Aid
UNTIL I’D TURNED THE CAR upside down I had been just like everyone else – I accepted the ordinary miracle of my senses and I expected them to get on with the job. For the past twenty-eight years I’d lived my life with perfect hearing and all the gifts that came with it: speech, communication, language, a link to other people, the freedom not to even think about the efficient functioning of my own body.
In the weeks after my appointment with Steve, I flicked through medical guides or skimmed web pages. Somewhere between the graphics I was aware that I wasn’t searching for a cold description of process but a line of hope, a few sentences shining out from the page: ‘Of course, in your case, you’ll definitely get better from this. In your case, we’re pretty sure it’s just wax.’ But the medical books didn’t say that. What they told me instead was a bit more about how we hear and sometimes why, though they never really said anything about what happens to us when we stop.
As Steve had pointed out, part of the genius of hearing is that so much of it takes place so deep inside our heads. The bit of the ear that we can actually see is the doorway to a line of secret chambers tucked deep into the skull. Each of those chambers is linked to the next in a chain of connection reaching all the way from the eardrum to the brain.
All sound – low or high, loud or faint – travels in waves. It’s relatively rare to be able to experience it as one, but it’s possible, particularly at low frequencies. The opening notes of Bach’s Toccata and Fugue, a truck rumbling past, dubstep – they all resonate through our bones. At higher frequencies those resonances appear to become more a sensory experience than a conductive one, but they’re still made of waves. It doesn’t matter whether a sound is high, low or ultrasonic, it’s there because something has rippled the shape of the air in the same way as a boat’s prow makes a bow-wave through water – small ripples for high-pitch frequencies, big for low. Every noise, whether it’s the song of a skylark or the crack of a rifle, is made of the same three things: air, pressure, time. And while frequencies are measured in kilohertz (kHz), their volume is usually expressed as decibel Sound Pressure Level (or dBs SPL). In other words, the notes up and down a piano would be measured in kHz, but the loudness at which they were played would be dBs SPL.
When the ripples of sound reach the ear, they’re gathered and channelled by the hard cartilage of the pinna (or auricle) into and down the ear canal to the eardrum. As its name implies, the eardrum is a taut membrane separating the outer ear from the middle ear which looks in cross-section a bit like a pea seedling. Like a musical drum, it vibrates as it’s struck by the incoming sound waves.
Behind it is an air-filled space containing the three smallest bones in the human body: the malleus (hammer), incus (anvil) and stapes (stirrup). Each of those bones has a separate function. The malleus is attached to the eardrum, the stapes connects to the inner ear, and the incus links the two. When a sound wave reaches the eardrum, each of those bones (or ossicles) vibrates in turn, transmitting and concentrating the sound as it connects to the inner ear and the cochlea. That little snail-shell contains not just the 2,700 individual hair cells (cilia) which Steve had been describing, but three separate chambers filled with fluid. Vibrations in the fluid stimulates the hair cells, and the cells release chemicals which in turn activate auditory nerve fibres to transmit information about the type and quality of that vibration through to the temporal lobe in the brain.
All the processes involved in the outer and middle ears are mechanical. In each stage, something physical happens – the pinna gathers, the eardrum vibrates, the ossicles conduct. It isn’t until the sound reaches the inner ear that the representation of that original ripple ceases to be a physical process and starts to become a sensory one. All that’s happened in the outer and middle ear is that different wave patterns have been used to generate variations in pressure within the fluids of the inner ear. It is the hair cells that transfer them from a purely mechanical energy into electrical signals, turning them from a form which the brain cannot comprehend into a form that it can. If you think of sound as cryptography, the outer and middle ears are the satellite dishes receiving the signals, but the temporal lobe and the auditory nerve are the parts doing the deciphering. In other words, sound is received and processed in two parts. The ear receives, the brain processes – a physical Enigma code.
