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Introduction

The Social Security Administration (SSA) requested that the National Academies of Sciences, Engineering, and Medicine (NASEM) assemble a committee to review new or improved diagnostic or evaluative techniques for assessing physically disabling impairments. SSA is interested in information about diagnostic or evaluative techniques that have become generally available within the last 30 years for assessing physical conditions in five body systems—cardiovascular, neurological, respiratory, hematological, and digestive. A main focus of the requested collection of information is whether more accurate or precise techniques have become available for determining if a previously evaluated physical impairment was either more or less severe. This report is the committee’s response to its charge, which is shown in Box 1-1.

In the course of considering the task and ways to create a useful report for SSA, the committee discussed concepts of disability and functional status and the various tests, techniques, and measures that are salient in the context of SSA disability assessment. This chapter frames the report by briefly describing SSA disability evaluation, the committee’s approach to the task, and chapters 2 through 8 of the report.

SOCIAL SECURITY ADMINISTRATION DISABILITY DETERMINATION

SSA provides benefits to adults and children who meet the eligibility requirements for a disability described in Title II and Title XVI of the Social Security Act. In adults the Social Security Act defines a disability as

the inability to engage in substantial gainful activity (SGA) by reason of any medically determinable impairment or impairments—physical, mental, or combination—that can be expected to result in death or which has lasted or can be expected to last for a continuous period of not less than 12 months. SSA considers a medically determinable physical or mental impairment to be “an impairment that results from anatomical, physiological, or psychological abnormalities that can be shown by medically acceptable clinical and laboratory diagnostic techniques. The medical evidence must establish that an individual has a physical or mental impairment; a statement about the individual’s symptoms is not enough” (SSA, 2022a). Under Title XVI a child is considered disabled if the child has a medically determinable physical or mental impairment(s) and the impairment(s)

results in marked and severe functional limitations and has lasted (or is expected to last) for at least 1 year or to result in death. SSA’s definition of a medically determinable physical or mental impairment is the same for adults and children (SSA, 2022b).

To establish whether an applicant meets the statutory definition of disability, SSA collects information from the applicant, health care providers, and non-medical sources about the applicant’s impairment and impairment-related symptoms, such as pain, that may affect what the adult applicant can do in a work setting or, in the case of children, at school, for example. The specific steps in SSA’s sequential evaluation process for adults are outlined below. A discussion focused on SSI disability assessment in children follows in a later section.

Medical Eligibility

SSA uses a five-step sequential evaluation process to determine whether a person is medically eligible for Security Disability Insurance (SSDI) or Supplemental Security Income (SSI) benefits¹ (Figure 1-1).

At the first step, for adults, SSA determines whether the applicant is currently engaging in SGA, defined as earning more than the SGA threshold, which in 2022 was set at $1,350 per month for non-blind people and $2,260 per month if a person is blind (SSA, 2022c). If the applicant is currently engaging in SGA, SSA will find that the applicant is not disabled. At the second step, the disability examiner considers the medical severity and expected duration of the applicant’s medically determinable physical or

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¹ 20 CFR § 404.1520.

mental impairment(s). A medically determinable physical or mental impairment is an impairment that results from anatomical, physiological, or psychological abnormalities that can be shown by medically acceptable clinical and laboratory diagnostic techniques (SSA, 2022a). If the applicant’s impairment or combination of impairments is not severe (having no more than a minimum effect on an individual’s ability to work) or has not lasted (or is unlikely to last) at least 12 months, SSA will find that the applicant is not disabled.

