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Flashcards in VESTIBULAR SYSTEM Deck (21)
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1. A 40 year old dentist complains of headaches and inability to control his walking (gait). His physician refers him to a neurologist for further evaluation. The man remembers that 10 years ago he noticed a noise in his right ear that sounded like frying bacon. Neurologic examination reveals the following. Loss of hearing on the right side and tinnitus, vertigo and nausea, wide based ataxic gait with lurching to the right side, dysphagia, facial weakness on the right side, sensory loss over the face on the right side, loss of the corneal reflex on the right side, absent gag reflex, and diplopia. The lesion site responsible for these neurologic deficits is the
A. lateral medulla D. medial pons
B. medial medulla E. cerebellopontine (CP) angle
C. lateral pons

1-E The acoustic neuroma (acoustic schwannoma), which represents 8% of primary intracranial neoplasma, is found in the cerebellopontine (CP) angle. Each of the examination findings is evidence of a particular condition. The loss of hearing on the right side and the tinnitus indicate damage to cochlear nerve, the vertigo and nausea indicate damage to the cestibular nerve, the wide based ataxie gait with lurching to the right indicates damage to the cerebellum, the dysphagia indicates damage to the glossopharyngeal and vagal nerves, the facial weakness on the right side indicates damage to the facial nerve, the sensory loss over the face on the right side indicates damage to the spinal trigeminal tract of CN V, the loss of the corneal reflex on the right side indicates damage to trigeminal (aggerent limb) and to facial (efferent limb) nerves, the absent gag reflex indicates damage to glossopharyngeal (afferent limb) and vagal (efferent limb) nerves, and the diplipia indicates damage to the abducent nerve.
A large tumor can damage the pyramidal tract and the abducent nerve. The differential diagnosis should include other tumors of the CP angle (Schwannoma, Arachnoid, Meningioma, Epidermoid; remember SAME)

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2. Tilting the head forward would maximally stimulate the hair cells in the
A. crista ampullaris of the anterior semicircular duct
B. crista ampullaris of the lateral semicircular duct
C. crista ampullaris of the posterior semicircular duct
D. macula of the utricle
E. macula of the saccule

2-D Tilting the head forward would maximally stimulate the hair cells in the utricle. Tilting the head to the side would maximally stimulate the hair cells in the saccule. The utricle and saccule both respond to linear acceleration and the force of gravity

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3. A comatose patient’s head is elevated 300 from the horizontal. Cold water is injected into the left external auditory meatus. If the brainstem is intact, which one of the following ocular reflexes would you see?
A. Horizontal nystagmus to the left
B. Vertical upper nystagmus
C. Horizontal nystagmus to the right
D. Deviation of the eyes to the left
E. Deviation of the eyes to the right

3-D Nystagmus is not seen in comatose patients. In this case, the patient’s eyes will deviate toward the side of cold water injection

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4. All of the following statements concerning decerebrate rigidity are correct EXCEPT
A. it results from a lesion transecting the brainstem between the superior and inferior colliculi
B. it is considered to be alpha rigidity
C. it is characterized by opisthotonos with arms and legs extended and adducted
D. it can be abolished by dorsal root rhizotomy
E. it can be abolished by section of the vestibular nerve

4-B Classic decerebrate (posturing) rigidity is considered to be gamma rigidity. Alpha rigidity is seen when the anterior cerebellum of a decerebrate preparation is infracted

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5. A patient sitting erect with his head inclined 30 forward is rotated to the right 10 turns in 20 seconds and then is suddenly stopped. All of the following symptoms are experienced EXCEPT
A. the patient would have a vertical nystagmus
B. the fast phase of the nystagmus would be to the right
C. the slow phase of the nystagmus would be to the right
D. the patient would past point to the right
E. the patient would experience a sensation of turning to the left

5-A The sensation of turning experienced by the patient is called vertigo. This type of nystagmus is called postrotational nystagmus. Stimulation of the hair cells of the posterior ducts results in vertical nystagmus.

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6. All of the following statements concerning endolymph are correct EXCEPT
A. it is found in the helicotrema
B. it is found in the utricle
C. it is found in the semicircular ducts
D. it is secreted by the stria vascularis
E. it is absorbed by the endolymphatic sae

6-A The helicotrema is a space at the apec of the cochlea through which the scale vestibule and the scale tympani communicate. The helicotrema contains perilymph

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7. Which of the following statements concerning coloric induced nystagmus is FALSE?
A. Cold water irrigation o the left ear results in nystagmus to the right (fast phase)
B. Cold water irrigation of the left ear results in post pointing to the left
C. Caloric testing permits the evaluation of the individual semicircular ducts
D. Caloric testing is contraindicated in comatose patients
E. Hot water irrigation results in the reverse reactions

7-D One of the advantages of caloric stimulation is that it can be uset safely in all states of consciousness. Caloric testing enables the examiner to evaluate the individual semicircular canals separately. Past pointing and falling are to the side of irrigation. Remember the mnemonic for calorics COWS = Cold, Opposite, Warm, Same

