Glossary of Terms
A - B - C - D - E - F - G - H - I - J - K - L - M - N - O - P - Q - R - S - T - U - V - W - X - Y - Z - ALL
A-weighting-de-emphasizes low frequencies, analogous to turning the bass all the way down on a stereo system.
Abscess - A swollen area within body tissue containing an accumulation of pus due to infection.
Abduction - the movement of a limb or other part away from the midline of the body, or from another part
Acetylcholine - a compound that occurs throughout the nervous system which functions as a neurotransmitter
Acoustic Admittance (Ya) - the reciprocal of the acoustic impedance or the reciprocal to the opposition to the flow of sound energy
Acoustic Immittance - term used for the analogous concepts when dealing with sound; sound pressure (p) in place of force and volume velocity is replaced with the velocity of sound flow, called volume velocity (U)
Acoustic Impedance Za - opposition to flow of sound energy.
Acoustic Reflex-refers to the reflexive middle ear muscle contraction that occurs in response to high levels of sound stimulation. in humans this is at least principally a stapedius reflex, while the tensor tympani contracts as part of a startle reaction to very intense sounds and also in response to certain kinds of nonacoustic stimulation such as an air jet directed toward the eye.
Acoustic Reflex Arc-the sensory (afferent) pathway proceeds via the auditory nerve to the ventral cochlear nucleus and then to the superior olivary complex on both sides of the brainstem (with crossover to the opposite side by way of the trapezoid body.) The motor (or efferent) pathway is followed bilaterally and runs from the motor nuclei of the facial nerve on both sides and then via the facial nerves to the stapedius muscles. The motor pathway for the tensor tympani activation goes from the trigeminal nerve nuclei to the tensor tympani muscles via the trigeminal nerves. Because contraction of the stapedius and tensor tympani muscles stiffen the middle ear system, the transmission of low frequencies is reduced.
Acoustic Reflex Decay - a measure of how long the response lasts if the stimulus is kept on for a period of time.
Acoustic Reflex Threshold - the lowest stimulus level that produces a reflex response
Action Potentials - all or none electrical discharges of a neuron which are recorded as spikes
Adduction - the movement of a limb or other body part toward the midline of the body, or from another part
Aditus Ad Antrum - Connects the antrum with the attic or upper part of the middle ear cavity
Admittance-the inverse of impedance, the ease at which energy flows through the system, measured in mho or mmho. the more mhos, the greater the ease at which energy flows. mo mho, mo flow.
Agonist - A drug that binds to a neurotransmitter receptor and mimics the action of an endogenous neurotransmitter
Air-bone gap (ABG) - The difference between the air-conduction threshold (AC) and the bone-conduction threshold (BC); AC-BC=ABG
Amnesia - A partial or total loss of memory
Amplitude - Aize or magnitude (peak, peak-to-peak)
Analgesia - The inability to feel pain
Antagonist - A drug that binds to a neurotransmitter receptor and has no effect other than to block the action of endogenous neurotransmitters and other receptor agonists.
Aortic Root
B-weighting - Also de-emphasizes low frequencies but not as much as A-weighting
Bandwidth - The range of frequencies between the lower and upper cutoffs
Basilar membrane - Is a fibrous membrane that runs horizontally from the issues spiral laminar to the spiral ligament. it is narrowest at the base and becomes progressively wider toward the apex.
Benign - not harmful in effect; in particular not malignant
Bone conduction-sound is transmitted via vibrations of the bones of the skull. Bone-conduction can be initiated by air conducted sounds that are intense enough to set the bones of the skull into vibration.
Bradycardia - abnormally slow heart action; typically under 60 bpm.
Bypass
Cauda Equina -
Cerebral Palsy -
C-weighting - barely different from a linear response, sound measurements are expressed in terms of A, B, or C; dBA, dBB, dBC
Central auditory system - aspects of the central nervous system that deal with this neurally encoded message
Claudication
Clonus -
Cochlear amplifier - the characteristics of outer hair cells that constitute an active, micromechanical system that desensitizes, and fine-tunes the responsiveness of the cochlea. in other words, the cochlear amplifier enhances the signal received by inner hair cells so they can be activated by faint sound levels and respond faithfully to narrow frequency ranges. this mechanism accounts for the sensitivity needed to hear soft sounds and the ability to hear fine frequency distinctions. the stria vascularis seems to be the source of metabolic energy for the cochlear amplifier. these active processes also appear to be responsible for the ability of the cochlea to produce sounds called otoacoustic emissions that can be picked up by sensitive microphones in the ear canal.
Cochlear Microphonic - an alternating current receptor potential signal that faithfully represents the stimulus waveform
Cold running speech - real-time communication
Complete
Complex wave-when two or more pure
Compression-the state of positive air pressure
Conductance (G) -the reciprocal to resistance
Conductive Mechanism-sound entering the outer ear is picked up by the tympanic membrane. the vibrations of the eardrum are transmitted to the ossicular chain, which vibrates essentially in the left-right plane. the resulting inward and outward displacements of the oval window are thus transmitted to the cochlear fluid. the conductive mechanism actually modifies sound in several ways that have a direct bearing on how and what we hear.
Conductive system- outer ear and middle ear; brings sound signal from the air to the inner ear
Coronary Artery Disease
Cross-Hearing/Shadow-Hearing - a sound being prevented to one ear is actually being heard by the opposite ear
Cross-links-tiny filaments between the sterocilia.
