Journal of Chronic Fatigue Syndrome
        Vol. 14, #2, pp 7-23
 Date:   Summer 2007
 http://jcfs.haworthpress.com
 
 
 Legal and Scientific Considerations of the Exercise Stress Test
 ---------------------------------------------------------------
 Margaret Ciccolella, EdD, JD; Staci R. Stevens, MA; Christopher R. Snell, 
 PhD; J. Mark VanNess, PhD

 - Margaret Ciccolella, Staci R. Stevens, Christopher R. Snell, and J. Mark
  VanNess are affiliated with the University of the Pacific, Pacific 
 Fatigue Laboratory, Stockton, CA.
 - Address correspondence to: J. Mark VanNess, University of the Pacific,
  Stockton, CA 95211 (E-mail: mvanness@pacific.edu).


 ABSTRACT

 This article examines the legal and scientific bases on which an exercise
 stress test can provide medically acceptable evidence of disability for 
 the Chronic Fatigue Syndrome (CFS) patient. To qualify for disability 
 benefits, a claimant must establish the existence of a serious medically determinable
 impairment (MDI) that causes the inability to work. The single stress test
 has been used to objectively establish whether a claimant can engage in
 "substantial gainful employment" and is an important determinant of the 
 award or denial of benefits. A review of case law indicates problems associated
 with a single test protocol that may be remedied by a "test-retest" 
 protocol.
 The results of a preliminary study employing this approach indicate that 
 the test-retest protocol addresses problems inherent in a single test and
 therefore provides an assessment of CFS related disability consistent with
 both medical and legal considerations.

 KEYWORDS. Serial exercise testing, functional impairment, differential
 diagnosis


 INTRODUCTION

 Denial of Benefits: Typical Scenario

 Denial of related disability benefits is a common problem for the patient
 with a medical diagnosis of Chronic Fatigue Syndrome (CFS). The typical
 scenario can be described as follows: Debilitating fatigue prevents 
 continued work and the CFS patient reports the diagnosis to his or her employer. The
 patient becomes a "claimant" upon application for related disability 
 benefits from the Social Security Administration (SSA) and/or a private insurance
 carrier. The initial burden is on the claimant who must objectively 
 establish the existence of a medically determinable impairment (MDI) that is serious
 enough to cause the inability to engage in any "substantial gainful
 employment." Claimant fails to provide sufficient objective evidence and
 disability for the inability to work is successfully challenged resulting 
 in the denial of benefits. Appeals are available but the burden rests with 
 the claimant to pursue a reversal of the denial.

 At the appeal and regardless of the agency involved, a review of the 
 medical record fails to provide sufficient objective evidence of a serious 
 impairment that causes disability. While the diagnosis is accepted, the central legal
 issue is whether the claimant can work on a regular and ongoing basis. The
 medical record documents that the diagnosis is largely based on 
 self-reports by the patient to the treating physician and that the symptoms upon which 
 a diagnosis or MDI is made overlap with other illnesses. This makes it
 difficult to distinguish CFS from other illnesses. It is undisputed that
 there is no widely accepted definitive laboratory test for CFS. However, 
 the record used to objectively document a FRC that precludes the ability to 
 work on a regular and ongoing basis includes a single exercise stress test. The
 test shows diminished metabolic capability consistent with the ability to 
 do at least sedentary work and the benefits are denied.

 Problem: The Single Stress Test

 The single stress test has been utilized to assess Function Residual 
 Capacity (FRC) and therefore determine whether a claimant can work. The problem is
 that a review of case law documents that both good and poor results of a
 single stress test have been used to deny benefits. A good result 
 contradicts the diagnosis of disability because it appears to show the ability to 
 work. A poor result is subject to the criticism that the claimant malingered by
 deliberately failing to exert maximal effort on the test.

 It is our position that utilization of a single test fails to objectively
 establish disability from both a legal and clinical perspective. We 
 premise this paper on the assertion that "post-exertional malaise" is the 
 cornerstone symptom of CFS related disability. The objective assessment of the fatigue
 suffered following a test is critical to the determination of ability to 
 work on a regular and ongoing basis. Such an assessment requires integration of
 law and science if meaningful consequences are to result for the CFS 
 patient.

