Measuring the impact of trigeminal neuralgia pain: the Penn Facial Pain Scale-Revised

Background and objective: The Penn Facial Pain Scale (Penn-FPS) was originally developed as a supplemental module to the Brief Pain Inventory Pain Interference Index (BPI-PI I) in order to fully assess the impact of trigeminal neuralgia (TN) pain on patients' health-related quality of life (HRQol.). The current objective is to create and establish the content validity of a new stand-alone version of the measure, the Penn-FPS-Revised (Penn-FPS-R). Methods: Twenty participants (15 USA and 5 UK) with confirmed TN engaged in concept elicitation and cognitive debriefing interviews. These semi-structured interviews allowed participants to spontaneously describe the ways in which TN impacts on HRQoL and report on the extent to which the Penn-FPS and BPI-PII measure concepts are most relevant to them. Participants were also asked to report on the suitability of the instructions, recall period, and response options. Results: Concept elicitation revealed nine themes involving TN restrictions on daily activities and HRQoL, including: talking, self-care, eating, eating hard foods/chewing foods, daily activities, activities with temperature change, touching, mood, and relationships. Cognitive debriefing confirmed that all of the Penn-FPS concepts and some of the BPI-PI I concepts (mood, general activities, and relations with others) were relevant, although some items required edits to better capture individuals' experiences. The impact of temperature and/ or weather on activities was also identified as an important concept that is not captured by the Penn-FPS or BPI-PH. Participants confirmed the acceptability of recall period, instructions, and response options. Results from the interviews were applied to create the Penn-FPS-R, a new brief outcome measure that assesses the impacts of TN most important to patients. Conclusion: The Penn-FPS-R is anew 12-item HRQoL outcome measure with content validity that can be used to assess and monitor the impact of TN treatment interventions in both clinical practice and research.