1.4.4 Fitting of Hearing Aids: Lack of benefit from appropriately fit hearing aids will be determined by the lack of progress in the development of simple auditory skills as defined by aided and unaided behavioral thresholds; auditory brainstem response testing; otoacoustic emission testing; steady state evoked potential testing; IT-MAIS and/or the lack of developmentally appropriate vocal behaviors. Criteria for appropriate vocal behaviors include achieving the production of canonical babble as defined by production of reduplicated sequences such as [mamama], [dadadal, or [bababal] (Oller and Eilers 1988). Hearing aid use will be determined by parental and educator reports.