 SSA explicitly states that continued research will produce new evidence to
 "clarify the nature of CFS and provide greater specificity regarding the
 clinical and laboratory diagnostic techniques that should be used to 
 document this disorder" (1). The purpose of this paper is to explore the 
 utilization of a "test-retest" protocol consistent with such a mandate. The legal
 considerations relevant to the use of a single stress test protocol will 
 be discussed followed by a report of preliminary "test-retest" research
 conducted at the Pacific Fatigue Laboratory.


 LEGAL CONSIDERATIONS

 Social Security Administration (SSA) Policy

       Social Security Ruling (SSR) 99-2p (1999)
       Mettlen v. Commissioner of the SSA (2003)

 Social Security rulings constitute general policy statements but they do 
 not have the full force and effect of law. While SSA rulings are not binding 
 upon a court, courts in fact frequently rely upon them. This reliance is 
 evident in a review of appeals denying benefits involving both SSA and private
 insurance companies. For this reason, SSA policy for evaluating CFS
 disability claims is briefly reviewed here.

 SSA accepts the definition of CFS established by an international group
 convened by the Centers for Disease Control and Prevention (CDC). Under 
 the CDC definition, the hallmark of CFS is the presence of clinically 
 evaluated and debilitating chronic fatigue that cannot be explained by another 
 physical or mental disorder. SSA requires a dual process in the establishment of 
 CFS disability in that a claimant must prove (1) the existence of a "medically
 determinable impairment" (MDI) and (2) the inability to engage in any
 substantial employment.

 1. Establishing the MDI.
 Physicians sometimes cannot make a conclusive diagnosis of CFS and there 
 is no "dipstick" laboratory test for diagnosing the condition. SSA accepts 
 the symptom-based criteria for the diagnosis of CFS established by the CDC,1 
 but requires a strict timeline for the concurrence of at least four symptoms 
 that include post-exertional malaise lasting more than 24 hours. Of the listed
 symptoms, post-exertional malaise is considered to represent the 
 cornerstone symptom of CFS and is therefore is especially relevant to this paper.

 While diagnosis may be based primarily on self-reported symptoms, 
 disability requires objective evidence. For example, SSA policy explicitly disallows 
 a finding of disability based solely on subjectively allegations of symptoms 
 or impairments. A serious impairment (MDI) must be objectively proven. Since 
 the medical community has not reached agreement on a definitive test, SSA 
 allows reliance on "certain" listed laboratory findings to establish the 
 existence of the MDI.2 The list of enumerated laboratory findings includes "an 
 abnormal stress test" using a "medically accepted" protocol.

