Hearing loss does not affect people in the same way. Generally we classify hearing loss into two categories: Conductive & Sensorineural. Naturally, a mix of the two is also possible.
Conductive hearing loss refers to hearing loss due to abnormalities in the physical structure of the middle ear. Such abnormalities impedes the transfer of mechanical sound waves through the middle ear cavity to the inner ear. These may be caused by blockage, such as ear wax buildup, or by physiological disorders. For persons that suffer from this type of hearing loss, simply amplifying the intensity of the sound may significantly help without the loss of comprehension.
Sensorineural hearing loss is due to physiological abnormalities to the inner ear that impede the neuro-signalling pathway. Most commonly this condition refers to the inability of picking up sound ques due to damage or absence of stimulatory inner ear hair cells. This type of hearing loss may also be due to neurological defects that prevent the proper transmission of nerve impulses. Sensorineural hearing loss is much harder to treat than conductive hearing loss and often results in deteriorated sound and speech comprehension.