Evaluation of the 24/7 EEG SubQ System for Ultra Long-Term Monitoring of Patients with Epilepsy


About this study

The main purpose of the study is to demonstrate the performance and safety of the 24/7 EEG™ SubQ system as a reliable ultra long-term recorder of epileptic electrographic seizures. First, by comparison to simultaneously recorded video-EEG in the epilepsy monitoring unit (gold standard). Second, by comparison to self-reported seizure log books throughout 12-52 weeks of outpatient EEG monitoring.

Participation eligibility

Participant eligibility includes age, gender, type and stage of disease, and previous treatments or health concerns. Guidelines differ from study to study, and identify who can or cannot participate. There is no guarantee that every individual who qualifies and wants to participate in a trial will be enrolled. Contact the study team to discuss study eligibility and potential participation.

Inclusion Criteria:

  • Subject is ≥ 18 and ≤ 75 years old.
  • Semiology of seizures compatible with temporal lobe involvement.
  • Paraclinical findings supporting temporal seizure focus. Such proof may consist of:
    • previous EEG recording interpreted as compatible with temporal involvement; OR
    • radiological findings demonstrating pathology in the temporal area (CT, MRI, FDG-PET or SPECT).
  • Uncontrolled epileptic seizures.
  • Subject has planned clinical EMU admission with an admission goal including capturing epileptic seizures within 12 weeks after the date of UNEEG™ SubQ implant.
  • Subject is willing and able to provide written informed consent.
  • Subject is able to complete all study-required procedures, assessments and follow-up.

Exclusion Criteria:

  • Subject has a condition that places him/her at a high at high risk of surgical complications, such as an active systemic infection or a hemorrhagic disease.
  • Subject receives frequent (more than 2 days per week) treatment with drugs of the following types:
    • antiplatelets;
    • anticoagulants;
    • chemotherapeutics;
    • non-steroid anti-inflammatory drugs (NSAID).
  • Subject has skeletal deformities or damage at the proposed implantation site to an extent that impedes correct electrode placement.
  • Subject has an active deep brain stimulation device.
  • Subject has or is exposed to a medical device that delivers electrical energy into the area around the implant.
  • Subject has a cochlear implant(s).     
  • Subject is pregnant, intends to become pregnant, is breastfeeding or is a female of childbearing potential not using an adequate contraceptive method during the study period.  Adequate methods of birth control include stable hormonal contraception, intrauterine device, double barrier (e.g., condom with spermicide), tubal ligation, sole vasectomized partner, or consistent abstinence.
  • Subject has profession or hobby that includes activity imposing extreme pressure variations; e.g., diving or parachuting. Diving/snorkeling is allowed to 5 meters depth.
  • Subject has a profession or hobby that includes activity imposing an unacceptable risk for trauma to the device or implant site; e.g., martial arts or boxing.
  • Subject is scheduled to undergo any of the following treatments within 4 months after enrollment:
    • MRI scan (the UNEEG™ SubQ implant is not known to be MRI safe)
    • Therapeutic ionizing radiation treatment close to the implant site; e.g., radiation therapy for cancer.
    • Therapeutic ultrasound treatment close to the implant site.
    • Electrical current induced close to the implant (e.g., electro knife, electroconvulsive therapy).
  • Subject operates an MRI scanner.
  • Subject has an infection at implant site.
  • Subject has a contraindication to the use of local anesthetic drugs used during implantation and explantation.
  • Subject is unable or does not have the necessary assistance to properly operate the device system.
  • Subject has an abnormal laboratory finding as follows:
    • Serum creatinine ≥ 3 times upper reference value;
    • Alanine aminotransferase (ALT), alkaline phosphatase or bilirubin ≥ 3 times upper reference value;
    • Activated Partial Thromboplastin Time (APTT) > 50 seconds;
    • Thrombocyte count < 50 or > 1000 x 10^9/L;
    • International Normalised Ratio (INR) ≥ 1.6;
    • Any other clinical or paraclinical finding that in the opinion of the Investigator would interfere with participation in the study or would confound interpretation of the study results.

Eligibility last updated 9/22/21. Questions regarding updates should be directed to the study team contact.


Participating Mayo Clinic locations

Study statuses change often. Please contact the study team for the most up-to-date information regarding possible participation.

Mayo Clinic Location Status Contact

Rochester, Minn.

Mayo Clinic principal investigator

Gregory Worrell, M.D., Ph.D.

Closed-enrolling by invitation

What is this? (?)
Not open to everyone who meets the eligibility criteria, but only those invited to participate by the study team.

Contact information:

Karla Crockett

(507) 538-4880


More information


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