Listing of Impairments

At the third step of the disability evaluation, the disability examiner assesses an applicant’s impairment using a regulatory list of medical conditions and criteria created by SSA, titled the Listing of Impairments. Part A of the Listings apply to the evaluation of impairments in adults age 18 and over (SSA, 2022d) and Part B of the Listings contains additional medical criteria that apply only to the evaluation of impairments of persons under age 18 (SSA, 2022e). The Listing of Impairments describes, for each of the major body systems, impairments that SSA considers to be severe enough to prevent a person from performing any gainful activity (or, in the case of children under age 18 applying for SSI, severe enough to cause marked and severe functional limitations). If the applicant’s impairment meets or medically equals the criteria in a listing, then SSA will find that the applicant is disabled and allowed benefits. Box 1-2 identifies the medical conditions in the SSA’s Listings of Impairments for the five body systems addressed in this report.

The examiner moves on to the fourth step, at which point the disability examiner assesses the applicant’s “residual functional capacity” (the maximum level of physical and mental performance that the applicant can achieve, given the functional limitations resulting from his or her medical impairment[s]) and determines whether the applicant is able to engage in any of his or her past relevant work; if so, the applicant will be found not to be disabled.²

At the fifth and last step, SSA will determine whether the applicant can perform any work in the national economy on the basis of the assessment of residual functional capacity and the applicant’s age, education, and work experience. If the applicant can make an adjustment to other work that exists to a significant degree in the national economy, SSA will find that the person is not disabled; otherwise, SSA will find the applicant is disabled.³Figure 1-1 provides a visual model of the steps involved in the evaluation.⁴

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² 20 CFR § 404.1560(b).

³ 20 CFR § 404.1560(c).

⁴ For additional details on the types of medical evidence considered in the disability-determination process and on the training and credentials required of disability examiners and medical/psychologic consultants, refer to The Promise of Assistive Technology to Enhance Activity and Work Participation (NASEM, 2017).

Continuing Disability Review

SSA performs periodic reviews of disability cases to determine if an individual entitled to disability benefits continues to be disabled (SSA, 2022f). A continuing disability review (CDR) is a process to determine if an individual’s impairment(s) has improved since the most recent favorable determination, referred to as the comparison point decision (CPD). An individual may submit medical and other evidence, as applicable, for consideration during the review. If the SSA determines that an individual no longer meets the SSA’s definition of disabled, benefits cease.

The frequency of the review is based on the likelihood of medical improvement. Income, resources, and living arrangements are also considered during the CDR (SSA, 2022g). The Social Security Act requires that SSA perform a CDR at least once every 3 years for beneficiaries with an impairment in which medical improvement is possible and more frequently in cases where the medical condition is expected to improve sooner. Even in the case of medical conditions that are not expected to improve, SSA will review each claimant’s case once every 7 years.

CDR Evaluation Process

For CDRs, SSA uses an eight-step sequential evaluation process (Figure 1-2). Some steps are the same as those under the five-step eligibility process (Figure 1-1, above). The steps that are repeated in the CDR evaluation include determining whether the individual is engaging in SGA and whether the individual’s impairments meet the Listings of Impairments criteria.

The first step in the CDR sequential evaluation process is to determine whether the individual is performing SGA; if the finding is no, the disability examiner will continue. In the second step, if the examiner finds that the beneficiary’s impairment(s) meets or equals a condition in the Listing of Impairments, then disability status continues. If it does not, the process continues to step 3, the identification of medical improvement.

SSA defines “medical improvement” as any decrease in the medical severity of a physical or mental condition that was present at the time of the beneficiary’s most recent favorable medical decision when the individual was disabled or continued to be disabled. A decrease in medical severity is determined on the basis of an improvement in the clinical or laboratory findings associated with the person’s medical condition. Medical evidence may come from the individual’s own medical sources, or in some cases, when additional information is needed, the disability examiner will arrange for a consultative examination from an independent source.

