Beyond Silence: The Power of Music and Vibrations for Deaf People
Hard-of-hearing or deaf people “listen” to music, just not in the way hearing people experience this process. To fully understand how deaf people listen to music, we must first explore what sound is and how the brain processes sound.
But first, it has to be pointed out that there are varying levels of deafness – ranging from mild hearing loss experienced later in life to profound (or complete) hearing loss from birth.
This means every deaf or hard-of-hearing person’s relationship with music will be different.
HOW THE BRAIN EXPERIENCES SOUND AND MUSIC
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Sound is produced when an object vibrates enough to create additional waves of vibration (energy). We call these waves of energy sound waves.
We hear sound when sound waves vibrate fast enough to create a path of vibration from the source object to our eardrum. Our eardrum then vibrates, pushing the sound waves through the middle and inner ear.
A sound wave’s volume and what it sounds like depends on the strength or frequency of the vibrations. The distance and the medium (solid, liquid or gas) the sound travels through to get to the eardrum impact the strength of the sound.
So sounds are quieter the further away you are from the source. And a wave that’s travelled through the air, rather than the air and brick wall, will sound louder to the human ear.
Another factor that impacts how, or even whether, we hear sound at all is our hearing threshold.
Your hearing threshold is determined by testing the range of frequencies (measured in hertz) against the volumes of sound (measured in decibels) that you can hear.
The “normal hearing” range includes quiet sounds of 20 dBHL and lower. The ranges for mild, moderate, severe and profound hearing loss are 20-40, 41-70, 71-95 and 95dBHL, respectively.
Meanwhile, completely deaf people can only hear what’s internal to them.
HOW THE BRAIN PROCESSES SOUND
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After sound waves travel from the outer to the inner ear, nerve endings change the vibrations into electrical impulses or neural messages. The brain receives these messages and uses them to process and interpret the different aspects of sound.
In short, this process is how hearing people assign meaning to sound.
Interestingly, this facet of the sound experience is similar for deaf or hard-of-hearing people because the same parts of the brain are involved in processing. The critical difference is that deaf people don’t receive neuronal messages about sound via the ears.
We need to understand brain plasticity to understand how deaf or hard-of-hearing people receive neural messages concerning sound.
In this context, brain plasticity is a process where parts of the brain begin to work together to account for the loss of one of the five senses, in this case, hearing. This process assigns different roles to different brain parts while the remaining senses become heightened.
While most of the processing is the same between hearing and deaf or hard-of-hearing people, the latter receive signals about sound through touch instead of hearing.
So the sound is processed in the same parts of the brain, but is experienced through sensing and touching vibrations that cause sound waves rather than hearing them.
According to Dr Dean Shibata, assistant professor of radiology at the University of Washington: “Vibrational information has essentially the same features as sound information – so it makes sense that in the deaf, one modality may replace the other modality in the same processing area of the brain.”
Multiple areas of the brain are integral to processing sound and, thus, experiencing music. But the nucleus accumbens, amygdala, and auditory and sensory cortex are especially critical for the deaf or hard-of-hearing.
NUCLEUS ACCUMBENS AND AMYGDALA
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The nucleus accumbens, and the amygdala invoke emotions in response to music. These brain parts also help us form emotional attachments to music.
Where someone might hear the opening notes or higher-pitched melody of their favourite song and instantly feel a positive emotional response, deaf or hard-of-hearing people might react similarly to the bass notes or beat.
This is because hearing damage means it’s more difficult for someone to hear higher pitches and softer sounds. The bass and beat also cause more vibration, which makes them easier to sense.
The auditory cortex processes and decodes sound information, including voices or music. As such, it’s the part of the brain that listens to sounds and interprets things like tone.
For hard-of-hearing or deaf people, the auditory cortex is still critical to how the brain recognises and experiences music. But instead of using the auditory cortex to receive neuronal messages from the ears, they receive messages by sensing vibrations through touch.
The sensory cortex is responsible for processing tactile feedback. When experiencing music, this relates to the tactile input produced by playing an instrument and dancing – or standing close to a speaker causing your body to feel low-frequency vibrations of the music.
For deaf people, the sensory cortex helps bridge the gap between hearing and touch.
