Musicophilia: Tales of Music and the Brain (17 page)

Jacob, of course, is overjoyed at this change, which promises to reopen a once-closing door, expanding his musical life and his enjoyment of music to the full again. And I, as a neurologist, am filled with wonder that the retuning in his musician’s brain has been able to counterbalance the patchy and inconstant output from his aging cochleas, that through intensive musical activity, attention, and will, Jacob’s brain has literally reshaped itself.

I
n 1996 I began corresponding with a Norwegian physician, Dr. Jorgen Jorgensen, who had written to tell me that his appreciation of music had been altered suddenly and radically when he lost all hearing in the right ear, after removal of an acoustic neuroma in the sensory nerve. “The perception of the specific qualities of music— pitch, timbre— did not change,” he wrote. “However, my emotional reception of music was impaired. It was curiously flat and two-dimensional.” Mahler’s music, in particular, had once had a “shattering” effect on him. But when he went to a concert soon after his surgery and heard Mahler’s Seventh Symphony, it sounded “hopelessly flat and lifeless.”

After six months or more, he began to adapt to this:

“This may be my own psychological adjustment to the loss,” Dr. Jorgensen added, “[but] our brain is a wonderful instrument. Hearing fibres may have crossed in the corpus callosum to receive input from my functioning left ear…. I also believe my left ear is better than should be expected from a seventy-year-old.”

When we listen to music, as Daniel Levitin has written, “we are actually perceiving multiple attributes or ‘dimensions.’ ” Among these he includes tone, pitch, timbre, loudness, tempo, rhythm, and contour (the overall shape, the up and down of melodies). One speaks of an amusia when the perception of some or all of these qualities is impaired, but Dr. Jorgensen was not amusic in this sense. His perception in the unaffected left ear was normal.

Levitin goes on to speak of two other dimensions. Spatial location, he writes, is “the perception of how distant the source is from us, in combination with how large a room or hall the music is in…it distinguishes the spaciousness of singing in a large concert hall from the sound of singing in your shower.” And reverberation, he writes, “has an underappreciated role in communicating emotion and creating an overall pleasing sound.”

It was precisely these qualities that Dr. Jorgensen missed when he lost the ability to hear in stereo. When he went to a concert, he found that it lacked spaciousness, voluminousness, richness, resonance— and this rendered the music “flat and lifeless.”

I was struck here by the analogy to the experience of those who lose the use of one eye, and with this their ability to see depth stereoscopically.
1
The resonances of losing stereoscopy can be unexpectedly far-reaching, causing not only a problem in judging depth and distance, but a “flattening” of the whole visual world, a flattening that is both perceptual and emotional. People in this situation speak of feeling “disconnected,” of a difficulty in relating themselves not only spatially but emotionally to what they are seeing. The return of binocular vision, if this occurs, can thus give great pleasure and relief, as the world once again seems visually and emotionally rich. Yet even if there is no restoration of binocular vision, there may be a slow change, an adaptation analogous to what Dr. Jorgensen described— the development of a pseudostereo effect.

It is important to emphasize the word “pseudostereo.” Genuine stereo perception, either visual or auditory, depends on the brain’s ability to infer depth and distance (and such qualities as rotundity, spaciousness, and voluminousness) from the disparities between what is transmitted by the two individual eyes or ears— a spatial disparity in the case of the eyes, a temporal disparity in the case of the ears. Tiny differences are involved here, spatial disparities of a few arc seconds with vision, or of microseconds with hearing. This allows some animals, especially nocturnal predators like owls, to construct a veritable sound map of the environment. We humans are not up to this standard, but we nevertheless use binaural disparities, no less than visual cues, for orienting ourselves, for judging or forming impressions of what lies around us. It is stereophony that allows concertgoers to enjoy the full complexity and acoustic splendor of an orchestra or a choir performing in a concert hall designed to make listening as rich, subtle, and three-dimensional as possible— an experience we try to re-create, as best we can, with two earphones, or stereo speakers, or surround sound. We tend to take our stereo world for granted, and it requires a mishap like Dr. Jorgensen’s to bring home, starkly and suddenly, the huge but often overlooked importance of having two ears.

No genuine stereo perception is possible if one has lost an eye or an ear. But as Dr. Jorgensen observed, a remarkable degree of adjustment or adaptation can occur, and this depends on a variety of factors. One of these is the increased ability to make judgments using one eye or ear, a heightened use of monocular or monaural cues. Monocular cues include perspective, occlusion, and motion parallax (the shifting appearance of the visual world as we move through it), and monaural cues are perhaps analogous to these, though there are also special mechanisms peculiar to hearing. The diffusion of sound with distance can be perceived monoaurally as well as binaurally, and the shape of the external ear, the pinna, provides valuable cues about both the direction and the asymmetries of sound reaching it.