> 2. Establishing the ability to engage in any substantial employment.
> SSA policy considers whether a claimant has the ability to engage in
> "substantial gainful employment," i.e., whether the claimant can sustain
> work-related activities in a work setting on a regular and continuing 
> basis.
> Residual functional capacity (FRC) laboratory test assesses whether the
> claimant, in spite of a serious impairment, has the physical and mental
> ability to perform activities required by competitive, remunerative work. 
> If
> an applicant's FRC fails to meet the requirements of regular, previous
> employment, then the burden is on the Commissioner to show that the 
> claimant
> can do work as it is generally performed in the "national economy" 
> (Mettlen
> v. Commissioner of the SSA, 2003).
>
>
> Examples of Appeals Using the Exercise Stress Test
>
> The most common use of the stress test in appeals is to objectively 
> establish
> FRC and work capacity by assessing the metabolic onset of fatigue. A 
> single
> stress test is ineffective in establishing a MDI because it cannot 
> document
> post-exertional malaise, a cornerstone symptom used to diagnose CFS, and 
> does
> not distinguish between CFS and other illnesses. It further fails to
> effectively assess disability in that both good and poor performances have
> been used to dispute an inability to work and deny benefits. The following
> cases illustrate the problems when a single stress test protocol is used.
>
>
> Problems Associated with a Good Result on a Single Stress Test
>
>       O'Sullivan v. The Prudential Insurance Co. of America (2002)
>       Marshall v. Sullivan (1990)
>
> In O'Sullivan v. Prudential (2002), the former director of human resources 
> in
> a New York City hotel (claimant) appealed a private insurance company's
> denial of long-term benefits. Prudential discontinued the long-term
> disability benefits after claimant, a CFS patient with overlapping 
> symptoms
> of fibromyalgia, alleged total disability. Prudential had the medical 
> records
> of the claimant reviewed by a consulting physician asking her to answer 
> two
> specific questions: (1) what objective medical evidence existed that 
> rendered
> claimant unable to perform the sedentary duties of her job and (2) based 
> on
> the medical evidence in the record, did the claimant have any restrictions 
> or
> limitations of her functional ability?
>
> The response to both questions focused in part upon the results of a 
> single
> exercise stress test in which the claimant's relatively good performance
> appeared to demonstrate the ability to work. With regard to claimant's
> ability to work, Prudential's consulting physician concluded that no
> objective evidence existed to support claimant's inability to perform a
> sedentary desk job. "She was able to reach 9 METs of exercise on a stress
> test... more than what is generally considered minimally necessary for a
> sedentary job." With regard to functional ability, the physician stated 
> that
> "very little documentation of [claimant's ] actual physical abilities is
> available in the medical records... The treadmill test documented that she
> is able to walk uphill for nearly 8 minutes at a time..."
>
> During the proceedings, Prudential did not contest claimant's complaints 
> of
> pain and fatigue or the fibromyalgia diagnosis. Instead, Prudential simply
> maintained that there was no objective medical evidence which established 
> how
> the claimant's condition rendered her totally disabled.
>
> The court addressed the question of disability by considering two issues: 
> (1)
> whether claimant was unable to perform the duties of her job due to 
> sickness
> and (2) whether the claimant was unable to perform the duties of any job
> consistent with her education, training, or experience. The court found 
> the
> record devoid of any evidence that the claimant's treating physicians were
> aware of the duties of the claimant's job and further concluded that they
> were apparently ignorant of her level of education, training, and 
> experience.
> The court found that the claimant's treating physicians offered "little 
> more
> than conclusionary assertions that do not establish that [claimant] is
> totally disabled." Here, while claimant was granted SSA benefits,
> Prudential's denial of long-term benefits was upheld.
>
> In Marshall v. Sullivan (1990),3 claimant appealed SSA denial of benefits 
> for
> chronic fatigue. Claimant was a 68-year-old accountant for the state of
> Virginia who was initially diagnosed with chronic infectious mononucleosis
