Post-chemotherapy cognitive impairment (PCCI) (also known in the scientific community as "CRCIs or Chemotherapy-Related Cognitive Impairments" and in lay terms as chemotherapy-induced cognitive dysfunction or impairment, chemo brain, or chemo fog) describes the cognitive impairment that can result from chemotherapy treatment. Approximately 20 to 30% of people who undergo chemotherapy experience some level of post-chemotherapy cognitive impairment. The phenomenon first came to light because of the large number of breast cancer survivors who complained of changes in memory, fluency, and other cognitive abilities that impeded their ability to function as they had pre-chemotherapy.[1]