibling, or child) who is an investigational site or sponsor staff directly involved with this trial.
* Has a Body Mass Index (BMI) \>34 kg/m², as higher BMI may prevent adequate fit within the MRI head coil with the ATTN201 device in place. BMI is calculated by taking the participant's weight in kg and dividing by the participant's height in meters, squared.
* Has a known allergy or sensitivity to ultrasound gel, silicone, or adhesive materials used in monitoring devices.
* Has an active skin condition (eczema, psoriasis, rash or active infection) at sensor placement sites that would prevent device wear.