> related to Epstein-Barr virus (EBV). Her treating physician concluded that
> she was totally disabled based upon her reports of debilitating fatigue
> following routine exertion and lab results showing persistent elevation of
> EBV antibody titers. It should be noted that by the end of her appeal EBV 
> and
> mononucleosis were ruled out as causing disability and the proper 
> diagnosis
> of Chronic Fatigue Immune Dysfunction Syndrome (CFIDS) was made.
>
> In addition to her treating physicians, three additional physicians 
> examined
> claimant (one each from SSA, a private insurance carrier, and the state
> retirement board) and all agreed that claimant was disabled. The only 
> report
> to contradict claimant's disability came from the medical advisor for SSA 
> who
> neither treated nor examined claimant. According to the medical advisor, 
> the
> results of the treadmill test revealed a lack of disability and he found 
> that
> claimant had the capacity "for at least light work." The claimant's high
> level of performance on the treadmill proved that she had the "residual
> functional capacity" to work comfortably at lower levels of activity. The
> Administrative Law Judge (ALJ) relied primarily on the medical advisor's
> opinions and the results of the treadmill test in finding claimant not
> disabled.
>
> At the appeal, the ALJ was found to have improperly analyzed claimant's
> fatigue.
>
>       In his decision, the ALJ refers to that test [treadmill test] as `an
>       objective tool by which the Administrative Law Judge can measure
>       the claimant's fatigue.' This is clearly not the case; Marshall's
>       [claimant's] performance on the treadmill revealed nothing about
>       the increased fatigue she suffered following the test.
>
> It was determined that the treadmill test failed to provide persuasive
> evidence to contradict the treating and examining physicians. Therefore, 
> the
> SSA decision to deny benefits was reversed and claimant was awarded 
> benefits.
> While the outcome was good for the claimant in this particular case, the 
> risk
> and burden on the claimant was clear. The objective results of a single 
> test
> resulted in an initial denial of benefits and the claimant was forced to
> pursue two appeals in order to ultimately prevail. This might have been
> avoided altogether had the claimant participated in a second test to
> objectively document the fatigue that she suffered following the first 
> test.
> See discussion below.
>
>
> Problems Associated with a Poor Result on a Stress Test
>
>       Coffman v. Metropolitan (2002)
>
> In Coffman v. Metropolitan (2002), claimant appealed the denial of 
> long-term
> benefits from a private insurance company. Claimant worked as a drug
> representative for a major company and was subsequently diagnosed with 
> CFS,
> hypothroidism, vertigo, and other conditions. Metropolitan denied 
> disability
> benefits claiming the medical record had "insufficient objective clinical
> findings" to support claimant's subjective complaints and did not support
> that [claimant] was "unable to perform the duties of his job." Further,
> Metropolitan offered expert testimony that the fatigue of a chronic nature
> experienced by claimant was more likely due to other conditions.
>
> At trial, claimant offered the results of a cardiopulmonary stress test to
> prove a significant impairment of functional aerobic work. Claimant's
> treating physician stated that maximal oxygen consumption was only 61% of
> predicted for sedentary individuals and that this poor performance showed
> the inability of claimant to "sustain work."
>
> Metropolitan responded that these conclusions were wrong because they were
> based on "a test which clearly revealed less than maximal effort" noting 
> that
> claimant reached only 73% of his predicted maximal heart rate. Claimant's
> treating physician responded to the criticism asserting that claimant was 
> on
> cardiac drugs (calcium channel blockers) that may have blunted heart rate 
> and
> that excellent effort on the test was observed in blood pressure readings
> that increased from 120/80 to 200/94 and increases in oxygen pulse and
> respiratory rate. He further stated that hyperventilation due to anxiety
> accounted for a respiratory quotient (RQ) greater than one at the 
> beginning
> of the test.
>
> Metropolitan used video-surveillance showing claimant running errands with
> his wife, driving a car, attending church, carrying two tote bags, etc. 
> This
> direct observation of claimant's activities was effectively used to
> contradict the claim that physical limitations precluded work and provided