SSA considers two categories of medical improvement to enable a careful consideration of all factors related to whether an adult continues to receive SSDI or SSI:

• Medical improvement not related to ability to do work: Medical improvement is deemed to be not related to an individual’s ability to work if there has been a decrease in the severity of the impairment(s) present at the time of the most recent favorable medical decision but the individual still meets or equals the listing, or any subsection of the listing, that the person met at his or her most recent favorable decision or there has been no increase in the individual’s functional capacity to do basic work activities. If there has been any medical improvement in the individual’s impairment(s), but it is not related to the person’s ability to do work and none of the exceptions apply, that individual’s benefits will be continued.
• Medical improvement that is related to ability to do work: Medical improvement is related to an individual’s ability to work if there has been a decrease in the severity of the impairment(s) present at the time of the most recent favorable medical decision and that person no longer meets or equals the listing, or any subsection of the listing, that the individual met at his or her most recent favorable decision or, if that person did not meet a listing at his or her most recent favorable decision, there has been an increase in his or her functional capacity to do basic work activities. A determination that medical improvement is related to an individual’s ability to do work has occurred does not necessarily mean that the person’s disability will be found to have ended unless it is also shown that

that person is currently able to engage in substantial gainful activity (see 20 CFR § 404.159).

The disability examiner continues to step 4 in the CDR process if medical improvement is evident; if it is not, then the examiner skips to step 5. Step 4 involves determining if any medical improvement is related to work ability. If it is not, the examiner continues to step 5; otherwise, the examiner skips to step 6. Step 5 involves exceptions to medical improvement that examiners use in limited situations to determine disability ceased, i.e., “even though there has been no improvement or improvement is not related to the ability to work, evidence shows that the person should no longer be considered disabled or never should have been considered disabled.”

Step 6 in the CDR process is evaluating the severity of the current impairment(s). If the individual currently has any severe impairment(s), then the examiner will continue to step 7; otherwise disability ceases. In Step 7, determinations are made about whether the individual has the ability to perform past relevant work. If yes, then disability ceases; otherwise the examiner continues to the final step 8, which assesses whether the individual has the ability to do other work. If the answer is yes, then disability ceases; otherwise, disability continues. Details about the process can be found in Section DI 28005.015 of the Program Operation Manual System (POMS) (SSA, 2022f).

Cumulative List of New or Improved Diagnostic or Evaluative Techniques

The medical diagnostic or evaluative techniques SSA may use when assessing continuing disability are contained in POMS subchapter DI 33535.000, Cumulative List of New or Improved Diagnostic or Evaluative Techniques.⁵ The techniques, which have come into use since 1970, include cardiovascular, gastrointestinal, musculoskeletal, ophthalmology, otolaryngology, and psychological tests and miscellaneous tests applicable to several body systems. Disability examiners consider the specified new or improved diagnostic or evaluative techniques in DI 33535.000 in the narrow situation, where despite the lack of evidence showing medical improvement, other evidence shows that the person should no longer be considered disabled or never should have been considered disabled. The list is usually applied if the new or improved technique has an important impact on the determination as shown by the following:

• an individual (with otherwise unchanged findings, allowed under the requirements in the SSA Listings of Impairments) has no impairment(s) of the severity included in the listings; or

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⁵ To view the cumulative list, see: https://secure.ssa.gov/poms.nsf/lnx/0433535000.

• an individual has more functional capacity than previously thought (based on otherwise unchanged findings).

In order to apply the Cumulative List of New or Improved Diagnostic or Evaluative Techniques in the continuing disability review, all of the following criteria must be met:

• Medical improvement (MI) has not occurred or MI is not related to the ability to work.
• The new or improved diagnostic or evaluative technique must be generally available after the most recent favorable medical determination or decision.
• The public has been notified of the new or improved technique.
• The current evidence shows the individual is capable of engaging in substantial gainful activity or, in a Title XVI childhood disability case, the child does not have an impairment(s) causing marked or severe limitations or that meets, medically equals, or functionally equals the listings.
• The diagnostic or evaluative procedure must be listed in the subchapter DI 33535.000.

Sections DI 28020.001 and DI 28020.250 of the POMS manual provides additional details about the use of the Cumulative List of New or Improved Diagnostic or Evaluative Techniques in the CDR process.

