In the article “Upgoing thumb sign: A sensitive indicator of brain involvement,” the authors describe the upgoing thumb test as a sensitive and reliable method to help differentiate between minor strokes and stroke mimics. Dr. Rosenberg, however, calculates the test's positive and negative likelihood ratios from the provided data and questions the reliability and utility of the test. Dr. Baron describes a similar test, “the cupped hand sign,” first noted in 1955, which can demonstrate subtle thumb extensor weakness. Dr. Meilof notes several errors in the data tables and figures in the article. Authors Hachinksi et al. respond to each point. They do not believe that positive and negative likelihood ratios are useful as the upgoing thumb sign is not meaningful apart from the clinical context. As an indicator to help differentiate between stroke and stroke mimics, it can be useful. The authors agree with comparing the cupped-hand sign to the upgoing thumb sign and describe the latter's possible pathoanatomy. In response to the errors noted by Dr. Meilof, the authors issue a correction to the original article. A correction appears on page 396. In the article “Upgoing thumb sign: A sensitive indicator of brain involvement,” the authors describe the upgoing thumb test as a sensitive and reliable method to help differentiate between minor strokes and stroke mimics.