> additional support for Metropolitan's challenge to the results of the 
> stress
> test. A Metropolitan expert testified that claimant's functional 
> capacities
> were "compatible with the Department of Labor Work Category definition of
> light to medium work." The shadow cast upon the results of the stress test
> and the lack of objective medical evidence to support disability resulted 
> in
> a ruling that upheld Prudential's denial of benefits.
>
>
> Relevance to the Need for a Test-Retest Protocol
>
> In good result/performance cases, a claim for benefits is compromised when 
> a
> single exercise stress test provides apparent and objective evidence of 
> the
> ability to work that conflict with the medical record. In such cases, the
> record is typically replete with subjective evidence of claimant's
> debilitating fatigue following routine exertion that includes walks, 
> running
> errands, doing household chores, etc. The failure to objectively document
> post-exertional malaise is a failure to distinguish fatigue from 
> disability.
> As a cornerstone symptom of CFS, it is imperative to document 
> post-exertional
> malaise in order to objectively demonstrate the inability to work on a
> regular and continuing basis. If post-exertional malaise effectively means
> that the patient who works on Monday will then suffer uncompromising 
> fatigue
> for several days thereafter, then it is reasonable to assert that there 
> can
> be no reasonable expectation of regular participation in the national
> economy.
>
> Poor result/performance cases provide objective evidence for disability 
> but
> have been successfully challenged on the basis that the claimant 
> malingered
> on the test. This raises the important issue of the endpoint used to
> determine both effort and fatigue. End point respiratory quotients (RQs) 
> are
> widely accepted as objective markers of effort and fatigue. RQs exceeding
> 1.09 at the end of an 8-12 minute test indicate that peak aerobic capacity
> has been met and that anaerobic metabolism explains continued 
> participation
> in the test. An RQ exceeding one coupled with evidence that either (1) 
> Peak
> VO_2 or (2) heart rates meeting or exceeding 85% of predicted maximal 
> rates
> is compelling evidence of maximal effort on a stress test.
>
> The ability to do errands and chores is often used as evidence of the 
> ability
> to work a job every day. Video-surveillance and third-party testimony is
> permitted to document a claimant's daily activities, e.g., doing household
> chores, shopping, running errands, attending church, driving a car, etc.
> (Coffman v. Metropolitan, 2002). However, at least one appeal ruled that 
> the
> ability to do limited daily activities is not inconsistent evidence of
> disability. In Smith v. Barnhart (2003), the ALJ found claimant not 
> markedly
> impaired because she was able to care for her personal needs, perform some
> household tasks, and regularly attend church and a Bible study. At appeal,
> this decision was found not to reflect whether the ALJ considered evidence
> showing that the claimant had difficulty performing her limited daily 
> tasks.
> The court cited authority that the ALJ must assess such activities by 
> their
> independence, appropriateness, effectiveness, and sustainability.
> Additionally, the ALJ did not analyze why claimant's daily activities were
> inconsistent with her ability to work. "The fact that a claimant is able 
> to
> engage in limited daily activities, such as washing dishes, doing laundry,
> and cooking meals does not necessarily demonstrate that she is not 
> disabled."
>
> Nonetheless, specific reference in the medical record of the caloric or
> metabolic requirements to perform specific jobs or tasks is important.
> O'Sullivan v. Prudential (2002) explicitly commented on the need for the
> medical record to specifically document the physician's knowledge of the
> metabolic requirements for certain jobs. A poor performance on a stress 
> test
> may not defeat an argument that sedentary work is within the metabolic
> capability of a claimant. This argument may be supported by reference to
> Department of Labor Work Category or specific lists of routine and 
> unskilled
> jobs within the capabilities of persons with aerobic impairments, e.g.,
> stationary security guard, toll booth operator, ticket taker, car lot
> attendant (Swenson v. Sullivan, 1989). Evidence of the caloric 
> requirements
> associated with various tasks/jobs and claimant's metabolic capability to
> perform would greatly support a rebuttal to the argument. This requires a