SSI Disability Assessment for Children

The definition of a child with disability is given by the Social Security Act, Section 1614(a) (3)(C)(i): “An individual under the age of 18 shall be considered disabled for the purposes of this title if that individual has a medically determinable physical or mental impairment, which results in marked and severe functional limitations, and which can be expected to result in death or which has lasted or can be expected to last for a continuous period of not less than 12 months.” An impairment results from anatomical, physiological, or psychological abnormalities that can be shown by medically acceptable clinical and laboratory diagnostic techniques. A physical or mental impairment must be established by medical evidence consisting of signs, symptoms, and laboratory findings, not only by an applicant’s statement of symptoms.

The listing of impairments for children does not map one-to-one to the listing of impairments for adults, discussed above. For example, there is a category for low birth weight and failure to thrive in the childhood listings, but no such category exists for adults. Furthermore, the medical conditions

differ in the categories of listings for children and adults because some conditions do not present in childhood and therefore are not in the childhood listings (amyotrophic lateral sclerosis, for example).

When a child has one or more severe impairments that do not meet or medically equal the listing, an assessment of functional equivalence is performed. In this step it is determined if the child’s impairment functionally equals the listing with either marked limitations in two domains of functioning or extreme limitations in one domain. For children there are six domains of functioning: acquiring and using information, attending and completing tasks, interacting and relating with others, moving around and manipulating objects, caring for yourself, and health and physical well-being.

As described above, continuing disability reviews (CDRs) include an assessment of whether medical improvement is evident. The process applies to both adults and children. As in the case of adults, the SSA uses the SSA Cumulative List of New or Improved Diagnostic or Evaluative Techniques in certain, limited situations in the disability evaluations of Title XVI children.

MODELS OF DISABILITY

According to SSA, the statutory definition of disability for adults is “the inability to do any substantial gainful activity by reason of any medically determinable physical or mental impairment which can be expected to result in death or which has lasted or can be expected to last for a continuous period of not less than 12 months” (See 20 CFR § 404.1505). Substantial gainful activity is defined via an earnings threshold. In short, for an adult to be determined as disabled, a medical condition must lead to limitations that themselves affect the ability to earn in the labor market. A finding of disability in both adults and children depends upon the severity of functional limitations arising from the claimant’s impairment or combination of impairments.

Recent National Academies of Sciences, Engineering, and Medicine (NASEM) reports have provided a detailed background of the evolution of concepts of disability over the past several decades (NASEM, 2019, 2020, 2021a, 2021b, 2021c). An important and relevant conclusion from those reports is that the effects of a given medical condition on an individual’s functioning, activity, and participation are mediated by the individual’s physical and social environments. This recognition has been embodied in the International Classification of Functioning, Disability and Health (ICF) developed by the World Health Organization (WHO) and illustrated in Figure 1-3. The ICF is a biopsychosocial model of disability in which person’s level of functioning is viewed as a dynamic interaction between

her or his health conditions, environmental factors, and personal factors. In the ICF model, disability is “an umbrella term for impairments [of body functions or structures], activity limitations and participation restrictions” (WHO, 2002, p. 2).

The ICF encompasses three levels of functioning. The first level, body function and structure, includes the “physiological functions of body systems, including psychological functions” and the functioning of body structures, or movement of “anatomical parts of the body such as organs, limbs and their components” (WHO, 2002, p. 10). ICF calls problems in body function or structure such as a significant deviation or loss “impairments.” Function at the level of the whole person, i.e., activity—includes actions or tasks performed by an individual, such as walking, lifting, keyboarding, or problem solving. ICF refers to difficulties in executing actions or tasks as “limitations.” The third level of functioning is participation, or the performance of tasks in a societal context. Work is an example of participation. ICF calls decrements in participation “restrictions.” Accommodations (e.g., assistive technologies, environmental modifications) are environmental contextual factors that act on ICF domains to enhance an individual’s activity and participation. In Chapter 2, the committee focuses on approaches for assessing functioning and elaborated on the environmental and social factors that influence clinical practice and patient care, including access to the latest diagnostic technologies.