As such, it plays a pivotal role in how deaf people sense vibrations and use them to interpret sound through feeling rather than hearing.
HOW DO DEAF PEOPLE LISTEN TO MUSIC?
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Rather than “listening’ as hearing people understand it, deaf people “experience” or sense music through physical sensations. And just like people on the “normal hearing” end of the spectrum, this felt sense will create a different music experience for everyone.
Here are some ways deaf and hard-of-hearing people engage with music.
One of the primary ways deaf people experience music is by feeling the vibrations of sound. The bass notes and, in some cases, the beat create more obvious vibrations that are easier to feel.
Meaning these elements of music are more impactful for someone who is deaf or hard-of-hearing.
These vibrations will feel differently depending on the medium the sound waves travel through. Feeling vibrations through the speakers in your home will be a different experience than the vibrating floor of a concert, for example.
The experience also differs if someone senses vibrations with their feet in an indoor (concrete) or outdoor (grass) venue – and if they feel vibrations by placing their hands on a speaker or pair of headphones.
Because of this, a deaf person could experience the same song in multiple ways by feeling the vibrations through different objects.
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Sign language is a mechanism of communication whereby the signer uses their hands to communicate meaning rather than relying on the spoken word.
Aside from sign language, deaf or hard-of-hearing people might also use lip reading to understand spoken words they can’t hear. So sign language is sometimes accompanied by a mouthed/silent version of the words to aid lip reading.
Both sign language and lip reading allow deaf and hard-of-hearing people to perceive the lyrics of a song.
It’s becoming increasingly common for musicians and bands (Pearl Jam and the Red Hot Chili Peppers, for example) to have sign language interpreters at their live performances. In doing so, they make their song lyrics and music more accessible for deaf and hard-of-hearing people.
There are also sign language interpreters like Amber Galloway Gallego, who specialise in music interpreting. She actively makes music more accessible at live concerts and through YouTube using American Sign Language (ASL).
Gallego has interpreted for Kendrick Lamar and runs a YouTube channel where she interprets songs for the deaf community through her signature energetic performances.
Pitch is what differentiates one sound within the entire spectrum of sound. And we perceive lower or higher pitches depending on the frequency of vibration. So, slower vibrations create the perception of lower sounds, and faster vibrations produce higher sounds.
Your hearing threshold dictates how well you can differentiate pitch (between higher or lower musical melodies, for example) or whether you can hear pitch.
Those with partial hearing loss can still hear pitch but might struggle to perceive higher pitches. And while those who are completely deaf won’t hear pitch, they can often feel and therefore perceive pitch.
HOW A PROFOUNDLY DEAF PERCUSSIONIST SENSES PITCH
Dame Evelyn Glennie is a profoundly deaf solo percussionist and composer. She began to lose her hearing during her teenage years, but before that, she experienced the sounds of different pitches.
When Glennie first realised she was losing her hearing, she spent time (along with her percussion teacher Ron Forbes) refining her ability to “detect vibrations” in place of hearing sound.
By doing so, she learned to distinguish “the rough pitch of notes” based on associating where on her body she felt the sound with the “sense of perfect pitch” she had before losing her hearing.
According to Glennie, she feels low sounds mainly in her legs and feet, and high sounds in particular places on her face, neck and chest.
Timbre is a unique sound created by different sources. In music, timbre varies depending on the instrument.
So, while a guitar and a flute could play the same note, the frequency of each instrument differs. Meaning the timbre or unique sound produced by each would be distinct.
As with pitch, hard-of-hearing or deaf people experience timbre in music differently than hearing people – and the ability to discriminate timbre changes depending on the severity of hearing difficulties.
In their study, Rumi Hiraga and Kazuhiko Otsuka found that hard-of-hearing people could distinguish timbres in instrument sets “in which all timbres were similar by comparison”; however, “they encountered difficulties in differentiating timbres in other cases”.
For similar articles, take a look at:
• Christine Sun Kim’s Ownership Of Sound
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Writer | Rachael Hope
Rachael Hope is a writer and visual artist. She loves to explore the connections between creativity in all its forms and broader culture. When not being creative herself, you’ll find her practising yoga or exploring nature.