CSA - EEG
Cycle-one complete replication of a vibratory pattern
Damping-the dying out of vibrations
Diencephalon
Diplegia - (spastic)
Disease
Disphasia
DSA - EEG
Ear canal resonance effect-sounds entering the ear will be enhanced if they are close to the resonant frequency range resulting in a boost in sound pressure level reaching the eardrum.
encephalopathy
Endolymphatic fluid-fills the scala media; has a high concentration of potassium ions; +80-100mV (endocochlear potential)
external auditory meatus (canal)-on average, its ~9mm by 6.5mm wide and roughly 2.5cm-3.5cm long. It is not quite a straight tube but has two curves forming a slight s-like pathway
Epicritic - relating to or denoting those sensory nerve fibers of the skin that are capable of fine discrimination of touch or temperature stimuli. Often contrasted with protopathic.
Epidural - On or around the dura mater; in case of anesthetic introduced into the space around the dura mater of the spinal cord
Epilepsy - A neurological disorder marked by sudden recurrent episodes of sensory disturbance, loss of consciousness, or convulsions, associated with abnormal electrical activity in the brain
Eustachian (auditory) tube -provides for the aeration and drainage of the middle ear system and makes it possible for air pressure to be the same on both sides of the tympanic membrane.
Extension - The action of moving a limb from a bent to a straight position (seizures with sudden rigid extension of the limbs)
Flexion - The action of moving a limb from a straight to a bent position (a soldier at ease moving to the position of attention)
Frequency-cycles per second
Functioning of the sensorineural mechanism - stimulation is transmitted to the cochlear fluids by the in-and-out motions of the stapedial footplate at the oval window at the base of the cochlea. The oval window leads into the upper chamber (scala vestibuli.) Hence, a given inward motion will cause the fluids to be displaced downward, pushing downward on the basilar membrane, and a given outward motion will displace the fluids and basilar membrane upward. The trick is to translate this vibratory stimulation into the bending of the hair cell stereocilia in the right direction, which we already know is necessary to activate the sensory process. In addition, the mechanism for accomplishing this activity must account for our ability to hear different pitches.
Fundamental frequency-the lowest frequency component of a complex periodic wave. the period (or time needed for one complete replication) of a complex periodic wave is the same as the period of its fundamental frequency.
Gait
Gamma-aminobutyric acid - The major inhibitory neurotransmitter in the human brain
Glioma
Glutamate - An amino acid that functions as the major excitatory neurotransmitter in the brain
Hair cells-are activated when their stereocilia are bent towards the basal body, hair cells respond when their stereo cilia are caused to bend toward the lateral wall of the duct or away from the modiolus.
Harmonics-whole number or integral multiples of the fundamental frequency
Head-related transfer function-how the sound reaching the eardrum is affected by the direction of the sound source relative to the head. in other words, the HRTF shows how the spectrum is changed by the acoustical path from the loudspeaker to the tympanic membrane.
Helicotrema-the two outer ducts meet at the far end of the tube at an opening called the helicotrema.
Hertz-frequency is expressed units in cycles per second Hz.
Hypertension
Hyperlipidemia
Hypnosis - The induction of a state of consciousness in which a person apparently loses the power of voluntary action; sleep
Hypothetico-deductive method - educated guessing plus testing; a short list of three to six most likely diagnoses is explored by questioning, examinations and investigations and the list revised until minimum acceptable certainty is achieved.
Immittance - general term to describe how well energy flows through a system
Immobility - the state of not moving; motionless
Impedance - the opposition to energy flow
Inner ear - begins at the oval window and includes the sensory organs of hearing and balance; the cochlea and semi-circular canals
International 10-20 System
Ischemia
Isoelectric
Kinesthesia
Mass (positive) Reactance (X) - opposition to the flow of energy due to mass and is related to inertia
Inner Hair Cells - single row, ~3500 in each ear, flask-shaped, 95% afferent (ascending). (1) the IHC's are innervated by inner radial fibers that continue outside the the organ of corti as type I auditory neurons (2) the OHCs are innervated by outer spiral fibers that continue outside
the organ of corti as type II auditory neurons
Interaural Attentuation - the number of dB that are "lost" in the process of signal crossover
Internal Auditory Meatus - the core of the modiolus itself is hollow and leads to it providing a conduit for the auditory nerve and blood supply to the cochlea.
Intercellular Potential - the electrical potential inside the hair cells and is approximately -40mV in the inner hair cells and -70mV in the outer hair cells
Lesion - a region in an organ or tissue that has suffered damage through injury or disease, such as a wound, ulcer, abscess, tumor, etc.
Malignant - tending to invade normal tissue or to recur after removal; cancerous (contrasted with benign)
Mass Suseptance (Bm) - the reciprocal of mass reactance
Middle Ear - air-filled cavity behind the ear drum also known as the tympanic cavity. the middle ear connects the the pharynx by the
eustachian tube. contains the ossicular chain; incus malleus and stapes
Middle Ear Muscles - pull in more or less opposite directions, they both exert forces that are perpendicular to the normal motion of the ossicles and their contraction has the effect of stiffening the ossicular chain, thereby reducing the energy that is delivered to the inner ear.
octave band filters-a group of filters that allows the SLM to "look at" a certain range of frequencies. The octave-band analyzer separates the overall frequency range into narrower ranges which are each one octave wide
Middle Ear Transformer - the transformer function of the middle ear is accomplished by the combination of three mechanisms: (1) the area ratio advantage to the eardrum to the oval window, (2) the curved membrane buckling effect of the tympanic membrane and (3) the lever action of the ossicular chain.
