|
Frequency Following Response
The frequency following response (FFR), also referred to as frequency following potential (FFP) or envelope following response (EFR), is an evoked potential generated by periodic or nearly-periodic auditory stimuli.Burkard, R., Don, M., & Eggermont, J. J. Auditory evoked potentials: Basic principles and clinical application. Philadelphia: Lippincott Williams & Wilkins. Part of the auditory brainstem response (ABR), the FFR reflects sustained neural activity integrated over a population of neural elements: "the brainstem response...can be divided into transient and sustained portions, namely the onset response and the frequency-following response (FFR)". It is often phase-locked to the individual cycles of the stimulus waveform and/or the envelope of the periodic stimuli. It has not been well studied with respect to its clinical utility, although it can be used as part of a test battery for helping to diagnose auditory neuropathy. This may be in conjunction with, or as a replacement ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Evoked Potential
An evoked potential or evoked response is an electrical potential in a specific pattern recorded from a specific part of the nervous system, especially the brain, of a human or other animals following presentation of a Stimulus (physiology), stimulus such as a light flash or a pure tone. Different types of potentials result from stimuli of different Stimulus modality, modalities and types. Evoked potential is distinct from spontaneous potentials as detected by electroencephalography (EEG), electromyography (EMG), or other electrophysiology, electrophysiologic recording method. Such potentials are useful for electrodiagnostic medicine, electrodiagnosis and monitoring (medicine), monitoring that include detections of disease and drug-related sensory dysfunction and intraoperative monitoring of sensory pathway integrity. Evoked potential amplitudes tend to be low, ranging from less than a microvolt to several microvolts, compared to tens of microvolts for EEG, millivolts for EMG, and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Periodic Function
A periodic function is a function that repeats its values at regular intervals. For example, the trigonometric functions, which repeat at intervals of 2\pi radians, are periodic functions. Periodic functions are used throughout science to describe oscillations, waves, and other phenomena that exhibit periodicity. Any function that is not periodic is called aperiodic. Definition A function is said to be periodic if, for some nonzero constant , it is the case that :f(x+P) = f(x) for all values of in the domain. A nonzero constant for which this is the case is called a period of the function. If there exists a least positive constant with this property, it is called the fundamental period (also primitive period, basic period, or prime period.) Often, "the" period of a function is used to mean its fundamental period. A function with period will repeat on intervals of length , and these intervals are sometimes also referred to as periods of the function. Geometrically, a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Auditory Brainstem Response
The auditory brainstem response (ABR), also called brainstem evoked response audiometry (BERA), is an auditory evoked potential extracted from ongoing electrical activity in the brain and recorded via electrodes placed on the scalp. The measured recording is a series of six to seven vertex positive waves of which I through V are evaluated. These waves, labeled with Roman numerals in ''Jewett'' and ''Williston'' convention, occur in the first 10 milliseconds after onset of an auditory stimulus. The ABR is considered an ''exogenous response'' because it is dependent upon external factors. The auditory structures that generate the auditory brainstem response are believed to be as follows: *Wave I through III – generated by the auditory branch of cranial nerve VIII and lower *Wave IV and V – generated by the upper brainstem *More in depth location – wave I and II originates from the distal and proximal auditory nerve fibers, wave III from the cochlear nucleus, IV showing acti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Auditory Neuropathy
Auditory neuropathy (AN) is a hearing disorder in which the outer hair cells of the cochlea are present and functional, but sound information is not transmitted sufficiently by the auditory nerve to the brain. Hearing loss with AN can range from normal hearing sensitivity to profound hearing loss. A neuropathy usually refers to a disease of the peripheral nerve or nerves, but the auditory nerve itself is not always affected in auditory neuropathy spectrum disorders. Prevalence in the population is relatively unknown. Neonates with high risk factors for hearing loss have a prevalence of up to 40% (Vignesh, Jaya, & Muraleedharan 2016). These high-risk factors are: hypoxia, low birth weight, premature birth, hyperbilirubinemia, jaundice, and aminoglycoside antibiotic treatments (NIDCD, 2018). Possible sites of lesion Based on clinical testing of subjects with auditory neuropathy, the disruption in the stream of sound information has been localized to one or more of three probable l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Otoacoustic Emissions
An otoacoustic emission (OAE) is a sound that is generated from within the inner ear. Having been predicted by Austrian astrophysicist Thomas Gold in 1948, its existence was first demonstrated experimentally by British physicist David Kemp (physicist), David Kemp in 1978, and otoacoustic emissions have since been 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 occur without external stimulation, and evoked otoacoustic emissions (EOAEs), which require an evoking Stimulus (physiology), stimulus. Mechanism of occurrence OAEs are considered to be related to the amplification function of the cochlea. In the absence of external stimulation, the activity of the coc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cochlear Nerve
