Hearing
Hearing
is the ability to perceive
sound via the
auditory sense or the
organ such as the ear. Hearing
is the act of
listening attentively.
Hearing is to receive a
communication from someone
in the range within which a
voice can be heard.
Hearing
is the ability to
perceive sound by detecting
vibrations and changes in
pressure of the surrounding
medium through
time.
Auditory System
is the
sensory system for the sense of hearing. It includes both the sensory
organs (the ears) and the auditory parts of the sensory system. Our
perception of sound starts with nerve cells in the inner ear that
transform pressure waves into electrical signals.
The brain needs to compare the signals from two ears to determine the
source of a sound. Then it needs to keep track of changes in volume,
pitch, timing and other characteristics. It takes a lot of brain power to
process the huge amount of auditory information it receives as well as
transform those signals into the auditory world we perceive.
Listening Effectively when
others Speak.
Ear
is the organ used for hearing and
balance. In
mammals, the ear is usually described as having three parts—the outer ear,
middle ear and the inner ear. The
outer ear consists of the pinna and the
ear canal. Since the outer ear is the only visible portion of the ear in
most animals, the word "ear" often refers to the external part alone. The
middle ear includes the tympanic cavity and the three ossicles. The
inner
ear sits in the
bony labyrinth, and contains structures which are key to
several senses: the semicircular canals, which enable balance and eye
tracking when moving; the utricle and saccule, which enable balance when
stationary; and the cochlea, which enables hearing. The ears of
vertebrates are placed somewhat symmetrically on either side of the head,
an arrangement that aids
sound localization.
Cochlea is the auditory portion of the
inner
ear. It is a spiral-shaped cavity in the
bony labyrinth,
in humans making 2.5 turns around its axis, the modiolus. A core component
of the cochlea is the Organ of Corti, the
sensory organ of hearing, which
is distributed along the partition separating fluid chambers in the coiled
tapered tube of the cochlea. The name is derived from the Latin word for
snail shell, which in turn is from the Greek κοχλίας kokhlias ("snail,
screw"), from κόχλος kokhlos ("spiral shell") in reference to its coiled
shape; the cochlea is coiled in mammals with the exception of monotremes.
Saccule is a bed of sensory cells situated in the
inner ear. The saccule translates head movements into neural impulses
which the brain can interpret. The saccule detects linear accelerations
and head tilts in the vertical plane. When the head moves vertically, the
sensory cells of the saccule are disturbed and the
neurons connected to them begin
transmitting impulses to the brain. These impulses travel along the
vestibular portion of the eighth cranial nerve to the vestibular nuclei in
the brainstem. The vestibular system is important in maintaining balance,
or equilibrium. The vestibular system includes the saccule, utricle, and
the three semicircular canals. The vestibule is the name of the
fluid-filled, membranous duct than contains these organs of balance. The
vestibule is encased in the temporal bone of the skull.
Hair
Cell are the sensory receptors of both the auditory system and the
vestibular system in the ears of all vertebrates. Through
mechanotransduction, hair cells detect movement in their environment. In
mammals, the auditory hair cells are located within the spiral organ of
Corti on the thin basilar membrane in the cochlea of the inner ear. They
derive their name from the tufts of stereocilia called hair bundles that
protrude from the apical surface of the cell into the fluid-filled
cochlear duct. Mammalian cochlear hair cells are of two anatomically and
functionally distinct types, known as outer, and inner hair cells. Damage
to these hair cells results in decreased hearing sensitivity, and because
the inner ear hair cells cannot regenerate, this damage is permanent.
However, other organisms, such as the frequently studied zebrafish, and
birds have hair cells that can regenerate. The human cochlea contains on
the order of 3,500 inner hair cells and 12,000 outer hair cells at birth.
The outer hair cells mechanically amplify low-level sound that enters the
cochlea. The amplification may be powered by the movement of their hair
bundles, or by an electrically driven motility of their cell bodies. This
so-called somatic electromotility amplifies sound in all land vertebrates.
It is affected by the closing mechanism of the mechanical sensory ion
channels at the tips of the hair bundles. The inner hair cells transform
the sound vibrations in the fluids of the cochlea into electrical signals
that are then relayed via the auditory nerve to the auditory brainstem and
to the auditory cortex.
Dizziness
-
Fainting
-
Head Spins
-
Noise -
Ringing
Vertigo is when a person feels as if they or the
objects around them are moving when they are not. Often it feels like a
spinning or swaying movement. This may be associated with nausea,
vomiting, sweating, or difficulties walking. It is typically worsened when
the head is moved. Vertigo is the most common type of
dizziness.
Vestibular System is the sensory system that
provides the leading contribution to the sense of balance and spatial
orientation for the purpose of coordinating movement with balance.
Together with the cochlea, a part of the auditory system, it constitutes
the labyrinth of the inner ear in most mammals, situated in the vestibulum
in the inner ear. As movements consist of rotations and translations, the
vestibular system comprises two components: the semicircular canal system,
which indicate rotational movements; and the otoliths, which indicate
linear accelerations. The vestibular system sends signals primarily to the
neural structures that control eye movements, and to the muscles that keep
an animal upright. The projections to the former provide the anatomical
basis of the vestibulo-ocular reflex, which is required for clear vision;
and the projections to the muscles that control posture are necessary to
keep an animal upright. The brain uses information from the vestibular
system in the head and from proprioception throughout the body to
understand the body's dynamics and kinematics (including its position and
acceleration) from moment to moment.
Audiology is a branch of science that studies hearing,
balance, and related disorders. Its practitioners, who treat those with
hearing loss and proactively prevent related damage are audiologists.
