What do different audiograms look like?
Different kinds of hearing loss have differently shaped audiograms. By comparing the air conduction thresholds (O or X) with the bone conduction thresholds ([, Δ, ] or Δ) at each pitch, we can determine if a hearing loss is conductive or sensorineural.
Some examples are given below:
What does an audiogram showing conductive deafness look like?
If the bone conduction levels differ from the air conduction levels, sound waves are probably being obstructed on their passage through the eardrum and middle ear. This audiogram shows a right sided conductive hearing loss, possibly caused by perforation of the eardrum or ‘glue ear’ (congestion behind the eardrum which is common in children).
What does an audiogram showing sensorineural hearing loss look like?
If air and bone conduction are the same, it indicates that the problem is likely to be located in the inner ear. We call this a sensorineural hearing loss. The audiograms below show (a) bilateral mild sensorineural hearing loss and (b) bilateral moderate sensorineural hearing loss.
(a) Bilateral mild sensorineural hearing loss
(b) Bilateral moderate sensorineural hearing loss
Age related hearing loss (presbyacusis)
The audiograms below show bilateral (both ears) age related hearing loss. With age related hearing loss a person can usually hear low-pitched sounds better than high-pitched sounds. Clarity of sound is affected – ‘I can tell that someone is talking but cannot understand what they have said’.
(a) Right sided age related hearing loss (presbyacusis)
(b) Left sided age related hearing loss (presbyacusis)
Hearing loss caused by Ménière’s Disease
Typically, the audiogram of someone with Ménière’s Disease slopes from right to left. Thus, the person with this audiogram will be able to hear high-pitched sounds better than low-pitched sounds in the left ear. The right ear hears perfectly.
So, if you have a moderate sensorineural unilateral hearing loss caused by infectious parotitis don’t panic. It is just the medical way of saying you have nerve deafness in one ear caused by mumps and have problems hearing sounds which are quieter than 41dB.
Please do not be afraid to ask the ENT doctor or audiologist to explain your hearing chart to you.