Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.


Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) as defined by the Institute of Medicine is "an acquired, chronic multi-systemic disease characterized by significant relapse after physical, cognitive, or emotional exertion of any sort. The disease includes immune, neurological and cognitive impairment, sleep abnormalities, and autonomic dysfunction, resulting in significant functional impairment accompanied by a pathological level of fatigue. The cause of the disease remains unknown, although in many cases symptoms may have been triggered by an infection or other prodromal event". [1] There are no approved diagnostics tests or treatments.

The objective of this research study is to begin to understand the clinical and biological characteristics of ME/CFS. Participants in the study will not receive treatment. However, insights obtained may lead to the development of new and effective treatments as well as diagnostic tests for this condition.

In this study, we will focus on those who developed symptoms of ME/CFS after an infection, which we refer to as 'post-infectious ME/CFS' (PI-ME/CFS). Information obtained from those with ME/CFS will be compared to that from two other groups of participants: 1) people with successfully treated Lyme disease and 2) healthy volunteers. We will also enroll some people with ME/CFS in focus group discussions to help us develop research questionnaires and others in a technical development sub-study to further refine certain study measures using functional MRI and Transcranial Magnetic Stimulation (TMS). The study will be conducted at the NIH Clinical Center in Bethesda, Maryland, a unique hospital with multi-disciplinary state-of-the art research and diagnostic facilities. We hope that information obtained in this study will be used to develop future studies of ME/CFS—both at the National Institutes of Health (NIH) and world-wide—of the entire range of ME/CFS clinical presentations

Screening of potential ME/CFS participants began in fall 2016.

All participants must be 18-60 years old and have at least a 7th grade education. Volunteers must fit into one of the groups below. There will be 3 inpatient groups, one outpatient focus group, and a technical development sub-study:

  1. Inpatient ME/CFS group: Those with ME/CFS that started after an episode of infection who have severe symptoms based lasting between 6 months to 5 years, based on the study evaluation
  2. Inpatient Lyme Group: Those who had Lyme disease that was treated and had complete resolution;
  3. Inpatient Healthy Volunteer Group: Those in good general health
  4. Outpatient ME/CFS Focus Group: Those with ME/CFS who will participate in telephone focus groups only. They will not have inpatient visits.
  5. Technical Development Sub-study: Healthy volunteers and people with ME/CFS having only functional magnetic resonance imaging (fMRI) and transcranial magnetic stimulation (TMS) and clinical MRI.

Inpatient Group Procedures

Participation in this study includes a pre-screening process and a 5-10 day initial phenotyping inpatient visit. Healthy volunteers and those with past Lyme Disease will also have a 10 day exercise stress inpatient visit. For those with ME/CFS, an adjudication panel composed of recognized experts in the diagnosis and care of ME/CFS will review medical records and results collected during the initial visit. The panel will determine which participants have post ME/CFS and are eligible for the exercise stress visit.

Brief description of the study procedures

Interested individuals will initially complete a telephone pre-screening with the study staff to determine if they might be eligible. We may ask for medical records regarding ME/CFS or Lyme disease and for permission to speak to health care providers.

The first inpatient visit lasts 5-10 days. Tests include:

  • An explanation of the study and signing of the research study consent form
  • Medical history
  • Physical exam and strength testing
  • Blood and urine collection
  • Saliva, cheek swab and stool sample collection
  • Questions about the participant's life and their quality of life
  • Questions about the participant's mental health
  • Thinking and memory tests
  • Magnetic resonance imaging (MRI) of the brain.
  • A lumbar puncture (spinal tap)
  • Tests of sweating. breathing, blood pressure in different positions, and heart rate
  • Questions about the participant’s diet and food preferences
  • Collection of a large volume of blood cells
  • Sleep test
  • Occupational therapy
  • Holter monitor
  • Consults with Internal Medicine and Muscular Dystrophy

Those who will continue to the exercise stress visit will need to wear an activity monitor and keep a fatigue diary and food records for at least one week at home between visits.

Participants who are on medications that could interfere with the study testing will be asked to stop those medications prior to the exercise stress visit, if it is possible to do so safely.

The second inpatient (exercise stress) visit lasts 10 days. Tests include:

  • An exercise stress test. Participants will pedal stationary bike until too tired to continue.
  • Interviews about fatigue, symptoms, diet, health, and mood
  • Sleeping in a metabolic chamber- a room that monitors energy and nutrient balance.
  • Eat a special metabolic diet where all of the food is weighed before being prepared
  • Wear a transparent hood to measure energy use
  • Saliva, blood, stool, and urine collection
  • Thinking and memory tests
  • Wearing an activity monitor and completing activity logs
  • Brain transcranial magnetic stimulation
  • X-rays to look at body composition
  • Magnetic resonance imaging (MRI) of the brain.
  • Lumbar puncture (spinal tap)
  • Have your brain waves measured while you sleep with an electroencephalogram (EEG)
  • Optional muscle and skin biopsies

ME/CFS Outpatient Focus Group Procedures

Those in the ME/CFS outpatient focus group will have a single 1-2 hour teleconference with other focus group participants. We will ask questions about their experience and symptoms of ME/CFS and post-exertional malaise and lead discussions among group members. We will use the information from the focus group to improve interviews and questionnaires about ME/CFS. Participants in the focus group will not participate in the study inpatient visits and tests.

Technical Development Sub-study

Additional healthy volunteers and persons with ME/CFS will be enrolled to have the TMS and fMRI studies only. These participants will be studied at the NIH Clinical Center during 1-2 outpatient visits. The information collected will be used to refine and streamline the TMS and fMRI procedures being used in the inpatient study. Healthy volunteers in the technical development sub-study may also participate in other parts of the study, including visits to the NIH and research examinations. ME/CFS volunteers in the technical development sub-study cannot participate in other parts of the study.

Link to references:
1: CFSAC recommendations (

To get started:

  • Navigate through the menu to learn more about the study.
  • Log in to the application and fill out questionnaires.

Please contact us if you have any questions or concerns.