• WANTED: Happy members who like to discuss audio and other topics related to our interest. Desire to learn and share knowledge of science required. There are many reviews of audio hardware and expert members to help answer your questions. Click here to have your audio equipment measured for free!

Ultrasound stimulates the brain differently than ordinary hearing.

Neuro

Member
Joined
May 23, 2019
Messages
63
Likes
87
Location
Sweden
Skärmavbild 2023-04-29 kl. 07.44.44.png

Bone-conducted ultrasounds (BCU) are sensed physiologically differently from normal air-conducted hearing. Bone-conducted ultrasounds do not produce a tonotopic stimulation of neurons in the brain. That is, the nerve cells are not stimulated from low to high frequencies. Other regions appear to be involved. The inner hair cells are involved and the auditory nerve brings the ultrasound signals to the brainstem, but already in the brainstem the BCU follows a different path than audible airborne frequencies.

We can sense ultrasound but not hear ultrasound in the normal sense.
 
Last edited:

charleski

Major Contributor
Joined
Dec 15, 2019
Messages
1,098
Likes
2,239
Location
Manchester UK
Nakagawa and his group have been working on ultrasonic bone-conduction hearing aids for the profoundly deaf for a couple of decades now, and it’s showing some promise.

The important things to note are that this involves very high intensity sound (a threshold 60dB higher than for the audible range), is applied directly to the temporal mastoid, has a very limited dynamic range, and lacks tonotopic mapping. This suggests that BCU perception is probably a consequence of high-intensity ultrasonic disturbance of normal inner hair cell function. Patients with profound IHC loss cannot hear BCU.

Does this mean we should be listening to high-res recordings that preserve ultrasonic content that’s 40dB below the average level of the audible range?
No.
 
OP
Neuro

Neuro

Member
Joined
May 23, 2019
Messages
63
Likes
87
Location
Sweden
There seems to be some kind of distortion product rather than a meaningful sound.
 
Top Bottom