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Flashcards in Brainstem & cerebellum Deck (89):
1

Pseudobulbar affect

Uncontrollable bouts of laughter or crying without feeling the usual associated emotions caused by abnormal reflex activation of laughter & crying in the brainstem

1

Lesions of the optic nerve result in

Monocular visual loss or monocular scotomas; can be partial

2

Hypertropia

Abnormal vertical deviation of one eye

2

What are the most common causes of acute ataxia in children?

Accidental drug ingestion, varicella-associated cerebellitis, migraine

3

One-and-a-half syndrome

Ipsilateral internuclear ophthalmoplegia plus ipsilateral lateral gaze palsy (only mvmt unaffected is CL lateral rectus) Caused by lesions to the MLF + adjacent abducens nucleus OR MLF + PPRF

3

How is the trigeminal nerve examined?

Light touch, pain by pinbrick, hot/cold, corneal reflex, jaw reflex, jaw movements

3

What are the most common causes of chronic ataxia in adults?

Brain metastases, chronic toxin exposure, MS, degenerative disorders

4

Bulbar palsy

Dysarthria, dysphagia, & hypoactive jaw/gag reflex not associated with cognitive changes (pseudo is)

5

Ptosis

Drooping of eyelid

5

Infarcts that involve both the lateral brainstem & the cerebellum are most likely in what vascular territories?

PICA & AICA

6

A complete lesion of the cavernous sinus results in

Total ophthalmoplegia + fixed, dilated pupil

7

Brainstem controlling centers for vertical eye mvmts are located in the

Rostral midbrain reticular formation & pretectal area

7

Middle cerebellar peduncle

Brachium pons; connects to pons; carries mainly inputs

7

What is the function of the lateral cerebellar hemispheres?

Motor planning for extremities

7

Where do cerebellar output pathways cross?

1) as they exit in decussation of superior cerebellar peduncle 2) as corticospinal & rubrospinal tracts descend to spinal cord

8

CN X

Vagus; parasympathetics to heart, lungs, digestive tract; pharyngeal & laryngeal muscles; taste from epiglottis & pharynx

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Ataxia-hemiparesis

Syndrome in which patients have a combo of unilateral UMN signs & ataxia, usually affecting the same side; often caused by lacunar infarcts, most often in corona radiata, IC, or pons

9

UMN vs LMN lesions of CN VII (facial)

UMN - spares forehead; LMN - affects entire half of face

10

Appendicular apraxia

Ataxia on movement of the extremities; caused by lesions of the intermediate & lateral portions of the cerebellar hemisphere, which affects the lateral motor systems

11

Function of the caudal reticular formation

Maintains important motor, reflex, & autonomic functions

12

The superior cerebellar artery supplies what structures?

Upper lateral pons, superior cerebellar peduncle, most of superior half of cerebellar hemispheres

13

Horner's syndrome

Ptosis, miosis, anhidrosis Caused by loss of sympathetic innervation

13

Benign anisocoria

Slight pupillary asymmetry in 20% of the general population

13

The posterior inferior cerebellar artery supplies what structures?

Lateral medulla, most of inferior half of cerebellum, inferior vermis

14

The anterior inferior cerebellar artery supplies what structures?

inferior lateral pons, middle cerebellar peduncle, strip of ventral cerebellum

15

Paramedian pontine reticular formation (PPRF)

Important horizontal gaze center that provides input from cortex & other pathways to abducens nucleus

15

Parinaud's syndrome

Impairment of vertical gaze, large & irregular pupils w/ light-near dissociation, eyelid abnormalities, impaired convergence

16

Smooth pursuit

Slower eye mvmts, not under voluntary control, allow stable viewing of moving objects

17

Common causes of internuclear ophthalmoplegia

MS plaques, pontine infarcts, MLF neoplasms

18

What is the most commonly injury cranial nerve in head trauma?

Trochlear

19

CN XI

Accessory; innervates the sternomastoid & upper part of trapezius muscle

21

Esotropia

Abnormal medial deviation of one eye

21

CN XII

Hypoglossal; innervates intrinsic muscles of the tongue

22

CN IX

Glossopharyngeal; motor to salivary glands & muscles of pharynx; sensory from posterior 1/3 of tongue, pharynx, middle ear

23

Locked-in syndrome

Large pointine lesions disrupt bilateral corticospinal tracts & abducens nuclei, eliminating body mvmts & horizontal eye mvmts

23

CN VIII

Vestibulocochlear; hearing & vestibular sensation

25

Oculomotor palsy

Paralysis of all extraocular muscles except lateral rectus & superior oblique (eye is "down and out"), upper lid is closed, pupil is dilated & unresponsive to light

26

Ataxia

Disordered contractions of agonist & antagonist muscles, lack of normal coordination between movements at different joints seen with cerebellar dysfunction

27

Trigeminal neuralgia (tic douloureux)

Recurrent episodes of brief pain in the distribution of the trigeminal nerve

28

What is the function of the cerebellar vermis & flocculonodular lobe?

Proximal limb & trunk coordination, balance & vestibulo-ocular reflexes

29

What are the most common causes of chronic ataxia in children?

