Chronic Fatigue Syndrome
Conditions
Keywords
Chronic Fatigue Syndrome, Lyme Disease, Healthy Volunteers, Movement Disorder
Brief summary
Background: Post-Infectious Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (PI-ME/CFS) refers to long-lasting and disabling fatigue or malaise, inability to recover after exercise, and physical and emotional discomfort that may occur after a person has an infection. Researchers want to learn more about its causes. Objective: To learn more about PI-ME/CFS. Eligibility: Adults ages 18-60 years who have finished at least 7th grade education and either: have ME/CFS that started after an infection OR had Lyme disease, were treated, and returned to normal health OR are healthy volunteers Design: Participants will initially have a 2-5 day inpatient visit at the National Institutes of Health Clinical Center in Bethesda. During the visit, participants will have: Medical history Physical exam Intravenous (IV) line. A thin plastic tube is inserted into a vein. Blood and urine collected Magnetic resonance imaging (MRI). Participants will lie in a machine that takes pictures of their brain. They may get a dye through their IV. Grip strength tested Saliva, cheek swab, and stool collected Tilt table test with measures of body functions such as sweating and breathing, blood pressure, and heart rate and blood and urine sample collection Collection of blood cells. Participants can choose to have the blood drawn through the IV or through a machine that filters blood cells and returns the liquid blood back into the participant s vein. Lumbar puncture. Fluid will be removed by placement of a needle between the back bones. Heart monitoring Sleep study for participants with PI ME/CFS Questions about the participant s life and how they are feeling Questions from a neuropsychologist Questions from an occupational therapist for participants with PI ME/CFS Questinos from a nutritionist After the initial visit participants will return home. Participants evaluated for PI-ME/CFS during the first visit will have their information reviewed by an adjudication panel of experts in the diagnosis and care of ME/CFS to determine if they are eligible to participate in the second study visit. Eligible participants will be invited back for a second study visit. If a participant was taking certain medications during the first visit, they may be asked to taper off of them prior to the second visit and report any problems. They will also receive an activity monitor, fatigue diary, and nutrition log to use for at least one week prior to their second visit. Participants who are eligible will return for a 5-10 day inpatient hospital visit at the National Institutes of Health Clinical Center. During the visit, participants will undergo measurements before and up to 96 hours after performing a stationary bike exercise test. The purpose of the exercise test is to provoke ME/CFS symptoms (post-exertional malaise). Tests will be performed before and after exercise testing. These include: Sleeping in a room that measures how the body uses energy with EEG monitoring Eating a controlled diet Performing vigorous exercise for 10-15 minutes Questions about how participants are feeling Questions about what participants usually eat Samples of saliva, blood, urine and stool Wearing an activity monitor Having an Xray that measures body composition Thinking and memory tests Heart monitoring Transcranial magnetic stimulation. A brief electrical current to the scalp creates a magnetic pulse that affects brain activity. Magnetic resonance imaging (MRI). Participants will lie in a machine that takes pictures of their brain. They will do thinking and exercise tasks during the MRI. Lumbar puncture. Fluid will be removed by placement of a needle between the back bones.
