Semester 2 Neuro, Quiz 8 - Auditory And Vestibular Systems
Questions and Answers
- 1.
A 58-year old woman has a paralysis on the right side of her face. She has difficulty in chewing and perceives sounds as annoyingly loud. Physical examination reveals a loss of taste on the anterior 2/3rds of her tongue. The hyperacusis in this case results from involvement of which of the following:
- A.
Auditory nerve
- B.
Nerve to stapedius
- C.
Lesser petrosal nerve
- D.
Chorda tympani nerve
- E.
Greater petrosal nerve
Correct Answer
B. Nerve to stapediusExplanation
The correct answer is "Nerve to stapedius." The patient's symptoms, including paralysis on the right side of her face, difficulty in chewing, and perception of sounds as annoyingly loud, suggest involvement of the facial nerve. The nerve to stapedius is a branch of the facial nerve that innervates the stapedius muscle in the middle ear. Dysfunction of the stapedius muscle can lead to hyperacusis, which is an increased sensitivity to sound. Therefore, the hyperacusis in this case is likely due to involvement of the nerve to stapedius.Rate this question:
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- 2.
A 30-year old conscious woman is brought to the ER following an accident. The caloric test was performed by irrigating the left ear with cold water and then with warm water. The physician concluded that the vestibulo-ocular reflex was present since he observed which eye movements?
- A.
Cold water induced the fast phase of nystagmus to the right side
- B.
Cold water induced the fast phase of nystagmus to the left side
- C.
Warm water induced the fast phase of nystagmus to the right side
- D.
No nystagmus was induced by cold water
- E.
No nystagmus was induced by the warm water
Correct Answer
A. Cold water induced the fast phase of nystagmus to the right sideExplanation
The physician concluded that the vestibulo-ocular reflex was present because the cold water induced the fast phase of nystagmus to the right side. Nystagmus is an involuntary eye movement that occurs in response to stimulation of the vestibular system. In this case, the cold water caused a rapid movement of the eyes towards the right side, indicating that the vestibulo-ocular reflex, which helps maintain visual stability during head movements, was intact.Rate this question:
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- 3.
A 50-year old man was admitted to the hospital complaining of a loss of hearing. The patient also reported unsteadiness in balance. Examination further revealed a facial palsy on the side of the face ipsilateral to the hearing loss. The most likely cause of this disorder is:
- A.
Acoustic neuroma of the cerebellopontine angle
- B.
Tumor in the external ear
- C.
Tumor in the middle ear
- D.
Tumor affecting the midline region of the cerebellum
- E.
Vascular lesion affecting the medial two third of the basilar pons
Correct Answer
A. Acoustic neuroma of the cerebellopontine angleExplanation
The most likely cause of the patient's symptoms is an acoustic neuroma of the cerebellopontine angle. This is suggested by the combination of hearing loss, unsteadiness in balance, and facial palsy on the same side. Acoustic neuromas are benign tumors that commonly arise from the vestibular nerve, which is responsible for balance and hearing. They often cause symptoms such as hearing loss, tinnitus, and vertigo. The location of the tumor in the cerebellopontine angle explains the combination of symptoms experienced by the patient.Rate this question:
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- 4.
A 34-year old man reported episodes of dizziness and vertigo to his physician. Two weeks later he reported hearing loss and a slight tinnitus in his right ear. These symptoms started to get worse with time. A neurological examination revealed no other signs of neurological dysfunction. The most likely site of the lesion/dysfunction in this patient is?
- A.
A lesion of the medial longitudinal fasciculus
- B.
A tumor of the cerebellar vermis
- C.
Damage to the spiral ganglion
- D.
A tumor affecting cranial VIII and VII at the cerebellopontine angle
- E.
Abnormal volume of endolymph in the inner ear
- F.
Tumor in pons compressing lateral lemniscus
Correct Answer
E. Abnormal volume of endolymph in the inner earExplanation
The most likely site of the lesion/dysfunction in this patient is the abnormal volume of endolymph in the inner ear. The patient's symptoms of dizziness, vertigo, hearing loss, and tinnitus are consistent with Ménière's disease, which is characterized by an abnormal buildup of endolymph in the inner ear. This excess fluid disrupts the normal function of the inner ear, leading to the symptoms experienced by the patient. The absence of other signs of neurological dysfunction suggests that the lesion/dysfunction is localized to the inner ear rather than the brain or other parts of the nervous system.Rate this question:
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- 5.
A 52-year old man reported feeling unsteady while walking. History taking revealed that this balance problem developed after a hearing loss associated with the left ear. The patient's muscles of facial expression on the left exhibited marked weakness. In addition, the patient's corneal reflex was absent on the left side. The most likely explanation of these symptoms is?
- A.
Lesion to the medial longitudinal fasciculus
- B.
Vascular occlusion affecting the medial region of the basilar pons
- C.
Acoustic schwannoma of cerebellopontine angle
- D.
Middle ear infection
- E.
