Summary

The U.S. Social Security Administration (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. 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 S-1.

In this report the committee presents information intended to inform SSA and interested audiences about selected new and improved techniques for diagnosis and evaluation, including types of evidence-based approaches that are important to the assessment of an individual’s physical health and functioning. In the context of the biopsychosocial model of disability embodied in the International Classification of Functioning Disability and Health (ICF), developed by the World Health Organization (WHO, 2002), 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 relevance to SSA’s evaluation of an individual’s severity of disability, ability to be employed, and eligibility for disability benefits.

OVERVIEW OF DISABILITY EVALUATION

SSA uses a five-step sequential evaluation process to determine whether a person is medically eligible for Social Security Disability Insurance or Supplemental Security Income (SSI) benefits. 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 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.” 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. 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, 2022).

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 work activity and impairment and the 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. At step 1 of the disability evaluation, if an applicant is engaging in SGA (determined by earnings), SSA will not proceed with a disability determination. At step 2, SSA determines whether the applicant has a medically determinable physical or mental impairment or a combination of impairments that meets the severity and duration requirements for disability. If so, at step 3 the agency determines whether the applicant’s impairment(s) meets or medically equals one of the listings in the Listing of Impairments, a number of which include functional criteria. The listings describe 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 an impairment meets or medically equals the criteria in the Listing of Impairments, SSA will determine the applicant to be disabled and allowed benefits. For impairments that do not meet or exceed the criteria, at steps 4 and 5, SSA considers residual functional capacity (maximum physical and mental performance despite limitations resulting from medical impairment[s]); if the applicant is able to engage in any work, SSA will decide that the applicant is not disabled.

At select intervals, SSA will conduct a continuing disability review (CDR) to determine if an individual entitled to disability benefits continues to be disabled.¹ CDR is a process to determine if an individual’s impairment(s) has improved since the most recent favorable determination (indicating a granting of disability benefits), referred to as the comparison point decision. If SSA determines that an individual is no longer disabled, benefits cease. The SSA Program Operation Manual System (POMS) is a primary source of information used by SSA to process claims for Social Security benefits. Sections DI 28020.001 and DI 28020.250 of the POMS provide for the use of the Cumulative List of New or Improved Diagnostic or Evaluative Techniques, which lists the techniques SSA may consider in some circumstances when reevaluating an individual for disability insurance during the CDR process. This list is not up to date; for example, some obsolete cardiovascular techniques are included, and there are no specific neurologic, respiratory, or hematologic techniques, which are areas addressed in this report.

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¹ The Social Security Act requires that SSA perform a CDR at least once every 3–7 years; the frequency depends on the nature of the condition and on the person’s expected improvement.

STUDY APPROACH AND SCOPE

The committee held six virtual meetings between December 2021 and January 2023 plus one open session, with SSA representatives in attendance at the first meeting. In deliberations about the study scope, committee members carefully considered the Statement of Task, published research, and information received from SSA. 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. 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 pertaining specifically to the cardiovascular, neurological, respiratory, hematological, and digestive body systems. 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.

Over the past 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. During the planning phase, the committee established 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 would be on studies, health conditions, and techniques in the adult population but that it would, where applicable, 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.

In this report the committee defines a diagnostic test as a test used by itself or in combination with other tests to confirm the presence of 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 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). That report, sponsored by SSA, presents a comprehensive review of the literature pertaining to the functional assessment of physical and mental health abilities relevant to work requirements. In general, this report should be reviewed in conjunction with the 2019 NASEM report, as the reports share many themes.

In its selection of techniques, the committee considered where there was 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 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 that it should search for tests with improved average accuracy or precision that may have the potential to change a prior assessment of disability. The challenges of addressing this point were revealed during the process of selecting the techniques and in completing the requested information in task. 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.

Chapters 1 and 2 of the report provide important contextual details about SSA disability evaluation and 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 diagnosis and evaluation used for a variety of medical conditions across body systems. Chapters 4 through 8 are devoted to the diagnostic and evaluative techniques for the five 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 functioning. Each one concludes with a brief discussion of emerging diagnostic techniques in the field. Chapter 9 presents the committee’s overall findings and conclusions from this review.

FUNCTIONAL ASSESSMENT IN DISABILITY EVALUATION

Echoing the conclusions in Functional Assessment for Adults with Disabilities (NASEM, 2019), this report underscores the importance of using evaluative information from functional assessments in disability determination. In conjunction with the medical interview and other tests, standardized measures of functioning can help quantify and track symptoms or outcomes. In the realm of functional assessment, capacity is what a person can do; while performance is what a person actually does in his or her environment. Nearly always, there are barriers to performing at the level of a person’s capacity. Therefore, it is important to determine both a person’s capacity and his or her performance in developing an accurate assessment of that person’s functioning, including the ability to carry out instrumental activities of daily living, fulfill job responsibilities, and participate in other life situations. Objective data on physical capacity are often measured by exercise-based performance tests, such as routine cardiac stress testing, cardiopulmonary exercise testing, and the 6-minute walk test. Measures of physical capacity use standardized protocols and have participants conduct activities in a controlled setting. In addition, a wide range of functional outcomes can be measured using patient-reported instruments, including return to work, physical function, cognitive function, emotional function, support network, and social supports. Like performance-based functional measures and unlike capacity measures, patient-reported assessments evaluate what a person does in everyday settings. Patient-report measures are valid and reliable indicators of the effects of disabling impairments which can identify factors acting as barriers or facilitators to a person’s ability to perform tasks.