Employing various testing strategies (e.g. hearing tests,
otoacoustic
emission measurements, videonystagmography, and electrophysiologic tests),
audiology aims to determine whether someone can hear within the normal
range, and if not, which portions of hearing (high, middle, or low
frequencies) are affected, to what degree, and where the lesion causing
the hearing loss is found (outer ear, middle ear, inner ear, auditory
nerve and/or central nervous system). If an audiologist determines that a
hearing loss or vestibular abnormality is present he or she will provide
recommendations to a patient as to what options (e.g. hearing aid,
cochlear implants, appropriate medical referrals) may be of assistance. In
addition to testing hearing, audiologists can also work with a wide range
of clientele in rehabilitation (individuals with tinnitus, auditory
processing disorders, cochlear implant users and/or hearing aid users),
from pediatric populations to veterans and may perform assessment of
tinnitus and the vestibular system.
Audiobooks -
E-Books
-
Sign LanguageAudible is something
able to be heard or something that is heard or
perceptible by the ear.
Sound.
Absolute Threshold of Hearing is the minimum
sound level of a pure
tone that an average human ear with normal hearing can hear with no other
sound present. The absolute threshold relates to the sound that can just
be heard by the organism. The absolute threshold is not a discrete point,
and is therefore classed as the point at which a sound elicits a response
a specified percentage of the time. This is also known as the auditory
threshold. The threshold of hearing is generally reported as the RMS sound
pressure of 20 micropascals, corresponding to a sound intensity of 0.98 pW/m2
at 1 atmosphere and 25 °C. It is approximately the quietest sound a young
human with undamaged hearing can detect at 1,000 Hz. The threshold of
hearing is frequency-dependent and it has been shown that the ear's
sensitivity is best at frequencies between
2 kHz and 5 kHz, where the
threshold reaches as low as −9 dB SPL.
Ultrasound is
sound waves
with
frequencies higher
than the upper audible limit of human hearing. Ultrasound is not different
from "normal" (audible) sound in its physical properties, except that
humans cannot hear it. This limit varies from person to person and is
approximately 20 kilohertz (20,000 hertz) in healthy young adults.
Ultrasound devices operate with frequencies from 20 kHz up to several
gigahertz. High power ultrasound produces
cavitation that facilitates particle disintegration or reactions.
Anyone can get super-hearing. New audio technique can track bats in
flight and help localise sources of ultrasonic sound. Humans can observe
what and where something happens around them with their hearing, as long
as sound frequencies lie between 20 Hz and 20 000 Hz. Researchers have now
developed a new audio technique that enables people to also hear
ultrasonic sources that generate sound at frequencies above 20,000 Hz with
simultaneous perception of their direction.
Masking Threshold is the sound pressure level of a
sound needed to make the sound audible in
the
presence of another noise called a "masker". This threshold depends
upon the frequency, the type of masker, and the kind of sound being
masked. The effect is strongest between two sounds close in frequency. In
the context of audio transmission, there are some advantages to being
unable to perceive a sound. In audio encoding for example, better
compression can be achieved by omitting the inaudible tones. This requires
fewer bits to encode the sound, and reduces the size of the final file.
Applications in audio compression it is uncommon to work with only one
tone. Most sounds are composed of multiple tones. There can be many
possible maskers at the same frequency. In this situation, it would be
necessary to compute the global masking threshold using a high resolution
Fast Fourier transform via 512 or 1024 points to determine the frequencies
that comprise the sound. Because there are bandwidths that humans are not
able to hear, it is necessary to know the signal level, masker type, and
the frequency band before computing the individual thresholds. To avoid
having the masking threshold under the threshold in quiet, one adds the
last one to the computation of partial thresholds. This allows computation
of the signal-to-mask ratio (SMR).
White Noise -
Tinnitus -
Electronic Noise
How the brain Distinguishes Speech from Noise. For the first time,
researchers have provided physiological evidence that a pervasive
neuromodulation system - a group of neurons that regulate the functioning
of more specialized neurons - strongly influences sound processing in an
important auditory region of the brain. The
neuromodulator, acetylcholine, may even help the main auditory brain
circuitry distinguish speech from noise. The team conducted
electrophysiological experiments and data analysis to demonstrate that the
input of the neurotransmitter
acetylcholine,
a pervasive neuromodulator in the brain, influences the encoding of
acoustic information by the medial nucleus of the trapezoid body (MNTB),
the most prominent source of inhibition to several key nuclei in the lower
auditory system. MNTB neurons have previously been considered
computationally simple, driven by a single large excitatory synapse and
influenced by local inhibitory inputs. The team demonstrates that in
addition to these inputs, acetylcholine modulation enhances neural
discrimination of tones from noise stimuli, which may contribute to
processing important acoustic signals such as speech. Additionally, they
describe novel anatomical projections that provide acetylcholine input to
the MNTB. Burger studies the circuit of neurons that are "wired together"
in order to carry out the specialized function of computing the locations
from which sounds emanate in space. He describes neuromodulators as
broader, less specific circuits that overlay the more highly-specialized
ones. This modulation appears to help these neurons detect faint signals
in noise. You can think of this modulation as akin to shifting an
antenna's position to eliminate static
for your favorite radio station.
Changing the connection between the hemispheres affects speech perception.
When we listen to speech sounds, our brain needs to combine information
from both hemispheres.
Head
Shadow Effect is the result of a Single-Sided Deafness. When one
ear has a hearing loss, then it's up to the other ear to process the sound
information from both sides of the head. That's why it's called a shadow:
the head blocks sound in the same way that it would block sunlight.
Optimal Features for Auditory Categorization. Sound sense:
Brain 'Listens' for Distinctive Features in Sounds. Researchers
explore how the auditory system achieves accurate speech recognition. For
humans to achieve accurate speech recognition and communicate with one
another, the auditory system must recognize distinct categories of sounds
-- such as words -- from a continuous incoming stream of sounds. This task
becomes complicated when considering the variability in sounds produced by
individuals with different accents,
pitches,
or intonations. Humans and vocal animals use vocalizations to communicate
with members of their species. A necessary function of auditory perception
is to generalize across the high variability inherent in vocalization
production and classify them into behaviorally distinct categories
(‘words’ or ‘call types’).
Hearing is believing: Sounds can alter our visual perception. Audio
cues can not only help us to recognize objects more quickly but can even
alter our visual perception. That is, pair birdsong with a bird and we see
a bird -- but replace that birdsong with a squirrel's chatter, and we're
not quite so sure what we're looking at.
