Hot answers tagged

46

Yes, we can. By means of bone conduction we can hear up to 50 kHz, and values up to 150 kHz have been reported in the young (Pumphrey, 1950). However, it is indeed generally agreed that 20 kHz is the upper acoustical hearing limit through air conduction. The reason for this is debated, but the transfer function of the ossicle chain in the middle ear is a ...


31

Hearing declines with age and, typically, high frequencies are affected first. Age-related hearing loss (or presbyacusis (Kujawa & Liberman, 2006)) is progressive and starts at the highest frequencies and as a person ages the lower frequencies are affected. The reduction in hearing sensitivity is caused by the loss of hair cells. Hair cells are sensory ...


20

Devices that bypass the hair cells in the inner ear and directly stimulate the auditory nerve are called cochlear implants. Cochlear implants are used to treat deafness caused by the loss of hair cells in the cochlea. The hair cells are the sensory cells that convert sound vibrations into electric neural signals (Purves et al., 2001). With state-of-the-art ...


16

The Cicada A careful study of the noise-making apparatus of the cicada can be found in a 1994 paper by Young and Bennet-Clark.$^1$ The authors generated sounds at about 0-16 kHz at peaks on the order of 100 dB using cicadas in various stages of deconstruction. The cicada uses a resonant organ-system called the tymbal which buckles and unbuckles rapidly to ...


12

Short answer The exact mechanism behind tinnitus (ringing in the ear) is unknown. Background Of the two theories you pose here, to the best of my knowledge the second one is the most widely accepted. It is a generally accepted phenomenon that whenever neural systems are being deprived of input, they start seeking new input, or even generate it ...


11

Short answer The pressure wave through the scala vestibuli drives the basilar membrane response (BM). Your option (1) is correct, (2) is not. The pressure not really permeates or penetrates Reissner's membrane though; it is the pressure differential across the scala vestibuli and scala tympani that is the driving force for the BM movement. Background The ...


10

I will provide an answer in 2 parts. The first part is a theoretical approach based on the absolute possible minimum (my original answer). The second part focuses on experiments in the peripheral auditory system (added edited answer). PART I: Absolute theoretical minimum (original answer) As you inquire about electrical signals in the auditory human system ...


9

Short answer: That MAY be the sound of the damaged hairs dying. You MAY not hear that frequency again but that's unlikely. Long answer: Okay, so tinnitus, or ringing in the ears, can happen because of many reasons. There are three real kinds: 1) Spontaneous tinnitus can happen because of slight shifts in the acoustic systems of the ears, some of the hairs ...


9

Short answer Yes, we can see with our ears. Background Bach-y-Rita famously stated "We see with our brains, not our eyes". Bach-y-Rita worked for decades on sensory substitution. Sensory substitution approaches in general aim to replace for a lost sense by redirecting information normally captured by that sense to another still functional one. Bach-y-Rita ...


8

Although tinnitus is usually described as a ringing in the ear, there's a whole range of tunes, buzzes, whooshing sounds, humming and hissing sounds that are described of as tinnitus. The sounds can either genuinely be there or be perceived to be there. If it is genuinely there it suggests muscles ate at play or some blood vessel disease if the sounds are in ...


8

If all the processes through which a signal passes are linear, then it makes sense to speak in terms of a maximum useful-content frequency. If a signal passes through non-linear stages, however, it is possible that frequency content which would in and of itself be above the range of hearing, may interact with other frequency content which is also above that ...


8

As @AliceD mentioned, cochlear implant is one of the earliest achievements of neural engineering. However, there are orders of magnitude more inner hair cells (IHC) and even more auditory nerve fibers (AN) in human cochlear than the current cochlear implants offer electrodes. If you are interested in a more detailed model of IHC to AN signal transmission, ...


7

The frequency-selectivity of loudness perception was first shown in the 1930s, when Fletcher and Munson published a set of curves showing the ear's sensitivity to loudness compared to frequency. These equal-loudness curves, as shown in the question above, are now known as Fletcher-Munson equal-loudness contours. One straightforward physical explanation is ...


7

There are a few things which can lead to miscommunication regarding the potency of acoustic weapons, but there are two main things to consider: source levels and duration. Most organisms can tolerate loud sounds, within reason, for a short period of time. However, no matter how short, at certain levels acoustic weapons can cause temporary or permanent ...


