Sensorineural deafness is due to the absence of, or destruction of, the hair cells in the cochlea which transducer acoustic signals into nerve impulses. These people are thus unable to derive suitable benefit from conventional hearing aid systems.

• 第二类患者由于基底膜上的毛细胞发生了病变或减少,传统助听器对其没有帮助,但是这类患者往往还保留着一定数量的听觉神经,若将声波转换为电信号送入耳内直接刺激听觉神经,则可使这类患者恢复部分听觉。