Mild-to-moderate hearing loss in children leads to changes in how brain
processes sound. Deafness in early childhood is known to lead to
lasting changes in how sounds are processed in the brain, but new research
published today in eLife shows that even mild-to-moderate levels of
hearing loss in young children can lead to similar changes.
Sounds influence the developing brain earlier than previously thought.
In experiments in newborn mice, scientists report that sounds appear to
change 'wiring' patterns in areas of the brain that process sound earlier
than scientists assumed and even before the ear canal opens.
Prevalence and global estimates of unsafe listening practices in
adolescents and young adults: More than
1 billion
young people could be at risk of hearing loss, a new study shows.
This study aimed to determine the prevalence of unsafe listening practices
from exposure to personal listening devices and loud entertainment venues
in individuals aged 12–34 years, and to estimate the number of young
people who could be at risk of hearing loss from unsafe listening
worldwide. For example, based on a maximum permissible level of noise
exposure of 80 dB for 8 hours a day (40 hours/week) with a 3 dB exchange
rate, the permissible exposure time of a 92 dB sound is 2.5 hours, of a 98
dB sound is 38 min, and of a 101 dB sound is only 19 min.
PLD users commonly choose volumes as high
as 105 dB and average sound levels at entertainment venues range from 104
to 112 dB, therefore exceeding permissible levels even for very short
periods of time. These findings suggest that many young people could be at
risk of developing permanent hearing loss. Damage from unsafe listening
can compound over the life course, and noise exposure earlier in life may
make individuals more vulnerable to age-related hearing loss. Hearing
loss, when it is unaddressed, has sizeable economic costs estimated at
almost $1 trillion annually, and has serious impacts on individuals and
families. In children, hearing loss and/or noise exposure has been
associated with poorer academic performance and reduced motivation and
concentration, which may lead to a trajectory of limited economic mobility
later in life. In adults, hearing loss has been associated with poorer
psychosocial well being, lower income and serious comorbid health
conditions such as cognitive impairment.
Tinnitus
also has important impacts on the health and well being of individuals and
is associated with poorer quality of life.
People 'Hear' Flashes due to Disinhibited flow of Signals around the
Brain, suggests study. Study sheds light on why some people hear the
'skipping pylon' and other 'noisy GIFs'. A
synaesthesia-like
effect in which people 'hear' silent flashes or movement, such as in
popular 'noisy GIFs' and memes, could be due to a reduction of inhibition
of
signals that travel
between visual and auditory areas of the brain, according to a new study.
It was also found that musicians taking part in the study were
significantly more likely to report experiencing visual ear than
non-musician participants.
Magnetic
Perception.
In the
auditory system,
the outer ear funnels
sound vibrations to
the eardrum, increasing the sound pressure in the middle frequency range.
The middle-ear ossicles further amplify the vibration pressure roughly 20
times. The base of the stapes couples vibrations into the cochlea via the
oval window, which vibrates the perilymph liquid (present throughout the
inner ear) and causes the round window to bulb out as the oval window
bulges in. Vestibular and tympanic ducts are filled with perilymph, and
the smaller cochlear duct between them is filled with endolymph, a fluid
with a very different ion concentration and voltage. Vestibular duct
perilymph vibrations bend organ of Corti outer cells (4 lines) causing
prestin to be released in cell tips. This causes the cells to be
chemically elongated and shrunk (somatic motor), and hair bundles to shift
which, in turn, electrically affects the basilar membrane’s movement
(hair-bundle motor). These motors (outer hair cells) amplify the traveling
wave amplitudes over 40-fold. The outer hair cells (OHC) are minimally
innervated by spiral ganglion in slow (unmyelinated) reciprocal
communicative bundles (30+ hairs per nerve fiber); this contrasts inner
hair cells (IHC) that have only afferent innervation (30+ nerve fibers per
one hair) but are heavily connected. There are three to four times as many
OHCs as IHCs. The basilar membrane (BM) is a barrier between scalae, along
the edge of which the IHCs and OHCs sit. Basilar membrane width and
stiffness vary to control the frequencies best sensed by the IHC. At the
cochlear base the BM is at its narrowest and most stiff
(high-frequencies), while at the cochlear apex it is at its widest and
least stiff (low-frequencies). The tectorial membrane (TM) helps
facilitate cochlear amplification by stimulating OHC (direct) and IHC (via
endolymph vibrations). TM width and stiffness parallels BM's and similarly
aids in frequency differentiation. nerve fibers’ signals are transported
by bushy cells to the binaural areas in the olivary complex, while signal
peaks and valleys are noted by stellate cells, and signal timing is
extracted by octopus cells. The lateral lemniscus has three nuclei: dorsal
nuclei respond best to bilateral input and have complexity tuned
responses; intermediate nuclei have broad tuning responses; and ventral
nuclei have broad and moderately complex tuning curves. Ventral nuclei of
lateral lemniscus help the inferior colliculus (IC) decode amplitude
modulated sounds by giving both phasic and tonic responses (short and long
notes, respectively). IC receives inputs not shown, including visual (pretectal
area: moves eyes to sound. superior colliculus: orientation and behavior
toward objects, as well as eye movements (saccade)) areas, pons (superior
cerebellar peduncle: thalamus to cerebellum connection/hear sound and
learn behavioral response), spinal cord (periaqueductal grey: hear sound
and instinctually move), and thalamus. The above are what implicate IC in
the ‘startle response’ and ocular reflexes. Beyond multi-sensory
integration IC responds to specific amplitude modulation frequencies,
allowing for the detection of pitch. IC also determines time differences
in binaural hearing. The medial geniculate nucleus divides into ventral
(relay and relay-inhibitory cells: frequency, intensity, and binaural info
topographically relayed), dorsal (broad and complex tuned nuclei:
connection to somatosensory info), and medial (broad, complex, and narrow
tuned nuclei: relay intensity and sound duration). The auditory cortex
(AC) brings sound into awareness/perception. AC identifies sounds
(sound-name recognition) and also identifies the sound’s origin location.