> test-retest protocol that measures oxygen consumption values that are 
> readily
> translated into caloric equivalents.
>
> The following preliminary study conducted at the Pacific Fatigue 
> Laboratory
> is directly relevant to the issues raised above. The study examines the
> test-retest protocol and discussion of the results directly connects the
> legal and scientific considerations relevant to stress testing.
>
>
> PACIFIC FATIGUE LABORATORY STUDY
>
> Results/Methods
>
> In this study, the exercise test-retest protocol was examined. The 
> objective
> of the study was to determine whether objective findings of 
> post-exertional
> malaise could be documented and to determine whether a serial stress test
> could objectively distinguish fatigue caused by CFS as opposed to fatigue
> caused by other illnesses. A brief summary is shown in Table 1.
>
> A standardized bicycle protocol was used in six CFS patients and six 
> normal
> controls. Expired gases were collected throughout the test so that the
> following values could be determined: Peak oxygen consumption (VO_2peak
> ml/kg/min), oxygen consumption at anaerobic threshold (VO_2 @AT 
> ml/kg/min),
> peak respiratory quotient (RQ), and percentage of predicted heart rate
> (beats/min). The premise of the study was that test-retest variability in
> these values should not exceed 8% (2). The rationale for examining these
> values in a serial protocol is as follows:
>
> Peak VO_2 documents maximal aerobic capacity that can be used to measure
> fatigue, post-exertional fatigue and determine functional work capacity.
> Oxygen consumption values can be translated into estimates of kilocalories
> that in turn can be used to compare the energy requirements of various 
> tasks.
> This allows for an objective determination of the ability to do work and
> therefore support or deny the existence of disability. Further, evidence 
> of
> the attainment of Peak VO_2 is one factor that documents maximal exertion 
> in
> a test.
>
> VO_2 @AT is the intensity of physical work when anaerobic metabolism takes 
> on
> a significant and increasing role in providing the energy necessary to
> continue work. Subjectively, this is the point in work that feels as if
> exhaustion will occur within a relatively short time in the absence of 
> rest
> or a reduced workload. Objectively, VO_2 @AT documents one parameter on 
> which
> to explain level of work that cannot be tolerated for long periods because 
> it
> represents a point when fatigue begins to lead to exhaustion. This too may 
> be
> translated into one's ability to produce and expend energy (kilocalories) 
> at
> the onset of fatigue allowing for comparison with the energy requirements 
> of
> various tasks.
>
> Peak RQ values objectively document the relative contribution of aerobic 
> and
> anaerobic metabolism at the end of a stress test. Values exceeding one
> indicate Peak VO_2 has been met and that anaerobic metabolism 
> preferentially
> contributes to the energy necessary to continue work. Values over 1.0 are
> widely accepted as an important factor that shows maximal effort was 
> exerted
> on a test.
>
> 85% of Predicted Maximal Heart Rate is a commonly accepted end-point
> representing fatigue and true effort in a stress test. There should not be
> exclusive or even preferential reliance on heart rate. While heart rate
> objectively reflects workload, it is also influenced by other factors, 
> e.g.,
> emotional status, influence of drugs, state of hydration. Further, it has
> been argued that blunted heart rates are characteristic of the CFS patient
> (3). Heart rate is important but should not be exclusively relied upon,
> especially under circumstances where objective documentation of effort is
> important.
>
>
> DISCUSSION OF CLINICIAL AND LEGAL ISSUES RELEVANT TO THE RESULTS AND A CFS
> DIAGNOSIS
>
> 1. Establishment of an MDI
>
> Can the Test-Retest Protocol Support a Diagnosis by Showing 
> Post-Exertional
> Malaise?
>
> On Test 1, a side-by-side comparison of Controls and CFS patients shows 
> the
> relatively "good performance" similar to the discussion above examining 
> legal
> appeals. In O'Sullivan v. Prudential (2002), claimant had a maximal MET 
> level
> of 9. Here, Test 1 Peak VO_2 values represent maximal MET levels of 8.11 
> and
> 7.48, respectively for Controls and CFS patients. Test 1 values alone are 
> not
> compelling evidence that the CFS patients are significantly more impaired
> that Controls. Additionally, Peak VO_2, VO_2 @AT, and RQ values show no
> significant differences between the two groups. This further suggests that
