- abnormal postural reactions - limb paresis

Vestibular and cerebellar disease Flashcards by Emily Stacey

Classic signs - ataxia

overstep

- cross over legs

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2 types of ataxia with alcohol

APPENDICULAR: jerky, uncoordinated limbs mvt, as though each mm were working independently from others
TRUNCAL: postural instability, gait instability - disorderly wide-based gait with inconsistent foot positioning

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Define ataxia

neurological sign consisting of gross incoordination of muscle movements. It is an aspecific clinical manifestation

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What to look at when observing ataxia. How to differentiate from MSK problems

limbs, head and how trunk moves during locomotion

- becomes better coordinated when running (MSK problems get worse with running

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3 types of ataxia

sensory, vestibular and cerebellar

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Define hypometria

shorter protraction phase of gait

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Define hypermetria

longer protraction phase of gait

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Define dysmetria - 3

ability to control teh distance, power and speed of an action in impaired. combination of hypo- and hypermetria

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Neurolocalisation - sensory ataxia

General proprioceptive pathways:

peripheral nn
dorsal root
SC
brainstem
forebrain

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CS - sensory ataxia

abnormal postural reactions

- limb paresis

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Neurolocalisation - vestibular ataxia

Vestibular apparatus:

vestibular nuclei (central)
vestibular portion of CN 8
vestibular receptors (peripheral_

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T/F vestibular system is a unilateral system

True - the RHS controls the RHS and vice versa

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CS - sciatica

arched back as this provides greatest pressure relief on nn root.

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How does the vestibular system affect the extensors?

Causes excitation/ tone to extensors –> head tilt and limp limbs if not working properly

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CS - vestibular ataxia

head tilt
leaning, falling or rolling to one side
abnormal nystagmus (slow side always to side with lesion)
positional strabismus
normal (peripheral) or abnormal (central) postural reactions

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Is prognosis of a vestibular problem affected by localisation (i.e. central/ peripheral)?

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T/F: nervous system copes better with acute than chronic changes

False - oppositve

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Why might you get reduced ear movement with vestibular disease?

lesion may spread and affect facial nerve –> paresis/ paralysis due to close proximity

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CS - Cerebellar ataxia

wide based stance
intention tremors of head
loss of balance and truncal sway
delayed onset and dysmetric hopping
ipsilateral menace deficits with normal vision
no limb paresis OR conscious proprioception deficits
pendular nystagmus

How do forebrain and cerebellum interact?

Forebrain - initiates movement

Cerebellum - coordinates movement

How are the 3 types of ataxia differentiated (sensory, vestibular, cerebellar)?

Outline the neuro exam in terms of observation and hands-on examination parts

OBSERVATION:
mental status and behaviour
posture
gait
identification of abnormal voluntary movements
HANDS-ON EXAMINATION
postural reaction testing
cranial nerves assessment
spinal reflexes, mm tone and size
sensory evaluation

2 components of inner ear

semicircular canals and cochlea (hearing)

What part of the vestibular system detects head motion and angular acceleration?

semicircular canals

What part of the vestibular system detects head position and gravity?

saccule and utricle

Which nn does bulla disease affect?

facial and vestibulocochlear nn and SNS trunk (--> Horner's)

Where do vestibular nuclei receive input from? 3

* semicircular canals * saccule and utricle * visual/ proprioceptive and tactile inputs - cerebellum: primarily inhibitory - spinal cord - potine reticular formation - contra-lateral vestibular nuclei

With the occulovestibular reflex, turning the head causes what?

Increased firing on the side where the head is turning to and decreased firing on the side the head is turning away from.

Where do vestibular nuclei communicate with?

* forebrain, perceived orientation * SC and cerebellum * oculomotor system, eye movements

Outline head tilting

- rotation of median plane of head - one ear lower than other - often indicates a vestibular disorder (i.e. a disorder of the balancing system)

Outline head turning

- where the median plane of the head remains perpendicular to the ground, i.e. nose turned to one side - may indicate a forebrain disorder

Describe pendular nystagmus

- siamese, birman, himalayan (melanin disorder and more fibres cross over) - congenital abnormality (larger # fibres cross chiasma) - cerebellar disorders and visual deficits - jerk nystagmus: horizontal, vertical and rotary

Name different types of nystagmus

- physiological - pendular - searching - jerk (horizontal, vertical, rotary)

Name the 5 features of Horner's syndrome (SA)

= loss of sympathetic innervation to eye: - enopthalmos - TE protrusion - ptosis - miosis - (congested BVs)

Features of Horner's syndrome in horses

- ptosis - examine eyelashes closely - miosis - enophthalmus - prominent TE - conjunctival and nasal hyperaemia - sweating

Name 4 important CS to determine whether a vestibular lesion is central or peripheral

* conscious proprioceptive deficit * consciousness - cranial nerve deficits - vertical nystagmus (will often improve with time)

Outline difference in CS between central and peripheral nystagmus

CENTRAL: possible conscious proprioceptive deficit, consciousness (normal, obtunded, stupor, coma), cranial nerves (5-8 may be affected), vertical nystagmus (yes) PERIPHERAL: no conscious proprioceptive deficit, consciousness (alert, disorientation possible), cranial nerve deficits (8 only), no vertical nystagmus

What is the first Q that should be asked when examining a pupil for a peripheral vestibular proble?

Ototoxic drugs

What is a myringotomy?

sx procedure, penetration of TM, remove fluid from middle ear, relatively safe, very diagnostically helpful

CS - bilateral vestibular problem

- no nystagmus - no occulovestibular response * head swaying from left to right

3 parts - cerebellum

- vestibulo-cerebellum (central) - spino-cerebellum (central) - cerebro-cerebellum (peripheral)

3 functions - cerebellum

- maintain equilibrium - regulate mm tone (--> preserves mm position at rest and mvt) - coordinate mvt

If the head tilt is away from the sign of the proprioceptive deficit, what should you consider?

paradoxical vestibular problem (head tilt usually towards lesion but may be away from it and thus also away from the proprioceptive deficit)

Name different regions of the cerebellum 5

- rostral lobe - caudal lobe - flocculonodular lobe - caudal cerebellar peduncle - cerebella nuclei fragment

CS - cerebellar syndrome

- spastic, dys- or hyper-metric ataxia (goose-stepping) - intention tremor - ipsilateral menace deficit + normal vision - broad-based stance - postural reactions delayed with exaggerated responses - menace deficit (ipsilateral) with normal vision +/- anisocoria (pupil dilate contralateral to side of lesion) +/- opisthotonus (rare) +/- vestibular signs

Define opisthotonus

tetanic spasm in which the body is bent back and stiffened, head will be in an extended position