AC is a topographical frequency map with bundles reacting to different
harmonies, timing and pitch. Right-hand-side AC is more sensitive to
tonality, left-hand-side AC is more sensitive to minute sequential
differences in sound. Rostromedial and ventrolateral prefrontal cortices
are involved in activation during tonal space and storing short-term
memories, respectively. The Heschl’s gyrus/transverse temporal gyrus
includes Wernicke’s area and functionality, it is heavily involved in
emotion-sound, emotion-facial-expression, and sound-memory processes. The
entorhinal cortex is the part of the ‘hippocampus system’ that aids and
stores visual and
auditory memories. The
supramarginal gyrus (SMG) aids in language comprehension and is
responsible for compassionate responses. SMG links sounds to words with
the angular gyrus and aids in word choice. SMG integrates tactile, visual,
and auditory info.
When sound waves travel toward
you, the first part of the process of hearing involves the ears.
The sound waves enter the ear and the sensitive structures of the inner
ear pick up the vibrations. These vibrations stimulate nerves and create a
signal which contains the sound information. The sound signal is
transmitted along the nerve toward the part of the brain that enables you
to perceive the sensation of hearing as sound. In this way, hearing and
the nervous system work together to enable you to hear.
When the ear receives sound vibrations,
there are hair cells in the cochlea that vibrate and translate the sounds
into electrical signals. These electrical signals are transmitted to the
auditory nerve, which transmits the information to the brain. The part of
the brain that enables you to understand electrical signals as specific
types of sounds is called the auditory cortex. It’s located within the
temporal lobe, which is on either side of the brain in the region called
the cerebral cortex. There are specific neurons in the auditory cortex
that can process specific frequencies of sound that we perceive as high or
low pitches. There are also parts of the brainstem and the midbrain that
provide automatic reflex reactions to certain types of sounds. You can’t
consciously notice this time difference because it’s only microseconds,
but hearing and the nervous system work together to make this miracle
possible. That’s why a stereo speaker system enables sounds to seem like
they are surrounding you rather than just coming from the speakers. When
each speaker is positioned correctly, your ears will hear the same sounds
at slightly different times, and your brain will give you a sense of the
sounds being in various locations.
Role of protein in development of new hearing hair cells. Finding
could lead to future treatments for hearing loss. Findings explain why
GFI1 is
critical to enable embryonic cells to progress into functioning adult hair
cells.
Mouse studies tune into hearing regeneration. A deafened adult cannot
recover the ability to hear, because the sensory hearing cells of the
inner ear don't regenerate after damage. In two new studies scientists
explain why this is the case and how we might be able to change it. USC
Stem Cell scientists explain why this is the case and how we might be able
to change it. An enzyme called TET can remove methyl groups from the DNA,
thus reversing the gene silencing and restoring the capacity of supporting
cells to convert into sensory hair cells. Accordingly, when the scientists
blocked the activity of TET, the supporting cells retained their DNA
methylation and therefore could not convert into sensory hair cells in the
Petri dish. Intriguingly, in a separate experiment, the researchers tested
the extent of gene silencing in supporting cells from a chronically
deafened mouse. They found that gene silencing was partially reversed,
meaning that the supporting cells had the capacity to respond to signals
to transform into sensory hearing cells. In embryonic mice lacking Sox4
and Sox11, progenitor cells in the inner ear failed to develop into
sensory hearing cells. Specifically, a loss of Sox4 and Sox11 made the
cells' DNA inaccessible -- an effect similar to DNA methylation. With
their DNA inaccessible, the progenitor cells couldn't respond to signals
from Atoh1. On the flip side, high levels of Sox4 and Sox11
activitystimulated mouse progenitor cells and supporting cells to form
sensory hearing cells in a Petri dish.
Hypothesis underlying the sensitivity of mammalian auditory system
overturned. How hair cells transform mechanical forces arising from
sound waves into a
neural electrical signal, a process called
mechano-electric
transduction. Hair cells possess an intrinsic ability to fine-tune the
sensitivity of the MET process (termed adaptation), which underlies our
capacity to detect a wide range of sound intensities and frequencies with
extremely high precision.
Testing Hearing Ability
Hearing Test
provides an evaluation of the sensitivity of a person's
sense of hearing
and is most often performed by an audiologist using an
audiometer. An audiometer is used to determine a person's hearing
sensitivity at
different frequencies. There are other hearing tests as
well, e.g.,
Weber test and
Rinne test.
Pure-Tone Audiometry is the main hearing test used to identify hearing
threshold levels of an individual, enabling determination of the degree,
type and configuration of a
hearing loss.
Audiologist
is a health-care professional specializing in identifying, diagnosing,
treating, and monitoring disorders of the auditory and vestibular systems.
Hearing Test to Check Hearing Loss -
Hearing Check -
Tinnitus
Online Hearing Test -
National Hearing Test
Dichotic Listening Test is a psychological test
commonly used to
investigate selective attention within the auditory
system and is a subtopic of cognitive psychology and neuroscience.
Specifically, it is "used as a behavioral test for hemispheric
lateralization of speech sound perception." During a standard dichotic
listening test, a participant is presented with two different auditory
stimuli simultaneously (usually speech). The different stimuli are
directed into different ears over headphones. Research Participants were
instructed to repeat aloud the words they heard in one ear while a
different message was presented to the other ear. As a result of focusing
to repeat the words, participants noticed little of the message to the
other ear, often not even realizing that at some point it changed from
English to German. At the same time, participants did notice when the
voice in the unattended ear changed from a male’s to a female’s,
suggesting that the selectivity of consciousness can work to tune in some
information."
Multisensory Integration is the study of how
information from the different
sensory modalities, such
as sight, sound, touch, smell, self-motion and taste, may be integrated by
the
nervous system. A coherent
representation of objects combining modalities enables us to have
meaningful perceptual experiences. Indeed, multisensory integration is
central to adaptive behavior because it allows us to perceive a world of
coherent perceptual entities. Multisensory integration also deals with how
different sensory modalities interact with one another and alter each other's processing.
