Disturbances of hearing

Question 1

401. An 89-year-old man has noticed that his hearing has gradually worsened with aging. This has probably developed because of which of the following?
     a. Calcification of ligaments stabilizing the ossicles
     b. Weakness of the tensor tympani
     c. Neuronal degeneration
     d. Weakness of the stapedius muscle
     e. Granulation tissue in the middle ear

Answer 1

c. Neuronal degeneration
Presbycusis is the most common cause of hearing loss in the elderly. High-frequency perception is impaired in this disorder because of sensorineural damage. The neurons most likely affected in this degenerative disorder are the spiral ganglion
neurons of the cochlea.

Question 2

402. A 65-year-old diabetic woman has aphasia secondary to a stroke involving the inferior division of the left middle cerebral artery. Her hearing is intact. Dominant temporal lobe infarction will not produce complete deafness because
     a. There is no temporal lobe representation for hearing
     b. Each cochlear nucleus projects to both temporal lobes
     c. Deafness results with nondominant hemisphere damage
     d. Both thalamic and temporal lobe damage must occur
     e. Both brainstem and temporal lobe damage must occur

Answer 2

b. Each cochlear nucleus projects to both temporal lobes
Hearing in each ear is represented bilaterally even at the level of the brainstem. Lesions rarely produce sufficient damage in the brainstem to cause unilateral deafness unless they are so massive that the patient is unlikely to be responsive to most stimuli
and unlikely to survive. If there is unilateral deafness, the patient should be evaluated to determine whether the hearing loss is conductive or sensorineural.

Question 3

403. A 72-year-old man is having difficulty hearing. He is being tested with a tuning fork. If he has disease of the middle ear, sound transmitted strictly by air conduction will be perceived as
     a. Louder than that transmitted by bone conduction
     b. Quieter than that transmitted by bone conduction
     c. Lower-pitched than that transmitted by bone conduction
     d. Higher-pitched than that transmitted by bone conduction
     e. Oscillating between high and low pitch

Answer 3

b. Quieter than that transmitted by bone conduction
The traditional test for detecting conductive deafness is the Rinne test. The vibrating tuning fork is applied to the mastoid process. When the patient can no longer hear the vibration of the fork, it is taken off the skull and moved to the external auditory meatus. With nerve deafness, acuity may be generally reduced, but perception
with air conduction will be superior to that with bone conduction. This will also be true in normal persons. With conductive hearing loss, the sound waves are transmitted more effectively to the cochlea directly through the bones of the skull than through the air and along the pathway that starts at the external auditory meatus.

Question 4

404. A 13-year-old girl has a severe case of mastoiditis. Despite treatment, she develops a fluent aphasia. Her aphasia is most likely the result of extension of the infection into the
     a. Frontal lobe
     b. Parietal lobe
     c. Temporal lobe
     d. Occipital lobe
     e. Cerebellum

Answer 4

c. Temporal lobe
Mastoiditis may extend either supratentorially into the temporal lobe or infratentorially into the cerebellum. Cerebellar involvement is likely to produce ataxia, vertigo, nausea, vomiting, and morning headache. Temporal lobe extension causes a fluent aphasia by damaging Wernicke’s area in the superior temporal gyrus. The lesion in either the cerebellum or the temporal lobe is usually an abscess formed by bacteria responsible for the mastoiditis. Surgical removal of the
abscess is essential in either location, as progression of the abscess in either the cerebellum or the temporal lobe will be lethal.

Question 5

405. A 19-year-old soldier was very close to an exceptionally loud explosion. If her hearing has been damaged, it is most likely a
     a. High-tone sensorineural loss
     b. Low-tone sensorineural loss
     c. High-tone conductive loss
     d. Low-tone conductive loss
     e. Central deafness

Answer 5

a. High-tone sensorineural loss
The principal site of damage with acoustic trauma is the cochlea. Mechanical trauma may produce a hightone conductive loss by perforating the eardrum. A strictly acoustic insult would not be expected to convey enough energy to the tympanum to disrupt
it, but it may convey enough energy to the cochlea to shear off receptor filaments from hair cells.

Question 6

406. A 79-year-old woman is brushing her teeth when she has an intense sensation that the room is moving as if she were on a ship. Examination
     and testing reveal a cerebellar stroke. Cerebellar damage may be associated
     with severe vertigo if the tissue damaged is in the distribution of the
     a. Superior cerebellar artery
     b. Posterior inferior cerebellar artery (PICA)
     c. Anterior inferior cerebellar artery (AICA)
     d. Anterior spinal artery
     e. Posterior cerebral artery

Answer 6

b. Posterior inferior cerebellar artery (PICA)
The PICA has both medial and lateral branches. The medial branches supply the brainstem. With occlusion of these, vestibular nuclei in the brainstem are infarcted, and vertigo is common. Even with an occlusion limited to the lateral branches,
vertigo is likely. If no brainstem damage occurs, cerebellar flocculonodular lobule injury may induce vertigo.

