Neurological Examination

Question 1

Outline the steps of the neurological examination

Answer 1

Observation from a distance (on approach)
Eye examination
Examining the cranial nerves
Spinal reflexes
Gait assessment
Restraint
Ocular exam

Question 2

Describe what observing from a distance means

Answer 2

Looking for changes un mentation

head tilts, tremors, intention tremors

Assess for abnormal posture

Neurogenic muscle atrophy

Assess eating (horse)

Changes in skin e.g sweating excessively (horse)

Question 3

Outline the tests for the optic nerve

Answer 3

Menace Response
PLR
Dazzle Reflex

Question 4

Outline the tests for the oculomotor nerve

Answer 4

PLR
Medial movement of the globe

Question 5

Outline the tests for the trochlear nerve

Answer 5

Ventrolateral rotation of the globe

Question 6

Outline the tests for the trigeminal nerve

Answer 6

Ear, eyelid & upper lip reflexes

chewing, jaw tone, muscle mass of masseter, pterygoid & temporalis muscles

Question 7

Outline the tests for the abducens nerve

Answer 7

Retraction of the globe (corneal reflex)

Lateral movement of globe

Question 8

Outline the tests for the facial nerve

Answer 8

Ear, eyelid & lip tone reflexes & movement, facial symmetry
Dazzle Reflex

Question 9

Outline the tests for the vestibulocochlear nerve

Answer 9

Response to noise

Head posture, gait, blindfold test

Question 10

How do you determine the difference between central and peripheral vestibulocochlear nerve damage?

Answer 10

Head tilt indicates VII lesion. If paired with other cranial nerve damage and/or proprioceptive issues then the lesion is highly likely to be central.
If head tilt

Ipsilateral Horner’s syndrome or facial nerve paresis/paralysis may occur in peripheral damage since the sympathetic to the head and the facial nerve pass through the inner ear.

If there is no head tilt present with circling then the issue will be lesion in the forebrain

Question 11

Outline the tests for the glossopharyngeal nerve

Answer 11

Swallowing, endoscopy

Question 12

Outline the tests for the vagus nerve

Answer 12

Swallowing, endoscopy, slap test

Changes in ‘voice’

Shortness of breath

Question 13

Outline the tests for the accessory nerve

Answer 13

Head posture

Question 14

Outline the tests for the hypoglossal nerve

Answer 14

Tongue size, tone & symmetry

Question 15

What are the spinal reflexes?

Answer 15

Assess the cervicofacial and cutaneous trunci (panniculus) reflexes, tail tone, perineal reflex, and anal tone.

Tendon reflexes can only be performed in recumbent adult horses and are difficult to interpret.

Withdrawal reflexes to assess pain sensation should be assessed in recumbent horses.

Question 16

Outline what you look for in a gait assessment

Answer 16

Assessment at walk.
Clinical signs of neurological dysfunction include ataxia (incoordination), circling,
weakness (paresis) or paralysis of any limbs, falling or stumbling.
Be careful of safety around very ataxic horses.

Subtle problems can be exacerbated by walking the horse in a zig zag, on and off a curb and up and down a slope or in a tight circle around examiner

Blindfolding the horse may exaggerate ataxia in vestibular disease.

Perform static tail pull to test for lower motor neuron (LMN) paresis, and dynamic tail pull (when horse walking) to test for upper motor neuron (UMN) paresis.

Toe scuffing and excessive wear of the toe may indicate weakness.

Question 17

When would you use restrain during an ocular exam?

Answer 17

A horse with a painful eye may require sedation and local nerve blocks to allow adequate ophthalmic examination.

Question 18

Outline the different methods of restraint for an ocular exam

Answer 18

Auriculopalpebral nerve block –
Blocks motor control of upper eyelid so stops blepharospasm
Does NOT anaesthetise the ocular surface
Make sure you test menace response BEFORE performing this nerve block

Supraorbital nerve block –
Blocks sensory innervation to medial 2/3 of upper eyelid (but not ocular
surface) so aids examination
Supraorbital foramen easily palpated as a small hole on the bony orbital rim
dorsal to the medial canthus of the eye. Inject 2mls local anaesthetic with a 5/8”
needle through the foramen and 1ml subcutaneously as needle withdrawn.

To anaesthetise ocular surface, topical local anaesthetic needs to be applied to the cornea (eg. Proxymetacaine, Tetracaine)

Question 19

Describe what is examined in a gross examination of the eye

Answer 19

adnexa and anterior chamber using bright light source (pen torch, phone torch)
- Change in colour of eye (red, cloudy etc)
- Foreign bodies

Question 20

Describe how to conduct distant direct ophthalmoscopy

Answer 20

Hold bright light source (pen torch, phone torch or direct ophthalmoscope) close to your eye and look at horse’s eye to observe reflected light from the retina – the tapetal or fundic reflex.
- Assess pupil size, symmetry, shape and response to light
- Tapetal reflectivity and symmetry
- Any opacities

Question 21

Describe how to conduct close direct ophthalmoscopy

Answer 21

Place ophthalmoscope up to your own eye with lens setting at 0 and look into the horse’s eye.

You will need to stand close to the horse (ophthalmoscope at 1-2 inches from the cornea).

Rest your hand on the horse’s facial crest so you can move with the horse.

At 0 you will be focused on the retina but you will only see a very small portion of it.
Move around to visualise as much of the retina as possible.

Initially you may see the tapetal fundus (usually green) and aiming more ventrally you may see the non-tapetal fundus (generally brown).

The horse’s optic disc is horizontally oval, salmon pink in colour and lies just within the non-tapetal fundus.

To visualise the disc you may need to aim the ophthalmoscope roughly towards the contralateral ear and lock slightly downwards.

Slowly increase through the lens settings (more +) to focus on rostral parts of the eye:

Question 22

Describe ho to conduct indirect ophthalmoscopy