Diagnosis and classification by physical therapists: a special communication.

Diagnosis and Classification by Physical Therapists: A Special Communication Physical therapists identify and classify clinical phenomena daily in their practice. Through the performance of history taking and physical examination, therapists identify and classify different types of information for use in their clinical reasoning and subsequent treatment. In physical therapy, this process of determining the nature of clinical phenomena through examination and classification is usually referred to as "evaluation," and it is very similar to the diagnostic process commonly performed by our medical colleagues. What differentiates diagnosis by the physical therapist from diagnosis by the physician is not the process itself but the phenomena that are being observed and classified.

Unfortunately, the scope of contemporary scientific classification in the clinical sciences in still quite narrow for the physical therapist's needs. The organization of information and thought in modern clinical practice in most health care disciplines is still based on the diagnostic classification of "disease." The narrowness of this mode of thinking was aptly emphasized by Feinstein, who stated,

What is archaic in clinical medicine today is not the idea of taxonomy, but the idea that the complex natural phenomena occurring in diseased people can be adequately classified by a taxonomy devoted only to disease....In preserving the diagnostic nomenclature of pathologic anatomy as the main contemporary system of identifying human ailments, clinicians perpetuate a mode of thinking that classifies morphologic form, but not clinical function; that classifies diseases, but not people or illness; and that classifies clinical inferences, but not clinical observations. [1(p71)]

Although the term taxonomy may be unfamiliar to many physical therapy practitioners, it can be defined as a "classification" or "system of classification." A diagnostic classification is thus nothing more than a taxonomy. The term taxonomy has been used for centuries to connote a branch of biology that deals with the classification of animals and plants according to their natural relationships. Only recently has the word been applied to the classification of clinical phenomena. [1]

Obviously, disease is by no means the only important clinical phenomenon relevant to physical therapy practice. To improve upon traditional clinical taxonomies, physical therapists need to clarify the nondisease clinical phenomena that they and other health care professionals should assess.

Physical therapy's efforts in developing diagnostic classifications hopefully will be influenced by some of the conceptual formulations that already exist. One formulation that I have found particularly helpful in my thinking about diagnosis by physical therapists is the International Classification of Impairments, Disabilities, and Handicaps (ICIDH) developed by the World Health Organization. [2] The declared purpose of the ICIDH is to provide a conceptual framework for the collection and classification of data relevant to the progress of chronic and disabling conditions in individuals and groups.

The first category in the ICIDH, "disease," represents any pathologic process associated with a characteristic and identifiable set of symptoms and signs. Thus, disease is described in morphologic, chemical, microbiologic, and physiologic terms.

An "impairment," the second element in the ICIDH, is any loss or abnormality of psychologic, physiologic, or anatomic structure within a specific organ or system of the body. Impairments can be either temporary or permanent, and they can reside in different systems (eg, the musculoskeletal or cardiovascular system). Examples of impairment include muscle weakness and restricted range of motion.

The ICIDH's next element, "disability," is defined as any restriction or lack of ability to perform an activity in the manner or within the range considered normal for a human being. As this definition implies, disabilities represent disturbances at the level of the person such as a person's ability to walk, transfer, or climb stairs. Disabilities, therefore, are different from both diseases and impairments.

The final component of the ICIDH, "handicap," is a term used to label a disadvantage that limits or prevents an individual's fulfillment of a role that is normal (depending on the individual's age, sex, and cultural background). Handicaps can be described as the potential social or cultural consequences of disease, impairment, or disability. One common handicap is the individual's inability to perform his or her occupation.

Sahrmann, in a recent article on diagnosis by physical therapists, uses the example of a physician who, after examination and adequate testing, reaches a disease diagnosis that the patient has suffered a cerebrovascular accident (CVA) and who may even specify whether the CVA was of embolic or thrombolytic origin. [3] This example can be used to illustrate how the elements of the ICIDH might be used by the physical therapist in his or her diagnosis and treatment. In Sahrmann's example, the diagnosis of "type 1 hemiplegia" or "nonfragmented volitional movement with severe tone dysfunction" identifies the specific nature of the impairment that results from the CVA. This diagnosis could be referred to as the impairment diagnosis made by the physical therapist. The physical therapist might further diagnose this patient's physical disabilities as "inability to ambulate on level surfaces" and "inability to transfer from bed to chair without human assistance." These diagnoses could be seen as diagnoses of physical disability. Finally, this patient's handicap diagnosis might be "inability to work outside the home." All three consequences flow from the CVA (the disease diagnosis) but are distinct clinical phenomena that may differ substantially in patients with the same disease.