> metabolic abnormalities are absent.
>
> It is the comparison between tests that shows a disturbing difference 
> between
> the two groups. Variability from Test 1 to Test 2 in Peak VO_2 and VO_2 
> @AT
> values documents impairment in CFS patient but not the controls. Controls
> show only 2-3% variability while CFS patients declined by an average of
> 22-27%. Based upon the premise that test-retest variability should not 
> exceed
> 8%, this study indicates significant impaired metabolic capability as well 
> as
> an atypical recovery response in the CFS patient but not the Controls. 
> This
> is directly relevant to a finding of post-exertional malaise.
>
> This type of analysis is precluded when only the results of a single test 
> are
> available. A serial protocol is required to document debilitating fatigue.
> The test-retest protocol does what the single test cannot do, namely
> objectively document post-exertional malaise, a cornerstone symptom upon
> which a CFS diagnosis can be founded.
>
>
> Can the Test-Retest Protocol Distinguish CFS from Other Illnesses?
>
> There remains the problem of distinguishing CFS from other illnesses. This
> raises the question of what results might occur when CFS patients are
> compared to patients with other illnesses. Wasserman argues that 
> test-retest
> variability should not exceed 8% in Peak VO_2 and VO_2 @AT values in 
> clinical
> and normal groups. Weisman reports a summary of five prior studies that
> examined test-retest variability in patients with different illnesses. The
> averaged variability in Peak VO_1 and VO_2/AT among patients suffering 
> from
> chronic obstructive pulmonary disease (COPD), interstitial lung disease
> (ILD), and chronic heart failure (CHF) was 7.2% (2).
>
> It is our contention that the dramatic decline in Peak VO_2 and VO_2 @AT
> values in CFS patients documented in the Pacific study is unique to CFS 
> and,
> therefore, represents a basis on which to distinguish fatigue caused by 
> CFS
> as opposed to fatigue caused by other illnesses. Further research is
> necessary but based on the results of Pacific's study, the potential to
> better understand and therefore articulate the nature of CFS to both 
> medical
> and legal arenas is clearly possible.
>
>
> 2. Establishment of the Ability to Work
>
> Can the Test-Retest Protocol More Effectively Document Functional
> Impairment/Ability to Work?
>
> Metabolic charts state the caloric requirements for certain tasks and VO_2
> and VO_2 @AT values can be translated into calorically based documentation 
> of
> an individual's metabolic ability or state of fatigue in any number of 
> tasks
> and jobs. Laboratory stress tests that produce such information may 
> provide
> explicit documentation of specific tasks that may be reasonably and 
> regularly
> done by the claimant. This goes to the heart of the ability to work every 
> day
> at a given job and therefore "engage in substantial employment."
>
> This is illustrated using data from the Pacific study from CFS Patients on
> Test 2 values of Peak VO_2 an VO_2 @AT and a hypothetical CFS patient
> weighing 150 pounds (68 kg). Oxygen consumption data is translated into
> Calories on the premise that one liter of oxygen consumed is the 
> equivalent
> of approximately 5 calories produced and expended.
>
> For example, Peak VO_2 averaged 20.5 ml/kg/min which translates to a 
> maximal
> ability to aerobically produce and expend 7kcals/min. VO_2 @AT work 
> capacity
> averaged 11 ml/kg/min which translates into 3.74 kcals/min3.
>
> It is imperative to distinguish the ability to work a regular job from
> engaging in daily activities that permit frequent and extended rest 
> periods.
> Providing specific metabolic information from a test-retest format allows
> discussion of job requirements in terms of Caloric requirements. This is
> terminology familiar even to the lay person and provides documentation
> required by policy, law, and precedent.
>
>
> Can the Test-Retest Protocol Distinguish Maximal Exertion from Malingered
> Effort?
>
> Peak RQ values with minimal variability and with values ranging from
> 1.09-1.21 give strong objective support that both groups in both tests
> exerted maximal effort. Unlike the Controls, the CFS Patients experienced 
> a
> dramatic decline in VO_2 @AT values between tests suggesting impaired
> metabolism sufficiently serious to result in the onset of fatigue at a
> significantly lower workload. This data is the type of objective
> documentation that can support self-reports by CFS Patients of 
> debilitating
> fatigue following routine exertion.
>
>
 CONCLUSION