Detailed description
Objective: The primary objective is to explore the clinical and biological phenotypes of post-infectious myalgic encephalomyelitis/chronic fatigue syndrome (PI-ME/CFS). The secondary objective is to explore the pathophysiology of fatigue and post-exertional malaise (PEM). Study population: Up to 206 persons will be enrolled as part of this protocol. Up to 150 persons aged 18-60 will be part of 3 study groups: 50 ME/CFS patients whose fatigue began after an infection, 50 non-fatigued participants with a documented history of a full recovery from COVID-19 infection, and 50 healthy volunteers. The study has a target of completing all study procedures on 20 enrolled participants in each group. Up to an additional 36 persons reporting a community diagnosis of ME/CFS will be enrolled into focus groups to discuss the experience of post-exertional malaise. Up to an additional 10 healthy volunteers and 10 ME/CFS patients may be enrolled to refine the protocol's electrophysiological and neuroimaging techniques. Design: This is a single-center, exploratory, cross-sectional study of PI-ME/CFS. Participants will have a phenotyping visit, which will encompass a 2-5 day long inpatient admission at the NIH Clinical Center. Case status for ME/CFS participants will be determined after the phenotyping visit by a case adjudication process utilizing an expert physician committee and published guidelines. Adjudicated participants meeting inclusion criteria will be invited back to participate in an exercise stress visit, which will encompass a 5-10 day long inpatient admission. Detailed subjective and objective measurements and biological specimens will be serially collected before and up to 96 hours after a peak exercise test capable of inducing post-exertional malaise during this visit. All procedures will be completed on all three study groups to allow for optimal inter-group comparisons. Outcome measures: The primary purpose of this protocol is to perform exploratory analysis of collected samples for the generation of new hypotheses regarding ME/CFS. The types of analyses to be performed will be wide ranging. Planned areas of focus include: 1. Characterization of the immune system and inflammation at baseline 2. Characterization of the pattern of microbiome in collected samples at baseline 3. Characterization of bioenergetics, autonomic, and metabolic function in collected samples at baseline 4. Characterization of neurocognition at baseline 5. Characterization of autonomic function at baseline
Interventions
All participants will undergo an exercise stress test
Sponsors
Study design
Eligibility
Inclusion criteria
* INCLUSION CRITERIA: * Inclusion criteria for all participants 1. Adult participants aged 18-60 years at the time of enrollment. 2. Self-reported completion of at least the 7th grade of school. 3. Ability to speak, read, and understand English. 4. Willing and able to complete all study procedures 5. Participant has a primary care physician at the time of enrollment. 6. Able to provide informed consent. * Additional inclusion criteria for participants with PI-ME/CFS for the phenotyping visit: 1. A self-reported illness narrative of the development of persistent fatigue and post-exertional malaise as the consequence of an acute infection. The persistent fatigue may have an acute onset or become progressively worse over 6 months. 2. Licensed Independent Practitioner documentation of ME/CFS onset: * Medical documentation of absence of symptoms within one year of ME/CFS onset. This may include medical records, letters, or information gathered from telephone calls with study personnel. * Documentation of a medical evaluation for symptoms of an acute infection or documentation of a medical evaluation of persistent symptoms within 2 months following an assumed infection. 3. Persistent fatigue and PEM onset less than 5 years prior to enrollment. * Additional inclusion criteria for participants with PI-ME/CFS for the exercise stress visit: 1. Be unanimously considered to be a case of PI-ME/CFS by the protocol s adjudication committee. 2. Meet the 1994 Fukuda Criteria or the 2003 Canadian Consensus Criteria for Myalgic Encephalomyelitis/Chronic Fatigue Syndrome or the Institute of Medicine Diagnostic Criteria.. 3. Have moderate to severe clinical symptom severity: * Severe fatigue as determined using the Multidimensional Fatigue Inventory (MFI): score of greater than or equal to 13 on the general fatigue subscale or greater than or equal to 10 on the reduced activity subscale. * Functional impairment as determined using the Short-Form 36 (SF-36): score of less than or equal to 70 physical function subscale, or less than or equal to 50 on role physical subscale, or less than or equal to 75 on social function subscale * Additional inclusion criteria for healthy volunteer group: None * Additional inclusion criteria for COVID-19 Healthy Volunteers: documented prior COVID19 infection as evidenced by: 1. A history of clinical manifestations compatible with COVID-19 2. Laboratory evidence of Covid-19 infection: * Detectionof SARS-CoV-2RNA or antigen in nasopharyngeal swab, sputum, other sample source with Emergency Use Authorization/approval from the FDA; OR * A positive antibody test using an assay that has received Emergency Use Authorization/approval from the FDA 3. Has been recovered from the COVID-19 infection for at least six months and no more than five years.