Because there are so many parts to hearing, there are an equal number of parts to hearing loss. Generally speaking, they can be split into three. There is conductive loss in which there’s been a failure of some part of those initial mechanical processes such as puncturing of the eardrum or damage to the ossicles. Or there’s sensorineural loss in which the nerves or the hair cells have been damaged. Partly because that damage is often caused either by ageing or external environmental factors, it’s a much more widespread form of hearing loss than the conductive type.
Any very loud noise may eventually damage or disrupt the stereocilia and lead to the death of hair cells, whether that’s an iPod always on full volume or listening to aircraft taking off at close proximity. Sometimes that damage results in hearing loss and sometimes it results in tinnitus, where true sound is replaced by sounds the brain itself has made. Some people hear hissing or fizzing or clicking, or a steady background noise like an internal fridge. Tinnitus can be loud or soft, constant or intermittent, but of all the different kinds of hearing disorders it’s often considered the worst because it covers over the sounds that people want to hear with a drizzle of sound that they don’t. And finally, there’s a mixture of both conductive and sensorineural loss, which is what the composer Ludwig van Beethoven had.
IN THE EVENT it took several months for the correctly fitted analogue aids to arrive. After a couple of false starts, I returned to Steve’s office in St Mary’s in the spring of 1999. As I sat down beside his desk, he passed across a small black hexagonal box in which were two hearing aids designed to fit down the canal to the eardrum. ‘Property of the NHS,’ said the lettering on the box.
I lifted one of the aids out and looked at it. Steve had said they were going to be discreet in-the-ear aids, so I’d had an image of something almost invisible to anyone looking at me face-on. But these things seemed enormous, great blocky lumps of plastic in the same flat grey-beige shade as a hernia gusset. At the inner end was a little hole for the sound to reach the eardrum and at the outer end was a square lump with a slot for a battery, a volume control and another, smaller hole to let the sound in. Compared to the abstract splendour of an eighteenth-century ear trumpet these were miracles of miniaturisation, but to me they looked as if you could have fitted long wave, short wave and FM onto them with ease.
‘Try them,’ said Steve encouragingly.
I slotted one into my right ear. Then I took it out again.
‘You need to wear these all the time for them to work.’
‘Why?’
He looked at me. ‘How much of what I told you last time did you take in?’
‘OK. Well. Just take it from me that in order to get the benefit from these, your brain needs to get used to them, and your brain will only get used to them if you wear them all the time. These things are only miniature microphones and loudspeakers, but they’re the best we can do. There are digital aids coming onto the market and hopefully some day soon the price will come down enough for the NHS to be able to offer them. But at the moment this is what’s available. If you use them right, they’ll make life much easier for you, but it will take about four months of full-time use for the brain to adjust to processing sound through the aids.’
He put the aids back into their box and pushed it towards me. ‘So,’ he said. I suspected he knew exactly what I was thinking. ‘You need to actually put these things in.’
Can I customise them? Is my hair long enough to cover them?
‘Go away,’ said Steve, exhaling. ‘Try them, get used to them. But for God’s sake just use them.’ He turned back to his screen. ‘Can you talk to reception about an appointment in six months’ time? Say, mid-May?’
AS IN SO MANY other things, I was – I am – astoundingly fortunate. I was born at the tail end of the twentieth century, a time in which the science of otology and acoustics has been racing along at the same rate of advance as neuroscience or genomics. I had the benefit of tiny, in-the-ear hearing aids, of science and of the drive to produce something that really works. Those born before me did not.
