Theory of unpleasant symptoms (TOUS)
The Theory of Unpleasant Symptoms (TOUS) is a nursing theory that explores the interplay between symptoms, influencing factors, and performance outcomes in patients. Developed in the 1990s by four nurse researchers—Audrey Gift, Renee Milligan, Linda Pugh, and Elizabeth Lenz—TOUS is a middle-range theory that emphasizes how subjective symptoms, such as fatigue and pain, are experienced by patients and can be measured across four dimensions: intensity, degree of distress, timing, and quality. The theory posits that symptoms are not only influenced by physiological, psychological, and situational factors but also impact the patient's physical, cognitive, and social functioning.
By recognizing that symptoms can cluster and interact, TOUS highlights the complexity of patient experiences, suggesting that performance outcomes can, in turn, affect both symptoms and the influencing factors. This cyclical relationship underscores the need for holistic nursing approaches that consider the multifaceted nature of patient care. Overall, TOUS provides a framework for understanding how various elements contribute to a patient's health experience and the importance of addressing both symptoms and their underlying causes in nursing practice.
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Theory of unpleasant symptoms (TOUS)
The theory of unpleasant symptoms (TOUS) is a nursing theory that examines symptoms and their relationship to two other groups of concepts called influencing factors and performance outcomes. Specifically, the TOUS is a middle-range theory, which is a nursing theory that involves a group of related ideas that are represented in a model. The TOUS maintains that the symptoms, influencing factors, and performance outcomes affect one another.
Overview
Four nurse researchers—Audrey Gift, Renee Milligan, Linda Pugh, and Elizabeth Lenz—developed the TOUS in the 1990s. First Pugh and Milligan collaborated to develop a model of fatigue during childbearing. Then Pugh and Gift collaborated to develop a dyspnea/fatigue model. Dyspnea is difficult breathing. Lenz then offered to evaluate the work of Pugh, Milligan, and Gift. Soon all four researchers began collaborating and developed the TOUS theory.
The main concepts of the TOUS are symptoms, influencing factors, and performance outcomes. Symptoms are subjective rather than objective. This means that the patient is experiencing perceived symptoms instead of symptoms that can be objectively observed. Symptoms typically are unpleasant sensations; only the patient is aware of and can describe the sensation. In other words, no one but the patient can know and describe the nature of the symptom. Fatigue, pain, and nausea are examples of such symptoms. A patient may experience a single symptom or multiple symptoms that may interact with one another. Multiple symptoms that a patient experiences collectively are referred to as a symptom cluster.
Symptoms have four dimensions that are related and can be measured: intensity (or severity), degree of distress, timing, and quality. The intensity dimension refers to the severity of the symptom. This dimension often is measured using a numeric scale, especially when the symptom is pain. The degree of distress dimension involves the degree that the patient is bothered by the symptom. The time dimension refers to the duration, frequency, and pattern of recurrence of the symptom. The quality dimension involves the characteristics of the symptom, which often are described using specific descriptors of the symptom.
Influencing factors include physiological, psychological, and situational factors, which are interrelated. Physiological factors involve anatomical variables, genetic variables, variables related to illness, and variables related to treatment. Psychological factors consist of affective variables and cognitive variables. Situational factors include social variables and variables related to the physical environment.
Performance outcomes consist of the physical, cognitive, and social functioning of the patient. Physical functioning includes physical activities and any limitations with them, determined by a physical examination. Cognitive functioning involves memory, concentration, comprehension, problem solving, and learning and any difficulties with these. Social functioning includes activities for carrying out social roles and any limitations with them.
The TOUS asserts that the influencing factors affect the symptoms. In turn, the symptoms affect the performance outcomes. The performance outcomes may circle back to affect the symptoms and the influencing factors. Therefore, the theory contends that all three categories of factors influence one another.
Bibliography
Lee, Seung, et al. "An Analysis and Evaluation of the Theory of Unpleasant Symptoms." Advances in Nursing Science, Jan./Mar. 2017, vol. 40, no. 1, pp. E16–E39.
Lenz, Elizabeth R., and Linda C. Pugh. "The Theory of Unpleasant Symptoms." Middle Range Theory for Nursing. 3rd ed., edited by Mary Jane Smith and Patricia R. Liehr, Springer Publishing Company, 2013, pp. 165–95.
Liehr, Patricia. "Looking at Symptoms with a Middle-Range Theory Lens." Advanced Studies in Nursing, vol. 3, no. 5, Aug. 2005, pp. 152–57.
Liehr, Patricia, and Mary Jane Smith. "Middle-Range Theories." Encyclopedia of Nursing Research. 3rd ed., edited by Joyce J. Fitzpatrick and Meredith Wallace, Springer Publishing Company, 2011, pp. 294–96.
McCaffrey, Ruth. "Middle Range Theory of Unpleasant Symptoms." Doctor of Nursing Practice: Enhancing Professional Development. F. A. Davis Company, 2012, pp. 77–9.
Peterson, Sandra J., and Timothy S. Bredow, editors. Middle Range Theories: Application to Nursing Research. 2nd ed., Wolters Kluwer Health, 2009.
Plichta, Stacey Beth, and Laurel S. Garzon. "Theory of Unpleasant Symptoms." Statistics for Nursing and Allied Health. Wolters Kluwer Health, 2009, p. 9.
Roy, Callista. Generating Middle Range Theory: From Evidence to Practice. Springer Publishing Company, 2013.