Musicophilia: Tales of Music and the Brain (16 page)

Unlike the eye, the organ of Corti is well protected from accidental injury; it is lodged deep in the head, encased in the petrous bone, the densest in the body, and floats in fluid to absorb accidental vibrations. But protected as it is from gross injuries, the organ of Corti, with its delicate hair cells, is highly vulnerable in other ways— vulnerable, as a start, to loud noise (each ambulance siren or garbage truck will destroy a few hair cells, to say nothing of airplanes, rock concerts, blaring iPods, and the like). The hair cells are vulnerable, too, to the effects of age and hereditary cochlear deafness— and once the hair cells are destroyed, it has long been thought, they are lost forever.
1

Jacob L., a distinguished composer in his late sixties, came to consult me in 2003. His problems had started, he said, about three months earlier. “I hadn’t been playing or composing much for a month,” he said, “and then I suddenly noticed the upper register of the piano I was playing was grossly out of tune. Terribly sharp…detuned.” In particular, these notes were sharpened, subjectively, by a quarter of a tone or so for the first octave and a semitone or so for the next octave up. When Jacob complained of this, his host, the owner of the piano, was surprised, and said that his piano had just been tuned and that everyone else had found it fine. Puzzled, Jacob returned home and tested his hearing on his electronic synthesizer, which is always exactly in tune. To his dismay, he found the same sharpening in the upper octaves here.

He arranged to visit the audiologist he had been seeing for the last six or seven years (because of a hearing loss in the upper ranges). The audiologist was struck, as Jacob himself had been, by the correspondence between his hearing loss and his hearing distortion, both starting at around 2,000 hertz (nearly three octaves above middle C), and the fact that his left ear sharpened sound more than his right (the difference was almost a major third at the top of the piano keyboard). This sharpening, Jacob said, was “not strictly linear.” One note might be scarcely sharpened, while notes on either side of it would be markedly sharpened— and there were also variations from day to day. There was, in addition, one strange anomaly: the E-natural ten notes above middle C, not in the hearing-impaired range, was flattened by almost a quarter tone, but no such flattening occurred with the notes to either side.

While there was a certain consistency, a certain logic in the sharpening of notes in the affected range, Jacob was very struck by the isolated flattening of the E. “It shows how sharply tuned the organ of Corti is,” he said. “A few hair cells out, the hair cells on either side in good shape, and you get one flattened note in the midst of normality— like one bad string on a piano.”

He was also conscious of what he called “contextual correction,” an odd phenomenon that made him wonder whether his problem was, in fact, located in his brain rather than his ears. If, say, there was only a flute or piccolo above a bass, it sounded strikingly out of tune, but when there was orchestral richness, a continuum of tones and pitches, the distortion was scarcely noticeable. Why, if it was only a question of a few hair cells, should this correction occur? Was there something happening with him neurologically, too?

These distortions were very distressing to Jacob— and disabling. He found it problematic, under the circumstances, to conduct his own music, for he would think some of the instruments were out of tune or that the players were hitting the wrong notes when they were not. It was not as easy, either, to compose, which he tended to do at his piano. I suggested, half seriously, that he get his piano or synthesizer mistuned to exactly the degree needed to counterbalance his perceptual distortions— this way it would sound normal to him, even if it sounded out of tune to everybody else. (Neither of us was quite certain of the logic of this, whether it would help him to compose or only exacerbate the problem.) I also wondered if his hearing aids could be purposely mistuned— but he had already discussed this with his audiologist, who felt that the erratic and unpredictable character of his distortions would make any such effort impossible.

While Jacob had managed very well when he had experienced only high-end hearing loss— stronger hearing aids had compensated for this— he had become worried when the distortions began, fearing that they might put an end to his conducting, to say nothing of undermining the pleasure of simply listening to music. But in the three months since the distortions had started, he had made some accommodations— for instance, he would work out high passages on the keyboard below the distorting range, then notate the music in the correct range. This allowed him to continue composing effectively.

He could do this because his musical imagery and memory were intact. He knew how music— his own music and others’—
should
sound. It was only his
perception
of music that was distorted.
2
It was Jacob’s ears, and not his brain, that had suffered damage. But what exactly was happening in Jacob’s brain?

People have compared the cochlea, the spiral organ, to a stringed instrument, differentially tuned to the frequency of notes; but such metaphors need to be extended to the brain as well, for it is here that the cochlea’s output, all eight or ten octaves of audible sound, are mapped tonotopically onto the auditory cortex. Cortical mappings are dynamic, and can change as circumstances alter. Many of us have experienced this, getting a new pair of glasses or a new hearing aid. At first the new glasses or hearing aids seem intolerable, distorting— but within days or hours, our brain adapts to them, and we can make full use of our now optically or acoustically improved senses. It is similar with the brain’s mapping of the body image, which adapts quite rapidly if there are changes in the sensory input or the use of the body. Thus if a finger, for example, is immobilized or lost, its cortical representation will become smaller or disappear entirely, the representations of other parts of the hand expanding to fill its place. If, conversely, the finger is used a great deal, its cortical representation will enlarge, as happens with the Braille-reading index finger in a blind person, or the fingers of a string player’s left hand.

