Validity of the Neurology Quality-of-Life (Neuro-QoL) measurement system in adult epilepsy

- We provide validation information on Neuro-QoL, a new health-related quality-of-life tool in epilepsy.
- We report on Neuro-QoL's internal consistency and test-retest reliability with a sample of adult patients diagnosed with epilepsy.
- We demonstrate Neuro-QoL's comparability to existing quality-of-life measures in adult epilepsy.
- We report on Neuro-QoL's ability to discern between known groups of seizure severity.
- We present information on the responsiveness of Neuro-QoL short forms over time.

Epilepsy is a chronic neurological disorder that results in recurring seizures and can have a significant adverse effect on health-related quality of life (HRQL). The Neuro-QoL measurement initiative is an NINDS-funded system of patient-reported outcome measures for neurology clinical research, which was designed to provide a precise and standardized way to measure HRQL in epilepsy and other neurological disorders. Using mixed-method and item response theory-based approaches, we developed generic item banks and targeted scales for adults and children with major neurological disorders. This paper provides empirical results from a clinical validation study with a sample of adults diagnosed with epilepsy. One hundred twenty-one people diagnosed with epilepsy participated, the majority of which were male (62%) and Caucasian (95%), with a mean age of 47.3 (SD = 16.9). Baseline assessments included Neuro-QoL short forms and general and external validity measures. The Neuro-QoL short forms that are not typically found in other epilepsy-specific HRQL instruments include Stigma, Sleep Disturbance, Emotional and Behavioral Dyscontrol, and Positive Affect and Well-Being. Neurology Quality-of-Life short forms demonstrated adequate reliability (internal consistency range = .86-.96; test-retest range = .57-.89). Pearson correlations (p < .01) between Neuro-QoL forms of emotional distress (anxiety, depression, stigma) and the QOLIE-31 Emotional Well-Being subscale were in the moderate-to-strong range (r's = .66, .71 and .53, respectively), as were relations with the PROMIS Global Mental Health subscale (r's = .59, .74 and .52, respectively). Moderate correlations were observed between Neuro-QoL Social Role Performance and Satisfaction and the QOLIE-31 Social Function (r's = .58 and .52, respectively). In measuring aspects of physical function, the Neuro-QoL Mobility and Upper Extremity forms demonstrated moderate associations with the PROMIS Global Physical Function subscale (r's = .60 and .61, respectively). Neuro-QoL measures of perceived cognitive function (executive function and general concerns) produced moderate-to-strong correlations with the QOLIE-31 Cognition subscale (r's = .65 and .75, respectively) and moderate relations with the Liverpool Adverse Events Profile (r's = .51 and .69, respectively). Finally, the Neuro-QoL Fatigue measure demonstrated moderate associations with the QOLIE-31 Energy/Fatigue subscale (r = − .65), Liverpool Adverse Events Profile (r = .69), and the Liverpool Seizure Severity Scale (r = .50). Five Neuro-QoL short forms demonstrated statistically significant responsiveness to change at 5-7 months, including Fatigue, Sleep Disturbance, Depression, Positive Affect and Well-Being, and Emotional and Behavioral Dyscontrol. Overall, Neuro-QoL instruments showed good evidence for internal consistency, test-retest reliability, convergent validity, and responsiveness to change over several months. These results support the validity of Neuro-QoL to measure HRQL in adults with epilepsy.