Physical therapy diagnosis: role and function.

Physical Therapy Diagnosis: Role and Function

Introduction

The Need to Define Role

and Function

The need to define the role and function of diagnosis in physical therapy practice stems from the importance of distinguishing this diagnosis from those made by other health care practitioners. Identifying the role and function of physical therapy diagnoses also should provide evidence that they have distinguishing characteristics, are limited to our body of knowledge and scope of practice, and are complementary to (and not in conflict with) diagnoses made by other health care practitioners. The current political-legal aspects of this issue mandate that the profession clearly communicate that the intention of the physical therapy diagnosis is not to infringe on the practice of others or to assume roles that are beyond the scope of our education and training.

These political-legal issues include the prerogative and extent of involvement of the physical therapist in the diagnostic process. Resolution of these issues is done within the legislative arena. The American Physical Therapy Association's goal of obtaining direct access to our services has fostered lively discussion, in that arena and others, regarding the ability of physical therapists to make diagnoses. The linkage between direct access and diagnosis is the inherent belief by the majority of those involved (professional participants and lay public alike) that seeing a patient in the direct-access mode requires the practitioner to make a medical diagnosis.

This central tenet is derived from the basic principle of medical practice that in order to treat disease effectively, the practitioner must know, or have a strong hypothesis regarding, the pathophysiological mechanisms of the patient's disease. The physical therapist's ability to perform diagnoses of disease apparently is a critical element in the decision by many legislators to grant patients or clients direct access to our services. These issues are now part of ongoing discussions and information gathering by APTA's House of Delegates (see RC 6-87, RC 5-87, and RC 42-88). The absence of a generally accepted description (ie, a definition) of a physical therapy diagnosis, or of a document that identifies the role and function of this diagnosis, allows legislators and members of the health care community to believe that physical therapists want to diagnose disease in a manner similar to that used by their physician colleagues.

This article will attempt to demonstrate that the objectives of a physical therapy diagnosis are focused on classifying dysfunction rather than disease and are directed primarily to planning and predicting outcome of treatment, and thus are distinctly different from a medical diagnosis.

Physical Therapy Diagnosis:

A Definition

Recently Sahrmann has proposed the following definition of a physical therapy diagnosis:

Diagnosis is the term that names the primary dysfunction toward which the physical therapist directs treatment. The dysfunction is identified by the physical therapist based on information obtained from the history, signs, symptoms, examination, and tests the therapist performs or request. [1]

The definition clearly states that naming dysfunction for the purpose of directing treatment is the expected outcome of the diagnostic process. Sahrmann's second sentence implicitly indicates that physical therapists would not diagnose clinical entities that require tests or procedures that fall outside the scope of their practice. Having a generally accepted definition like the one proposed by Sahrmann should dispel the fears of the medical community that physical therapists wish to diagnose disease, infringe on the practice of others, or perform clinical acts outside their scope of expertise. This definition is the operational framework for my reflections on the roles and functions of a physical therapy diagnosis.

Physical Therapy Diagnosis:

Roles and Functions

Clinical Practice

A fundamental objective of the physical therapy clinician is to either prevent or remediate dysfunctions that are primarily, but not exclusively, of the movement system. By implementing treatment or management strategies that predominantly involve the use of exercise and physical agents, the clinician attempts to change what nature or circumstance has done or prevent what they may do. Choosing the most useful and least harmful strategy for a given patient is one of the clinical decisions made by the clinician daily. Establishing a physical therapy diagnosis allows the clinician to name and classify clusters of symptoms, signs, and demographic data of similar patients who have responded successfully to a specific treatment. Using the systematic process of classifying clinical data, developing categories based on the classification process, and naming categories of successfully treated patients increases the probability that the clinician will replicate--or surpass--the best results obtained in previous situations.

Classifying and Naming of

Clinical Data

The process of classifying clinical data into named categories of clinical entities is currently accepted as a scientifically sound method for establishing a diagnosis. After the elements of, or criteria for, the categories of a clinical entity are established by the process of classification, it is essential to determine whether the categories are mutually exclusive and exhaustive. Then a meaningful or descriptive name is assigned to each category. The act of naming the categories provides a shorthand for communication with colleagues.

Interestingly, providing a name to the patient's clinical condition usually brings "psychological comfort" to the patient and the practitioner. For example, many patients with low back pain with or without radiculopathy are told, based on no real evidence or criteria, that their probable diagnosis is a herniated nucleus pulposus. This diagnosis may have virtue in that it gives the impression to the patient that something is "realy" wrong. Practitioners and patients alike have difficulty dealing with the statement "We really don't know what's wrong with you." Thus the diagnosis provides a name that creates a sense of reality that is beneficial to the patient and the practitioner. Naming, therefore, has the wonderful clinical value of providing a shorthand for communication and, in many instances, a source of comfort for both practitioner and patient.

Before the development of sophisticated technology (eg, computer-assisted tomography scans, magnetic resonance imaging, and biochemical techniques that quantify minute components of chemical molecules) to aid in the diagnostic process, physicians satisfied their need to conduct their practice in a scientific manner by emulating the popular scientific method of that time--classifying biological and physical entities. Scientists of this era busily worked at classifying the plant and animal domains and developing the periodic table of elements. Scientifically accepted methods were developed to identify characteristics of biological and physical entities that could be grouped to form mutually exclusive and exhaustive categories.

To develop their diagnoses, physicians spent their time classifying clinical data presented by their patients using methods similar to those of their colleagues in the basic sciences. Establishing these classifications allowed physicians to communicate more effectively about the distinctive characteristics and treatments for specific patient types. As the need for classification research diminished in the physical and biological sciences, so did the importance of utilizing and classifying clinical data to make medical diagnoses. Classification of clinical data was replaced by direct measurement of human biological phenomena, developed first at the general physiological level and progressing to the current molecular and submolecular levels.

