Hearing disorders of the middle ear Tympanic membrane: Perforations Tympanosclerosis: Thickening/Scarring http://www.ent-usa.com/eardrum_and_middle_ear.htm 1 1

http://www.bestforhearing.com/images/normal-ed.jpg http://www.hmc.psu.edu/ume/fcmonline/case32/images/normal-ear.jpg

TM Perforation http://www.ghorayeb.com/files/TYMPANIC_PERFORATION_LEFT_LABELED.jpg

TM Perforation http://texasearcenter.com/userfiles/Image/tmp-1.jpg

In some cases, spontaneous recovery (depends on location) Consequences Mild hearing loss Treatment In some cases, spontaneous recovery (depends on location) Myringoplasty: Surgical reconstruction 5 5

Middle ear cavity Otitis media: Very common (~70% of children in the U.S.) Infection of the mucous membrane lining the middle ear Predisposing factors: Poorly functioning Eustachian tubes Barotrauma Abnormal functioning of mucous membrane cilia Anatomical deformities Gender and demographic factors Exposure to toxic fumes 6 6

TM Retraction http://img.medscape.com/pi/emed/ckb/otolaryngology/834279-858557-860080-860208.jpg

Acute OM http://www.mdconsult.com/das/book/body/161330440-2/0/1608/f4-u1.0-B978-1-4160-2450-7..50641-1..gr3.jpg

Acute OM http://upload.wikimedia.org/wikipedia/commons/5/58/Otitis_media_entdifferenziert2.jpg

Acute OM http://knol.google.com/k/-/-/Y0fzk46N/nxV32A/AOM.jpg

Possible mechanisms Through ruptured tympanic membrane Through Eustachian tube Through blood 11 11

Characteristics of otitis media infection Two types: Acute and chronic Rapidly progressive Negative pressure in middle ear because of ET malfunction TM is retracted and appears red Pain, high temperature, pus accumulates in middle ear mucosa In severe cases, TM ruptures due to pressure. If left untreated, can progress to mastoid air cells and cause mastoiditis. http://www.ent-usa.com/eardrum_and_middle_ear.htm 12 12 12

Consequences Flat conductive hearing loss (degree depends on the amount of fluid) Low static compliance Type B tympanogram Absent reflexes Absent OAEs High latencies for all ABR peaks 13 13 13

Treatment Antibiotics Surgery Myringotomy and suction Mastoidectomy (if infection has spread to mastoid region) Tympanoplasty 14 14 14

PE Tubes http://www.pedisurg.com/PtEducENT/tube_in_TM.jpg

Complications of otitis media Cholesteotoma: Sac-like growth due to presence of skin in the middle ear. Dangerous, progressive, highly erosive Foul-smelling discharge (otorrhea) Treatment: Surgical removal http://www.ent-usa.com/eardrum_and_middle_ear.htm 16 16 16

Cholesteatoma http://chicagoear.com/med_info/images_med_info/cholesteatoma.jpg

Cholesteatoma http://www.earsurgery.org/images/Photo-31%20copy.jpg

Cholesteatoma http://my.clevelandclinic.org/PublishingImages/Head_Neck/cholesteatoma.jpg

Facial palsy If erosion of bone occurs, facial nerve may be exposed. Partial/Full paralysis of one side of the face. Treatment: Surgery

Eustachian tube problems Cause: Infections, allergies, blockage due to overgrown adenoids, structural problems. Consequences: Negative middle ear pressure, retracted TM. Audiometric findings: Mild conductive hearing loss, normal static compliance, type C tympanogram. 21 21

Methods to open ET Valsalva: Close nostrils and cheek and blow out. Toynbee: Close nostrils and swallow Complications of ET malfunction: Serous effusion Mucous otitis media 22 22

Otosclerosis Causes: Hereditary in 70% of cases. Progressive in nature Higher incidence in women, adults. Clinical manifestation: Spongy bone formation over the stapes footplate. Footplate becomes fixed in the oval window. 23 23

Other clinical signs Progressive hearing loss Tinnitus Difficulty hearing while chewing Very vascular promontory, rosy glow through TM (Schwartze sign) Paracusis willisii: Speech easier to understand in the presence of background noise. 24 24

Audiometric findings Low frequency conductive hearing loss with air-bone gap. As disease progresses, hearing loss spreads to high frequencies. Bone conduction is affected, primarily at 2000 Hz (called Carhart’s notch). Type As tympanogram, absent reflexes 25 25

Treatment Earlier: Surgery to free immobilized stapes footplate. Not very successful. Fenestration (new window created in lateral semicircular canal). Effects of fenestration: ~ 25 dB hearing loss to total hearing loss, vertigo, tinnitus, poor word recognition scores, facial paralysis, repeated infections of cavity Stapes mobilization: Middle ear cavity exposed through incision in TM. Effects: Immediate improvement in hearing, however, refixation of stapes often occurred. Most successful treatment: Stapedectomy. Replaced with prosthesis Modification: Stapedotomy 26 26

Inner ear Series of interconnecting canals or ‘labyrinths’ in the temporal bone Two types: Osseous Bony Bigger cross-sectional area Contains fluid called perilymph Membraneous Soft tissue Situated within the bony labyrinth Contains fluid called endolymph http://research.meei.harvard.edu/Otopathology/3dmodels/download.html