The cochlear nerve (also auditory nerve or acoustic nerve) is one of two parts of the vestibulocochlear nerve, a cranial nerve present in amniotes, the other part being the vestibular nerve. The cochlear nerve carries auditory sensory information from the cochlea of the inner ear directly to the brain. The other portion of the vestibulocochlear nerve is the vestibular nerve, which carries spatial orientation information to the brain from the semicircular canals, also known as semicircular ducts. Anatomy and connections In terms of anatomy, an auditory nerve fiber is either bipolar or unipolar, with its distal projection being called the peripheral process, and its proximal projection being called the axon; these two projections are also known as the "peripheral axon" and the "central axon", respectively. The peripheral process is sometimes referred to as a dendrite, although that term is somewhat inaccurate. Unlike the typical dendrite, the peripheral process generates and cond ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hair Cell
Hair cells are the sensory receptors of both the auditory system and the vestibular system in the ears of all vertebrates, and in the lateral line organ of fishes. 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. The stereocilia number from 50-100 in each cell while being tightly packed together and decrease in size the further away they are located from the kinocilium. The hair bundles are arranged as stiff columns that move at their base in response to stimuli applied to the tips. 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electrocochleography
Electrocochleography (abbreviated ECochG or ECOG) is a technique of recording electrical potentials generated in the inner ear and auditory nerve in response to sound stimulation, using an electrode placed in the ear canal or tympanic membrane. The test is performed by an otologist or audiologist with specialized training, and is used for detection of elevated inner ear pressure (endolymphatic hydrops) or for the testing and monitoring of inner ear and auditory nerve function during surgery. Clinical applications The most common clinical applications of electrocochleography include: * Objective identification and monitoring of Ménière's disease and endolymphatic hydrops (EH) * Intraoperative monitoring of auditory system function during surgery on the brainstem or cerebellum * Enhancement of Wave I of the auditory brainstem response, particularly in patients who are hard of hearing * Diagnosis of auditory neuropathy Cochlear physiology The basilar membrane and the hair cell ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Otoacoustic Emission
An otoacoustic emission (OAE) is a sound that is generated from within the inner ear. Having been predicted by Austrian astrophysicist Thomas Gold in 1948, its existence was first demonstrated experimentally by British physicist David Kemp in 1978, and otoacoustic emissions have since been 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 occur without external stimulation, and evoked otoacoustic emissions (EOAEs), which require an evoking stimulus. Mechanism of occurrence OAEs are considered to be related to the amplification function of the cochlea. In the absence of external stimulation, the activity of the cochlear amplifier increases, leading to the prod ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cochlear Implant
A cochlear implant (CI) is a surgically implanted neuroprosthesis that provides a person who has moderate-to-profound sensorineural hearing loss with sound perception. With the help of therapy, cochlear implants may allow for improved speech understanding in both quiet and noisy environments. A CI bypasses acoustic hearing by direct electrical stimulation of the auditory nerve. Through everyday listening and auditory training, cochlear implants allow both children and adults to learn to interpret those signals as speech and sound. The implant has two main components. The outside component is generally worn behind the ear, but could also be attached to clothing, for example, in young children. This component, the sound processor, contains microphones, electronics that include digital signal processor (DSP) chips, battery, and a coil that transmits a signal to the implant across the skin. The inside component, the actual implant, has a coil to receive signals, electronics, and an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hearing
Hearing, or auditory perception, is the ability to perceive sounds In physics, sound is a vibration that propagates as an acoustic wave, through a transmission medium such as a gas, liquid or solid. In human physiology and psychology, sound is the ''reception'' of such waves and their ''perception'' by the ... through an organ, such as an ear, by detecting Vibration, vibrations as periodic changes in the pressure of a surrounding medium. The academic field concerned with hearing is auditory science. Sound may be heard through solid, liquid, or gaseous matter. It is one of the traditional five senses. Partial or total inability to hear is called hearing loss. In humans and other vertebrates, hearing is performed primarily by the auditory system: mechanical waves, known as vibrations, are detected by the ear and transduction (physiology), transduced into nerve impulses that are perceived by the brain (primarily in the temporal lobe). Like touch, audition requires sen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Otology
Otology is a branch of medicine which studies normal and pathological anatomy and physiology of the ear (hearing and vestibular sensory systems and related structures and functions) as well as their diseases, diagnosis and treatment. Otologic surgery generally refers to surgery of the middle ear and mastoid related to chronic otitis media, such as tympanoplasty, or ear drum surgery, ossiculoplasty, or surgery of the hearing bones, and mastoidectomy. Otology also includes surgical treatment of conductive hearing loss, such as stapedectomy surgery for otosclerosis. Neurotology, a related field of medicine and subspecialty of otolaryngology, is the study of diseases of the inner ear, which can lead to hearing and balance disorders. Neurotologic surgery generally refers to surgery of the inner ear or surgery that involves entering the inner ear with risk to the hearing and balance organs, including labyrinthectomy, cochlear implant surgery, and surgery for tumors of the temporal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
