Cogan's lid twitch for myasthenia gravis: A systematic review

IntroductionMyasthenia gravis is an autoimmune condition affecting the neuromuscular junction of skeletal muscles and may be difficult to diagnose. Several clinical signs may have diagnostic utility, including Cogan's lid twitch. This systematic review aims to synthesise the literature on the accuracy of Cogan's lid twitch for diagnosing myasthenia gravis.MethodsA systematic search of the databases PubMed/MEDLINE, Embase and CENTRAL was performed from inception to August 2022. Risk of bias analysis and data extraction were performed in accordance with the PRISMA 2020 guidelines.ResultsSeven articles satisfied the inclusion criteria. The results showed that for the diagnosis of myasthenia gravis, Cogan's lid twitch has a sensitivity between 50% and 99% and specificity between 75% and 100%.ConclusionsCogan's lid twitch is a physical examination finding with moderate diagnostic performance in the diagnosis of myasthenia gravis with ocular involvement. Future studies may seek to evaluate the performance of Cogan's lid twitch in conjunction with other signs of myasthenia gravis with ocular involvements, such as fatigable ptosis or a positive icepack test.