Question 7

407. A 62-year-old man has started getting a haircut every week. Whenever he lays his head back to have his hair washed, he has the sensation of spinning. With vertigo that develops on extreme extension or rotation of the head, the patient probably has insufficiency in the
     a. Left subclavian artery
     b. Internal carotid arteries bilaterally
     c. Vertebrobasilar system
     d. Internal maxillary artery
     e. Innominate artery

Answer 7

c. Vertebrobasilar system
The vertebral arteries ascend through foramens in the transverse processes of the cervical vertebrae. With bony spurs on the vertebrae or with severe atherosclerotic disease in the vertebral arteries, flow through the vertebrobasilar system may be transiently reduced when the head is extended or rotated. Because vertigo may
be positional without any associated vascular insufficiency, a diagnosis of
vertebrobasilar ischemia should be reached only after other causes, such as cerebellar tumor, have been eliminated.

Question 8

408. Early in the evolution of Ménière’s disease, hearing is lost
     a. Over all frequencies
     b. Primarily over high frequencies
     c. Primarily over middle frequencies
     d. Primarily over low frequencies
     e. In virtually no patients

Answer 8

d. Primarily over low frequencies
Unlike the deficit of presbycusis, lower tones are most susceptible to impaired perception during the initial phases of Ménière’s disease. The severity of the hearing loss typically fluctuates considerably. As fluctuations in the low-tone loss abate, high tones become progressively more involved. The attacks of vertigo associated with Ménière’s disease usually abate as hearing loss in the affected ear peaks.

Question 9

409. A 52-year-old diabetic man on multiple medications develops vertigo.Which of the following medications may cause a toxic labyrinthitis?
     a. Promethazine
     b. Penicillin
     c. Dimenhydrinate
     d. Acetylsalicylic acid
     e. None of the above

Answer 9

d. Acetylsalicylic acid
Salicylates, as well as alcohol, quinine, and aminoglycoside antibiotics, may produce a toxic labyrinthitis with vertigo as a prominent feature. Vertigo is also a common sequela of head trauma or whiplash injury. Promethazine (Phenergan), dimenhydrinate (Dramamine), and meclizine (Antivert) are all commonly used agents to reduce symptoms of vertigo.

Question 10

410. A 50-year-old man is being evaluated for tinnitus. It is worse on some days than others. Which of the following should he be told may exacerbate
the tinnitus?
a. Alcohol
b. Aspirin
c. Glucose
d. Diazepam
e. Steroids

Answer 10

b. Aspirin
Aspirin may produce tinnitus in persons usually unaffected by this problem. Patients on high doses of aspirin for rheumatoid arthritis are especially susceptible to this
drug-induced tinnitus. Those patients with chronic tinnitus from acoustic trauma or Ménière’s disease will find their symptoms worsen with aspirin.

Question 11

411. A 26-year-old man has multiple café au lait spots. Which of the following tumors is most likely to occur in this patient?
     a. Medulloblastoma
     b. Acoustic schwannoma
     c. Neurofibroma
     d. Ependymoma
     e. Meningioma

Answer 11

c. Neurofibroma
Café au lait spots characteristically occur in both type 1 and type 2 neurofibromatosis. Meningiomas, acoustic schwannomas, and other types of CNS tumors occur with these
hereditary disorders, but the neurofibroma is the most common lesion. Type 1 neurofibromatosis develops with a defect on chromosome 17, type 2 with a defect on chromosome 22.

Question 12

412. A 30-year-old woman has progressive hearing loss. An MRI reveals bilateral acoustic schwannomas (neuromas). She most likely has which of the following?
     a. Type 1 neurofibromatosis (von Recklinghausen’s disease)
     b. Type 2 neurofibromatosis
     c. Meningeal carcinomatosis
     d. Multifocal meningiomas
     e. Disseminated ependymomas

Answer 12

b. Type 2 neurofibromatosis
Schwannomas most often occur on the eighth cranial nerve, but they may also develop on the fifth, seventh, ninth, or tenth cranial nerves. With type 2 neurofibromatosis, bilateral tumors are more the rule than the exception. The tumors that develop on the eighth cranial nerve usually develop on the vestibular division of the nerve.