Modiolus - superstructure of the spiral duct is a bony shelf called the osseus spiral latina that makes a ~2 3/4 turn around a central core; modiolus is the central core
Monosynaptic spinal H-reflex -
Narcotic - A drug that relieves pain and induces drowsiness, stupor, or insensibility; typical term for opioids (make numb)
Negative Feedback - feedback that tends to dampen a process
Neoplasm - any growth that develops inside or on the body.
Neurofibroma - A tumor formed on a nerve cell sheath, frequently symptomless but occasionally malignant.
Neurotransmitter - A chemical that is released by nerve cells and diffuses extracellularly to bind to receptors on nerve cell membranes, thereby mediating intercellular communication of neural signals.
Neurotransmitter receptor - Proteins found in nerve cell membranes that specifically bind neurotransmitters, undergo conformation change, and thereby mediate changes in cell membrane electric potential or initiate various intracellular biochemical processes
Nociceptive - relating to or denoting pain arising from the stimulation of nerve cells
Occlusion Effect - a stronger signal reaches the cochlea when bone-conduction signals are presented with the ears occluded compared with unoccluded, this boost is called the occlusion effect. As a result, occluded bone-conduction thresholds are lower (better) than unoccluded ones and a given bone-conduction signal will sound louder with the ears covered compared with when the ears are open. An occlusion effect occurs when the cartilaginous section of the ear canal is occluded but not when the bony portion is blocked. It is also absent when there is a disorder of the conductive system. The occlusion effect can be used clinically to help determine whether a conductive impairment is present in the form of the Bing test as well as to help determine how much noise is needed for masking during . bone-conduction testing.
Octave Bands - range of frequencies that is an octave wide
Oligodendroglioma -
Olivocochlear Bundle - a series of descending pathways that go from
the superior olivary complex to the cochlea. approximately 1600 efferent neurons from the olivocochlear bundle enter the temporal bone along with the vestibular branch of the eighth nerve.
Organ of Corti - is the sensory organ for hearing and sits in the basilar membrane lateral to the internal spiral sulcus. it is a complex arrangement of sensory hair cells along with various accessory cells and structures.
Ossicular Chain - malleus, incus, stapes. transmits the sound-induced vibrations of the tympanic membrane to the cochlea via the oval window. they are suspended in the middle ear cavity by ligaments and tendons as well as its attachments to the tympanic membrane and the oval window.
Outer Ear - auricle (pinna) and ear canal
Outer Hair Cells - three rows, ~12,000 per ear, tall & skinny, 5%, directly connected to the tectorial membrane, receive neural signals from the olivocochlear bundle and have the capability of motility.
PBmax - patient's optimal performance or what we commonly call the PB-max;normal hearers show a function that reaches its maximum around 25 to 40 dB SL.Individuals with sensorineural hearing loss, however, show a performance function that reaches its maximum at generally less than 100%. They can either show performance that stays at that level as intensity increases, or they can show a curve that reaches its maximum and then decreases in performance as intensity increases. This is known as roll-over.
performance intensity function-plots speech performance in percent correct on the Y-axis, as a function of the level of the speech signal on the X-axis.
Perilymphatic Fluid - two outer ducts, scala tympani and scales vestibuli; high concentration of sodium; 0mV (resting potential)
Peripheral
Period - duration of a cycle
Phase - relationships between two waves that are displaced relative to each other
Phase Angle - theta-angle between the radius and the horizontal
Phase Locking - even though a particular neuron may not discharge very often, when it does fire it will do so in synchrony with a certain phase of the stimulus. The synchronous nature of neural discharges with respect to a certain phase of the signal is called phase locking.
Pillars/Rods of Corti - enclose a triangular space called the tunnel of corti.
Pinna (auricle) - externally visible aspect of the ear, odd-shaped appendage composed mostly of cartilage (except for the ear-lobe)
Pivot Points - conditions or symptoms that have a limited differential diagnosis
Protopathic - relating to or denoting those sensory nerve fibers of the skin that are capable of discriminating only among such relatively coarse stimuli as heat, cold, and pain
Psychedelic - Relating to or denoting drugs that produce hallucinations and apparent expansion of consciousness; a psychedelic drug
Psychoactive Drug - A chemical that in small amounts influences the functioning of the human brain in such a way as to have effects on the psyche or mind
Pure Tones - sounds that are associated with simple harmonic motion
reference value-the softest sound that can be heard by normal people; which has an intensity of 20uPa
Pterionoal
Pure Tone Average (PTA) - is usually calculated for each ear. The PTA, which is simply the mean of the air-conduction thresholds at 500, 1000 and 2000 Hz, is an attempt to summarize the degree of hearing loss. Pure-tone averages up to 15 dB HL are considered to be within the normal limits. The pure tone average was originally based on the 500, 1000 and 2000 Hz thresholds because it often agrees with hearing ability for speech. The PTA is usually compared with a measure of hearing for speech called the Speech Recognition (Reception) Threshold (SRT) and significant differences between the PTA and SRT are of clinical signiicance.
Reference Equivalent Threshold Sound Pressure Levels (RETSPLs) - physical intensities needed by normal people to reach the threshold of hearing.
Resection
Retrocochlear - disorder occurring at the central or neural nerve that causes hearing impairment; "literally backward from the cochlea"
Sebaceous (oil) Glands - contained in the cartilaginous portion and concha. combined with the ceruminous (wax) glands serve as lubricating and anti-microbial functions and help keep the canal free of debris and even some foreign bodies and insects.
Sensorineural Hearing Loss - is indicated by air and bone-conduction thresholds that are equal, or at least very close to one another. sensorineural losses can be caused by a disorder of the cochlea or auditory nerve or both. The combination term sensorineural is used to highlight the fact that we cannot distinuguish between cochlear (sensory) and eighth nerve (neural) disorders from the audiogram.
Sensorineural System - cochlea and eighth cranial nerve, named because it involves the physiological response to the stimulus, activation of the associated nerve cells and the encoding of the sensory response into a neural signal
Shadow Curve - eventually, the tone presented to the deaf ear will be raised so high that it can actually be heard in the opposite ear, at which point the patient will finally respond. The patient's response to the signal directed to a deaf ear is the result of hearing the signal in the other ear. thus the ear's threshold curve is due to cross hearing and is called a shadow curve
Shearing - the stereocilia extend between these two differently hinged membranes and are subjected to a shearing action or shearing force when displacement of the duct causes these two membranes to move relative to each other. The shearing action bends the cilia away from the modiolus when the cochlear duct is displaced upward.
Skull - 8 cranial bones and 14 facial bones
Somatotopy - the point for point correspondence of an area of the body to a specific point on the central nervous system.
Spatial - relating to space, a continuous area or expanse that is free or available; the spatial distribution of population
Speech Frequencies - 500, 1000 and 2000 Hz are typically considered however speech recognition actually depends on a much wider range of frequencies. three frequencies typically don't agree when there is a sloping so a two-frequency pure tone average is often used.
Stenger Effect - a sound presented to both ears is perceived only in the ear where it is louder.
Stenosis - an abnormal narrowing of a passage in the body
Stiffness (compliant) Susceptance (Bs) - reciprocal of stiffness reactance
Stiffness (negative) Reactance (Xs) - related to the restoring force that develops when an elastic element is displaced.
Somatosensory Evoked Potential (SEP) - the recorded electrical activity of the brain resulting from a stimulus of the periphery that is recorded at the scalp from activation of the dorsal column medial lemniscal system
Tactile - of or connected with the sense of touch
Tectorial Membrane - arises from the upper lip of the limbus and forms the overlying membrane of the organ of Corti. it is mainly composed of collagen fibers that give it considerable tensile strength and make it quite compliant.
Temporal - relating to time
Third-Octave - bandes-frequency range that is one third of an octave wide
Traveling Wave Theory - describes how frequency is coded by place in the cochlea. Bekesy found that the basilar membrane is not under any tension but that its elasticity is essentially uniform. Because the basilar membrane gets wider going toward the top, the apex, the result is a gradation of stiffness along is length, going from stiffest at the base (near the stapes) to least stiff at the apex (near the helicotrema). As a result of this stiffness gradient, sounds transmitted to the cochlea develop a special kind of wave pattern on the basilar membrane that always travels from the base up toward the apex, called the traveling wave. the traveling wave involves a displacement pattern that (1) gradually increases in amplitude as it moves up the basilar membrane (2) reaches a peak at a certain location and (decays in amplitude rather quickly just beyond the peak.
Random Noise - has a completely random waveform so it contains all possiblefrequencies at the same average amplitude over the long run; also called white noise
Rarefaction - the state of lower than ambient pressure
Resonant Frequencies - the frequency at which a body or medium vibrates most readily
Seizure - A sudden attack of illness, especially a stroke or an epileptic fit; the patient had a seizure
Simple Harmonic Motion - oscillations that repeat themselves at the same rate over and over again;also known as sinusoidal function
Spiral Ganglia - neural fibers that twist like the fibers of a rope to form the auditory nerve. in general, neurons originating from the apex of the cochlea are arranged toward the core of the nerve trunk and those from the base of the cochlea spiral are closer to the outside.
Stapedius Muscle - smallest muscle in the body and is innervated by the facial nerve.
Sterile - free from bacteria or other living organisms
Stria Vascularis - a rich network of capillaries that maintain the chemical environment of the scala media
Styloid Process - anteroinferior pillar-like projection from the base of the temporal bone that varies widely in size. it does not contribute to the auditory structures but is of interest to us as the origin of several muscles involved in the speech mechanism.
Summating Potential - the other receptor potential which appears as a deviation or shift in the DC (direct current) baseline
Tachycardia - An abnormally rapid heart rate
Tegmen Tympani - the roof of the antrum is composed of this thin bony plate which separates them from part of the brain cavity known as the middle cranial fossa
Third-Octave Band Filters - an even finer level of analysis, each filter is a third of an octave wide.
Threshold - the lowest level at which 50% or at least 50% of the words are correctly repeated; The ASHA-recommended procedure is a descending technique where two spondees are presented at each decrement from the starting level.
Tensor Tympani Muscle - innervated by the trigeminal nerve
Tympanic Antrum - anterosuperior cavity located just behind the middle ear cavity
Vascular - of, relating to, affecting, or consisting of a vessel or vessels, especially those that carry blood; the blood vascular system
White Noise - random noise
Abscess - A swollen area within body tissue containing an accumulation of pus due to infection.
Abduction - the movement of a limb or other part away from the midline of the body, or from another part
Acetylcholine - a compound that occurs throughout the nervous system which functions as a neurotransmitter
Acoustic Admittance (Ya) - the reciprocal of the acoustic impedance or the reciprocal to the opposition to the flow of sound energy
Acoustic Immittance - term used for the analogous concepts when dealing with sound; sound pressure (p) in place of force and volume velocity is replaced with the velocity of sound flow, called volume velocity (U)
Acoustic Impedance Za - opposition to flow of sound energy.
Acoustic Reflex-refers to the reflexive middle ear muscle contraction that occurs in response to high levels of sound stimulation. in humans this is at least principally a stapedius reflex, while the tensor tympani contracts as part of a startle reaction to very intense sounds and also in response to certain kinds of nonacoustic stimulation such as an air jet directed toward the eye.
Acoustic Reflex Arc-the sensory (afferent) pathway proceeds via the auditory nerve to the ventral cochlear nucleus and then to the superior olivary complex on both sides of the brainstem (with crossover to the opposite side by way of the trapezoid body.) The motor (or efferent) pathway is followed bilaterally and runs from the motor nuclei of the facial nerve on both sides and then via the facial nerves to the stapedius muscles. The motor pathway for the tensor tympani activation goes from the trigeminal nerve nuclei to the tensor tympani muscles via the trigeminal nerves. Because contraction of the stapedius and tensor tympani muscles stiffen the middle ear system, the transmission of low frequencies is reduced.
Acoustic Reflex Decay - a measure of how long the response lasts if the stimulus is kept on for a period of time.
Acoustic Reflex Threshold - the lowest stimulus level that produces a reflex response
Action Potentials - all or none electrical discharges of a neuron which are recorded as spikes
Adduction - the movement of a limb or other body part toward the midline of the body, or from another part
Aditus Ad Antrum - Connects the antrum with the attic or upper part of the middle ear cavity
Admittance-the inverse of impedance, the ease at which energy flows through the system, measured in mho or mmho. the more mhos, the greater the ease at which energy flows. mo mho, mo flow.
Agonist - A drug that binds to a neurotransmitter receptor and mimics the action of an endogenous neurotransmitter
Air-bone gap (ABG) - The difference between the air-conduction threshold (AC) and the bone-conduction threshold (BC); AC-BC=ABG
Amnesia - A partial or total loss of memory
Amplitude - Aize or magnitude (peak, peak-to-peak)
Analgesia - The inability to feel pain
Antagonist - A drug that binds to a neurotransmitter receptor and has no effect other than to block the action of endogenous neurotransmitters and other receptor agonists.
Aortic Root
B-weighting - Also de-emphasizes low frequencies but not as much as A-weighting
Bandwidth - The range of frequencies between the lower and upper cutoffs
Basilar membrane - Is a fibrous membrane that runs horizontally from the issues spiral laminar to the spiral ligament. it is narrowest at the base and becomes progressively wider toward the apex.
Benign - not harmful in effect; in particular not malignant
Bone conduction-sound is transmitted via vibrations of the bones of the skull. Bone-conduction can be initiated by air conducted sounds that are intense enough to set the bones of the skull into vibration.
Bradycardia - abnormally slow heart action; typically under 60 bpm.
Bypass
Cauda Equina -
Cerebral Palsy -
C-weighting - barely different from a linear response, sound measurements are expressed in terms of A, B, or C; dBA, dBB, dBC
Central auditory system - aspects of the central nervous system that deal with this neurally encoded message
Claudication
Clonus -
Cochlear amplifier - the characteristics of outer hair cells that constitute an active, micromechanical system that desensitizes, and fine-tunes the responsiveness of the cochlea. in other words, the cochlear amplifier enhances the signal received by inner hair cells so they can be activated by faint sound levels and respond faithfully to narrow frequency ranges. this mechanism accounts for the sensitivity needed to hear soft sounds and the ability to hear fine frequency distinctions. the stria vascularis seems to be the source of metabolic energy for the cochlear amplifier. these active processes also appear to be responsible for the ability of the cochlea to produce sounds called otoacoustic emissions that can be picked up by sensitive microphones in the ear canal.
Cochlear Microphonic - an alternating current receptor potential signal that faithfully represents the stimulus waveform
Cold running speech - real-time communication
Complete
Complex wave-when two or more pure
Compression-the state of positive air pressure
Conductance (G) -the reciprocal to resistance
Conductive Mechanism-sound entering the outer ear is picked up by the tympanic membrane. the vibrations of the eardrum are transmitted to the ossicular chain, which vibrates essentially in the left-right plane. the resulting inward and outward displacements of the oval window are thus transmitted to the cochlear fluid. the conductive mechanism actually modifies sound in several ways that have a direct bearing on how and what we hear.
Conductive system- outer ear and middle ear; brings sound signal from the air to the inner ear
Coronary Artery Disease
Cross-Hearing/Shadow-Hearing - a sound being prevented to one ear is actually being heard by the opposite ear
Cross-links-tiny filaments between the sterocilia.
CSA - EEG
Cycle-one complete replication of a vibratory pattern
Damping-the dying out of vibrations
Diencephalon
Diplegia - (spastic)
Disease
Disphasia
DSA - EEG
Ear canal resonance effect-sounds entering the ear will be enhanced if they are close to the resonant frequency range resulting in a boost in sound pressure level reaching the eardrum.
encephalopathy
Endolymphatic fluid-fills the scala media; has a high concentration of potassium ions; +80-100mV (endocochlear potential)
external auditory meatus (canal)-on average, its ~9mm by 6.5mm wide and roughly 2.5cm-3.5cm long. It is not quite a straight tube but has two curves forming a slight s-like pathway
Epicritic - relating to or denoting those sensory nerve fibers of the skin that are capable of fine discrimination of touch or temperature stimuli. Often contrasted with protopathic.
Epidural - On or around the dura mater; in case of anesthetic introduced into the space around the dura mater of the spinal cord
Epilepsy - A neurological disorder marked by sudden recurrent episodes of sensory disturbance, loss of consciousness, or convulsions, associated with abnormal electrical activity in the brain
Eustachian (auditory) tube -provides for the aeration and drainage of the middle ear system and makes it possible for air pressure to be the same on both sides of the tympanic membrane.
Extension - The action of moving a limb from a bent to a straight position (seizures with sudden rigid extension of the limbs)
Flexion - The action of moving a limb from a straight to a bent position (a soldier at ease moving to the position of attention)
Frequency-cycles per second
Functioning of the sensorineural mechanism - stimulation is transmitted to the cochlear fluids by the in-and-out motions of the stapedial footplate at the oval window at the base of the cochlea. The oval window leads into the upper chamber (scala vestibuli.) Hence, a given inward motion will cause the fluids to be displaced downward, pushing downward on the basilar membrane, and a given outward motion will displace the fluids and basilar membrane upward. The trick is to translate this vibratory stimulation into the bending of the hair cell stereocilia in the right direction, which we already know is necessary to activate the sensory process. In addition, the mechanism for accomplishing this activity must account for our ability to hear different pitches.
Fundamental frequency-the lowest frequency component of a complex periodic wave. the period (or time needed for one complete replication) of a complex periodic wave is the same as the period of its fundamental frequency.
Gait
Gamma-aminobutyric acid - The major inhibitory neurotransmitter in the human brain
Glioma
Glutamate - An amino acid that functions as the major excitatory neurotransmitter in the brain
Hair cells-are activated when their stereocilia are bent towards the basal body, hair cells respond when their stereo cilia are caused to bend toward the lateral wall of the duct or away from the modiolus.
Harmonics-whole number or integral multiples of the fundamental frequency
Head-related transfer function-how the sound reaching the eardrum is affected by the direction of the sound source relative to the head. in other words, the HRTF shows how the spectrum is changed by the acoustical path from the loudspeaker to the tympanic membrane.
Helicotrema-the two outer ducts meet at the far end of the tube at an opening called the helicotrema.
Hertz-frequency is expressed units in cycles per second Hz.
Hypertension
Hyperlipidemia
Hypnosis - The induction of a state of consciousness in which a person apparently loses the power of voluntary action; sleep
Hypothetico-deductive method - educated guessing plus testing; a short list of three to six most likely diagnoses is explored by questioning, examinations and investigations and the list revised until minimum acceptable certainty is achieved.
Immittance - general term to describe how well energy flows through a system
Immobility - the state of not moving; motionless
Impedance - the opposition to energy flow
Inner ear - begins at the oval window and includes the sensory organs of hearing and balance; the cochlea and semi-circular canals
International 10-20 System
Ischemia
Isoelectric
Kinesthesia
Mass (positive) Reactance (X) - opposition to the flow of energy due to mass and is related to inertia
Inner Hair Cells - single row, ~3500 in each ear, flask-shaped, 95% afferent (ascending). (1) the IHC's are innervated by inner radial fibers that continue outside the the organ of corti as type I auditory neurons (2) the OHCs are innervated by outer spiral fibers that continue outside
the organ of corti as type II auditory neurons
Interaural Attentuation - the number of dB that are "lost" in the process of signal crossover
Internal Auditory Meatus - the core of the modiolus itself is hollow and leads to it providing a conduit for the auditory nerve and blood supply to the cochlea.
Intercellular Potential - the electrical potential inside the hair cells and is approximately -40mV in the inner hair cells and -70mV in the outer hair cells
Lesion - a region in an organ or tissue that has suffered damage through injury or disease, such as a wound, ulcer, abscess, tumor, etc.
Malignant - tending to invade normal tissue or to recur after removal; cancerous (contrasted with benign)
Mass Suseptance (Bm) - the reciprocal of mass reactance
Middle Ear - air-filled cavity behind the ear drum also known as the tympanic cavity. the middle ear connects the the pharynx by the
eustachian tube. contains the ossicular chain; incus malleus and stapes
Middle Ear Muscles - pull in more or less opposite directions, they both exert forces that are perpendicular to the normal motion of the ossicles and their contraction has the effect of stiffening the ossicular chain, thereby reducing the energy that is delivered to the inner ear.
octave band filters-a group of filters that allows the SLM to "look at" a certain range of frequencies. The octave-band analyzer separates the overall frequency range into narrower ranges which are each one octave wide
Middle Ear Transformer - the transformer function of the middle ear is accomplished by the combination of three mechanisms: (1) the area ratio advantage to the eardrum to the oval window, (2) the curved membrane buckling effect of the tympanic membrane and (3) the lever action of the ossicular chain.
