Cortex of one side substitutes for other side as does the peripheral endorgan. This occurs because of the bilateral ascending pathways for sound. A bilateral cortical auditory lesion (B) produces a major loss in hearing. Unilateral cortex or single cochlea lesions hardly produce detectible loss.

• Cortex of one side substitutes for other side as does the peripheral endorgan. This occurs because of the bilateral ascending pathways for sound. A bilateral cortical auditory lesion (B) produces a major loss in hearing. Unilateral cortex or single cochlea lesions hardly produce detectible loss.

• Unilateral single component lesions ( cochlea or cortex) have negligible hearing loss.

• Only with cortical and labyrinth lesions does the loss become detectable.