Physicians perform a pneumatic otoscopy to see how well the eardrum (tympanic membrane) responds to changes in pressure.

The ear is made up of three sections: the outer ear, middle ear and inner ear. The outer ear begins with the visible, exposed part of the ear. It ends inside the head at the eardrum, a circular piece of tissue the size of a fingertip. Behind the eardrum is a space filled with air known as the middle ear. The small eustachian tube connects the middle ear to the back of the nose.

Three tiny bones (the malleus, incus and stapes – more commonly known as the hammer, anvil and stirrup) are collectively called the auditory ossicles. These connect the eardrum through the middle ear and into the inner ear. The inner ear is furthest inside the head and is important for hearing and balance.

The various components of the ear work together to conduct sound. As sound waves enter the ear, they cause the eardrum to move back and forth. This moves the three bones inside the middle ear, sending the sound waves across the middle ear to the inner ear, and finally on to the brain.

Physicians use a pneumatic otoscope when they suspect a patient has recurring ear infections (otitis media) or fluid behind the eardrum (otitis media with effusion). Such ear infections can result from severe nasal allergies (e.g., allergic rhinitis). Allergic reactions can produce mucus in the nasal passages that can flow back into the eustachian tube, creating a blockage. The tube becomes inflamed, which keeps air from passing to the middle ear and prevents fluid from draining away from the middle ear – increasing the risk of infection. A blocked eustachian tube can also cause ear pressure and pain, decreased hearing, ringing in the ears (tinnitus) and dizziness (vertigo).

Pneumatic otoscopy allows the physician to test the patient’s eardrum (tympanic membrane) for abnormalities. As in an exam with a traditional otoscope, the examiner looks through the speculum attached to a handheld device with a light. However, a pneumatic otoscope also allows the exam to be taken a step further.

While studying the eardrum, the physician can squeeze a bulb attached to the pneumatic otoscope. This sends a small puff of air into the ear, allowing the physician to see how well the eardrum moves in response to pressure changes inside the ear.

Poor eardrum response to pressure changes indicates fluid in the middle ear, which prevents the eardrum and middle ear bones from moving properly and causes a corresponding impairment of hearing.