In sum, in considering the study focus on diagnosis and evaluation within the context of the biopsychosocial model of disability, the committee underscores a distinction between the determination of a medical diagnosis and the presence or severity of deficits in physical functioning. While medical tests may allow for the accurate and precise measurement of disease characteristics, those characteristics may be relatively uninformative when evaluating the degree of an individual’s functional limitations. This has particular relevance to SSA’s evaluation of an individual’s severity of disability, ability to engage in SGA, and eligibility for SSI or SSDI benefits.

STUDY APPROACH

The committee held six virtual meetings between December 2021 and January 2023. The committee met mostly in closed session, but it held an open session with SSA representatives in attendance at the first meeting.⁶ In deliberations about the study scope, committee members carefully considered the statement of task, published research, and information received from SSA. The committee discussed the topics and areas to prioritize in the report, accounting for the collective and individual expertise of the committee members and the project timeline. Consequently, the committee decided that the primary focus of this report should be on studies, health conditions, and techniques in the adult population and that, where applicable, it would highlight pertinent information about children.

As directed by the Statement of Task, the committee focused on physical impairments, but notes that individuals with disabling impairments often have multiple comorbidities, including mental health conditions that influence and interact with physical health and functioning, and thus may affect the approach to assessment. Therefore, the reader should be aware that the report references SSA operational and regulatory policy language, which may include terms (such as “mental health conditions”) that are not covered in the scope of the report. Information about conditions and impairments associated with psychological and mental health, as well as cancer in adults and children, is available in recent SSA-sponsored NASEM comprehensive reviews on these topics. See Psychological Testing in the Service of Disability Determination (IOM, 2015), Childhood Cancer and Functional Impacts Across the Care Continuum (NASEM, 2021a), Diagnosing and Treating Adult Cancers and Associated Impairments (NASEM, 2021b); and Exploring the State of the Science of Solid Organ Transplantation and Disability: Proceedings of a Workshop (NASEM, 2021c).

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⁶ See the NASEM website for meeting details://www.nationalacademies.org/our-work/newor-improved-diagnostic-or-evaluative-techniques-used-in-disability-reviews.

Selection of Techniques

Over a 30-year period, numerous techniques have been developed, refined, and upgraded for the purposes of diagnosing and evaluating individuals with a wide range of conditions within each of the five body systems in the report. As a starting point, the committee reviewed the Cumulative List of New or Improved Diagnostic or Evaluative Techniques (discussed above), which lists the techniques SSA uses to reevaluate an individual for disability insurance who had been evaluated previously. The list includes tests that are applicable to several body systems (e.g., computed tomography), as well as specific cardiovascular, gastrointestinal, musculoskeletal, ophthalmologic, otolaryngologic, and psychologic tests. However, the list does not include any specific tests for neurologic, respiratory, or hematologic conditions, which are areas addressed in this report. After engaging in many in-depth conversations about the nature of the task, the committee developed an approach for selecting the subset of techniques representing the focus of the task.

In this report, the committee defines a “diagnostic test” as a test used by itself or in combination with other tests to diagnose a condition for which a threshold of a measurable phenomenon must be reached for the diagnosis, while “evaluative tests” are considered to be tools used to assess health and functional status; some techniques may be both diagnostic and evaluative. (The characteristics of diagnostic and evaluative tests are more fully described in Chapter 2). The committee selected a subset of techniques that span diagnostic and biophysical tests and, to a lesser extent, functional assessments, by turning to a recent NASEM publication on the topic. Functional Assessment for Adults with Disabilities (NASEM, 2019) is an in-depth, extensive review of the literature pertaining to the functional assessment of physical and mental health abilities relevant to work requirements. In its selection, the committee considered where there is evidence to determine that the technique

1. Was made generally available in the last 30 years and is generally considered accepted medical practice,
2. Demonstrates improvement over a previous test. “Improvement” includes, but is not limited to, refinement of measurement methodology or interpretation, successful application in the assessment of additional populations or conditions, or the identification of previously unknown limitations to allow a more valid application of the technique,
3. Primarily aids in establishing, correcting, or refining a diagnosis or level of severity when the improvement in accuracy and/or precision is likely to improve the assessment of impairments that may affect functional capacity, and

4. Is relevant to the SSA disability program and the conditions in SSA’s Listings of Impairments for the cardiovascular, neurologic, respiratory, hematologic, and digestive body systems.