One might expect something similar to happen with the mapping of tones from a damaged cochlea. If high-frequency notes are no longer clearly transmitted, their cortical representations shrink, become narrow and compressed. But such changes are not fixed or static, and a rich and varied tonal input can serve to reexpand the representations, at least while the stimulus lasts, as Jacob had found out for himself.
3
And when we pay attention to or focus on a sound, this too temporarily enlarges its cortical representation, and it becomes sharper and clearer, at least for a second or two. Could such a concentration or focus allow Jacob to correct his misperception of tones? He thought about this, and said yes: when he was aware of distortions, he could indeed sometimes diminish them by an effort of will— the danger, he said, was that he might be unaware of them. He compared this sort of voluntary alteration to the way in which one might “will” oneself to see a particular aspect of a visual illusion, such as the face-vase illusion.

Was this explicable wholly in terms of the dynamic mapping of tones in the cortex and the ability to enlarge or shift these in relation to circumstances? Jacob felt his perception changing as he pulled a note in and as it escaped him once again. Could he actually be retuning his cochlea, if only for a second or two?

What might seem a preposterous notion has gained support from recent work demonstrating that there are massive efferent connections (the olivocochlear bundles) going from the brain to the cochlea and thence to the outer hair cells. The outer hair cells serve, among other things, to calibrate or “tune” the inner hair cells, and they have an exclusively efferent nerve supply; they do not transmit nerve impulses
to
the brain, they get orders
from
the brain. Thus one has to see the brain and ear as forming a single functional system, a two-way system, with the ability not only to modify the representation of sounds in the cortex but to modulate the output of the cochlea itself. The power of attention— to pick out a tiny but significant sound in our environment, to home in on a single soft voice in the ambient din of a crowded restaurant— is very remarkable and seems to depend on this ability to modulate cochlear function, as well as on purely cerebral mechanisms.

The ability of the mind and brain to exercise efferent control over the cochlea can be heightened by training and musical activities, and is (as Christophe Micheyl et al. have shown) particularly powerful in musicians. In Jacob’s case, of course, this ability is constantly in training, as he has to confront and control his pitch distortions every day.

Discovering that he had at least some voluntary control made Jacob feel less helpless, less the victim of an inexorable deterioration, and more hopeful. Could he hope for a longer-lasting improvement? Could his musician’s brain, with its vivid and accurate memory of pitch, its exact and detailed knowledge of how things should sound— could this musical brain not compensate for and transcend the aberrations of a damaged cochlea?

But a year later, he reported that his distortions were “worse, more erratic…some notes have a greater pitch shift, sometimes as much as a minor third or more.” He said that if he played a note repeatedly it might shift its pitch, but if it began off pitch, he could sometimes “pull it in,” at least for a while. He used the term “audio illusion” for the two notes, the “true” and the “phantom,” or distorted, one, and spoke of how they might interweave and alternate with each other like a moiré pattern or the two aspects of an ambiguous figure. This shifting or alternation was much more obvious now that the tonal disparities had increased from a quarter tone to a full tone or more. The range of distortion, too, was “creeping down.” “The two highest octaves,” he said, “are more and more useless to me.”

Jacob’s cochlear function, it was clear, was still deteriorating, but he continued to play and compose in a lower register. “You work with the ears you have,” he said wryly, “not the ears you want.” Though Jacob was an affable man, it was nonetheless evident that the last year had been a difficult one. He had trouble rehearsing his own compositions, which he could not hear in reality as clearly as he heard them in his mind’s ear. He could not listen to music in the higher ranges and experience it without distortions, though he could still enjoy Bach cello suites, for instance, which stay in a lower register. Overall, he was finding that “music doesn’t sound as delicious as it used to” and lacked the “glorious, spacious resonance” it once had. Jacob’s father, also a musician, had become very deaf as he grew older. Would Jacob, finally, like Beethoven, be unable to hear any music at all, except in his own mind?

O
NE OF JACOB’S CONCERNS
, on his first visit to me, was that he had never met or heard of anyone else with a condition like this. Nor, apparently, had any of the otologists or audiologists he had consulted. Surely, he thought, he could not be “unique.” This set us both thinking, wondering whether, in fact, pitch distortions might be relatively common in people with advancing hearing loss.
4

Such changes might go unnoticed by a nonmusician; and professional musicians might be loath to admit, publicly at least, that their hearing was “off.” In early 2004, Jacob sent me a clipping from the
New York Times
(“The Shushing of the Symphony,” by James Oestereich), detailing the hearing problems in musicians caused by the ever-increasing decibel level of the modern orchestra. He highlighted an excerpt of this that had leapt off the page:

“So there it is,” Jacob concluded, “a confirmation of both pitch distortion as an adjunct symptom to the hearing loss, and of our suspicion that the malady is usually a guarded secret…. I will, of course, continue accepting and accommodating just as I have for many months…but it’s of considerable intellectual and psychological comfort to learn…that, as far as this particular malady is concerned, I’m indeed part of a large club after all.”

I was moved by Jacob’s philosophical attitude, his acceptance of the increasing loss of a power so crucial to his life and his art. I was intrigued, too, by his ability sometimes to rectify the pitches he heard, briefly, by attention or will, by a rich musical context, and, in more general terms, by musical
activity.
With these he could fight against the distortions, using the brain’s power and plasticity to compensate for his damaged cochleas— up to a certain point. But I was greatly surprised when, three years after his initial visit, Jacob sent me the following letter: