4A: Auditory Disorders Flashcards
Sound pressure wave
Sound is a mechanical wave that results from the back and fourth vibration of the particles of the medium through which the sound wave a moving.
frequency
low to high are associated with increases in the perceptual experience of pitch
amplitude
from small to large are associated with increases in the perceptual experiences of loudness
Audibility curve
a graph that depicts the relationship between the loudness of a pure tone, expressed in decibels, sound pressure level, and the frequency of the tone
outer ear
includes the pinna and auditory canal and ends at the tympanic membrane.
tympanic membrane
a thin membrane that separates the external ear from the middle ear whose functions is to transmit sound from the air to the ossicles inside the middle ear
middle ear
from tympanic membrane to oval window; includes the ossicles and drains out the eustachian tube to the back of the throat
ossicles
three smallest bones in the human body. Contained in the middle ear and serve to transmit and amplify sounds from the air to the fluid filled cochlea. The absence of the ossicles would cause moderate to severe hearing loss.
malleus
the malleus or hammer is a hammer shaped small bone or ossicle of the middle ear which connects with the incus and is attached to the inner surface of the eardrum
incus
the incus is a small bone or ossicle in the middle ear. It connects the malleus to the stapes.
Stapes
small bone or ossicle in the middle ear which is attached to the incus and oval window; bottom of the stapes on the oval window is called the footplate.
conductive hearing loss
mechanical hearing loss, resulting from blockage in the ear canal, a ruptured eardrum, or restriction of the movement of the tiny bones in the middle ear, which prevents sound vibrations being transferred to the cochlea.
Otosclerosis
a form of conductive hearing loss,
a condition in which there is abnormal growth of bone in the middle ear which can result in hearing loss.
Inner ear
from the oval window to auditory nerve; includes oval window, round window, cochlea, auditory nerve finers, and the semicircular canals of the vestibular system
Cochlea
the coiled and channeled main structure of the inner ear, which contains three fluid filled canals that run along its entire convoluted length; the fluid filled canals are separated by membranes, one of which is the basilar membrane, on which thousands of hair cells are arranged and stimulated by the vibration of the stapes.
Basilar membrane
within the cochlea of the inner ear is a stiff structural element that separates two liquid filled tubes that run along the coil of the cochlea, forming a base for the hair cells to transduce the sound waves in the cochlear fluid to electrochemical signals in the brain
tonotopic organization
each section of the basilar membrane responds to a preferential frequency and the sections are organized from high to low
inner hair cells
the sensory receptors of the auditory system located on the basilar membrane in the cochlea that convert sound waves to nerve signals by having their hair like stereocilia being physically moved by sounds waves in the cochlear fluid
tectorial membrane
moves back and fourth with each cycle of sound, tilting the cilia and allowing electric current into the hair cell
Stereocilia and Kinocilium
stereocilia are projections at the top of the hair cell that are attached to one another by structures which link the tips of one cilium to another
-kinocilium is one larger, more stable cilium to which the stereocilium attach the tips
outer hair cells
hair like cells on basilar membrane that are involved in amplifying sounds and improving frequency selectivity
organ of corti
organ in the inner ear of mammals that contains the hair cells
sensorineural hearing loss
hearing loss caused by damage to the sensory cells and/or nerve fibers of the vestibulocochlear nerve, inner ear, or central processing centers of the brain
cochlear implant
surgically implanted electronic device that provides sense of sound to a person who is profoundly deaf or severely hard of hearing. Most commonly, a cochlear implant is used when the hair cells of the patient are damaged with a genetic abnormally affecting action potentials.
cochlear nucleus
a group of cell bodies in the lower section of the brainstem that receives the input from the auditory nerve fibers coming from the cochlea
superior olive
a small group of cell bodies in the middle section of the brainstem involved in the localization of sound by determining differences in the timing and intensity level of neural responses from each ear for a particular sound
medial superior olive
interaural time difference- the time difference of arrival of sounds between the ears
lateral superior olive
interaural level difference- the difference of the intensity level of sounds between the ears
Inferior colliculus
located just below the visual processing centers known as the superior colliculus. it contains neurons that are tonotopically organized and it likely integrated information regarding sound localization
Medial geniculate nucleus
section of the thalamus that the auditory pathway connects through prior to reaching primary auditory cortex
lateral sulcus
the lateral sulcus is the sulcus that divides the frontal and temporal lobes of the brain
Primary auditory cortex
located within the lateral sulcus
-the main area of cortex which first processes auditory information in the brain, situated on the inferior surface of the lateral sulcus; contains core, belt, and parabelt subdivisions
Superior temporal gyrus
the most superior gyrus in the temporal lobe, situated just below the lateral sulcus, on which is much of auditory cortex
superior temporal sulcus
the most superior sulcus on the temporal lobe, situated just below the superior temporal gyrus
tonotopy
is a cortical map of sound frequency (single tones)
periodotopy
is a cortical map of sound time duration (periodicity)
Cortical deafness
a rare form of sensorineural hearing loss caused by bilateral cortical lesions in the primary auditory cortex located in the temporal lobes of the brain. Patient is unable to hear sounds but has no apparent damage to the anatomy of the ear, which can be thought of as the combination of auditory verbal agnosia and auditory agnosia.
Auditory agnosia
a rare form of agnosia that manifests itself primarily on the inability to recognize or differentiate between sounds. It is not a defect of the ear or hearing but rather a neurological inability of the brain to process sound meaning.
Pure word deafness
the selective inability to comprehend the spoken word, in the absence of aphasia or defective basic hearing. Perception of environmental sounds and other complex, non-speech sounds is generally normal. Pure word deafness is caused by bilateral damage to temporal lobes
non verbal auditory agnosia
selective impairment in nonverbal auditory comprehension, in the absence of verbal comprehension deficits, other aphasias, or defective basic hearing; may arise from lesions in/near Wernicke’s area
Amusia
the selective inability to recognize musical tones or to reproduce them. Amusia can be congenital (at birth) or acquired sometime later in life (from brain damage)
Word meaning deafness
a comprehension deficit specific to the auditory modality; written comprehension is impaired.
