Topical ReviewEffects of Testosterone Therapy on Cognitive Function in Aging: A Systematic ReviewHua, Jeremy T. MD*,†; Hildreth, Kerry L. MD†; Pelak, Victoria S. MD*,‡Author Information Departments of *Neurology †Medicine ‡Ophthalmology, University of Colorado School of Medicine, Aurora, Colorado Supported in part by NIH Grant T35 EY021455 and Alzheimer's Association Grant SAGA-17-419222 (V.S.P.). The authors declare no conflicts of interest. Reprints: Victoria S. Pelak, MD, Mail Stop B 185, Academic Office 1, Room 5217, 12631 E. 17th Avenue, Aurora, Colorado 80045 (e-mail: firstname.lastname@example.org). Cognitive And Behavioral Neurology: September 2016 - Volume 29 - Issue 3 - p 122-138 doi: 10.1097/WNN.0000000000000104 Buy Metrics Abstract Endogenous testosterone in the aging man has been scrutinized extensively in regard to its effects on performance in many cognitive domains, especially verbal fluency, visuospatial and visuoperceptual abilities, memory, and executive function. Studies of testosterone supplementation have sought to identify potential cognitive improvements in men with and without baseline cognitive impairment, and have had a wide range of results. The variability in outcomes is likely related, in part, to the lack of consensus on methods for testosterone measurement and supplementation and, in part, to the disparate measures of cognitive function used in randomized controlled studies. Despite the limitations imposed by such inconsistent methods, promising associations have been found between cognition and testosterone supplementation in both eugonadal men and men with low testosterone levels, with and without baseline cognitive dysfunction. This systematic review highlights the cognitive measures used in and the outcomes of existing studies of testosterone and cognition in aging men. The review suggests that larger studies and a more standardized approach to assessment will be needed before we can fully understand and realize sustained benefits from testosterone supplementation in the elderly male population, particularly given the substantial increase in testosterone supplementation in clinical practice. Copyright © 2016 Wolters Kluwer Health, Inc. All rights reserved.