Transmissive hypoacusis
With damage in the outer ear or in the middle ear, i.e. in those parts of the ear responsible for the mechanical transmission of sound. Subjects affected by this type of hearing loss hear all the low tones, weakened independently to the type of frequency. They have the feeling their ears are plugged and speak softly because they hear them unusually loudly.

Neurosensory hypoacusis
Concerns the inner ear which becomes incapable of transforming the sound vibrations into correct nerve impulses. Subjects affected by this type of hypoacusis hear without understanding: they do not recognize the sounds.

Mixed type hypoacusis
This occurs when the injury affects both the middle ear and the inner ear at the same time. Obviously, with this type of hearing loss the above two types combine.

Central hypoacusis
The center of hearing is located in the brain. Sometimes, the sounds sent by the ear are not correctly interpreted. This is called central deafness.

Whistling
these are all those annoying noises and sounds that a person with this problem says he can hear. They can be more or less associated with hypoacusis. It is not a case of weaker hearing, however it does cause a series of difficulties in understanding words and sounds which are covered by these noises.