Modiolus - superstructure of the spiral duct is a bony shelf called the osseus spiral latina that makes a ~2 3/4 turn around a central core; modiolus is the central core
Monosynaptic spinal H-reflex -
Narcotic - A drug that relieves pain and induces drowsiness, stupor, or insensibility; typical term for opioids (make numb)
Negative Feedback - feedback that tends to dampen a process
Neoplasm - any growth that develops inside or on the body.
Neurofibroma - A tumor formed on a nerve cell sheath, frequently symptomless but occasionally malignant.
Neurotransmitter - A chemical that is released by nerve cells and diffuses extracellularly to bind to receptors on nerve cell membranes, thereby mediating intercellular communication of neural signals.
Neurotransmitter receptor - Proteins found in nerve cell membranes that specifically bind neurotransmitters, undergo conformation change, and thereby mediate changes in cell membrane electric potential or initiate various intracellular biochemical processes
Nociceptive - relating to or denoting pain arising from the stimulation of nerve cells
Occlusion Effect - a stronger signal reaches the cochlea when bone-conduction signals are presented with the ears occluded compared with unoccluded, this boost is called the occlusion effect. As a result, occluded bone-conduction thresholds are lower (better) than unoccluded ones and a given bone-conduction signal will sound louder with the ears covered compared with when the ears are open. An occlusion effect occurs when the cartilaginous section of the ear canal is occluded but not when the bony portion is blocked. It is also absent when there is a disorder of the conductive system. The occlusion effect can be used clinically to help determine whether a conductive impairment is present in the form of the Bing test as well as to help determine how much noise is needed for masking during . bone-conduction testing.
Octave Bands - range of frequencies that is an octave wide
Oligodendroglioma -
Olivocochlear Bundle - a series of descending pathways that go from
the superior olivary complex to the cochlea. approximately 1600 efferent neurons from the olivocochlear bundle enter the temporal bone along with the vestibular branch of the eighth nerve.
Organ of Corti - is the sensory organ for hearing and sits in the basilar membrane lateral to the internal spiral sulcus. it is a complex arrangement of sensory hair cells along with various accessory cells and structures.
Ossicular Chain - malleus, incus, stapes. transmits the sound-induced vibrations of the tympanic membrane to the cochlea via the oval window. they are suspended in the middle ear cavity by ligaments and tendons as well as its attachments to the tympanic membrane and the oval window.
Outer Ear - auricle (pinna) and ear canal
Outer Hair Cells - three rows, ~12,000 per ear, tall & skinny, 5%, directly connected to the tectorial membrane, receive neural signals from the olivocochlear bundle and have the capability of motility.
PBmax - patient's optimal performance or what we commonly call the PB-max;normal hearers show a function that reaches its maximum around 25 to 40 dB SL.Individuals with sensorineural hearing loss, however, show a performance function that reaches its maximum at generally less than 100%. They can either show performance that stays at that level as intensity increases, or they can show a curve that reaches its maximum and then decreases in performance as intensity increases. This is known as roll-over.
performance intensity function-plots speech performance in percent correct on the Y-axis, as a function of the level of the speech signal on the X-axis.
Perilymphatic Fluid - two outer ducts, scala tympani and scales vestibuli; high concentration of sodium; 0mV (resting potential)
Peripheral
Period - duration of a cycle
Phase - relationships between two waves that are displaced relative to each other
Phase Angle - theta-angle between the radius and the horizontal
Phase Locking - even though a particular neuron may not discharge very often, when it does fire it will do so in synchrony with a certain phase of the stimulus. The synchronous nature of neural discharges with respect to a certain phase of the signal is called phase locking.
Pillars/Rods of Corti - enclose a triangular space called the tunnel of corti.
Pinna (auricle) - externally visible aspect of the ear, odd-shaped appendage composed mostly of cartilage (except for the ear-lobe)
Pivot Points - conditions or symptoms that have a limited differential diagnosis
Protopathic - relating to or denoting those sensory nerve fibers of the skin that are capable of discriminating only among such relatively coarse stimuli as heat, cold, and pain
Psychedelic - Relating to or denoting drugs that produce hallucinations and apparent expansion of consciousness; a psychedelic drug
Psychoactive Drug - A chemical that in small amounts influences the functioning of the human brain in such a way as to have effects on the psyche or mind
Pure Tones - sounds that are associated with simple harmonic motion
reference value-the softest sound that can be heard by normal people; which has an intensity of 20uPa
Pterionoal
Pure Tone Average (PTA) - is usually calculated for each ear. The PTA, which is simply the mean of the air-conduction thresholds at 500, 1000 and 2000 Hz, is an attempt to summarize the degree of hearing loss. Pure-tone averages up to 15 dB HL are considered to be within the normal limits. The pure tone average was originally based on the 500, 1000 and 2000 Hz thresholds because it often agrees with hearing ability for speech. The PTA is usually compared with a measure of hearing for speech called the Speech Recognition (Reception) Threshold (SRT) and significant differences between the PTA and SRT are of clinical signiicance.
Reference Equivalent Threshold Sound Pressure Levels (RETSPLs) - physical intensities needed by normal people to reach the threshold of hearing.