Hearing Impairment - Deafness
Hearing Impairment or
Hearing Loss is a partial or total inability to hear.
A
Deaf person has little to no hearing. Hearing loss may occur
in one or both ears. In children hearing problems can affect the ability
to learn spoken language and in adults it can cause work related
difficulties. In some people, particularly older people, hearing loss can
result in loneliness. Hearing loss can be temporary or permanent.
American Society
for Deaf Children - Every year in the U.S., about 24,000 children are
born with some degree of hearing loss.
Language Deprivation.
Deaf Professional Arts Network"
People with Disabilities are
are like Gifts from God. We learn just as much about people with
disabilities as we do ourselves. Sometimes they help us realize our own
disabilities, ones that we never knew we had."
Auditory Processing Disorder is an umbrella term for
a variety of disorders that affect the way the brain processes auditory
information. Individuals with APD usually have normal structure and
function of the outer, middle and inner ear (peripheral hearing). However,
they cannot process the information they hear in the same way as others
do, which leads to difficulties in recognizing and interpreting sounds,
especially the sounds composing speech. It is thought that these
difficulties arise from dysfunction in the central nervous system.
Music Disorders -
Language Disorders -
Sensory Disorders
-
Amygdala -
Noise
Auditory Scene Analysis is a proposed model for the
basis of auditory perception. This is understood as the process by which
the human auditory system organizes sound into perceptually meaningful
elements. The term was coined by psychologist Albert Bregman. The related
concept in machine perception is computational auditory scene analysis
(CASA), which is closely related to source separation and blind signal
separation. The three key aspects of Bregman's ASA model are:
segmentation, integration, and segregation.
Spatial Hearing Loss refers to a form of deafness
that is an inability to use spatial cues about where a sound originates
from in space. This in turn impacts upon the ability to understand speech
in the presence of background noise.
Auditory Verbal Agnosia also known as pure word
deafness, is the inability to comprehend speech. Individuals with this
disorder lose the ability to understand language, repeat words, and write
from dictation. However, spontaneous speaking, reading, and writing are
preserved. Individuals who exhibit pure word deafness are also still able
to recognize non-verbal sounds. Sometimes, this agnosia is preceded by
cortical deafness; however, this is not always the case. Researchers have
documented that in most patients exhibiting auditory verbal agnosia, the
discrimination of consonants is more difficult than that of vowels, but as
with most neurological disorders, there is variation among patients.
Hearing Loss and Cognitive Decline in Older Adults.
Hyperacusis is a health condition characterized by an
increased
sensitivity to certain
frequency and
volume ranges of sound (a
collapsed tolerance to usual environmental sound). A person with severe
hyperacusis has difficulty tolerating everyday sounds, some of which may
seem
unpleasantly or painfully loud to that person but not to others.
The
Hum is a name often given to widespread reports of a persistent and
invasive low-frequency humming, rumbling, or droning noise audible to many
but not all people.
Humming.
Otoacoustic Emission is a
sound which
is
generated from within the inner ear, shown to arise through a number of
different cellular and mechanical causes within the inner ear. Studies
have shown that OAEs disappear after the inner ear has been damaged, so
OAEs are often used in the laboratory and the clinic as a measure of inner
ear health. Broadly speaking, there are two types of otoacoustic
emissions: spontaneous otoacoustic emissions (SOAEs), which can occur
without external stimulation, and evoked otoacoustic emissions (EOAEs),
which require an evoking
stimulus.
Tinnitus
is the hearing of sound when no external sound is present. While often
described as a ringing, it may also sound like a clicking, hiss or
roaring. Rarely, unclear voices or music are heard. The sound may be soft
or loud, low pitched or high pitched and appear to be coming from one ear
or both. Most of the time, it comes on gradually. In some people, the
sound causes depression or anxiety and can interfere with concentration.
Cell Towers
-
Wi-Fi -
Diet -
Sugar -
Noise Pollution -
Dry Skin -
White Noise -
Electronic Noise
-
Background Radiation
Tinnitus Maskers are a range of devices based on simple
white noise machines used to
add natural or
artificial sound into a tinnitus sufferer's environment in order to
mask or cover up the ringing. The noise is supplied by a sound generator,
which may reside in or above the ear or be placed on a table or elsewhere
in the environment. The noise is usually white noise or music, but in some
cases, it may be patterned sound or specially tailored sound based on the
characteristics of the person's tinnitus.
Diagnosis and management of somatosensory tinnitus: review article.
Tinnitus is the perception of sound in the absence of an acoustic external
stimulus. It affects 10–17% of the world's population and it a complex
symptom with multiple causes, which is influenced by pathways other than
the auditory one. Recently, it has been observed that tinnitus may be
provoked or modulated by stimulation arising from the somatosensorial
system, as well as from the somatomotor and visual–motor systems. This
specific subgroup – somatosensory tinnitus – is present in 65% of cases,
even though it tends to be underdiagnosed. As a consequence, it is
necessary to establish evaluation protocols and specific treatments
focusing on both the auditory pathway and the musculoskeletal system.
Subjected Tinnitus.
Pure-Tone Audiometry is the main
hearing test
used to identify hearing threshold levels of an individual, enabling
determination of the degree, type and configuration of a hearing loss.
Does being
exposed to
quiet or low
noise places for long periods of time make your hearing more
sensitive? After I
listened to music with my
headphones
on, I notice less ringing in my ears. It's like a workout for your ears
that have been underused. Acute is having or demonstrating ability to
recognize or draw fine distinctions.
Why we Hear other Peoples Footsteps and Ignore our Own. A team of
scientists has uncovered the neural processes mice use to ignore their own
footsteps, adjustable "
sensory
filter" that allowed them to ignore the sounds of their own footsteps.