Question 13

413. The olfactory cortex in humans is located in the
     a. Anterior perforated substance
     b. Lateral olfactory gyrus (prepiriform area)
     c. Posterior third of the first temporal gyrus
     d. Angular gyrus
     e. Calcarine cortex

Answer 13

b. Lateral olfactory gyrus (prepiriform area)
The olfactory tract divides into medial and lateral striae. The medial stria sends fibers across the anterior commissure to the opposite hemisphere. The lateral stria terminates in the medial and cortical nuclei of the amygdaloid complex, as well as the
prepiriform area. This primary olfactory cortex is in area 34 of Brodmann and is restricted to a small area on the end of the hippocampal gyrus and the uncus. This distribution of fibers makes olfaction unique among the senses in that it does not send fibers through the thalamus.

Question 14

414. The hypogonadism and anosmia of Kallman syndrome usually attract medical attention during
     a. The newborn period
     b. Infancy
     c. Childhood
     d. Adolescence
     e. Adult life

Answer 14

d. Adolescence
Development of genitalia and secondary sexual characteristics during puberty and adolescence is usually negligible in boys affected by Kallman syndrome. The olfactory defect is congenital but may be unsuspected until the hypogonadism
becomes apparent. The defects responsible for both the anosmia and hypogonadism are developmental rather than acquired. Until the defect in secondary sexual characteristics becomes apparent, the affected person is usually perceived as normal.

Question 15

415. A 22-year-old woman is involved in a head-on motor vehicle accident. She was not wearing a seat belt, and she received a skull fracture when her head hit the windshield. By what mechanism would this patient develop anosmia?
     a. Subarachnoid blood causes pial adhesions on the olfactory nerve
     b. Injury to the temporal tip injuries the olfactory cortex
     c. Torsion on the brainstem injures trigeminal tracts
     d. Shearing forces sever filaments of the receptor cells as they cross the cribriform
     plate
     e. Traction on the chorda tympani damages fibers as they course through the skull

Answer 15

d. Shearing forces sever filaments of the receptor cells as they cross the cribriform
plate
Anosmia is most likely to develop with head trauma if the trauma is sufficient to cause a skull fracture. If anosmia does occur in the setting of a skull fracture, it is likely to be permanent. With head trauma that does not cause a fracture, anosmia will persist
in about 75% of cases.

Question 16

416. A 45-year-old man has noticed over the past 6 months that his sense of smell is not as sensitive as it used to be. On examination he has unilateral anosmia, ipsilateral optic atrophy, and contralateral papilledema. He
most likely has which of the following?
a. Pseudotumor cerebri
b. Multiple sclerosis (MS)
c. Olfactory groove meningioma
d. Craniopharyngioma
e. Nasopharyngeal carcinoma

Answer 16

c. Olfactory groove meningioma
Ipsilateral optic atrophy and contralateral
papilledema in association with an intracranial tumor constitute the Foster-Kennedy syndrome. A meningioma of the olfactory groove may produce this syndrome if it extends posteriorly to involve the ipsilateral optic nerve. Compression on the optic nerve by the tumor produces atrophy and interferes with transmission of the increased intracranial pressure down the optic sheath. The increased intracranial pressure is reflected in the papilledema apparent in the contralateral eye.

Question 17

Choose the condition that best matches the clinical scenario.
a. Ménière’s disease
b. Cholesteatoma
c. Vestibular schwannoma
d. Benign positional vertigo (BPV)
e. Aminoglycoside toxicity
f. Salicylate toxicity
g. Vestibular neuronitis
h. Posttraumatic vertigo
i. Vertebral artery occlusion
j. Bilateral vestibular hypofunction
k. Bell’s palsy
417. A 60-year-old woman complains of feeling dizzy intermittently during the day. Her symptoms are worse when she turns her head to the left, to the point that she tends to keep her head stiff, looking forward. She becomes particularly dizzy when she lies down in bed at night or turns
onto her left side. She occasionally wakes up in the middle of the night feeling dizzy. She had a similar experience 2 years ago, which lasted for 2 weeks and then spontaneously resolved. She has otherwise felt well, and her hearing is normal. On examination, putting her head back and the left ear down elicits a feeling of dizziness and nausea associated with rotatory nystagmus, which lasts for 15 s and then resolves. (SELECT 1 CONDITION)

Answer 17

417. The answer is d.
     Benign positional vertigo commonly affects people in middle age or older. It is characterized by recurrent attacks of rotational vertigo occurring on changes in head position, typically lying down or turning onto the side of the affected ear. The symptoms may persist on standing as well, leaving the patient with a continuous
     sense of disequilibrium. Provocative maneuvers (Nylan-Barany or Hallpike maneuver) are used to confirm that the patient’s complaint is due to a peripheral cause of vestibulopathy rather than a central process affecting the brainstem. In a peripheral vestibulopathy, putting the patient’s head in a position hanging at 45° off the end of the examining table, with the
     head turned to the affected side, will produce rotatory nystagmus with a latency of up to 40 s, a brief duration (generally less than 1 min), and fatigability (a decrease in symptoms and signs with successive maneuvers). The cause of BPV is thought to be related to a calcified piece of otolithic material moving within the posterior semicircular canal. Treatment may include
     vestibular exercises, which entails the patient performing provocative maneuvers at home, or a maneuver designed to free the otolith from the posterior semicircular canal.