Exclusion criteria
*
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Cardiopulmonary Exercise Test (CPET) - ATVO2rel | At time of AT during CPET | The Relative Volume of Oxygen at the Anaerobic Threshold (ATVO2rel) was determined during a cardiopulmonary exercise test (CPET). ATVO2rel represents the volume of oxygen being consumed when a participant reaches AT, adjusted for their weight during the CPET. Results compared Healthy Volunteer Participants to ME/CFS Participants. |
| Cardiopulmonary Exercise Test (CPET) - RER | At time of AT during CPET | The Respiratory Exchange Ratio (VCO2/VO2) was determined during a cardiopulmonary exercise test (CPET). VCO2/VO2 is calculated by measuring the volume of carbon dioxide and oxygen the participant breathes during CPET. When the volume of carbon dioxide exceeds that of oxygen, it reflects a change from aerobic metabolism to anaerobic metabolism. When a participant has a Respiratory Exchange Ratio (RER) during CPET that is equal or greater than 1.1 it is considered a sufficient exercise effort. Results compared Healthy Volunteer Participants to ME/CFS Participants. |
Other
| Measure | Time frame | Description |
|---|---|---|
| Characterization of the Immune System and Inflammation - ESR | Baseline | Blood and CSF were collected from healthy and ME/CFS participants at baseline. A comparison of the results of the Erythrocyte Sedimentation Rate (ESR), i.e., a measure of how quickly red blood cells settle at the bottom of a test tube, in the two populations is reported. A faster than normal rate of settling suggests inflammation. |
| Characterization of the Immune System and Inflammation - CRP | Baseline | Blood and CSF were collected from healthy and ME/CFS participants at baseline. A comparison of the results of C-Reactive Protein (CRP), i.e., a measurement of a protein that is made by the liver, in the two populations is reported. A higher level than normal suggests inflammation. |
| Characterization of the Immune System and Inflammation - WBC in CFS | Baseline | Blood and CSF were collected from healthy and ME/CFS participants at baseline. A comparison of the White Blood cell Count in Cerebrospinal Fluid (WBC in CFS), i.e., a measurement of the number of white blood cells in the cerebrospinal fluid, in the two populations is reported. Higher levels than normal suggest inflammation or infection in the central nervous system. |
| Mitochondrial Extracellular Flux Assay | Baseline | The oxygen consumption rate of peripheral blood mononuclear cells per unit of time when the cells are in their normal, unprovoked state of function measured in Basal (units) was measured in Healthy and ME/CFS participants at baseline. This is a standard measure of mitochondrial respiration that is responsible for providing energy to cells. |
| Characterization of Total Body Energy Use (Bioenergetics/Metabolic) | 12 hours | The total amount of energy expended per unit of time as measured by whole-room indirect calorimetry. This method measures the amount of oxygen consumed and carbon dioxide produced which can be used to calculate the amount of energy produced by biological oxidation and is measured by kilocalories per day. Measures were taken from Healthy and ME/CFS participants. |
| Clinical Response Effect of Tilt Table Testing | Baseline | Persons with autonomic dysfunction will often have symptoms provoked by having an up-to-40 minutes long tilt table test. The percentage of participants in each group having severe enough symptoms which required the test to be stopped in Healthy and ME/CFS participants at baseline. |
| Characterization of the Pattern of Microbiome in Stool | Baseline | Stool samples were taken from Healthy and ME/CFS participants at baseline. The number of specific types of bacteria, using the Least Known Taxon (LTK) units, were measured with the Shotgun Metagenomic method. |
| Test of Variables of Attention (TOVA) | Baseline | The TOVA is a measure of cognitive function that assesses attention and inhibitory control. The test is used to measure a number of variables involving the test taker's response to either a visual or auditory stimulus measured during a simple, yet boring, computer game. These measurements are then compared to the measurements of a group of people without attention disorders who took the T.O.V.A. The range of values for the score, after normalization to the population, is -10 to +10, with a lower score representing a worse attention score. The test was administered to Healthy and ME/CFS participants at baseline. |
| Paced Auditory Serial Addition Test (PASAT) | Baseline | The PASAT is a measure of cognitive function that assesses auditory information processing speed and flexibility, as well as calculation ability. Single digits are presented every 3 seconds and the patient must add each new digit to the one immediately prior to it. The test score is the total number of correct trials out of a possible 60. The test was administered to Healthy and ME/CFS participants at baseline. |
| Effect of Maximal Exertion on Autonomic Function as Measured by SDNNi in Healthy and ME/CFS Participants. | Baseline | Variability of the time between heartbeats can be used to measure alterations in autonomic function. The Standard Deviation of the Normal-to-Normal Intervals (SDNNi) is a measure of the amount of beat to beat variability between each normal heartbeat collected over a 24 hour period. These results compare the SDNNi in healthy and ME/CFS participants at baseline. |
| Characterization of the Immune System and Inflammation - WBC | Baseline | Blood and CSF were collected from healthy and ME/CFS participants at baseline. A comparison of the White Blood Cell (WBC) Count, i.e., a measurement of the number of white blood cells in the blood, in the two populations is reported. Low values can suggest immune deficiencies. High values can suggest infection or inflammation. |
Countries
United States
Participant flow
Recruitment details
Participants were either referred to study investigators by their primary care physician or were self-referred either through the Patient Recruitment and Public Liaison (PRPL) office or direct contact. Interested participants were contacted by telephone to evaluate eligibility. Eligible participants were subsequently seen at the NIH Clinical Center for study visits. Recruitment began February 2016 and ended February 2020.