In turn, this allowed them to better detect other sounds arising from
their surroundings. When we
learn to
speak or to play
music, we predict what
sounds we're going to hear, such as when we prepare to strike keys on a
piano, and we compare this to what we actually hear. We use mismatches
between expectation and experience to change how we play and we get better
over time because our brain is trying to minimize these errors. Being
unable to make predictions like this is also thought to be involved in a
spectrum of afflictions. Overactive prediction circuits in the brain are
thought to lead to the
voice-like
hallucinations.
Noise Filters -
Tuning Out.
Neural “Auto-Correct” Feature We Use to Process Ambiguous Sounds
Discovery of new Neurons in the Inner Ear can lead to new therapies for
Hearing Disorders. Researchers have identified four types of neurons
in the peripheral auditory system, three of which are new to science. The
analysis of these cells can lead to new therapies for various kinds of
hearing disorders, such as tinnitus and age-related hearing loss.
Possible new therapy for Hearing Loss Regrows the Sensory Hair Cells found
in the Cochlea -- a part of the inner ear -- that converts sound
vibrations into electrical signals and can be permanently lost due to age
or noise damage.
New tool to create hearing cells lost in aging. Hearing loss due to
aging, noise and certain cancer drugs has been irreversible, because
scientists have not been able to reprogram existing cells to develop into
the outer and inner ear sensory cells -- essential for hearing -- once
they die. But scientists now have discovered a single master gene that
programs ear hair cells into either outer or inner ones, overcoming a
major hurdle that had prevented the development of these cells to restore
hearing.
Usher Syndrome is an extremely rare genetic disorder
caused by a mutation in any one of at least 11 genes resulting in a
combination of hearing loss and visual impairment. It is a leading cause
of
deaf-blindness and is at present incurable.
Hearing through the Tongue.
Sensory Deprivation is the deliberate reduction or
removal of stimuli from one or more of the
senses. Simple devices
such as blindfolds or hoods and earmuffs can cut off sight and hearing,
while more complex devices can also cut off the sense of smell, touch,
taste, thermoception (heat-sense), and 'gravity'. Sensory deprivation has
been used in various alternative medicines and in psychological
experiments (e.g. with an isolation tank). Short-term sessions of sensory
deprivation are described as relaxing and conducive to meditation;
however, extended or forced sensory deprivation can result in extreme
anxiety, hallucinations, bizarre thoughts, and depression. A related
phenomenon is perceptual deprivation, also called the ganzfeld effect. In
this case a constant uniform stimulus is used instead of attempting to
remove the stimuli; this leads to effects which have similarities to
sensory deprivation. Sensory deprivation techniques were developed by some
of the armed forces within NATO, as a means of interrogating prisoners
within international treaty obligations. The European Court of Human
Rights ruled that the use of the five techniques by British security
forces in Northern Ireland amounted to a practice of inhumane and
degrading treatment.
Spatial Intelligence
-
Special Needs -
Sonar
(sound navigation)
Photoacoustic Imaging is a biomedical imaging modality based on the
photoacoustic effect. In photoacoustic imaging, non-ionizing laser pulses
are delivered into biological tissues (when radio frequency pulses are
used, the technology is referred to as thermoacoustic imaging). Some of
the delivered energy will be absorbed and converted into heat, leading to
transient thermoelastic expansion and thus wideband (i.e. MHz) ultrasonic
emission. The generated ultrasonic waves are detected by ultrasonic
transducers and then analyzed to produce images. It is known that optical
absorption is closely associated with physiological properties, such as
hemoglobin concentration and oxygen saturation. As a result, the magnitude
of the ultrasonic emission (i.e. photoacoustic signal), which is
proportional to the local energy deposition, reveals physiologically
specific optical absorption contrast. 2D or 3D images of the targeted
areas can then be formed. Fig. 1 is a schematic illustration showing the
basic principles of photoacoustic imaging.
Thermoacoustic Imaging is a strategy for studying
the absorption properties of human tissue using virtually any kind of
electromagnetic radiation. But Alexander Graham Bell first reported the
physical principle upon which thermoacoustic imaging is based a century
earlier. He observed that audible sound could be created by illuminating
an intermittent beam of sunlight onto a rubber sheet.
CDK2 Inhibitors as Candidate Therapeutics for Cisplatin-and Noise-Induced
Hearing. inhibiting an enzyme called cyclin-dependent kinase 2 (CDK2)
protects mice and rats from noise- or drug-induced hearing loss. The study
suggests that CDK2 inhibitors prevent the death of inner ear cells, which
has the potential to save the hearing of millions of people around the
world.
Researchers find proteins that might restore damaged sound-detecting cells
in the ear. Using genetic tools in mice, researchers say they have
identified a pair of proteins that precisely control when sound-detecting
cells, known as hair cells, are born in the mammalian inner ear. The
proteins may hold a key to future therapies to restore hearing in people
with irreversible deafness. In order for mammals to hear, sound vibrations
travel through a hollow, snail shell-looking structure called the cochlea.
Lining the inside of the cochlea are two types of sound-detecting cells,
inner and outer hair cells, which convey sound information to the brain.
An estimated 90% of genetic hearing loss is caused by problems with hair
cells or damage to the auditory nerves that connect the hair cells to the
brain. Deafness due to exposure to loud noises or certain viral infections
arises from damage to hair cells. Unlike their counterparts in other
mammals and birds, human hair cells cannot regenerate. So, once hair cells
are damaged, hearing loss is likely permanent.
Scientists develop new gene therapy for deafness. Breakthrough may
help in the treatment of children with hearing loss. Deafness is the most
common sensory disability worldwide. Genetic deafness is caused by a
mutation in the
gene SYNE4.
Hearing and Deaf Infants Process information Differently. Deaf
children face unique communication challenges, but a new study shows that
the effects of hearing impairment extend far beyond language skills to
basic cognitive functions, and the differences in development begin
surprisingly early in life. Researchers have studied how deaf infants
process visual stimuli compared to hearing infants and found they took
significantly longer to become familiar with new objects.
Link between hearing and cognition begins earlier than once thought. A
new study finds that cognitive impairment begins in the earliest stages of
age-related hearing loss -- when hearing is still considered normal.