I believe the ICIDH can be useful in helping physical therapists clarify and begin to classify the range of phenomena they might address from a diagnostic and treatment perspective. It provides an initial framework in which to move the traditional organization of data and clinial thought beyond disease to a form that facilitates the classification according to the clinical function of specific organs and body systems (impairments), the individual (disability), or the relationship between the individual and his or her environment (handicap). The development of a "Uniform National Data System" for medical rehabilitation by Granger and colleagues at the State University of New York at Buffalo illustrates the use of the ICIDH in this manner. [4] This data system organizes the collection of admission and discharge information around the patient's disease, impairment, or disability and is being used in rehabilitation hospitals throughout the United States.

The movement within physical therapy toward the systematic observation, classification, and measurement of clinical phenomena important to our scope of practice is critical to the emergence of a scientific basis for our profession. I believe that physical therapists have an important clinical responsibility to properly identify and classify consequences of disease within our scope of practice. This responsibility entails the establishment and investigation of taxonomies that reflect the consequence of disease, that is, how disease interacts with the host who provides the environment in which a disease conducts its life and how the individual with disease interacts with his or her environment. Building upon existing classification schemes such as the ICIDH will allow physical therapists to identify systematically clusters of clinical manifestations that constitute the patient's general clinical state, the sequence in which these manifestations appear, the timing and duration of each sequence, and the coexistence of illness attributable to other diseases.

Is diagnosis an appropriate term to describe this process? I think it is because diagnosis is a term that appropriately describes this classification process and because it is a term that has meaning and understanding to patients seen by physical therapists. Through its acceptance and use, patients will begin to understand that physical therapists do diagnose as well as treat the impairments and disabilities for which they seek help.

There are pitfalls along the way into which physical therapists might easily fall. One that particularly concerns me is the use of the phrase "physical therapy diagnosis." I concur with Sahrmann, who recommends that the term "diagnosis" be used by the physical therapist in referring to the identified condition that is the focus of the physical therapist's treatment. [3] It should not be used to reflect ownership of the condition, which would be the inevitable consequence of using the phrase "physical therapy diagnosis." I believe the purpose of having a physical therapist establish a diagnosis is to name and communicate the primary impairment, disability, or handicap toward which the clinician directs his or her treatment within that professional's appropriate scope of practice.

Conditions diagnosed by the physical therapist will not always be within the physical therapist's unique area of expertise in the same way that specific disease are not within the unique purview of the physician. Classification schemes developed by physical therapists will hopefully gain wide use by other health care professionals, thus contributing to improved communication and discussion about patient care. I will use the earlier example of the patient with a CVA to illustrate this point. The disability diagnosis of "inability to ambulate on level surfaces" is a very appropriate diagnosis to be made by the physical therapist. But is it a physical therapy diagnosis? I think not. It is a diagnosis that could appropriately be made by a physician, a nurse, or an occupational therapist. Communication will best be enhanced across disciplines when the same or similar diagnostic classifications or taxonomies are being used. If every discipline develops and uses its own unique classifications (eg, nursing diagnosis, medical diagnosis, physical therapy diagnosis), we will inhibit communication and understanding across disciplinary boundaries. Once ownership of diagnostic classifications is established, it will be very difficult to eliminate. One of the great advantages of the ICIDH, which is currently in use around the world, is its utility across many different disciplines.

A final caution is to resist bringing the development of classification schemes to closure too quickly in our understandable urge to advance the profession of physical therapy. Physical therapy is in its infancy in its efforts to develop its scientific base. As leaders in other sciences have long advocated, a science cannot develop a system of ordering its observations until it has passed through a long stage of systematic observation and trial. Physical therapy has begun this important and exciting journey but should heed Bronowski's warning that "a science which orders its thought too early is stifled." [5]

References

[1] Feinstein AR: Clinical Judgment. New York, NY, R E Krieger Publishing Co Inc, 1967

[2] International Classification of Impairments, Disabilities, and Handicaps. Geneva, Switzerland, World Health Organization, 1980

[3] Sahrmann SA: Diagnosis by the physical therapist--A prerequisite for treatment: A special communication. Phys Ther 68:1703-1706, 1988

[4] Granger C, Hamilton B, Keith R, et al: Advances in functional assessment for medical rehabilitation. Topics in Geriatric Rehabilitation 1(3):59-74, 1986

[5] Bronowski J: The Common Sense of Science. New York, NY, Vintage Books, 1978

A Jette, PhD, PT, is Senior Research Scientist, New England Research Institute, 9 Galen St, Watertown, MA 02172, and Adjunct Associate Professor, Graduate Program in Physical Therapy, MGH Institute of Health Professions, 15 River St, Boston, MA 02108-3402 (USA).

This article was submitted March 7, 1989; was with the author for revision for five weeks; and was accepted May 11, 1989.