Pre-assignment details
Participants underwent telephone screening followed by a medical record review/discussion with the participant's physician to determine general eligibility. Participants were invited to campus to determine if they met inclusion/exclusion criteria for the phenotyping phase of the study. After the phenotyping visit, results were reviewed by a panel of expert adjudicators to determine case status and eligibility for the exercise phase of the protocol. No Lyme disease participants were recruited.
Participants by arm
| Arm | Count |
|---|---|
| Healthy Volunteer Participants Participants found to be healthy after a medical and psychiatric evaluation. | 25 |
| ME/CFS Participants Participants with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome | 27 |
| Total | 52 |
Withdrawals & dropouts
| Period | Reason | FG000 | FG001 |
|---|---|---|---|
| Overall Study | Excluded - determined NOT post-infectious | 0 | 4 |
| Overall Study | Lost to Follow-up | 1 | 0 |
| Overall Study | Medical Condition | 3 | 4 |
| Overall Study | Withdrawal by Subject | 0 | 2 |
Baseline characteristics
| Characteristic | Healthy Volunteer Participants | ME/CFS Participants | Total |
|---|---|---|---|
| Age, Categorical <=18 years | 0 Participants | 0 Participants | 0 Participants |
| Age, Categorical >=65 years | 0 Participants | 0 Participants | 0 Participants |
| Age, Categorical Between 18 and 65 years | 25 Participants | 27 Participants | 52 Participants |
| Age, Continuous | 42.24 Years STANDARD_DEVIATION 13.46 | 37.82 Years STANDARD_DEVIATION 14.72 | 40.35 Years STANDARD_DEVIATION 13.48 |
| Ethnicity (NIH/OMB) Hispanic or Latino | 2 Participants | 2 Participants | 4 Participants |
| Ethnicity (NIH/OMB) Not Hispanic or Latino | 23 Participants | 25 Participants | 48 Participants |
| Ethnicity (NIH/OMB) Unknown or Not Reported | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) American Indian or Alaska Native | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) Asian | 0 Participants | 2 Participants | 2 Participants |
| Race (NIH/OMB) Black or African American | 1 Participants | 0 Participants | 1 Participants |
| Race (NIH/OMB) More than one race | 3 Participants | 0 Participants | 3 Participants |
| Race (NIH/OMB) Native Hawaiian or Other Pacific Islander | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) Unknown or Not Reported | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) White | 21 Participants | 25 Participants | 46 Participants |
| Sex: Female, Male Female | 13 Participants | 13 Participants | 26 Participants |
| Sex: Female, Male Male | 12 Participants | 14 Participants | 26 Participants |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk |
|---|---|---|
| deaths Total, all-cause mortality | 0 / 25 | 0 / 27 |
| other Total, other adverse events | 14 / 25 | 23 / 27 |
| serious Total, serious adverse events | 0 / 25 | 0 / 27 |
Outcome results
Cardiopulmonary Exercise Test (CPET) - ATVO2rel
The Relative Volume of Oxygen at the Anaerobic Threshold (ATVO2rel) was determined during a cardiopulmonary exercise test (CPET). ATVO2rel represents the volume of oxygen being consumed when a participant reaches AT, adjusted for their weight during the CPET. Results compared Healthy Volunteer Participants to ME/CFS Participants.
Time frame: At time of AT during CPET
Population: COVID-19 pandemic halted return visit for participation in Exercise Phase of trial.
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Healthy Volunteers | Cardiopulmonary Exercise Test (CPET) - ATVO2rel | 16.0 mL/kg/min | Standard Deviation 4.3 |
| ME/CFS Participants | Cardiopulmonary Exercise Test (CPET) - ATVO2rel | 10.6 mL/kg/min | Standard Deviation 3.8 |
Cardiopulmonary Exercise Test (CPET) - RER
The Respiratory Exchange Ratio (VCO2/VO2) was determined during a cardiopulmonary exercise test (CPET). VCO2/VO2 is calculated by measuring the volume of carbon dioxide and oxygen the participant breathes during CPET. When the volume of carbon dioxide exceeds that of oxygen, it reflects a change from aerobic metabolism to anaerobic metabolism. When a participant has a Respiratory Exchange Ratio (RER) during CPET that is equal or greater than 1.1 it is considered a sufficient exercise effort. Results compared Healthy Volunteer Participants to ME/CFS Participants.