Victorian child hearing-loss databank to go global. A unique databank
that profiles children with hearing loss will help researchers globally
understand why some children adapt and thrive, while others struggle.
Victorian Childhood Hearing Impairment Longitudinal Databank (VicCHILD).
Earwax
or cerumen, is a brown, orange, red, yellowish or gray waxy substance
secreted in the ear canal of humans and other mammals. It protects the
skin of the human ear canal, assists in cleaning and lubrication, and
provides protection against bacteria, fungi, and water. Earwax consists of
dead skin cells, hair, and the secretions of cerumen by the ceruminous and
sebaceous glands of the outer ear canal. Major components of earwax are
long chain fatty acids, both saturated and unsaturated, alcohols, squalene,
and cholesterol. Excess or compacted cerumen is the buildup of ear wax
causing a blockage in the ear canal and it can press against the eardrum
or block the outside ear canal or hearing aids, potentially causing
hearing loss.
Bebird N3 Pro: Ear Cleaning Tweezer and Rod 2-in-1.
Hearing Aids - Audio Amplifiers
Hearing Aid is a device designed to improve hearing.
Hearing aids are classified as medical devices in most countries, and
regulated by the respective regulations. Small audio amplifiers such as
PSAPs or other plain sound reinforcing systems cannot be sold as "hearing
aids".
Sound Location (sonar).
Cochlear Implant is a surgically implanted
electronic device that provides a sense of sound to a person who is
profoundly deaf or severely hard of hearing in both ears; as of 2014 they
had been used experimentally in some people who had acquired deafness in
one ear after learning how to speak. Cochlear implants bypass the normal
hearing process; they have a microphone and some electronics that reside
outside the skin, generally behind the ear, which transmits a signal to an
array of electrodes placed in the cochlea, which stimulate the cochlear
nerve.
Prosthetics
(bionics).
Auditory Brainstem Implant is a surgically implanted
electronic device that provides a sense of sound to a person who is
profoundly deaf, due to retrocochlear hearing impairment (due to illness
or injury damaging the cochlea or auditory nerve, and so precluding the
use of a cochlear implant).
ProSounds H2P: Get Up To 6x Normal Hearing Enhancement with Simultaneous
Hearing Protection.
Muzo - Personal Zone Creator w Noise Blocking Tech.
Wireless earphones as inexpensive hearing aids. Some commercial
earbuds can perform as well as hearing aids. The result could help a large
proportion of people with hearing loss access more affordable sound
amplification devices.
AMPSound Personal Bluetooth Stereo Amplifiers & Earbuds Hearing Aid.
Hearing aids may delay cognitive decline.
Experiencing Music through a Cochlear Implant.
Bone Conduction
BLU - World’s Most Versatile Hearing Glasses.
Olive: Next-Gen Hearing Aid.
Sleeping Aids
-
Headphones
iPS cell-derived inner ear cells may improve congenital hearing loss.
A possible therapy for hereditary hearing loss in humans.
Scientists develop method to repair damaged structures deep inside the ear,
developed a new approach to repair cells deep inside the ear, we figured
out how to deliver a drug into the inner ear.
How the brain understands one voice in a noisy crowd. Previous work is
honored for its impact on improving hearing devices. Researchers find that
the brain is taking an extra step when listening to one speaker in a
crowd, and not taking that step with the other words swirling around the
conversation.
Artificial Intelligent Sensors.
Good noise, bad noise: White noise improves hearing. White noise is
not the same as other noise -- and even a quiet environment does not have
the same effect as white noise. With a background of continuous
white noise, hearing pure sounds becomes
even more precise, as researchers have shown. Their findings could be
applied to the further development of cochlear implants.
Cochlear implant as a sensor. The cochlear implant is the most
successful neural prosthesis worldwide. Thanks to direct stimulation of
the auditory nerve, it enables more than half a million people worldwide
to hear, even though those affected were born deaf or deafened.
Researchers have developed a method to convert the stimulation electrodes
of common CIs into electrochemical
sensors.
With the help of this novel sensor function, the functionality of cochlear
implants could be monitored directly in the inner ear in the long term.
Sign Language - Visual Communication
Sign
Language is a language which chiefly uses manual
communication to convey meaning, as opposed to acoustically conveyed sound
patterns. This can involve simultaneously combining hand
shapes,
orientation and movement of the hands,
arms or body,
and
facial
expressions to express a speaker's thoughts. Sign languages share many
similarities with spoken languages (sometimes called "oral languages"),
which depend primarily on sound, and linguists consider both to be types
of natural language. Although there are some significant differences
between signed and spoken languages, such as how they use space
grammatically, sign languages show the same linguistic properties and use
the same language faculty as do spoken languages. They should not be
confused with
body language, which is a kind of non-linguistic
communication.
Symbols
-
Visual Language - Let Your Fingers Do the Talking.
American Sign Language is the predominant sign language of Deaf
communities in the United States and most of anglophone Canada. ASL
signs have a number of phonemic components, including movement of the face
and torso as well as the hands. ASL is not a form of pantomime, but
iconicity does play a larger role in ASL than in spoken languages. English
loan words are often borrowed through fingerspelling, although ASL grammar
is unrelated to that of English. ASL has verbal agreement and aspectual
marking and has a productive system of forming agglutinative classifiers.
Many linguists believe ASL to be a subject–verb–object (SVO) language, but
there are several alternative proposals to account for ASL word order.
American Sign Language (youtube)
ASL speakers amount to
about 1 % of the 231 million English speakers in America.
List of
Sign Languages. There are perhaps three hundred sign languages in use
around the world today.
SignAloud: Gloves Translate Sign Language into Text and
Speech (youtube)
Christine Sun Kim: The enchanting music of Sign Language
(video)
Uni, 1st Sign Language to Voice System
Start American Sign Language
Hand Gestures
(people smart)
American
Hand Gestures in Different Cultures (youtube)
7 Ways to Get Yourself in
Trouble Abroad (youtube)
Song in Sign Language, Eminem Lose Yourself (youtube)
Hand Symbols
Cherology are
synonyms of phonology
and phoneme previously used in the study of sign languages.
