Losing sound

One year later and I have enough material for about 1,000 posts.  I’ll start with this evening: an Institute of Acoustics screening of Lost and Sound, a documentary by Lindsey Dryden about three individuals with different experiences of hearing loss.

The film is centred around the concept of hearing music, and how important this is to humans.  People can have profoundly different experiences of music and they can also have profoundly different experiences of losing music.  One interviewee was a music critic who’s life was his record collection before he lost all hearing in one ear; he spoke about music being reduced from a three-dimensional architecture of sound to a flat, planar reduction that paled in comparison.  A little girl lost her hearing to Meningitis but has nonetheless become an excellent pianist for her age, and a young woman who was born completely deaf is a dancer.

They have both had cochlear implants, amazing mechanisms which take the place of part of the inner ear in transmitting sound waves to the brain.  Here is where I wander off on a tangent and explain the physiology of the ear, feel free to skip if you remember it all from Biology or just aren’t interested!

The ear has three main parts: outer, middle and inner.

The Ear

The outer ear consists of the pinna (what you think of as your ear), the external meatus (ear canal) and the tympanic membrane (ear drum).  Its function is to gather sound and amplify it, funneling it down to the middle ear and causing the ear drum to vibrate.

The middle ear, along with other things, contains three bones: the mallues, incus and stapes (or hammer, anvil and stirrup).  These form a conductive chain from the ear drum to the oval window, which is a membrane forming the barrier between the middle and inner ear.  The bones are effectively a mechanical system, transforming the relatively large displacement and small force provided by the ear drum movement into a small displacement with a large force at the oval window.

The inner ear contains the cochlea, which is made up of three coiled, fluid-filled canals called concha: the scala vestibuli, scala tympani and scala media.  They are separated by two membranes: the Reissner’s membrane, and the Basilar membrane.  Within the Basilar membrane is the Organ of Corti, which has inner hair cells and outer hair cells.  The OHCs amplify the faint mechanical motions into ones detectable by the IHCs, which convert the signals from analogue to digital and transmit them to the auditory nerve fibres of the brain.

A cochlear implant consists of:

  • a microphone
  • a processor to filter environmental sounds and prioritise speech
  • a transmitted attached to the outer skull
  • a receiver and stimulator inside the skull and
  • an array of electrodes wound through the cochlea to send impulses to the brain.

A number of medical and musical professionals spoke during the documentary about the body and the brain’s responses to music.  They spoke of nostalgia, and the importance of music in memory.  They also spoke about the preemptive nature of our response to music; a natural urge to predict what comes next and the constant adjustments that our brain makes while listening to a new piece.  Both of these topics are fascinating and require much more than a paragraph to discuss.

I’ll end with a suggestion from the film’s website to create a ‘panic playlist‘ – a list of the songs or pieces of music you would listen to if you only had a few minutes left to do so.  Off the top of my head mine would have to include:

  • Aphex Twin – Vordhosbn
  • Nine Inch Nails – 09 Ghosts
  • A Perfect Circle – Over
  • The Cure – Siamese Twins
  • Radiohead – High and Dry

That’s quite a weird and depressing list actually, but I suppose if I was losing the ability to hear music I wouldn’t be in the frame of mind to appreciate happy songs.

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