The ear consists of the external, middle, and inner ear. The inner ear contains the cochlea, which is spiral-shaped and divided into three fluid-filled sections. Within the cochlea lies the organ of Corti, which transforms sound waves into neural signals. These signals travel through the cochlear nerve and into the brainstem and auditory cortex for processing. Hearing impairment can result from various causes that can be identified on imaging studies, including otitis media, cholesteatoma, fractures of the petrous bone, acoustic neuromas, and more. Treatment options depend on the underlying cause and may include surgery or use of a cochlear implant.

1. HEARING IMPAIRMENT

2. The ear consists of three parts: external , middle and inner ear with each part
performing a certain function in sound transmission and transduction. Pic.
Credit : Wikipedia
Anatomy of the Ear

3. The cochlea has a fascinating architecture being spiral having 2 and
half turns and furtherly divided into sacla tympani, scala vestibuli and
scala media in between having the organ of corti. Pic. credit Gray’s
anatomy
Internal architecture of the cochlea

4. It’s the part of the cochlea responsible for transforming the sound from
its mechanical state into neural impulses. The basilar membrane
oscillate causing the hair cells to brush against the tectorial membrane
and creating an action potential transmitted into the cochlear nerve
bundles. Pic. Credit Wikipedia.
The Organ Of Corti

5. Sagittal T2 WIs MR through mid-lAC shows all four normal nerves:
Arrow ; Facial nerve. Open arrow; Cochlear nerve. Curved arrow; Inferior
vestibular nerve. Superior vestibular nerve not labeled. Pic. Credit
Diagnostic imaging series, head and neck
Contents of internal auditory canal

6. Diagram and MRI image through inferior lAC shows normal inferior
cerebellar peduncle-cochlear nuclei (arrow), cochlear nerve(open
arrow) & inferior vestibular nerve (curved arrow). Pic. Credit
Diagnostic imaging series, head and neck
Vestibulo-cochlear nerve

7. The sound neural impulses is transmitted through the cochlear
nerve and relay into different brain stem centers before reaching
the auditory center. Pic Credit Wikipedia.
The hearing Pathway

8. The final stage of impulse travel is within the auditory cortex A1
lying at the superior temporal lobe and is tonotopic same as the
cochlea then A1 is associated with surrounding 2ry auditory
cortex for further sound processing. Pic. Credit Wikipedia
the Central Auditory cortex A1

9. As a general rule CT and otoscope are
used to evaluate the external and middle
ear while MRI is used to evaluate inner ear
contents
Following are examples of causes of hearing
impairment through imaging

10. Often referred to as swimmer’s or surfer’s ear due to cold water
irritation and causing conductive hearing impairment. CT Pic.
Credit Radiology assistant
Bilateral bony Exostosis of the external
ear

11. Congenital disorder where the external canal is not formed and closed by
bony coverage causing conductive hearing impairment, CT is important to
assess for the middle and inner ear structure to guide the surgical
intervention need. CT Pic. Credit Radiology assistant
Congenital external canal Artesia

12. The ear drum perforation can occur either traumatically, inflammatory or
with middle ear pathology. Normal ear drum appearance by otoscope is
seen above and perforated ear drum is seen below. Pic Credit
entbristol.co.uk
Ear drum perforation

13. Complete opacification of the tympanic cavity and mastoid air cells with
soft tissue in chronic otitis media in coronal CT image causing conductive
hearing impairment. CT Pic. Credit Radiology assistant
Otitis media

14. Congenital or Acquired tumor formed of epithelial cells causing erosion of
the bony ossicles and tympanic cavity leading to conductive hearing
impairment. The lesion is noted on the right side with normal left side. CT
Pic. Credit Radiology assistant
Cholesteatoma

15. Upperpicture shows transverse fracture through the petrous (arrows) causing
cochlear and facial nerve injury and resulting in SNHL. Pic Credit Joel D.
Swartz, Radiographics
Lower picture shows longtudinal fracture through the petrous (yellow arrow)
causing incodo-malleous dislocation (blue arrow) resulting in Conductive HL.
Petrous bone fractures

16. Widening of the vestibular aqueduct is the most common cause of
congenital SNHL. Pic Credit Joel D. Swartz, Radiographics
Vestibular aqueduct syndrome

17. Acoustic schwannoma or neuroma (arrow) is a tumor arising from the
covering sheath of the vestibulo-cochlear nerve causing SNHL, it may be
bilateral in cases of neurofibromatosis type II. CT Pic. Credit Radiology
assistant
Acoustic Shwannoma

18. A case of bilateral otoscelrosis which is a metabolic disease causing
calcification of either the oval window causing conductive HL or the
cochlea itself causing SNHL. CT Pic. Credit Radiology assistant
Otosclerosis

19. A case of MS with plaques noted at the cochlear nuclei bilaterally (arrows)
causing SNHL. Pic Credit Joel D. Swartz, Radiographics
Central hearing affection

20. Right temporal brain tumor in MRI image affecting the A1 cortex and
causing unilateral SNH impairment. Pic. Credit vabrainandspine.com
Central hearing affection

21. Cochlear implant is a device used to fix SNH impairment in the lower
picture is an implant electrode passing through the facial recess to the
scala tympani intra-opratively. Upper Pic. Credit Wikipedia
Cochlear implant