Primary reasons why it is not practical to simply send every patient in for an MRI are the high cost of an MRI, its impact on patient comfort, and limited availability in rural areas and third-world countries. In 1997, Dr. Manuel Don and colleagues published on the Stacked ABR as a way to enhance the sensitivity of the ABR in detecting smaller tumors. Their hypothesis was that the new ABR-stacked derived-band ABR amplitude could detect small acoustic tumors missed by standard ABR measures. In 2005, he stated that it would be clinically valuable to have available an ABR test to screen for small tumors. In a 2005 interview in Audiology Online, Dr. Don of House Ear Institute defined the Stacked ABR as "..an attempt to record the sum of the neural activity across the entire frequency region of the cochlea in response to a click stimuli."