Over the last 30 years, extensive efforts have been made to develop new instruments and to improve upon the accuracy, precision, methods, and scope of existing instruments. For example, computer-adapted testing uses algorithms to adjust to a participant’s ability level, allowing a more accurate assessment of abilities in real-time with less time needed to perform the test. Reviewing the full range of new and improved functional assessments goes beyond the committee’s task, given the very large number of measures available; however, information and resources for a range of functional assessment measures are included in this report.

SOCIAL DETERMINANTS OF HEALTH AND DISABILITY

In an assessment carried out in a controlled setting, the impacts of the environmental, social, and personal factors are obscured or minimized. Two individuals diagnosed with the same health condition may experience vastly different social determinants of health and circumstances; as such, their

associated disabilities may be markedly different, and this is especially true when the individuals have various co-occurring health conditions. The committee considered the study task in terms of the ICF model of disability, in which a person’s disease or disorder as well as environmental factors (including access to evaluations and treatments) and personal factors together influence a person’s deficits in body function and structure, limitations of activities, and restrictions in participation. When considering disability, understanding what people are able to do in their typical environments and how they are able to perform tasks can be more illustrative than objective measures of capacity that eliminate actual environmental and personal factors. Notably, literature searches conducted for the study revealed few research studies examining factors in test validity that are related to race, ethnicity, or other population characteristics. While there is a lack of data in this regard, there is ample compelling evidence that there are disparities in access to new and improved diagnostic and evaluative techniques.

TRANSFORMATIONAL CHANGES IN TECHNOLOGY

The report describes selected new or improved techniques in the diagnosis and evaluation of disease and abnormalities in the five body systems addressed in the Statement of Task. Over the past 30 years, medical assessment and treatment have been steadily transforming in the wake of scientific discoveries and technological innovations across all fields of medicine. Increased precision in state-of-the-art imaging and genetic testing, enabled by advances in computing technology, artificial intelligence, nanotechnology, and molecular biology, are generating more diagnostic information with greater detail to help clinicians diagnose disease or determine how well a particular therapy is working. For example, the visualization of the various systems in the body and the measurement of physiologic functioning of tissues and organs have greatly improved with the use of wireless devices, advanced anatomic imaging with computed tomography and magnetic resonance imaging, and molecular imaging with single-photon emission computed tomography and positron emission tomography. Additionally, newer diagnostic techniques that focus on individualized molecular diagnoses and targeted therapeutics will continue to revolutionize the diagnosis and treatment of many diseases and conditions. Although these major innovations in imaging, biomarkers, and genetics are improving the diagnostic process across all organ systems and future technologies promise even more enhanced capabilities to visualize, access, measure, and repair abnormalities within the human body, the assessment of the functional status of an individual, including the possibility of disability, is not dependent on any single test and requires a holistic approach integrated across organ systems and the individual’s environment.

OVERALL CONCLUSIONS

From its review the committee reached consensus on eight main conclusions with relevance to SSA’s evaluation of an individual’s severity of disability and appropriateness for benefits. For each conclusion, the committee presents its rationale and summarizes the information and findings that it reviewed and that are discussed in the report.

1. Tremendous progress has occurred in the development of new—and the improvement of existing—diagnostic and evaluative tests used in clinical practice over the last 30 years.

The committee reviewed evidence on many selected diagnostic and evaluative tests that demonstrate increased accuracy over previously generally available tests or that fulfill functions for which tests were previously unavailable. In many cases these important advances are helping improve the ability to diagnose conditions in the pre-symptomatic phase of disease (such as genetic testing for neurodegenerative conditions) or at the early stages, when the disease may be less severe. Earlier diagnosis allows earlier treatment initiation, which may help reduce the risks and disabling consequences of severe disease.

2. Despite displaying new or improved diagnostic capabilities, new diagnostic tests are limited in their ability to provide information regarding the presence or severity of disability.

Many of the new and improved diagnostic techniques reviewed provide information that was previously unavailable about the presence and nature of a disorder or disease and its stage of development. Diagnostic tests may demonstrate that an individual has a condition that is serious enough to cause severe, long-lasting, or permanent impairments and thus support a determination of disability. Advances in medical diagnostics could also increase the opportunities for disabled individuals to be diagnosed with another condition in the pre-symptomatic or early symptomatic phase that eventually may also be disabling. However, diagnostic accuracy is not always sufficient, and even medical tests that make possible the precise measurement of disease characteristics may not provide accurate or useful informative about the degree of an individual’s functional limitations. In the context of continuing disability review, new or improved diagnostic tests will often yield little or no information on the functional consequences of previously identified health conditions.