The committee interpreted its charge to mean a search for tests with improved average accuracy or precision that may have the potential ability to change a prior assessment of disability. The committee notes that it is impossible to know with certainty if a different result using a new and “improved” test reflects a true change in an individual’s disability over time or a difference in the accuracy or precision of the older and newer tests. Given the broad scope of the task, the techniques selected may not represent an exhaustive review of all possible techniques available in the five health fields, and, depending on the available literature, they address each criterion to varying degrees.

The committee conducted a review of the published scientific and medical literature pertaining to diagnostic and evaluative tests to assess physical health and function in general and, specifically, to the cardiovascular, neurological, respiratory, hematological, and digestive body systems. Committee members and project staff conducted online searches encompassing Medline (Ovid) and PubMed. For each of the 5 body system chapters, search terms included “advances,” “innovations,” “diagnostics,” “technology,” “physical functioning” and “functional assessment.” The report presents a summary of the evidence and information about the selected techniques and responds to the requested items a–j of the Statement of Task. Additionally, the committee identified emerging techniques expected to be generally available within approximately the next 5 years that serve as illustrations of promising advances in patient diagnosis and evaluation. Several National Academies reports informed the committee’s work, including Improving Diagnosis in Health Care (NASEM, 2015), Functional Assessment for Adults with Disabilities (NASEM, 2019), Selected Health Conditions and Likelihood of Improvement with Treatment (NASEM, 2020).

The literature searches conducted for the study revealed few research studies examining disparities in test performance that are related to race, ethnicity, or other population characteristics. This gap in the evidence is an impediment to a greater understanding of an important question in the study task (item b) regarding whether any improvement in a diagnostic or evaluative technique is seen with equally strong effect among different racial, ethnic, or gender sub-populations. There is ample evidence demonstrating differences or disparities in the incidence of disease, the severity and manifestations of disease, and the severity of disability related to disease. In contrast to this evidence regarding disparities in the incidence and severity of diseases, the evidence concerning the differences in test performance is sparse. For example, there is literature demonstrating poor performance of

pulse oximeters for the identification of hypoxemia in darker pigmented individuals (Patterson et al., 2022; Valbuena et al., 2022), but the committee did not find data regarding differences in test performance for new or improved diagnostic or evaluative techniques that would allow the committee to specifically address item b in the Statement of Task. Importantly, while there is a lack of data regarding disparities in performance of diagnostic or evaluative techniques, the committee notes there is compelling evidence that there are disparities in access to new and improved diagnostic and evaluative techniques.

ORGANIZATION OF THE REPORT

Chapter 2 provides important contextual details about evidence-based models for assessing physical health conditions in the context of disability assessment. Chapter 3 is a general overview of current techniques and newer technologies for patient diagnosis and evaluation used for a variety of medical conditions. Chapters 4 through 8 are devoted to the diagnostic and evaluative techniques for the specific body systems in the Statement of Task: cardiovascular (Chapter 4), neurological (Chapter 5), respiratory (Chapter 6), hematological (Chapter 7), and digestive (Chapter 8). In response to the requested items a-j of the Statement of Task, chapters 4 through 8 identify the committee’s selection of advanced techniques and technologies related to the capacity to diagnose the presence of specific disease and associated impairments that can affect a person’s functioning. Each one concludes with a brief discussion of emerging diagnostic techniques in the field. Lastly, Chapter 9 presents the committee’s overall findings and conclusions from this review.

REFERENCES