Tactical Hand Signals (Info-Graph)
Communication
vl2 Story Book Apps
Bilingual Interfaces through Visual Narratives
Life Print Sign Language
Lip Reading is a technique of understanding speech by
visually interpreting the movements of the lips, face and tongue when
normal sound is not available. It relies also on information provided by
the context, knowledge of the language, and any residual hearing.
Lip-reading is not easy, as this clip demonstrates. Although ostensibly
used by deaf and hard-of-hearing people, most people with normal hearing
process some speech information from sight of the moving mouth.
Viseme
is any of several speech sounds that look the same, for example when lip
reading.
Al-Sayyid Bedouin Sign Language
Voices from El-Sayed (youtube)
American Speech-Language-Hearing Association.
American
Speech-Language-Hearing Association.
Speech and Language Center.
Learning Specialist
Sign-language exposure impacts infants as young as 5 months old. While
it isn't surprising that infants and children love to look at people's
movements and faces, recent research studies exactly where they look when
they see someone using sign language. The research uses eye-tracking
technology that offers a non-invasive and powerful tool to study cognition
and
language learning in pre-verbal infants.
Chimpanzees gesture back and forth quickly like in human conversations.
When people are having a
conversation, they rapidly take turns speaking and sometimes even
interrupt. Now, researchers who have collected the largest ever dataset of
chimpanzee 'conversations' have found that they communicate back and forth
using
gestures
following the same rapid-fire pattern.
Speech Recognition
-
Voice Activated
Computer system transcribes words users 'speak silently'. Electrodes
on the face and jaw pick up otherwise undetectable neuromuscular signals
triggered by internal verbalizations.
Sonitus
Medical SoundBite Hearing System -
Etymotic
Manually Coded English is a variety of visual
communication methods expressed through the hands which attempt to
represent the English language. Unlike deaf sign languages which have
evolved naturally in deaf communities, the different forms of MCE were
artificially created, and generally follow the grammar of English.
Morse Code -
Codes
Dragon Notes -
Dragon Dictation
Smartphone Technologies
Closed Captioning and
subtitling are both processes of displaying text on a television, video
screen, or other visual display to provide additional or interpretive
information. Both are typically used as a transcription of the audio
portion of a program as it occurs (either verbatim or in edited form),
sometimes including descriptions of non-speech elements. Other uses have
been to provide a textual alternative language translation of a
presentation's primary audio language that is usually burned-in (or
"open") to the video and unselectable.
Closed Caption Software -
Closed Captioning Jobs
Audio Description (blind and visually
impaired)
Real-Time Text is text transmitted instantly as it is typed or
created. Recipients can immediately read the message while it is being
written, without waiting. Real-time text is used for conversational text,
in collaboration, and in live captioning. Technologies include TDD/TTY
devices for the deaf, live captioning for TV, Text over IP (ToIP), some
types of instant messaging, software that automatically captions
conversations, captioning for telephony/video teleconferencing,
telecommunications relay services including ip-relay, transcription
services including Remote CART, TypeWell, collaborative text editing,
streaming text applications, next-generation 9-1-1/1-1-2 emergency
service. Obsolete TDD/TTY devices are being replaced by more modern
real-time text technologies, including Text over IP, ip-relay, and instant
messaging. During 2012, the Real-Time Text Taskforce (R3TF) designed a
standard international symbol to represent real-time text, as well as the
alternate name Fast Text to improve public education of the technology.
Real-Time Transcription is the general term for transcription by court
reporters using real-time text technologies to deliver computer text
screens within a few seconds of the words being spoken. Specialist
software allows participants in court hearings or depositions to make
notes in the text and highlight portions for future reference. Typically,
real-time writers can produce text using machines at the rate of at least
200 words per minute. Stenographers can typically type up to 300 words per
minute for short periods of time, but most cannot sustain such a speed.
Real-time transcription is also used in the broadcasting environment where
it is more commonly termed "captioning."
Auditory Training
-
Listening -
Communication -
Languages -
Sound -
Music -
Dyslexia -
Learning Styles
Instant Messaging technology is a type of online chat that offers
real-time text transmission over the Internet. A LAN messenger operates in
a similar way over a local area network. Short messages are typically
transmitted between two parties, when each user chooses to complete a
thought and select "send". Some IM applications can use push technology to
provide real-time text, which transmits messages character by character,
as they are composed. More advanced instant messaging can add file
transfer, clickable hyperlinks, Voice over IP, or
video chat.
Visual Language
Visual Language is a system of communication using visual
elements. Speech as a means of communication cannot strictly be separated
from the whole of human communicative activity which includes the visual
and the term 'language' in relation to vision is an extension of its use
to describe the perception, comprehension and production of visible signs.
Visual
Language -
Visual Language -
Knowledge Visualization
-
Visual Learning -
Body Language
-
Visual Perception
(spatial intelligence)
Communication Boards
Boardmaker Software
Alphabet Card (PDF) -
Place Mat (PDF)
Augmentative & Alternative Communication devices (AAC)
Facilitated Communication is a discredited technique used by some
caregivers and educators in an attempt to assist people with severe
educational and communication disabilities. The technique involves
providing an alphabet board, or keyboard. The facilitator holds or gently
touches the disabled person's arm or hand during this process and attempts
to help them move their hand and amplify their gestures. In addition to
providing physical support needed for typing or pointing, the facilitator
provides verbal prompts and moral support. In addition to human touch
assistance, the facilitator's belief in their communication partner's
ability to communicate seems to be a key component of the technique.
Ways to Communicate with a Non-Verbal Child.
Communication Devices for Children who Can't Talk.
Communication Boards
Speech and Communication
Communication Needs
World’s First Touch Enabled T-shirt - BROADCAST: a programmable
LED t–shirt that can display any slogan you want using your smartphone.
Software turns Webcams into Eye-Trackers
Sound Pollution -
Noise Pollution Tools