Tumor affecting cerebellar vermis
Correct Answer
C. Acoustic schwannoma of cerebellopontine angleExplanation
The most likely explanation for the patient's symptoms is an acoustic schwannoma of the cerebellopontine angle. Acoustic schwannoma, also known as vestibular schwannoma, is a benign tumor that arises from the Schwann cells of the vestibulocochlear nerve (CN VIII). It typically presents with unilateral hearing loss, tinnitus, and balance problems. In this case, the patient's symptoms of balance problems and hearing loss, along with the weakness of facial muscles and absence of the corneal reflex on the affected side, are consistent with the involvement of CN VII (facial nerve) and CN V (trigeminal nerve), which are adjacent to CN VIII in the cerebellopontine angle.Rate this question:
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- 6.
Opening of ion channels in stereocilia results in inner hair cell depolarization. If we were to take the ions responsible for this depolarization of hair cells and add these ions to the extracellular solution surrounding a cerebellar purkinje cell, what would happen to the resting membrane potential of the cerebellar purkinje cell?
- A.
Nothing
- B.
Hyperpolarization
- C.
Depolarization
- D.
Repolarization
Correct Answer
C. DepolarizationExplanation
If the ions responsible for the depolarization of hair cells are added to the extracellular solution surrounding a cerebellar Purkinje cell, it would result in depolarization of the Purkinje cell's resting membrane potential. This is because the opening of ion channels in stereocilia leads to the influx of ions into the hair cells, causing depolarization. Therefore, if these ions are added to the extracellular solution surrounding the Purkinje cell, they would enter the cell and cause depolarization of its resting membrane potential.Rate this question:
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- 7.
Your 82-year old patient is in very good overall health. He does have, however, some deficits in hearing. He cannot hear the full l range of sounds that a young person can normally hear. You explain to him that this loss of hearing is common with aging and that he shouldn't worry about it. The hearing loss he is experiencing is most likely?
- A.
The result of damage to hair cells that respond maximally to low frequency sounds
- B.
The result of damage to hair cells that respond maximally to mid frequency sounds
- C.
The result of damage to hair cells at base of basilar membrane
- D.
The result of damage to hair cells at apex of basilar membrane
Correct Answer
C. The result of damage to hair cells at base of basilar membraneExplanation
The correct answer is the result of damage to hair cells at the base of the basilar membrane. As people age, the hair cells in the inner ear can become damaged or die, leading to a loss of hearing. The hair cells at the base of the basilar membrane are responsible for detecting high frequency sounds, so damage to these cells would result in a loss of the ability to hear high frequency sounds.Rate this question:
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- 8.
What is the main function of the outer hair cells?
- A.
Production of endolymph
- B.
Cochlear amplification
- C.
Production of perilymph
- D.
Emission of sound
- E.
Inhibition of inner hair cells
Correct Answer
B. Cochlear amplificationExplanation
The main function of the outer hair cells is cochlear amplification. Outer hair cells in the cochlea amplify the sound vibrations that enter the ear, making them more sensitive and allowing for better detection of low-intensity sounds. This amplification process helps in enhancing the auditory signals and improving the overall hearing sensitivity.Rate this question:
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- 9.
A 48-year-old woman, with triple cardiac valve prostheses, became completely deaf after a bitemporal embolism. Investigation confirmed intact peripheral and brainstem pathways, and the rare condition of cortical deafness was diagnosed. Which part of both temporal lobes was involved?
- A.
Middle temporal gyrus
- B.
Hippocampus
- C.
Inferior temporal gyrus
- D.
Superior temporal gyrus
- E.
Parahippocampal gyrus
Correct Answer
D. Superior temporal gyrusExplanation
The superior temporal gyrus is involved in processing auditory information and is responsible for hearing. In this case, the patient became completely deaf after a bitemporal embolism, indicating damage to the auditory processing areas in both temporal lobes. This suggests that the superior temporal gyrus, which is responsible for auditory perception, was involved in the injury, leading to cortical deafness.Rate this question:
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- 10.
A 70-year old woman has suffered with hypertension and diabetes mellitus for the past 10 years. She now has presented with vertigo for the past 2 days. MRI showed a lesion in the lateral medulla. A lesion to which of the following structures is most likely responsible for the above symptoms?
- A.
Inferior colliculus
- B.
Dentate nucleus
- C.
Inferior vestibular nucleus
- D.
Superior vestibular nucleus
- E.
Medial geniculate nucleus
Correct Answer
C. Inferior vestibular nucleusExplanation
The most likely explanation for the correct answer is that a lesion in the inferior vestibular nucleus is responsible for the patient's symptoms of vertigo. The inferior vestibular nucleus is involved in the processing of information related to balance and spatial orientation, and a lesion in this area can disrupt these functions, leading to symptoms such as vertigo. Given the patient's history of hypertension and diabetes mellitus, it is possible that vascular damage or ischemia has occurred in the region of the inferior vestibular nucleus, resulting in the observed symptoms.Rate this question:
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Mar 20, 2023Quiz Edited by
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Jan 24, 2012Quiz Created by
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