Measuring Intolerance of Uncertainty after Acquired Brain Injury. Part 1: The Factor Structure of the Intolerance of Uncertainty Scale-12

Intolerance of uncertainty (IU) is a risk factor for poor mental health. Acquired brain injury (ABI), such as stroke or traumatic brain injury, often brings considerable uncertainty. This is the first of a two-part investigation of the psychometric properties of the Intolerance of Uncertainty Scale-12 (IUS-12) in ABI. Here, we evaluate its internal consistency and factor structure in 176 adults with ABI. A two-factor structure (Prospective Anxiety and Inhibitory Anxiety) was superior to a one-factor model. However, some fit statistics were unacceptable. In an exploratory factor analysis, a new two-factor model emerged with a superior fit. A bifactor model provided even better fit, though the sample size precluded exhaustive evaluation. For now, retaining the original Prospective Anxiety and Inhibitory Anxiety subscales is recommended for ABI. IUS-12 scores did not differ pre- or during COVID-19 assessment, suggesting the IUS-12 is measuring individual differences regardless of uncertainty levels.