Validation of the Mishel's uncertainty in illness scale-brain tumor form (MUIS-BT).

The Mishel uncertainty in illness scale (MUIS) has been used extensively with other solid tumors throughout the continuum of illness. Interventions to manage uncertainty have been shown to improve mood and symptoms. Patients with primary brain tumors (PBT) face uncertainty related to diagnosis, prognosis, symptoms and response. Modifying the MUIS to depict uncertainty in PBT patients will help define this issue and allow for interventions to improve quality of life. Initially, 15 experts reviewed the content validity of the MUIS-brain tumor form (MUIS-BT). Patients diagnosed with PBT then participated in the study to test validity and reliability. Data was collected at one point in time. Six out of 33 items in the original MUIS were modified to better describe PBT patients' uncertainty. 32 of the 186 patients in the second-stage of the study were newly diagnosed with PBT, 85 were on treatment, and 69 were followed-up without active treatment. The validity of the MUIS-BT was demonstrated by its correlations with mood states (P < 0.01) and symptom severity (P < 0.01) and interference (P < 0.01). The MUIS-BT measures four constructs: ambiguity/inconsistency, unpredictability of disease prognosis, unpredictability of symptoms and other triggers, and complexity. Cronbach's alphas of the four subscales were 0.90, 0.77, 0.75 and 0.65, respectively. The 33-item MUIS-BT demonstrated adequate select measures of validity and reliability in PBT patients. Based on this initial validation and significant correlations with symptom distress and mood states, further understanding of uncertainty and evaluation of measures to help manage patients' uncertainty can be evaluated which in turn may improve coping and quality of life.