auditory cortex: the parts of the brain primarily devoted to hearing.

cochlea: The sensory organ of the ear, directly connected to the auditory nerve. A healthy cochlea is tuned to all frequencies from high to low (nearest the brain). In a cochlea, million of hair cells of varying lengths vibrate like tuning forks to specific frequencies. Damage to the cochlea can strike only some frequencies or all of them.

cochlear implants: technology developed since the 1970s, first approved for medical use in the late 1980s, which consists of electrodes implanted to the auditory nerve. Many early candidates were not suited for these because they never had functional hearing, so lacked a solid neurological basis for processing sound. Some of these reported non-auditory sensations such as electroshock from their implants. Further research on how the brain actually learns to hear has prompted pressure to implant deaf children in infancy. It’s a shame that there is no non-invasive procedure available for training hearing and speech comprehension when conventional hearing aids aren’t sufficient.

cross-modal processing: processing information from more than one sense mode.

McGurk effect: When a visual “ga” combines with the sound “ba” to create the illusion of a different sound—“da.” This illusion is delayed in children with Autistic spectrum disorder.

neurons: electrically excitable cells that process and transmit information by electrical and chemical signaling.

neuroplasticity: the ability of the brain to physically adapt to injury and experience throughout life by forming new connections between neighboring neurons.

nystagmus: major involuntary movement of the eyes making visual tracking impossible. Nystagmus can be triggered by vertigo, by eye disorders, or neurological disorders.

peripheral visual processing: awareness of objects on edge of vision. Deaf adults do better than hearing adults due to brain reorganization.

posturography: also known as moving platform posturography, uses a moving platform to assess balance problems not related to vestibular disorders.

proprioception: our innate sense of our body’s posture, movement and location in space. This is based on a combination of sensory input from our joints, vestibular system, vision, and sense of touch.

saccades: very quick, imperceptible movements of the eyes necessary for normal vision.

tactile hearing aids: Alternative sensory technology that use vibration to provide hearing input and increase speech comprehension. Some models are: OSCAR ( and Minifonator (

tinnitus: a ringing sensation in the ears generally caused by hearing loss. Tinnitis is triggered by sudden sounds, and persists in one pitch. Cochlear implantation may make this better or worse, but existing tinnitus significantly impacts the utility of cochlear implants. Olze, H. "Hearing Aids, Implantable Hearing Aids and Cochlear Implants in Chronic Tinnitus Therapy." HNO 58.10 (2010): 1004-012.

vestibular system: provides our sense of balance by detecting our acceleration and rotation. It feeds information to our eyes and the muscles that keep us upright. The vestibulo-ocular reflex is important for stabilizing our vision. (