If one has lost stereoscopy or stereophony, one must, in effect, recalibrate one’s environment, one’s spatial world— and movement here is especially important, even relatively small but very informative movements of the head. Edward O. Wilson describes in his autobiography,
Naturalist,
how he lost an eye in childhood but nonetheless is able to judge distances and depths with great accuracy. When I met him I was struck by a curious nodding of the head, and took this to be a habit or a tic. But he said it was nothing of the sort— it was a strategy designed to give his remaining eye alternating perspectives (such as normally the two eyes would receive), and this, he felt, combined with his memories of true stereopsis, could give him a sort of simulacrum of stereo vision. He said that he adopted these head movements after observing similar movements in animals (like birds and reptiles, for instance) whose visual fields have very little overlap. Dr. Jorgensen did not mention any comparable head movements in himself— they would not be too popular in a concert hall— but such movements might well help one construct a richer, more diverse soundscape.

There are other cues that stem from the complex nature of sounds and the vicissitudes of sound waves as they bounce off objects and surfaces around one. Such reverberation can provide an enormous amount of information even to a single ear, and this, as Daniel Levitin has remarked, has an essential role in communicating emotion and pleasure. It is for this reason that acoustical engineering is a major science and art. If a concert hall or lecture hall is badly designed, sounds may be “killed,” voices and music seem “dead.” Through centuries of experience, the builders of churches and auditoriums have become remarkably adept at making their buildings sing.

Dr. Jorgensen says that he believes his good ear is “better than should be expected from a seventy-year-old.” One’s ear, one’s cochlea, cannot improve as one gets older, but as Jacob L. clearly demonstrated, the brain itself can improve its ability to make use of whatever auditory information it has. This is the power of cerebral plasticity. Whether or not “hearing fibres may have crossed in the corpus callosum” to the other ear, as Jorgensen suggests, is questionable— but there most assuredly have been significant changes in his brain as he has adapted to life with one ear. New connections must have been made, new areas recruited (and a sufficiently subtle brain-imaging technique might be able to demonstrate such changes). It seems probable, too— for vision and hearing normally complement each other and tend to compensate for each other if one is impaired— that Dr. Jorgensen, consciously or unconsciously, is using vision and visual data to map the position of instruments in the orchestra and the dimensions, spaciousness, and contours of the concert hall, as a way of reinforcing a sense of auditory space.

Perception is never purely in the present— it has to draw on experience of the past; this is why Gerald M. Edelman speaks of “the remembered present.” We all have detailed memories of how things have previously looked and sounded, and these memories are recalled and admixed with every new perception. Such perceptions must be especially powerful in a strongly musical person, a habitual concertgoer like Dr. Jorgensen, and imagery is surely recruited to complement one’s perceptions, especially if perceptual input is limited. “Every act of perception,” Edelman writes, “is to some degree an act of creation, and every act of memory is to some degree an act of imagination.” In this way the brain’s experience and knowledge are called upon, as well as its adaptability and resilience. What is remarkable in Dr. Jorgensen’s case, at least, is that, after such a severe loss, with no possibility of function being restored in the ordinary sense, there has nonetheless been a significant
reconstruction
of function, so that much of what seemed irretrievably lost is now available to him again. Though it took some months, he has, against all expectation, been able to recover in large measure what was most important to him: the richness, the resonance, and the emotional power of music.

D
R. JORGENSEN’S ACCOUNT
was the first I had received of the effects of sudden deafness on one side, but since he wrote to me, I have found that his experience is far from unusual. One friend of mine, Howard Brandston, related to me how, twenty years ago, he had an attack of sudden vertigo, followed by an almost complete loss of hearing in his right ear. “I could still hear sounds on that side,” he said, “but could not unscramble words or distinguish tonal differences.” He continued:

There were other problems, too. Howard was an avid hunter, and on his first deer-hunting trip after his hearing loss, he found that his ability to locate sounds was severely undermined:

After several months, Howard discovered many ways to compensate for his hearing loss on one side. He would alternate between analyzing a scene visually and auditorily, trying to meld the two perceptual inputs. “After a while,” he said, “I no longer had to close my eyes if I kept scanning the scene by moving my head in a side-to-side motion, with a very slight up-and-down wave motion. After quite a while I began to feel comfortable enough to go dangerous game hunting again. Now I was searching for sounds that were familiar to me.”
2

In a concert hall, Howard learned to turn his head slightly, “as if I was looking at the instruments that would be playing at that moment— to the left for the violins and slightly to the right for the bass and percussion.” The sense of touch, as well as that of sight, was crucial in helping him reconstruct a sense of musical space. He experimented with his stereo’s subwoofer, which, he said, “made me most aware of the tactile physical nature of the sounds I was listening to.” In his trophy room, which he had designed to be a perfect listening environment for his high-end stereo, he would use the power of the subwoofer to help him “round up” memories and images of sound and space. Perhaps all of us, unconsciously, use visual and tactile cues along with auditory ones to create the fullness of musical perception. With these and doubtless many other accommodations, both conscious and unconscious, Howard now gets a pseudostereo effect, as Dr. Jorgensen does, and he enjoys music once again.