My point in presenting all of this history is that I believe the physical therapy profession is at the same stage in its growth as was the practice of medicine before the advent of its technological development. We should emulate the success of medicine in this arena by using our clinical skills, scope of knowledge, and intellect to establish diagnostic categories. Developing these categories should aid physical therapy practitioners in making their clinical decisions regarding treatment or management strategies for their patients, and should provide the necessary data for developing more sophisticated technology. In today's world, the scientific process of classification should be enhanced by the use of personal computers and software driven by clinical requirements. The use of such statistical techniques as factor and cluster analysis should provide more powerful methods for quickly identifying the clustering of clinical data.

The physical therapy diagnosis should be the end result of using scientific methods of classification to develop mutually exclusive and exhaustive categories of clinical entities. The elements of our diagnoses are patients' clinical data (symptoms, signs, and personal demographics). At certain times, however, we may use paraclinical tests performed and interpreted by other practitioners. The primary purpose of the physical therapy diagnosis is to make clinical decisions regarding which therapeutic maneuver or management strategy is the most valid for a given individual patient. Our diagnoses, therefore, should identify similar patients or clinical conditions that respond successfully to a specific treatment. This strategy (ie, establishing a diagnosis) seems to increase the likelihood that a clinician will replicate a successful result, which is the essence of our clinical existence.

Developing Theories of Practice

One approach to developing theories of practice is to identify and characterize the relationship between a specific clinical entity (ie, a diagnostic category) and a specific treatment or management strategy. Classifying and diagnosing involves deciding "what goes with what" and giving that entity a name. rational practice, using diagnoses, begins with linking the named entity with a specific course of action--again, a clinical decision of "what goes with what." Establishing our theoretical bases for practice using the observed relationships between a given diagnosis, which provides a specific patient description and a specific treatment, would lead to the following:

1. It would prevent us from searching for a singular treatment for all patients for whom only the general nature of the clinical problem has been identified. Using the diagnosis to establish the theoretical basis of our practice does not allow us to consider treating all patients with low back syndrom with manipulation, or giving all patients with arthritis heat and isometric exercise, or applying neurodevelopmental treatment techniques to all patients with hemiplegia. Applying identical treatment or management strategies to all patients of a given general medical diagnosis (eg, arthritis, hemiplegia) has not been proven to be productive.

2. It would provide an experiential basis for the theory rather than using hypothetical mechanisms. Basing the relationships of a theory on observations of real-life situations should increase the probability that the theory has validity and will make a contribution to daily practice.

As these individual relationships are identified and our expectations of the outcomes are either confirmed or rejected, a comprehensive theory can be built and tested with classical research designs.

Research

As we have said before in a different way, a given diagnosis is a named category of specific clinical data. Patients are assigned to a category or given a diagnosis on the basis of specific clinical data that define the category. Establishing these categories of patients can have implications for research. The diagnostic categories can form the basis for descriptions of a population or sample from which investigators make either their random selection or assignment to groups for comparison.

The fact that these categories are established in the "trenches of practice" and then used to provide comparison groups should increase the probability that if all other things are done correctly, the research will be relevant. Although inferences might extend only to the specific patient groups in the study (limited external validity), one could argue the desirability of limited generalization when applying the results of efficacy studies.

The homogeneity of patients forming the comparison groups can protect studies against a "washout effect." Consider the situation in which comparison groups are formed by random assignment from a heterogeneous rather than a homogeneous population of patients. Although the groups are randomly assigned, one comprises equal numbers of patients who will respond positively and negatively to the treatment under study. In this situation, even though the experimental treatment has a positive effect on certain patients in the group, this effect is "washed out" by the negative responders in the group when means of outcome variables are calculated. The assumption is that having a more homogeneous group of patients (ie, those with the same diagnosis) increases the probability that the patients will respond in a similar manner.

Diagnosis: Some Limitations

Regardless of one's attitude about diagnosis, it is important to understand its limitations. I will consider two basic problems in making physical therapy diagnoses. One is endemic to physical therapy; the other is generic to all diagnoses.

The problem endemic to physical therapy is that there is no unified concept or agreement about the substance of a physical therapy diagnosis. Most of our colleagues, when I ask "What do we diagnose?" respond by saying that we diagnose and treat dysfunction. When pressed regarding a definition of "dysfunction," their concepts vary. Coming to grips with defining both substance and terminology is a critical first step that should increase the probability of reliability (ie, consistence) of physical therapy diagnoses.

The general issue concerning diagnosis is the reality of the diagnostic categories. Does an individual patient fit neatly into a diagnostic category? Should a "complete" fir be the expectation? If a compete fit is not the expectation, how many of the diagnostic criteria are needed before a given diagnosis is assigned? The answers to these questions will come as more physical therapy clinicians start to think about, develop, and use the diagnostic process in their daily practice.

Although limitations currently exist, the diagnostic process is a productive method for making clinical decisions about applying the most appropriate treatment or management strategy for a given individual patient. Our newly emerging role and responsibility for determining treatment and management strategies dictates that physical therapist make diagnoses. Excellence in practice, now and in the future, requires physical therapists to be skillful diagnosticians.

Reference

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

S Rose, PhD, PT, FAPTA, died on Apr 4, 1989. He was Associate Director for Research, Division of Physical Therapy, School of Medicine, University of Miami, 5801 Red Rd, Coral Gables, FL 33143 (USA).