3. Evaluative tests can measure functioning and disability. There is insufficient evidence to conclude that any new or improved evaluative test could demonstrate that an individual is more or less disabled than had been previously found in the disability determination process.

There are a wide variety of evaluative tests available that measure functioning and disability, addressing the interplay among body functions and structures at the organ level, activities at the person level, and participation at the societal level. Many of these tests have excellent validity and reliability and can help identify functional limitations that lead to disability. However, the committee’s review did not reveal sufficient evidence from high-quality comparative evaluations between various evaluative tests to demonstrate that any particular evaluative test is more precise or accurate than other tests to the point that an individual evaluated using that test should be deemed more or less disabled than the person was when previously evaluated. Furthermore, focusing solely on the accuracy or precision of any one evaluative test to understand whether an individual may be more or less disabled oversimplifies the dynamic nature of, and contextual influences on, disability. A change in a person’s level of functioning may be due to the nature of his or her health conditions, to medical treatments, or to the influences of the physical and social environments on health.

4. Measuring functional limitations accurately requires gathering multiple sources of information as no single source can reliably and definitively determine a person’s ability to engage in substantial gainful activity.

Results from functional testing are important in disability determinations because there is not always a strong correlation between diagnosis and an individual’s functional limitations. Furthermore, rarely is a single evaluative test adequate to determine whether a person can or cannot perform substantial gainful activity. It is essential to interpret the results of evaluative tests in the context of an individual’s history, findings on physical examination, and other relevant testing (e.g., functional testing in a real work or school environment) in assessing disability. A test of a person’s capacity (e.g., 6-minute walk test) cannot provide a comprehensive understanding of the consequences of an individual’s functional limitations in real-world settings. Contextual factors (physical and social environment) and personal factors (such as motivation) that influence a person’s performance in everyday settings are critical in the assessment and interpretation of disability. In the pediatric population, tests used to assess impairments are often similar to those used in adults but are normed based on age, development, and size. Understanding the developmental trajectory in children is crucial to interpreting findings from measures of physical functioning in children. Overall, the committee found that SSA’s current process for examining residual functional capacity would likely benefit from improvements in the systematic collection of information from multiple sources, increased objectivity in the process, and more comprehensive examination of all aspects of whole person function.

5. There are barriers to the widespread use of diagnostic and evaluative medical technologies.

Even for generally available diagnostic and evaluative tests, barriers to access and availability often exist, depending on the social, economic, and other characteristics of patient, provider, insurance coverage, and health care systems. Studies show that people unable to access timely, appropriate care are less likely to be diagnosed with early-stage disease, are more likely to have co-morbid conditions, and are more likely to experience poorer health outcomes overall, including disabling consequences. If an individual does not have access to important diagnostic and evaluative tests, it limits the clinician’s ability to determine the nature and severity of the person’s condition with increased specificity. Many modern diagnostic techniques today use highly specialized equipment and require specific expertise in the use and interpretation, and neither the equipment nor the expertise is uniformly available across health care settings. There is greater access to these resources at major medical centers, academic centers, and in specialty medical practices. The variable distribution and availability of diagnostic and evaluative resources can be a barrier to the integration of these resources into routine clinical practice in some areas of the country.

6. Functional assessments using patient-reported measures are valid and reliable indicators which deserve greater attention by SSA.

The use of patient-reported measures in functional assessments can provide an enhanced understanding of the effects of disease on health, functioning, and quality of life, and thus these are important tools in monitoring disease progression across a wide spectrum of diseases. There are hundreds of validated patient-reported measures relating to nearly all body regions and conditions that are used clinically to assess a range of functional outcomes, such as return to work, physical function, cognitive function, emotional function, support network, and social supports. Functional Assessments for Adults with Disabilities (NASEM, 2019) is an important source of information and insight about functional assessments in disability and provides a detailed compendium of functional assessment instruments, including patient-reported measures.

7. There are important gaps in the literature and in knowledge for each of the body systems regarding how diagnostic and evaluative tests perform differently across subpopulations and in comparison with other tests.

The committee found important gaps in the existing research literature regarding how various diagnostic and evaluative tests may perform differently across racial/ethnic groups, by age of the participants, or by other sociodemographic characteristics. Furthermore, the committee notes that some diagnostic or evaluative tests may not be culturally or linguistically

sensitive and results may not be reliably compared between subpopulations. Research focused on determining the validity of generally available diagnostic and evaluative tests across the full range of developmental, demographic, cultural, linguistic, and socioeconomic groups would enhance SSA’s ability to make disability determinations.

8. Advances in health care are constantly occurring, which makes staying abreast of new and improved diagnostic and evaluative tests important for assessment and care.

Frequent updates to SSA program guidance performed in a timely manner would help ensure that the disability evaluation process consistently reflects the best current practice in clinical diagnosis and in the evaluation of disability.

REFERENCES