Hearing
The ear receives sound; the brain gives it meaning. These pages explain how hearing works, what the common tests measure — and what they miss.
Air conduction <Bone conduction Air-bone gap
Beyond the audiogram
- Thresholds
- Speech
- Noise
- Space
- Binaural function
- Listening effort
- Patient experience
An audiogram is part of the story — not the whole story.
How hearing works The path of sound through the outer, middle and inner ear, along the auditory nerve and pathways to the brain — and why hearing is both peripheral and central. Understand your audiogram How to read a pure-tone audiogram — frequencies, decibels, air and bone conduction, the air-bone gap — and what the graph cannot tell you about real-world hearing. Conductive hearing loss What conductive hearing loss is, what an air-bone gap means, the causes in the outer and middle ear, and why conductive losses are the ones surgery can help. Carhart notch Carhart notch: a dip in bone conduction around 2 kHz on the audiogram in otosclerosis. Why it happens, how specific it is, and why surgery often improves it. Sensorineural hearing loss What sensorineural hearing loss is, its causes, why it affects clarity as well as loudness, and what can and cannot be done about it. Sudden hearing loss Sudden hearing loss in one ear needs assessment the same day. Definition, causes, MRI, steroid tablets and injections, hyperbaric oxygen and recovery. Speech understanding Why hearing sounds and understanding words are different abilities, how speech audiometry measures them, and what a poor word score means for treatment decisions. Hearing in noise Why background noise is the hardest listening situation, what the ear and brain do to separate voices, how speech-in-noise tests work, and what helps. Binaural hearing How the brain combines two ears — summation, squelch and the head shadow — why two treated ears beat one, and what is lost when one ear is left behind. Spatial hearing How the auditory system locates sound using timing and level differences and the shape of the outer ear, and why spatial hearing is lost with one-sided hearing loss. Noise and hearing Noise-induced hearing loss: how loud music harms the inner ear, ringing after concerts, safe listening times, which earplugs work, and when to seek care. Listening effort Why understanding speech with a hearing loss is mentally exhausting, how listening effort is measured, and why it matters as an outcome of treatment. Single-sided deafness Single-sided deafness treatment compared: no device, a CROS aid, a bone-conduction device or a cochlear implant. What each restores, and what the trials show. Central auditory function What happens to sound beyond the cochlea — binaural processing, timing, attention and adaptation — for patients, with a professional layer.