Time frame: At time of AT during CPET
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Healthy Volunteers | Cardiopulmonary Exercise Test (CPET) - RER | 1.3011 Ratio | Standard Deviation 0.0791 |
| ME/CFS Participants | Cardiopulmonary Exercise Test (CPET) - RER | 1.2415 Ratio | Standard Deviation 0.1156 |
Characterization of the Immune System and Inflammation - CRP
Blood and CSF were collected from healthy and ME/CFS participants at baseline. A comparison of the results of C-Reactive Protein (CRP), i.e., a measurement of a protein that is made by the liver, in the two populations is reported. A higher level than normal suggests inflammation.
Time frame: Baseline
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Healthy Volunteers | Characterization of the Immune System and Inflammation - CRP | 3.29 mg/L | Standard Deviation 6.85 |
| ME/CFS Participants | Characterization of the Immune System and Inflammation - CRP | 1.4 mg/L | Standard Deviation 2.22 |
Characterization of the Immune System and Inflammation - ESR
Blood and CSF were collected from healthy and ME/CFS participants at baseline. A comparison of the results of the Erythrocyte Sedimentation Rate (ESR), i.e., a measure of how quickly red blood cells settle at the bottom of a test tube, in the two populations is reported. A faster than normal rate of settling suggests inflammation.
Time frame: Baseline
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Healthy Volunteers | Characterization of the Immune System and Inflammation - ESR | 7.43 mm/hr | Standard Deviation 6.13 |
| ME/CFS Participants | Characterization of the Immune System and Inflammation - ESR | 10.1 mm/hr | Standard Deviation 11.9 |
Characterization of the Immune System and Inflammation - WBC
Blood and CSF were collected from healthy and ME/CFS participants at baseline. A comparison of the White Blood Cell (WBC) Count, i.e., a measurement of the number of white blood cells in the blood, in the two populations is reported. Low values can suggest immune deficiencies. High values can suggest infection or inflammation.
Time frame: Baseline
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Healthy Volunteers | Characterization of the Immune System and Inflammation - WBC | 5.907 number of WBCs(K)/uL | Standard Deviation 1.536 |
| ME/CFS Participants | Characterization of the Immune System and Inflammation - WBC | 6.143 number of WBCs(K)/uL | Standard Deviation 1.243 |
Characterization of the Immune System and Inflammation - WBC in CFS
Blood and CSF were collected from healthy and ME/CFS participants at baseline. A comparison of the White Blood cell Count in Cerebrospinal Fluid (WBC in CFS), i.e., a measurement of the number of white blood cells in the cerebrospinal fluid, in the two populations is reported. Higher levels than normal suggest inflammation or infection in the central nervous system.
Time frame: Baseline
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Healthy Volunteers | Characterization of the Immune System and Inflammation - WBC in CFS | 1.0 number WBCs/uL | Standard Deviation 1.124 |
| ME/CFS Participants | Characterization of the Immune System and Inflammation - WBC in CFS | 1.313 number WBCs/uL | Standard Deviation 1.662 |
Characterization of the Pattern of Microbiome in Stool
Stool samples were taken from Healthy and ME/CFS participants at baseline. The number of specific types of bacteria, using the Least Known Taxon (LTK) units, were measured with the Shotgun Metagenomic method.
Time frame: Baseline
Population: Single batch analyzed on subset of participants
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Healthy Volunteers | Characterization of the Pattern of Microbiome in Stool | 477 LTK | Standard Deviation 32.9 |
| ME/CFS Participants | Characterization of the Pattern of Microbiome in Stool | 427 LTK | Standard Deviation 44.1 |
Characterization of Total Body Energy Use (Bioenergetics/Metabolic)
The total amount of energy expended per unit of time as measured by whole-room indirect calorimetry. This method measures the amount of oxygen consumed and carbon dioxide produced which can be used to calculate the amount of energy produced by biological oxidation and is measured by kilocalories per day. Measures were taken from Healthy and ME/CFS participants.
