The empirical adequacy of the TOUS is further evidenced by a study in which a researcher examined the relationship between symptoms and functional performance. For example, in patients with COPD,researchers found a negative association between fatigue and functional performance. Although limited research was identified for cognitive activity, researchers found positive relationships between symptoms of pain,
shortness of breath, and edema; and cognitiveactivity(cognitiveimpairment)innursing home residents with cancer.