Sensorineural hearing loss affects the auditory signal generally in two ways: attenuation (resulting in less intense sounds being inaudible), and distortion (resulting in audible sounds having relatively less clarity than in a normal auditory system). While generally more severe loss on the attenuation side also results in more distortion, there is massive variability in the amount of distortion created, particularly in the moderate to severe loss range. This is because sensorineural hearing loss is often the result of a combination of abnormal function of many different areas of the system (outer hair cells, inner hair cells, other cochlear structures, the auditory nerve, the lower and upper auditory neural pathways, etc) and this combination can cause infinite variability from patient to patient. Loss restricted to predominantly outer hair cell loss tends to have less distortion, while once inner hair cells and neural structures are involved there tends to be a greater distortion aspect to the loss (reflected during testing with poorer performance on word/speech recognition tasks). The amplification and compression aspects of hearing instruments do a good job treating the attenuation aspect to a loss but are limited in overcoming high distortion. The signal-to-noise improving aspects of hearing instruments become all the more vital as distortion is poorer.