Somewhere deep in the recesses of Blythe House in London, thousands of objects from Henry Wellcome’s medical collections are interred, including a selection of early aids ranging in origin from the late seventeenth century to the early twentieth. Among them are trumpets of every conceivable shape and material from the practical to the hilarious. There are elegant double shell shapes ergonomically sculpted to catch sound in tiny tortoiseshell side buckets next to primitive tubas shrunk down to a tenth of normal size. There’s a small Victorian bicycle horn next to what appears to be a series of miniature policemen’s helmets with teapot spouts attached. There’s a small chemical retort made of copper in a drawer also containing what must surely be the dispossessed end of a clarinet. There’s something which, when stood on its end, looks exactly like an old kettle. There are two big shallow circles made of black papier mâché designed to sit behind the wearer’s ears as ready-to-wear satellite dishes. There are things in wood, cloth, tortoiseshell, shellac, papier mâché, brass, copper, Bakelite and steel, some of which would have conducted sound beautifully and some of which would probably have swallowed every last particle. There’s even a Victorian mourning-trumpet, its opening so clogged with black lace that it could only have been used by someone who had absolutely no intention of hearing anything at all.
Looking at the variety in all these different drawers, two things become clear. One, that for as long as ear trumpets remained the main way of amplifying sound, no one ever reached agreement about the most efficient form of design. And two, anyone venturing out with one of these in public needed considerable resilience of character.
In Bonn, the Beethoven Haus has four of the ear trumpets once belonging to the composer. All are made of copper, and all are elegant variations on a horn shape – long tapering stalks flaring down to an open end. Three of them are shaped into the bell of a conventional trumpet and one has a little circular box with a perforated speaking surface like a primitive telephone receiver. Two were designed to be worn with headbands, leaving the hands free but presenting a challenging look even without the composer’s freestyle approach to personal grooming. Each design has a narrow end designed to fit down the ear canal and a wide receptacle designed both to receive sound and to reflect it inwards. The irony is, of course, that all four of them look less like medical aids than musical instruments. Any wind instrument works by channelling air pressure waves into a particular shape so that those waves then resonate with a note of a particular pitch. It almost certainly wasn’t lost on Beethoven that he had reached – and then passed – the point at which he now required a trumpet in order to hear a flute.
Beethoven’s relationship with the trumpets was as turbulent as most other things in his life. In 1812 he bought the first of several ‘hearing devices’ from the Viennese inventor Johann Mälzel. Over time he experimented with different shapes, searching for the optimum amplification, and by 1815 had concluded that ‘One should have different ones for music, speech, and also for halls of various sizes’. Some of his visitors reported that he used the devices for conversation, and some that they just had to yell. By 1820 he’d stopped using all of them, partly because his hearing was now so bad that they no longer made a difference, and partly because (judging by the number of dents) he often got so frustrated he yanked the trumpets off and hurled them across the room. When he did finally give them up, he accused them – and Mälzel – of further damaging his hearing, and wrote dismissively that ‘They were not of any real use to me’.
Compared to the first generation of electronic aids which came with more wiring than the Apollo space programme, even the most basic modern digital aid is a technical and technological marvel. There are still plenty of people around who remember the aids of the 1980s – solid chunks of plastic worn behind the ear connected with a wire to a transistor worn on a chest harness. Even if the wearer looked perfectly intelligent beforehand, just putting on one of the boxes appeared to drop their IQ by a good 70 points, and as a great big mid-chest bullseye for bullies, they could scarcely have been bettered. Even once the boxes disappeared and all that was left was the first generation of behind-the-ear aids, the best result possible was still somewhere between Unfortunate and Low-Key Remedial.
It wasn’t until the late twentieth century that hearing aids began to shrink to the point where they could be worn relatively unobtrusively. As the aids got smaller, the difficulty for manufacturers was that they had to fit a great deal of complex technology into a very small object. Effectively they have to cram an entire mixing desk into a strange-shaped space which would, at most, only be a few millimetres long. Both analogue and digital aids have to allow sound to enter effectively and then to pass that amplifed sound through to the eardrum, while digital hearing aids also need the technology to discriminate between different frequencies. Unlike the analogue aids, on which only the volume can be controlled, digital aids can be tuned by an audiologist so, for instance, they give greater amplification on high and mid frequencies, but less on low. By doing so, they help the human brain to discriminate between important noises (voices) and unimportant ones (traffic). Which, you might say, is what true hearing does. But that’s not quite right. True hearing edits all the time. Every second of every day it judges and discards, picking through what it understands to be significant and ignoring everything else. So sticking a small pair of amps in your ears might help a lot with the volume of what you hear, but it’ll do absolutely nothing for the sense.