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8. Which of the following statements concerning the semicircular ducts is FALSE?
A. They are three in number D. They are found within the vestibule
B. They contain endolymph E. They comprise the kinetic labyrinth
C. They contain hari cells

8-D The three semicircular (membranous) ducts lie within the three semicircular (osseus) canals of the petrous part of the temporal bone. They contain endolymph and have hair cells within the cristate ampullares. The kinetic labyrinth consist of the semicircular ducts; the static labyrinth consists of the semicircular ducts; the static labyrinth consistes of the utricle and saccule. The vestibule is a central cavity of the inner ear that contains the saccule and the utricle

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9. All of the following statements concerning the hair cells of the vestibular apparatus are correct EXCEPT
A. hair cells contain one kinocilium and many stereocilia (microvilli)
B. hair cells of the semicircular ducts are stimulated by perilymphatic flow
C. hair cells are innervated by bipolar cells found in the internal auditory meatus
D. hair cell are found in the cristae ampullares
E. hair cells are found in the maculae of the saccule and utricle

9-B The hair cells of the vestibular apparatus contain one kinocilium and many stereocilia (microvilli). Hair cells of the semicircular ducts are stimulated by endolymphatic flow (not perilymphatic flow); they are innervated by bipolar cells gound in the fundus of the internal auditory meatus. Hair cells are found in the cristae ampullares and in the maculae of the utricle and saccule

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10. All of the following statements concerning the static labyrinth are correct EXCEPT
A. it responds to linear acceleration
B. it responds to the pull of gravity
C. it lies within the vestibule of the bonylabyrinth
D. it includes the macula of the utricle
E. it is tested clinically by caloric stimulation

10-E The static labyrinth consists of the utricle and saccule, which are found in the vestibule of the bony labyrinth. The hair cells of the maculae of the utricle and saccule respond to linear acceleration and deceleration and gravitational pull. Introduction of warm or cold water into the external auditory meatus stimulates the hair cells of the semicireular ducts (i.e., kinetic labyrinth).

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11. All of the following statements concerning the vestibular ganglion are correct EXCEPT
A. it lies within the bony modiolus
B. it innervates the hari cells of the cristae ampullares
C. it innervates the hair cells of the utricle and saccule
D. it contains bipolar ganglion cells
E. it projects directly to the cerebellar cortex

11-A The vestibular ganglion of Scarpa lies in the fundus of the internal auditory meatus. It contains bipolar neurons that innervate the hair cells of the cristae ampullares and the maculae of the utricle and the sacculus. Bipolar neurons project centrally to the vestibular nuclei of the brainstem and the flocculonodular lobe of the cerebellum. The spiral (cochlear) ganglion of the cochlear nerve lies in the modiolus of the petrosal bone.

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12. All of the following statements concerning the vestibular nuclei are correct EXCEPT
A. they are three in number
B. they receive input from the fastigial nuclei
C. they project to the medial longitudinal fasciculi (MLFs)
D. they project to the nuclei of the extraocular muscles
E. they are found in the medulla and pons

12-A There are four vestibular nuclei; lateral, medial, inferior, and superior. They receive input from the fastigial nuclei via uncinate fasciculus and the juxtarestiform body. Vestibulocerebellar fibers project to the nodulus, flocculus, and uvula but not to the fastigial nucleus. They project via the medial longitudinal fasciculus (MLF) to the ocular motor nuclei (of CN III, CN IV, and CN VI). Vestibular nuclei are found in the medulla and pons

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13. All of the following statements concerning the lateral vestibulospinal tract are correct EXCEPT
A. it arises from the lateral vestibular nucleus
B. it is located in the ventral funiculus of the spinal cord
C. it is found at all spinal cord levels
D. it facilitates extensor muscle tone in antigravity muscles
E. it is a crossed pathway

13-E The lateral vestibulospinal tract arises from the ipsilateral lateral vestibular nucleus of Deiters, located in the lateral pontine tegmentum, and descends to all spinal cord levels in the ventral funiculus. It facilitates extensor muscle tone in the antigravity muscles. It is an uncrossed tract

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14. All of the following statements concerning the medial longitudinal fasciculus (MLF) are correct EXCEPT
A. it is located in the midbrain
B. it is located in the spinal cord
C. it contains vestibule oculomotor fibers
D. it mediates adduction in lateral conjugate gaze on command
E. transaction results in paralysis of convergence

14-E Transection of the medial longitudinal fasciculus (MLF) results in a medial rectus palsy on attempted lateral gaze; convergence remains intact. The MLF extends from the spinal cord to the rostral midbrain; it contains vestibule oculomotor fibers that mediate eye movements in response to head and neek posture. It carries fibers to the medial rectus subnucleus from the pontine lateral conjugate gaze center