Time frame: 12 hours
Population: Procedure added to Phenotyping Phase after enrollment started.
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Healthy Volunteers | Characterization of Total Body Energy Use (Bioenergetics/Metabolic) | 1858.9 kcal/day | Standard Deviation 353.3 |
| ME/CFS Participants | Characterization of Total Body Energy Use (Bioenergetics/Metabolic) | 1862.1 kcal/day | Standard Deviation 390.5 |
Clinical Response Effect of Tilt Table Testing
Persons with autonomic dysfunction will often have symptoms provoked by having an up-to-40 minutes long tilt table test. The percentage of participants in each group having severe enough symptoms which required the test to be stopped in Healthy and ME/CFS participants at baseline.
Time frame: Baseline
Population: Two participants were unable to complete due to technical difficulties with procedure.
| Arm | Measure | Value (NUMBER) |
|---|---|---|
| Healthy Volunteers | Clinical Response Effect of Tilt Table Testing | 36.8 percentage of participants |
| ME/CFS Participants | Clinical Response Effect of Tilt Table Testing | 58.8 percentage of participants |
Effect of Maximal Exertion on Autonomic Function as Measured by SDNNi in Healthy and ME/CFS Participants.
Variability of the time between heartbeats can be used to measure alterations in autonomic function. The Standard Deviation of the Normal-to-Normal Intervals (SDNNi) is a measure of the amount of beat to beat variability between each normal heartbeat collected over a 24 hour period. These results compare the SDNNi in healthy and ME/CFS participants at baseline.
Time frame: Baseline
Population: Data from participants on cardiac medications were excluded.
| Arm | Measure | Value (MEAN) |
|---|---|---|
| Healthy Volunteers | Effect of Maximal Exertion on Autonomic Function as Measured by SDNNi in Healthy and ME/CFS Participants. | 67.8 ms |
| ME/CFS Participants | Effect of Maximal Exertion on Autonomic Function as Measured by SDNNi in Healthy and ME/CFS Participants. | 56.3 ms |
Mitochondrial Extracellular Flux Assay
The oxygen consumption rate of peripheral blood mononuclear cells per unit of time when the cells are in their normal, unprovoked state of function measured in Basal (units) was measured in Healthy and ME/CFS participants at baseline. This is a standard measure of mitochondrial respiration that is responsible for providing energy to cells.
Time frame: Baseline
Population: Technical issues with assay prevented complete dataset.
| Arm | Measure | Value (MEDIAN) |
|---|---|---|
| Healthy Volunteers | Mitochondrial Extracellular Flux Assay | 46.7 Pmol/min |
| ME/CFS Participants | Mitochondrial Extracellular Flux Assay | 52.1 Pmol/min |
Paced Auditory Serial Addition Test (PASAT)
The PASAT is a measure of cognitive function that assesses auditory information processing speed and flexibility, as well as calculation ability. Single digits are presented every 3 seconds and the patient must add each new digit to the one immediately prior to it. The test score is the total number of correct trials out of a possible 60. The test was administered to Healthy and ME/CFS participants at baseline.
Time frame: Baseline
Population: Not all participants were able to complete test.
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Healthy Volunteers | Paced Auditory Serial Addition Test (PASAT) | 52.4 score on a scale | Standard Deviation 12.1 |
| ME/CFS Participants | Paced Auditory Serial Addition Test (PASAT) | 52 score on a scale | Standard Deviation 11 |
Test of Variables of Attention (TOVA)
The TOVA is a measure of cognitive function that assesses attention and inhibitory control. The test is used to measure a number of variables involving the test taker's response to either a visual or auditory stimulus measured during a simple, yet boring, computer game. These measurements are then compared to the measurements of a group of people without attention disorders who took the T.O.V.A. The range of values for the score, after normalization to the population, is -10 to +10, with a lower score representing a worse attention score. The test was administered to Healthy and ME/CFS participants at baseline.
Time frame: Baseline
Population: Not all participants were able to complete test.
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Healthy Volunteers | Test of Variables of Attention (TOVA) | 1.1 score on a scale | Standard Deviation 3.6 |
| ME/CFS Participants | Test of Variables of Attention (TOVA) | 0.9 score on a scale | Standard Deviation 4.7 |