Music is a fundamental attribute of the human species. Virtually all cultures, from the most primitive to the most advanced, make music. It's been true through history, and it's true throughout an individual's lifespan. In tune or not, we humans sing and hum; in time or not, we clap and sway; in step or not, we dance and bounce.
The human brain and nervous system are hard-wired to distinguish music from noise and to respond to rhythm and repetition, tones, and tunes. Is this a biologic accident, or does it serve a purpose? It's not possible to say. Still, a varied group of studies suggests that music may enhance human health and performance.
Music and the brain
Like any sound, music arrives at the ear in the form of sound waves. The external ear collects sound waves, and the ear canal funnels them to the eardrum. As the waves strike the eardrum, they cause it to vibrate. The vibrations are relayed along the chain of tiny bones in the middle ear until they reach the third bone, the stapes, which connects to the cochlea.
The cochlea is a busy little world of its own. It is filled with fluid that surrounds some 10,000 to 15,000 tiny hair cells, or cilia. Vibrations of the stapes send fluid waves through the spiral-shaped cochlea. The fluid waves produce swaying movements of the hair cells. In turn, these cells release chemical neurotransmitters that activate the auditory nerve, sending miniature electric currents to the auditory cortex in the temporal lobe of the brain.
From there, things get even more complicated. Studies using MRI and positron emission tomography (PET) scans suggest that nerve networks in different parts of the brain bear primary responsibility for decoding and interpreting various properties of music. For example, a small area in the right temporal lobe is essential to perceive pitch, which forms the basis of melody (patterns of pitch over time), chords (several pitches that sound at the same time), and harmony (two or more melodies at the same time). Another nearby center is responsible for decoding timbre, the quality that allows the brain to distinguish between different instruments that are playing the same note. A different part of the brain, the cerebellum, processes rhythm, and the frontal lobes interpret the emotional content of music. And music that's powerful enough to be "spine-tingling" can light up the brain's "reward center," much like pleasurable stimuli ranging from alcohol to chocolate.
Although every healthy human brain can perform all the complex tasks needed to perceive music, musicians' brains are, so to speak, more finely attuned to these tasks. At the other end of the spectrum, patients with brain damage may display remarkable defects in musicality; the noted neurologist and writer Dr. Oliver Sacks discusses many fascinating varieties of amusia in his book Musicophilia.
The neurobiology of music is a highly specialized field. But music also has major effects on many aspects of health, ranging from memory and mood to cardiovascular function and athletic performance.
Music and the mind
The most highly publicized mental influence of music is the "Mozart effect." Struck by the observation that many musicians have unusual mathematical ability, researchers at the University of California, Irvine, investigated how listening to music affects cognitive function in general, and spatial-temporal reasoning in particular. In their first study, they administered standard IQ test questions to three groups of college students, comparing those who had spent 10 minutes listening to a Mozart piano sonata with a group that had been listening to a relaxation tape and one that had been waiting in silence. Mozart was the winner, consistently boosting test scores. Next, the investigators checked to see if the effect was specific to classical music or if any form of music would enhance mental performance. They compared Mozart's music with repetitive music by Philip Glass; again, Mozart seemed to help, improving spatial reasoning as measured by complex paper cutting and folding tasks and short-term memory as measured by a 16-item test.
How might music enhance cognitive performance? It's not clear, but the researchers speculated that listening to music helps organize the firing of nerve cells in the right half of the cerebral cortex, the part of the brain responsible for higher functions. According to this construct, music — or at least some forms of music — acts as an "exercise" that warms up selected brain cells, allowing them to process information more efficiently. It's an interesting theory, but before you rush out to stock up on recordings of Mozart's music, you should know that even in the original research, the "Mozart effect" was modest (8 to 9 IQ points) and temporary (15 minutes). And in reviewing 16 studies of Mozart's music and human cognitive function, a Harvard psychologist concluded that the effect was even smaller, amounting to no more than 2.1 IQ points. It's a sour note, but it's hardly a requiem for the theory that music may boost cognitive function. In fact, the divergent results should serve as a prelude to additional research. And even if listening to music turns out to have little long-term effect on cognition, a 2010 review reported that learning to play an instrument may enhance the brain's ability to master tasks involving language skills, memory, and attention.
Music and stress
In every era of human history and in every society around the globe, music has allowed people to express their feelings and communicate with others. More than simply expressing emotions, music can alter them; as British dramatist William Congreve put it in 1697, "Music has charms to soothe a savage breast."
Few things are more stressful than illness and surgery. Can music reduce stress in these difficult circumstances? Several trials show it can.