 Proving CFS disability is a mandate for a claimant seeking associated
 benefits. Examination of legal considerations relevant to the proof of
 disability and the process of securing benefits is important to CFS 
 research.
 The alliance of science and law allows for consideration of the 
 development of laboratory findings that have the potential to better understand the
 nature of CFS and to provide objective and acceptable evidence for CFS
 disability.

 It is our contention that the Pacific study on serial testing reflects 
 this alliance. It is clear that the Pacific study is preliminary and begs 
 further review. But the initial data suggests that the test-retest format offers a
 superior basis on which to establish disability consistent with SSA policy
 and other relevant case law. If the preliminary data holds, the 
 contribution to the CFS patient may be immeasurable.

 NOTES

 1. Diagnosis requires concurrence of at least four self-reported symptoms
   that include: (1) short-term memory loss or impaired concentration that
   causes substantial reduction in previous levels of performance in work,
   social or personal activities; (2) sore throat; (3) tender lymph nodes 
 in
   the neck or auxiliary area; (4) muscle pain; (5) joint pain without
   redness or swelling; (6) non-refreshing sleep; and (7) post-exertional
   malaise lasting more than 24 hours. Social Security Ruling (SSR) 99-2p
   (1999).
 2. The following lab findings establish the existence of a MDI in CFS
   patients: An elevated antibody titer to Epstein-Barr virus capsid 
 antigen
   equal to or greater than 1:5120, or early antigen equal to or greater 
 that
   1:640; An abnormal MRI brain scan; Neurally mediated hypotension as 
 shown
   by tilt table testing or another clinically accepted form of testing; 
 or,
   Any other lab findings that are consistent with medically accepted
   clinical practice and are consistent with the other evidence in the case
   record; for example, an abnormal exercise stress test or abnormal sleep
   studies. Social Security Ruling (SSR) 99-2p (1999).
 3. Unpublished dispositions when used in this paper are not included as
   legal precedent. Rather, they are included because they offer insight
   into the legal use and interpretation of stress tests for the CFS 
 patient.

 CASE LAW REFERENCES

 Kansky v. Coca-Cola Bottling Company of New England, (2006 WL 1167781 at 
 D.
   Mass).
 Marshall v. Sullivan, 914 F.2d. 248, Unpublished Disposition, 1990 WL 
 135840
   (4th Cir. Va 1990).
 Mettlen v. Commissioner of the Social Security Administration, 2003 WL 
 1889011,
   86 Soc.Sec.Rep.Serv. 600 (E.D. Tex. 2003).
 O'Sullivan v. The Prudential Insurance Co. of America, 2002 WL 484847 
 (S.D.N.Y.).
 Smith v. Barnhart, 59 Fed.Appx. 901 (7th Cir. In 2003) Unpublished 
 Disposition.
 Swenson v. Sullivan, 876. F.2d 683 (9th Cir. Wa 1989).

>
> TABLE CAPTION
>
 Table 1

 Controls:
 Test 1 Test 2 (Var)

 VO2 Peak 28.4 28.9 (2%)

 V02@AT 17.5 18.0 (3%)

 Peak RQ 1.19 1.21 (2%)

 Predicted HR% 94.8 97.6 (3%)

 ---------------

 CFS patients

 Test 1 Test 2 (Var)

 VO2 Peak 26.2 20.5 (-22%)

 V02@AT 15.0 11.0 (-27%)

 Peak RQ 1.15 1.09 (5%) (TK: this should be
 -5%)

 Predicted HR% 87.0 87.8 (1%)
 -----------------------------------------------------


 Results: "differences between control and CFS, respectively, for test 1: 
 ..
 HR% (87.0 ± 25.4%; 94.8 ± 8.8%)."
 as the heart rate is inverted.


 TABLE 1. A summary of the results of the preliminary study with 6 CFS
 patients and 6 control subjects. The values for peak oxygen consumption 
 (VO_2 Peak) oxygen consumption at the anaerobic threshold (VO_2 @AT), peak
 respiratory quotient (Peak RQ) and the percent of age-predicted maximal 
 heart rate attained at peak exercise (Predicted HR%) are shown for the first
 exercise test (Test 1) and the second exercise test (Test 2) administered 
 24 hours later. The percent variability (Var) between Test 1 and Test 2 is 
 shown to illustrate the magnitude of the difference in between the metabolic
 responses.

> REFERENCES
>
> 1. SSR 99-2p (1999 WL 271569 (S.S.A.)) April 30, 1999.
> 2. Weisman, I.M., & Zeballos, J. (Eds.) (2002) Clinical exercise testing.
>   New York: Karger. In Progress in Respiratory Research (Volume 32; C.T.
>   Bolliger, Editor).
> 3. VanNess, J.M., Snell C.R., Dempsey W.L., Strayer D.R., Stevens S.R. 
> Sub-
>   classifying Chronic Fatigue Syndrome Through Exercise Testing. Med Sci
>   Sports Exerc 2003; 35(6), 908-913.
>
> --------
> (c) 2007 The Haworth Press
>