There are many good resources and references about Item Response Theory and Computerized Adaptive Testing so this list will be quite incomplete. However, if you are new to these topics, below are places to consider finding more information:
1. NIH PROMIS at http://www.healthmeasures.net/explore-measurement-systems/promisis an NIH funded initiative to advance the science of self-report measurement. There are many resources on their site.
2. Another site with self-report instruments and information is neuroqol at http://www.healthmeasures.net/explore-measurement-systems/neuro-qol
3. One reference written about IRT targeting people in the field of communication sciences and disorders is:
Baylor, C., Hula, W., Donovan, N., Doyle, P., Kendall, D., & Yorkston, K. (2011). An introduction to Item Response Theory and Rasch models for speech-language pathologists. American Journal of Speech-Language Pathology, 20, 243-259.