Neuro exam of LA

Question 1

What are the 2 types of approaches to the neuro LA exam?

Answer 1

systemic/modality approach (tests unconscious proprioception)
anatomic approach (head to tail)
combined approach is most suitable in horses

Question 2

What is important to note about the hx for a neuro exam?

Answer 2

did horse look/act clumsy before it was found down
any evidence of respiratory dz on property or other horses
are other horses involved
descriptions of behavioural abnormalities
client videos

Question 3

What is the behaviour in a horse with forebrain lesion?

Answer 3

circling
hyperaesthesia
head turn
odd postures

Question 4

What are signs associated with cerebellar dysfunction?

Answer 4

spastic or exagerated movements
absent or diminished menace response
intention tremor
ataxia without weakness

Question 5

What are signs of brainstem dysfunction in horses?

Answer 5

weakness and ataxia (ascending proprioceptive and descending motor)
cranial nerve nuclei affected
reticular formation affected

Question 6

What does the PLR test in horses?

Answer 6

true reflex
afferent: optic nerve
efferent: parasymapthetic fibers in oculomotor nerve 3 to constric pupil
direct response
consensual response not strong in horses

Question 7

What does the menace response test in horses?

Answer 7

requires perception of the stimulus
optic nerve
optic chiasm
thalamus
opposite occipital cortex
facial nerve and nucleus
+/- cerebellum

Question 8

What CN are affected if eye position is affected?

Answer 8

oculomotor 3
trocheal 4
abducens 6

Question 9

What does the retractor oculi relfex test in horses?

Answer 9

press on cornea through eyelid, feel for reflex retraction of the globe
afferent: trigeminal 5
efferent: abducens 6

Question 10

What are the signs of Horner’s in the horse?

Answer 10

interruption of sympathetic nerve pathway between hypothalamus and eye

ptosis (examine eyelash closely)
miosis
enophthalmus
prominent 3rd eyelid
conjunctival and nasal hyperaemia
sweating!

Question 11

What are the signs of ataxia in horses?

Answer 11

functional deficit associated with defective proprioception
hypermetria
hypometrai
dysmetria (both)
truncal sway
pacing (vs normal trot)
circumduction

Question 12

How do we differentiate pelvic limb lameness and ataxia

Answer 12

ataxia is usually associated with irregular irregularities

Question 13

What is the difference between UMN and LMN weakness?

Answer 13

UMN: inability to control the muscles, normal or increased tone, NO muscle atrophy

LMN: inability to contract the muscles, flaccidity, muscle atrophy if chronic