6

From what I could gather, there is a decent amount of variability in the ability to detect which direction sound is coming from in unilateral hearing impaired people. It would appear that some people have severely impaired localization skills, akin to someone with an earplug in one ear, but others can use their monaural hearing cues to better locate sound. ...


6

This is a fascinating case of sensory adaptation and neural adaptation. Another example of this would be when you stop smelling something after being exposed to it for long periods of time (as you probably know, this "long period of time" happens to only be a few minutes). A great representation of this happening with the nerves in the skin was done by Georg ...


6

The brain does not "shut down" during sleep. While not everything about sleeping is understood, we do know that certain areas in the brain remain active during sleep. There is a good overview on sleep on the website of the National Institute of Neurological Disorders and Stroke. Until the 1950s, most people thought of sleep as a passive, dormant part of ...


6

The frequency tuning in the cochlea is due to a number of factors. The primary factors of cochlear frequency tuning are generally ascribed to the passive physical characteristics of the basilar membrane (BM), which OP already identified in the question - The BM is wider and more flexible at the apical end (low-frequency region) and narrower and stiffer at ...


6

Are there (apart from those with no sense of hearing at all) any animals that are unable to hear human voices at all? I don't know of any examples off the top of my head, but let's think about this systematically. The voiced speech of a typical adult male will have a fundamental frequency from 85 to 180 Hz, and that of a typical adult female from 165 to ...


5

It's a phenomenon called Frisson. From the wikipedia page. Frisson (French for 'shiver') is a sensation somewhat like shivering, usually caused by stimuli. It is typically expressed as an overwhelming emotional response combined with piloerection (goosebumps). Stimuli that produce a response are specific to the individual. Frisson is of short ...


5

Short answer Sound localization in the vertical plane should not be affected too much, while localization in the horizontal plane is impaired in unilateral deafness. Background The two most important mechanisms used to localize sounds can be grossly divided into localizing sounds in the horizontal (azimuth) and vertical plane (elevation). In the horizontal ...


5

Short answer Perceived tinnitus pitch tends to resemble the frequency content of the loud sound that induced the tinnitus. Background Solid, laboratory-controlled studies to the perceived pitch of temporary, noise-induced tinnitus ("ringing in the ears") are ethically questionable, because researchers have to deliberately expose study subjects to ...


5

+1 for giving a solid answer to @AP, but being older I've had friends who have had tinnitus and I'd like to add some notes to try to flesh this out a bit. I don't think tinnitus is the result of nerve damage usually. Nearly everybody experiences episodic tinnitus at one point or another. When exposed to a loud sound or a blow to the head can cause it. ...


5

Short answer Echolocating bats have relatively large sensory epithelia in their inner ear, that may correlate with their high upper frequency limit of up to 200 kHz. The basilar membrane is thinner and stiffer, possibly allowing it to decode higher frequencies. Background In terms of the place theory of hearing, the cochlea acts as a frequency transformer, ...


5

Interesting hypothesis! - all of those animals you mentioned in fact do have ears, they just don't have external pinnae. You are probably thinking of these external structures when you are thinking of ears. Importantly, pinnae are unique to the mammals, and not even all mammals have them. Since most mammals do not lay eggs, that is probably the joint ...


5

Tympanic displacement measurement (TMD) is a well studied field using hi-tech tools (i.e. stroboscopic holography), and complex units: Vm = volume displacement in nl nanoLiters. μm/pa (UDTF) = Linear tympanic membrane displacement is known as the umbo displacement transfer function. The graph on the left gives you a value of 0.8-0.6 = 0.2 microns: The ...


5

I'm able to create rumbling in my ears at will. Unlike the poster of the video, I don't need to yawn to do so; I can do it without my face appearing to move. I actually discovered this alongside another ability of mine when I was little: the ability to create warmth flowing from the base of my neck outwards into the rest of my body. After some research I ...


5

Short answer Mammalian hearing is unique and amazing. The mammalian ear is unique and highly sensitive with a built in amplification system that means even minute changes in sound can be detected. The bony amplification is also the reason the mammalian (or at least therian) cochlea is huge, every incremental increase yielded markedly more information, it ...


4

Misophonia Misophonia is a relatively unexplored chronic condition in which a person experiences autonomic arousal (analogous to an involuntary “fight-or-flight” response) to certain innocuous or repetitive sounds such as chewing, pen clicking, and lip smacking. Misophonics report anxiety, panic, and rage when exposed to trigger sounds, ...


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