In rehabilitation, patients focus on rebuilding the brain's pathways, which are often damaged after an injury. Learning core cognitive skills at CNS is a vital component of treatment, but keeping those skills current requires practice. Below is a list of online brain apps that test memory, math, comprehension, and language. Challenging, engaging and fun, these apps provide an enjoyable way of retaining knowledge acquired in therapy. Easy to navigate, the innovative designs have a simple user interface and colorful graphics that help users to extend their learning experience.