Question 18

Choose the condition that best matches the clinical scenario.

a. Ménière’s disease
b. Cholesteatoma
c. Vestibular schwannoma
d. Benign positional vertigo (BPV)
e. Aminoglycoside toxicity
f. Salicylate toxicity
g. Vestibular neuronitis
h. Posttraumatic vertigo
i. Vertebral artery occlusion
j. Bilateral vestibular hypofunction
k. Bell’s palsy
418. A 34-year-old investment banker complains of intermittent episodes of vertigo associated with a feeling of fullness in his right ear. These last for several hours. He has had progressive hearing loss in the right ear. There are no other symptoms. He takes no medications and has no history of head trauma. (SELECT 1 CONDITION)

Answer 18

418. The answer is a.
     Ménière’s disease is characterized
     by repeated brief episodes of fullness in the ear, tinnitus, hearing loss, and severe vertigo. The episodes may last from hours to days. Attacks may be so severe as to cause the patient to fall to the ground due to severe disequilibrium. The cause is generally idiopathic, but is thought to relate to distension of the semicircular canal and an increase in the volume of the endolymphatic fluid. For this reason, the condition has been called endolymphatic
     hydrops. Treatment is generally with salt restriction and diuretics. Surgery with endolymphatic shunts is of unproven value.

Question 19

Choose the condition that best matches the clinical scenario.

a. Ménière’s disease
b. Cholesteatoma
c. Vestibular schwannoma
d. Benign positional vertigo (BPV)
e. Aminoglycoside toxicity
f. Salicylate toxicity
g. Vestibular neuronitis
h. Posttraumatic vertigo
i. Vertebral artery occlusion
j. Bilateral vestibular hypofunction
k. Bell’s palsy
419. A 47-year-old woman with a history of orthotopic heart transplantation 6 months ago has had a complicated postoperative course and was readmitted 3 months ago with pneumonia. She was treated with gentamicin, vancomycin, and clindamycin, as well as her usual regimen of immunosuppressant medications, lipid lowering drugs, and aspirin. Since then, she has had severe but stable disequilibrium, with inability to walk without a cane. There has been no hearing loss or weakness. (SELECT 1 CONDITION)

Answer 19

419. The answer is e. Aminoglycoside antibiotics may cause vestibulopathy and ototoxicity. The vestibular end organ is affected by streptomycin and gentamicin; kanamycin, tobramycin, and neomycin
     tend to have a greater effect on the cochlea. Disequilibrium may progress after exposure. The cause is probably related to the fact that these drugs are concentrated in the endolymphatic fluid, exposing the cochlear hair cells to high levels of the drug. Renal disease may exacerbate the effects of the drugs.

Question 20

Choose the condition that best matches the clinical scenario.

a. Ménière’s disease
b. Cholesteatoma
c. Vestibular schwannoma
d. Benign positional vertigo (BPV)
e. Aminoglycoside toxicity
f. Salicylate toxicity
g. Vestibular neuronitis
h. Posttraumatic vertigo
i. Vertebral artery occlusion
j. Bilateral vestibular hypofunction
k. Bell’s palsy
420. A 72-year-old man awakens with severe vertigo associated with nausea and vomiting. He is ataxic. Over the next several days, he develops numbness of the left side of his body, dysphagia, and hiccups. On examination he has a left homonymous hemianopsia, left-sided sensory loss, dysmetria with the right hand, and no weakness. He has had intermittent episodes of dizziness for the past month. (SELECT 1 CONDITION)

Answer 20

420. The answer is i. This patient has a history of progressive vertigo, ataxia, sensory loss, dysphagia, and hiccups, all symptoms of the lateral medullary syndrome, usually due to distal vertebral
     artery occlusion. This patient’s hemianopsia reflects the probable occurrence of occipital lobe infarction, perhaps related to embolism from the
     occluded vertebral artery. This could have occurred at the time of the lateral medullary stroke or at an independent time. The preceding history of dizzy episodes is indicative of the importance of a thorough evaluation for the cause of dizziness in the elderly patient, particularly when other symptoms occur as well.