The Use of Ultrasonic Bone Conduction to Treat Tinnitus

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Title: The Use of Ultrasonic Bone Conduction to Treat Tinnitus

1
The Use of Ultrasonic Bone Conduction to Treat
Tinnitus

2
What is Tinnitus?

Tinnitus is the perception of sound in the ears
when no external source is present
Typically, it is perceived as a bell-like or
ringing tone however, some people report hearing
sounds such as crickets, music, waves or buzzing
Many people experience this condition at one
point in their lives after events such as
concerts however it usually disappears after
24-48 hours
In severe cases, tinnitus will effect the patient
24 hours a day, seven days a week
Tinnitus Sample

3
What causes Tinnitus

Tinnitus is usually caused by a head injury, an
infection, diseases ranging from the common cold
to diabetes, or exposure to loud sounds such as
gunshots and explosions
It is estimated that in the United States alone,
over 36 million people suffer from tinnitus.
Around 10 million of these people have a severe
case

It can also be a sign of hearing loss. People who
work with loud equipment, such as power tools,
commonly develop the condition
The cochlea contains thousands of tiny hairs
which vibrate in response to sound waves and
cells which convert neural signals back into
acoustical vibrations. The sensing cells are
connected with the vibratory cells through a
neural feedback loop, which is regulated by the
brain. This loop is normally adjusted just below
the onset of self-oscillation, which gives the
ear its spectacular sensitivity and selectivity.
If something changes, it's easy for the delicate
adjustment to cross the barrier of oscillation
and tinnitus results.
Evidence has been found that the brain reprograms
its nerve cells based on sensory loss. If the
brain changes its response as a result of some
hearing loss, then this could be the cause of
tinnitus.

5
Current Tinnitus Treatments

There are many different forms of tinnitus
treatments available today for patients ranging
from herbal remedies to cochlear implants
With most methods of treatment, a great deal of
time and patience is required for the therapy to
be effective

6
Bone Conduction

Conduction of sound through the bones of the
skull to the inner ear
A transducer is used to convert an electrical
signal into mechanical vibrations
Vibrations are conducted through the skull bones
to the cochlea, which interprets and sends the
signal to the brain

7
Why Use Bone Conduction?

Humans typically cannot hear ultrasound ( gt 20
kHz) through basic air conduction, but can
perceive sound at frequencies up to 108 kHz
through bone conduction
It has been suggested that the reprogramming of
the brain could be reversed with high frequency
stimulation.
Bone conduction has many applications in the
medical and communications industries such as
headphones, hearing aids, cell phones, and
communications systems used in high-noise
environments

8
The Tests

Used Kyma X and the Capybara 320 to run tests
Kyma X allows us to adjust sound filters and the
value of the ultrasonic frequency

9
Amplitude Modulation (AM)

10
AM in Frequency Domain

Frequency components of the input signal are
reproduced at the carrier frequency

11
The Tests

Live input given to subject in sound booth
Subject wore headphones which gave clean signal,
and a transducer which delivered processed signal
Objective was to make speech sound as
intelligible and pleasant as possible so that
patients will stay with treatment
The longer a patient undergoes therapy, the better

12
What We Tried

Searched for proper filtering algorithms and
appropriate value for carrier
Multiple Carriers at different values decreased
intelligibility
Placement of Ultrasonic Transducer depends on
individual
Number of Transducers (one vs. two) one was
easier to understand the two transducers seemed
to produce an echo or delay within the head