Resection
Retrocochlear - disorder occurring at the central or neural nerve that causes hearing impairment; "literally backward from the cochlea"
Sebaceous (oil) Glands - contained in the cartilaginous portion and concha. combined with the ceruminous (wax) glands serve as lubricating and anti-microbial functions and help keep the canal free of debris and even some foreign bodies and insects.
Sensorineural Hearing Loss - is indicated by air and bone-conduction thresholds that are equal, or at least very close to one another. sensorineural losses can be caused by a disorder of the cochlea or auditory nerve or both. The combination term sensorineural is used to highlight the fact that we cannot distinuguish between cochlear (sensory) and eighth nerve (neural) disorders from the audiogram.
Sensorineural System - cochlea and eighth cranial nerve, named because it involves the physiological response to the stimulus, activation of the associated nerve cells and the encoding of the sensory response into a neural signal
Shadow Curve - eventually, the tone presented to the deaf ear will be raised so high that it can actually be heard in the opposite ear, at which point the patient will finally respond. The patient's response to the signal directed to a deaf ear is the result of hearing the signal in the other ear. thus the ear's threshold curve is due to cross hearing and is called a shadow curve
Shearing - the stereocilia extend between these two differently hinged membranes and are subjected to a shearing action or shearing force when displacement of the duct causes these two membranes to move relative to each other. The shearing action bends the cilia away from the modiolus when the cochlear duct is displaced upward.
Skull - 8 cranial bones and 14 facial bones
Somatotopy - the point for point correspondence of an area of the body to a specific point on the central nervous system.
Spatial - relating to space, a continuous area or expanse that is free or available; the spatial distribution of population
Speech Frequencies - 500, 1000 and 2000 Hz are typically considered however speech recognition actually depends on a much wider range of frequencies. three frequencies typically don't agree when there is a sloping so a two-frequency pure tone average is often used.
Stenger Effect - a sound presented to both ears is perceived only in the ear where it is louder.
Stenosis - an abnormal narrowing of a passage in the body
Stiffness (compliant) Susceptance (Bs) - reciprocal of stiffness reactance
Stiffness (negative) Reactance (Xs) - related to the restoring force that develops when an elastic element is displaced.
Somatosensory Evoked Potential (SEP) - the recorded electrical activity of the brain resulting from a stimulus of the periphery that is recorded at the scalp from activation of the dorsal column medial lemniscal system
Tactile - of or connected with the sense of touch
Tectorial Membrane - arises from the upper lip of the limbus and forms the overlying membrane of the organ of Corti. it is mainly composed of collagen fibers that give it considerable tensile strength and make it quite compliant.
Temporal - relating to time
Third-Octave - bandes-frequency range that is one third of an octave wide
Traveling Wave Theory - describes how frequency is coded by place in the cochlea. Bekesy found that the basilar membrane is not under any tension but that its elasticity is essentially uniform. Because the basilar membrane gets wider going toward the top, the apex, the result is a gradation of stiffness along is length, going from stiffest at the base (near the stapes) to least stiff at the apex (near the helicotrema). As a result of this stiffness gradient, sounds transmitted to the cochlea develop a special kind of wave pattern on the basilar membrane that always travels from the base up toward the apex, called the traveling wave. the traveling wave involves a displacement pattern that (1) gradually increases in amplitude as it moves up the basilar membrane (2) reaches a peak at a certain location and (decays in amplitude rather quickly just beyond the peak.
Random Noise - has a completely random waveform so it contains all possiblefrequencies at the same average amplitude over the long run; also called white noise
Rarefaction - the state of lower than ambient pressure
Resonant Frequencies - the frequency at which a body or medium vibrates most readily
Seizure - A sudden attack of illness, especially a stroke or an epileptic fit; the patient had a seizure
Simple Harmonic Motion - oscillations that repeat themselves at the same rate over and over again;also known as sinusoidal function
Spiral Ganglia - neural fibers that twist like the fibers of a rope to form the auditory nerve. in general, neurons originating from the apex of the cochlea are arranged toward the core of the nerve trunk and those from the base of the cochlea spiral are closer to the outside.
Stapedius Muscle - smallest muscle in the body and is innervated by the facial nerve.
Sterile - free from bacteria or other living organisms
Stria Vascularis - a rich network of capillaries that maintain the chemical environment of the scala media
Styloid Process - anteroinferior pillar-like projection from the base of the temporal bone that varies widely in size. it does not contribute to the auditory structures but is of interest to us as the origin of several muscles involved in the speech mechanism.
Summating Potential - the other receptor potential which appears as a deviation or shift in the DC (direct current) baseline
Tachycardia - An abnormally rapid heart rate
Tegmen Tympani - the roof of the antrum is composed of this thin bony plate which separates them from part of the brain cavity known as the middle cranial fossa
Third-Octave Band Filters - an even finer level of analysis, each filter is a third of an octave wide.
Threshold - the lowest level at which 50% or at least 50% of the words are correctly repeated; The ASHA-recommended procedure is a descending technique where two spondees are presented at each decrement from the starting level.
Tensor Tympani Muscle - innervated by the trigeminal nerve
Tympanic Antrum - anterosuperior cavity located just behind the middle ear cavity
Vascular - of, relating to, affecting, or consisting of a vessel or vessels, especially those that carry blood; the blood vascular system
White Noise - random noise