The retrospective component consists of examining archival data from Lumosity, previously collected as part of routine clinical care. The data contain pre- and post-assessments of post-concussive symptoms, symptom frequency, and cognitive testing. The investigators expect that data analysis will reveal evidence of improvement in severity of post-concussive symptoms, in frequency of troublesome cognitive problems, and in performance on neuropsychological tests when pre- and post-assessments are compared.