Cerebellar astrocytoma, medulloblastoma, Friedreich's ataxia, ataxia-telangiectasia

31

Lesions to the PPRF lead to

Ipsilateral lateral gaze palsy

33

Marcus Gunn pupil

Afferent pupillary defect; the direct response to light in the affected eye is decreased/absent while consensual response of the affected eye to light in the opposite eye is normal Caused by decreased sensitivity to light secondary to lesions of optic nerve, retina, or eye

35

Accommodation response

Occurs when a visual object moves from far to near, involves pupillary constriction, accommodation of the lens ciliary muscle, and convergence of the eyes

36

Argyll Robertson pupil

Light-near dissociation (pupil accommodates but doesn't react to light) plus small & irregular pupils; associated with neurosyphilis

37

Bilateral acoustic neuromas are associated with

Neurofibromatosis Type 2

37

Pseudobulbar palsy

Used to describe dysarthria & dysphagia caused by UMN lesions in corticobulbar pathways (e.g., frontal lobe) not the brainstem; is associated with cognitive changes

37

Pupillary effects of opiate use

B pinpoint pupils

39

True vertigo

Spinning sensation of mvmt that is caused by lesions anywhere in the vestibular pathways

40

Friedrich's ataxia

Hereditary (excessive trinucleotide repeats), progressive gait ataxia Speech may be affected, but cognition intact; emotional lability may be present

41

Right-way eyes

Cerebral hemisphere lesions normally impair eye mvmts in the CL direction, resulting in gaze preference toward sign of lesion, way from side of weakness

42

Symptoms of vagus nerve damage

Hoarseness, poor swallowing, loss of gag reflex

43

Exotropia

Abnormal lateral deviation of one eye

44

Medial longitudinal fasciculus (MLF)

Interconnects III, IV, VI, X nuclei

45

Pupillary effects of barbiturate overdose

B small pupils

47

Caloric test

Test of vestibulocochlear function that involves irrigating the ear

48

Which cranial nerves are located in the pons?

5-8

50

Effects of damage to the abducens nerve versus the abducens nucleus

Nerve - impaired abduction of IL eye Nuclei - IL gaze palsy in both eyes

51

Inferior cerebellar peduncle

Restiform body; connects to medulla; carries mainly inputs

53

Early symptoms of acoustic neuroma

Hearing loss, tinnitus, unsteadiness

55

Divisions of the trigeminal nerve

Ophthalmic, maxillary, mandibular

56

Trochlear palsy

Causes vertical dipolopia & hypertropia (eye is up & in)

57

Supranuclear pathways

Involve brainstem & forebrain circuits that control eye mvmts through connections with CN III, IV, & VI

59

Which cranial nerves are located in the medulla?

9-12

61

CN V

Trigeminal; general sensation for face, mouth, anterior 2/3rds of tongue; muscles of mastication & tensor tympani muscle

62

CN VII

Facial; motor for facial muscles, most salivation, anterior 2/3 tongue taste

63

What is the typical presentation of a cerebellar stroke?

Vertigo, nausea & vomiting, horizontal nystagmus, limb ataxia, unsteady gait, HA

64

What is the function of the intermediate cerebellar hemispheres?

Distal limb coordination

65

Ciliary muscle

Adjusts thickness of lens in response to viewing distance

66

What are the most common causes of acute ataxia in adults?

toxin ingestion, ischemic or hemorrhagic stroke

68

Function of the rostral reticular formation

Maintains alert conscious state in brain

69

Nuclear & infranuclear pathways

Involve brainstem nuclei of III, IV, & VI; the peripheral nerves arising from these nuclei, & the eye mvmt muscles

70

Damage to glossopharyngeal nerve leads to

spasms of pain in posterior pharynx

72

Pupillary effects of anticholinergic agents

Dilated pupils

73

Wrong-way eyes

Eyes look toward side of weakness; possible causes include seizure activity, large lesions such as thalamic hemorrhage, lesions of pontine basis & tegmentum

75

CN III

Oculomotor; innervates all extraocular muscles, except superior oblique & lateral rectus; also controls pupillary constriction & accommodation reflex

76

Internuclear ophthalmoplegia

Eye ipsilateral to lesion does not fully adduct on attempted horizontal gaze, nystagmus in opposite eye

77

CN VI

Abducens; innervates lateral rectus muscle, causes abduction of eye (turns eye out)

78

Sensory ataxia

Occurs when posterior column-medial lemniscus pathway is disrupted, resulting in loss of joint position sense

79

UMN vs LMN damage to CN XII (Hypoglossal)

UMN = CL tongue weakness LMN = IL tongue weakness

80

Herpes zoster causes sensory loss in the distribution of what cranial nerve?

V - trigeminal

82

Saccades

Rapid eye mvmts that bring target of interest into field of view

83

Conductive vs. sensorineural hearing loss

Conductive = abnormalities of external auditory canal or middle ear Sensorineural = disorders of cochlea or 8th nerve

84

Superior cerebellar peduncle

Brachium conjunctivum; connects to midbrain; carries mainly outputs

85

CN IV

Trochlear; innervates superior oblique muscle, causes depression & intorsion of eye

86

Common causes of oculomotor palsy

Diabetic neuropathy, head trauma, intracranial aneurysms, tentorial herniation, ophthalmoplegic migraine in children

87

Truncal ataxia

Wide-based, unsteady "drunklike" gait; caused by lesions in the vermis, which primarily affect the medial motor systems

88

Orbital apex

Region where nearly all nerves, arteries, & veins of the orbit converge before communicating with the intracranial cavity via the optic canal & superior orbital fissure

89

Bell's palsy

unilateral paralysis of the muscles supplied by the facial nerve