Project Summary/ Abstract Dizziness in the emergency department (ED) is a common problem with many opportunities to implement efficient and evidenced-based practices. In DIZZTINCT-1, we developed and evaluated an implementation strategy that focused on increasing the performance of the Dix-Hallpike test (DHT) and canalith repositioning maneuver (CRM) in the ED by applying a benign paroxysmal positional vertigo (BPPV) -centric approach. We found that the strategy substantially increased DHT and CRM performance. In implementation fidelity interviews, providers who started using the DHT and CRM typically reported positive experiences, as reflect by the following quote: “He immediately felt better and walked out about 20 minutes later…it was awesome.” There was also a decrease in the use of head CTs, which are typically unnecessary with a BPPV-centric approach. Importantly, the decrease in head CTs did not lead to an increase in stroke misdiagnosis. DIZZTINCT-1, however, is limited in its potential to scale-up because it used investigator led education sessions, cash incentives, and did not have adequate engagement at nonacademic facilities. We learned about important revisions to the strategy that could increase generalizability and more routine provider use, particularly at nonacademic EDs. In DIZZTINCT-2, we will enhance and refine the strategy in four ways. First, the education sessions will be more generalizable because we will utilize local providers and an online CME program. Second, we will broaden the target providers to include nurses since we learned that nurses can play a major role in implementing the BPPV-centric approach. Third, we will respond to provider requests to expand the topic to include best practices for assessing stroke risk in dizziness visits and evidence-based diagnosis & management for vestibular neuritis. Expanding the topic could both increase exposures to the BPPV-centric resources and create more opportunities for best practices. Fourth, we will add patient-oriented resources, which also responds to providers’ requests and increases opportunities for best management. For DIZZTINCT- 2, we have partnered with Kaiser Permanente Southern California (KPSC) to test the strategy. KPSC has 12 EDs and ~40,000 annual dizziness visits. DIZZTINCT-2 will use a hybrid type 3 implementation-effectiveness trial of a stepped wedge randomized trial for the ED implementation strategy and an embedded randomized patient-level dissemination strategy. We have the following specific aims: Aim 1. To determine the impact of the revised and enhanced BPPV-centric implementation strategy on DHT/CRM performance in dizziness visits, at academic and nonacademic EDs, using a randomized stepped wedge design. Aim 2. To evaluate clinical outcomes associated with the implementation strategy using both a stepped wedge ED-level strategy and an embedded randomized clinical trial of a patient-level dissemination strategy. DIZZTINCT-2 is the first study to a...