A study from New York examined how music affects surgical patients. Forty cataract patients with an average age of 74 volunteered for the trial. Half were randomly assigned to receive ordinary care; the others got the same care but also listened to music of their choice through headphones before, during, and immediately after the operations. Before surgery, the patients in both groups had similar blood pressures; a week before the operations, the average was 129/82 millimeters of mercury (mm Hg). The average blood pressure in both groups rose to 159/92 just before surgery, and in both groups, the average heart rate jumped by 17 beats per minute. But the patients surrounded by silence remained hypertensive throughout the operation, while the pressures of those who listened to music came down rapidly and stayed down into the recovery room, where the average reduction was an impressive 35 mm Hg systolic (the top number) and 24 mm Hg diastolic (the bottom number). The listeners also reported that they felt calmer and better during the operation. The ophthalmologic surgeons had no problems communicating with their patients over the sound of the music, but the researchers didn't ask the doctors if their patients' improved blood pressure readings made them more relaxed as they did their work. Earlier research, though, found that surgeons showed fewer signs of stress and demonstrated improved performance while listening to self-selected music.
A study of 80 patients undergoing urologic surgery under spinal anesthesia found that music can decrease the need for supplementary intravenous sedation. In this trial, patients were able to control the amount of sedative they received during their operation. Patients who were randomly assigned to listen to music needed less calming medication than those assigned to listen to white noise or to the chatter and clatter of the operating room itself.
In the cataract and urologic surgery studies, the patients were awake during their operations. But a study of 10 critically ill postoperative patients reported that music can reduce the stress response even when patients are not conscious. All the patients were receiving the powerful intravenous sedative propofol, so they could be maintained on breathing machines in the intensive care unit (ICU). Half the patients were randomly assigned to wear headphones that played slow movements from Mozart piano sonatas, while the other half wore headphones that did not play music. Nurses who didn't know which patients were hearing music reported that those who heard music required significantly less propofol to maintain deep sedation than those patients wearing silent headphones. The music recipients also had lower blood pressures and heart rates as well as lower blood levels of the stress hormone adrenaline and the inflammation-promoting cytokine interleukin-6.
Neither of the operating room studies specified the type of music used, while the ICU trial used slow classical music. An Italian study of 24 healthy volunteers, half of whom were proficient musicians, found that tempo is important. Slow or meditative music produced a relaxing effect; faster tempos produced arousal, but immediately after the upbeat music stopped, the subjects' heart rates and blood pressures came down to below their usual levels, indicating relaxation.
Music and mood
Soothing jangled nerves is one thing; raising sagging spirits, another. Bright, cheerful music can make people of all ages feel happy, energetic, and alert, and music may even has a role in lifting the mood of people with depressive illnesses. Bach may never replace Prozac, but when it comes to depression, even a little help strikes a welcome chord.
Music and movement
Falling is a serious medical problem, particularly for people over 65; in fact, one of every three senior citizens suffers at least one fall during the course of a year. Can music help? An older study says it can. The subjects were 134 men and women 65 and older who were at risk of falling but who were free of major neurologic and orthopedic problems that would limit walking. Half the volunteers were randomly assigned to a program that trained them to walk and perform various movements in time to music, while the other people continued their usual activities. At the end of six months, the "dancers" exhibited better gait and balance than their peers — and they also experienced 54% fewer falls. Similar programs of movement to music appear to improve the mobility of patients with Parkinson's disease.
Maladies of musicians
If there is a link between musicians and medics, perhaps musicians should be able to heal themselves. Many could use the help.
The most common problems stem from the repetitive motion of playing, often in combination with an awkward body position and the weight or pressure of the musical instrument. A Canadian study found that 39% to 47% of adult musicians suffer from overuse injuries; most involve the arms. The report suggests that musicians are as vulnerable to repetitive-use injury as newspaper workers (41% incidence) and that their risk is only slightly below that of assembly line food packers (56%). And since the survey included only classical musicians, it may underestimate the risk in the world of rock and pop. Even if music is good for the mind, it may not be so good for the wrist.
A particularly disabling ailment of highly trained musicians is focal dystonia, a movement disorder that may be caused by overuse of parts of the nervous system. Another hazard is hearing loss caused by prolonged exposure to loud music. Brass and wind players may develop skin rashes triggered by allergies to the metal in their instruments. And the list includes disorders ranging from fiddler's neck to Satchmo's syndrome (rupture of a muscle that encircles the mouth). One reassuring note: "cello scrotum," first reported in the British Medical Journal in 1974, was revealed to be a hoax 34 years later.
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