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15. All of the following statements concerning vestibular nystagmus are correct EXCEPT
A. it is named after the fast component
B. it has a slow component that is opposite the direction of rotation
C. it may be horizontal, vertical, or rotator
D. it is frequently associated with nausea and vertigo
E. it results in nystagmus to the same side with ice water irrigation of the external auditory meatus

15-E Nystagmus is named after the fast component; the slow component is opposite the direction of rotation, thus maintaining visual fization. Nystagmus may be horizontal, vertical, or rotator and is frequently associated with nausea, vomiting, and vertigo. Irrigation of the external auditory meatus (with the head tilted back 600) with ice water results in nystagmus to the opposite side. Remember the mnemonic COWS = Cold, Opposite, Warm, Same

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16. All of the following statements concerning the primary vestibular correct EXCEPT
A. it receives input from the central posteroinferrior (VPI) nucleus
B. it receives input from the ventral posterolateral (VPL) nucleus
C. it is located in areas 2 and 3
D. it is located in the somesthetic cortex
E. it is located in the paracentral libule

16-E The primary vestibular cortex (areas 2v and 3a) is located in the posteentral gyrus, the somesthetic cortex of the parietal lobe, The vestibular cortex receives input from the ventral posteroinferior (VPI), ventral posterolateral (VPL), and the ventral lateral nuclei of the thalamus. The paracentral lobule is a continuation of the motor and sensory strips onto the medial surface of the hemisphere; it receives no vestibular input.

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A. Meniere disease
B. Benign positional vertigo
C. Acoustic schwannoma
D. Medial longitudinal fasciculus (MLF) syndrome
E. Multiple selerosis

17. Causes the symptoms of cranial nerves (CNs) V, VII, and VIII

17-C The acoustic schwannoma, which is found in the cerebellopotine (CP) angle of the posterior cranial fossa, impinges on CNs V, VII, and VIII. CN C lesions result in loss of pain and temperature sensation on the ipsilateral face and loss of the corneal reflex; CN VII lesions result in a lower motor neuron paralysis of the ipsilaterla muscles of facial expression and loss of the corneal reflex and CN VII lesions result in loss of hearing, nystagmus, tinnitus, nausea, vertigo, and vomiting. (See Chapter 13, Cranial Nerves).

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A. Meniere disease
B. Benign positional vertigo
C. Acoustic schwannoma
D. Medial longitudinal fasciculus (MLF) syndrome
E. Multiple selerosis

18. Is an inner ear disease associated with increased endolymphatic fluid pressure

18-A Meniere disease (labyrinthine vertigo) is the most common cause of true vertigo. It is characterized by abroupt attacks of vertigo, nystagmus, nasea and vomiting, tinnitus, fullness in the ear. And hearing loss. This disease is caused by a distention of the endolymphatic system (labyrinthine hydrops). Drugs used to treat motion sickness may be helpful. Destruction (decompression) of the vestibule and an endolymphatic-subarachnoid shunt have proved useful.

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A. Meniere disease
B. Benign positional vertigo
C. Acoustic schwannoma
D. Medial longitudinal fasciculus (MLF) syndrome
E. Multiple selerosis

19. Is the most common cause of internuclear ophthalmoplegia (INO)

19-E The most common cause of internuclear ophthalmoplegia is multiple sclerosis. Other causes of INo are vascular insults and intraparenchymal tumors (pontine gliomas). Multiple sclerosis, a demyelinating disease of the central nervous system is characterized signs (deafness, vertigo, ataxia, and intention tremor); pyramidal tract signs (spastic paresis with Babinski sign); sensory disturbances (paresthesias or dysesthesias); and bladder and rectal incontinence.

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A. Meniere disease
B. Benign positional vertigo
C. Acoustic schwannoma
D. Medial longitudinal fasciculus (MLF) syndrome
E. Multiple selerosis

20. Results in cuprolithiasis of the posterior semicircular duct

20-B Benign positional vertigo, which is more common than Meniere disease, is characterized by paroxysmal vertigo, oscillopsia, and nystagmus. It occurs as the result of assumption of certain positions of the head (i.e. lying down or rolling over in bed). Such vertigo is due to cuprolithiasis of the posterior semicircular duct – a dislocation of the otoliths that moye freely with movement of the head.
The following procedure is diagnostic. The patient is moved from a sitting to a recumbent position (on an examination table), and the head is tilted 30o down over the edge of the table, then 30o to one side, and then 30o to the other side. The patient has a paroxysm of vertigo (Hallpike maneuver).

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A. Meniere disease
B. Benign positional vertigo
C. Acoustic schwannoma
D. Medial longitudinal fasciculus (MLF) syndrome
E. Multiple selerosis

21. Consists of lateral gaze palsy and monocular nystagmus

21-D Medial longitudinal fasciculus (MLF) syndrome [internuclear ophthalamoplegia (INO)] consists of a medial rectus palsy on attempted lateral gaze. Nystagmus in the abducting eye is evident. (Convergence is intact. This syndrome is seen frequently in multiple sclerosis.