Meanwhile, cochlea implants are becoming an increasingly significant form of treatment for conditions of the inner ear. An implant works by bypassing the damaged hair cells completely and passing signals directly to the auditory cortex. At the moment they’re only given to those with severe or profound hearing loss caused by damage or deformation of the cochlea, though the age of implantees drops every year – at the time of writing, the youngest recipient is a baby of three and a half months. But, as with hearing aids, there’s always a time-lag while the brain learns to translate these strange new soundings into something containing sense and fluency. Which means that, broadly speaking, the younger the recipient, the greater the chance their brain will learn to process these new signals as meaningful – and conversely that when older, deafened, implantees hear voices or music for the first time in many years, it may well sound horrendous.
Hearing isn’t a single-cell process – it takes place in many parts of the brain, which means its effects are registered in all parts of the body. But its full complexity only really becomes apparent when placed beside science’s artificial alternatives. It’s like hands, or kidneys. The greatest minds in medical invention have been working on a prosthetic hand for generations and though they’ve undoubtedly reached a point of great sophistication, the results don’t even come close to the real thing. As for twist-grips, so for cilia – all our brilliance can only produce a rough imitation, a golem to the sheer evolutionary beauty of true hearing.
IT WAS MAKING that May appointment which finally changed things. Though by then it had been nearly eighteen months since I’d started losing my hearing, I’d somehow managed to delude myself that this was something temporary. A long-running totally asymptomatic case of flu. Uncleared air-pressure build-up –anything that allowed for the possibility of waking up one morning with the wool pulled out of my ears. And, though I was aware that the NHS didn’t traditionally give away expensive items of customised hardware to audiology outpatients, I’d even managed to convince myself that they too were available purely on a trial basis.
Until that moment I’d taken all Steve’s information in but I hadn’t really absorbed it. I’d understood it, but I hadn’t comprehended it. Now, finally, it dropped into me – all of me. If Steve was suggesting appointments several months in advance, it meant that he knew that I would still be deaf in six months’ time. Or a year. Or quite a lot more than a year.
I didn’t wear the aids. Or rather, I didn’t wear the aids as they should have been worn. I didn’t like them, and I found them uncomfortable. Instead, I bought a couple of small pots of brightly coloured nail varnish and customised them, painting out the gusset-coloured plastic and adding a bit of glitter. When I put the new sparkly aids in they felt better. I wore them occasionally, taking them in and out according to circumstance. If I was in a room with one or two other people the aids could be helpful but I soon found they amplified all sound, not just the ones I wanted to hear. Outside in the street the volume of traffic noise overbore the voice of the person I was talking to. Inside, the sound of the washing machine drowned out conversation. On the phone they were screechy with feedback and got in the way. I couldn’t seem to get the volume right.
When I returned to St Mary’s in May, Steve was still wearing the pink shoes and the Scooby Doo tie, and looked if anything marginally more exhausted than he had six months ago.
When I produced the coloured hearing aids, he laughed. ‘I approve. Anything that makes you happier about wearing them has got to be a good thing.’
It was at that point that I finally plucked up the courage to ask the only question that seemed relevant. ‘Is it going to get worse?’
Steve looked at me. ‘Probably,’ he said. ‘It will probably go so slowly you scarcely notice. In two years, who knows? You could be a psychological jellyfish. All your social skills could be completely eroded. You’d still be hanging in there, but you wouldn’t really be able to get by in any kind of normal human interaction.’
‘Or,’ he said, putting the aids back in their box and handing it back, ‘you could wear these.’