Evidence from the literature supports the contribution of intensity. A review of aphasiarehabilitation studies found that significant treatment effects resulted whenever intensive (at least 8.8 hours per week) training was provided for a total of approximately 100 hours. A comparison of CILT studies to other intensively administered treatments revealed that performance on language outcome measures was generally better and tended to be preserved longer on follow up testing with CILT. Only two studies have controlled for intensity. One compared CILT with traditional therapy and one compared CILT to an individually tailored therapy. Neither found a clear advantage for CILT suggesting that intensity is a main contributor to positive outcomes following CILT.