Neuro exam cranial nerves Flashcards by Aaska Banthiya

How do you usually test for CN 1

Ask if they’ve noticed a change in their sense of smell

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What are some causes of anosmia?

Covid
Cold/flu
Head trauma
Brain tumor
Covid
Meningitis
Parkinsons
Blocked nostrils
Genetic eg Kalmans

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Is CN 1 sensory or motor?

Sensory

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Is CN II sensory or motor?

Sensory

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What should you look for when inspecting pupils?

Size
Shape
Symmetry

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What is the medical name for asymmetry in pupil size?

Anisocoria

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What are some causes of anisocoria?

Physiological
Oculomotor nerve palsy
Horner’s syndrome
Holmes-Adie syndrome

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What is Holmes-adie syndrome?

Uneven pupil due to viral/bacterial infection

Pupil does not respond well to light but will accomodate

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What does a down and out dilated pupil suggest?

3rd nerve palsy

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What does pupilary constriction and ptosis indicate?

Horner’s syndrome

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How do you identify an abnormal pupil?

Shine a light in their eyes and whichever is larger is likely to be abnormal, similarly in a dark room the smaller pupil is likely to be abnormal

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How do you test for visual acuity when testing CH II?

Use Snellen’s chart (with glasses/contacts if they usually wear them)
Get them to stand 6 meters away and read downwards

If not use a pinhole

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How is visual acuity using snellen’s chart calculated?

Chart distance (numerator)/lowest line read (denominator)

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What happens if they are unable to read snellen’s chart at 6 meters?

Bring the chart closer ie 3 meters, if still not then at 1 meter, if not get them to count fingers, if not ask them to say when their hand moves, if not ask if they can see light

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How do you test identification of hand movement?

Tell them to point to the moving hand, move both one by one then together, when you move both they can only focus one at a time

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Where will a lesion be if there is neglect wherein the patient cannot identify movement?

Parietal lobe

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Where will a lesion be if a patient has visual neglect on the left?

Right side of parietal lobe (contralateral)

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How do you test for peripheral vision in the visual field?

Get them to cover one eye and tell them to look at your nose. Bring your finger from a corner in towards and ask them to say when they can see your finger. Do this 4 times starting at each corner and then repeat for the other eye. Make sure your hand is in the midline!!!

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How does the PITS acronym help you identify what visual field loss there will be?

Parietal lobe lesion = inferior quadrantanopia

Temporal love lesion= superior quadrantanopia

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What are the afferent and efferent pathways for the pupillary light reflex

Afferent= optic nerve/ CNII
Efferent= oculomotor nerve/ CN III

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How do you do the pupillary light reflex?

Shine a light into one eye and look for constriction then do the same and look in the other eye for consensual constriction.

Don’t bring it in slowly bring it from outside straight in front of the eye

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What does the swinging light test test for?

Relative afferent pupillary defect

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How does the swinging light test work?

If you suspect a defect in one eye, shine a light in it and it will constrict a bit (and look normal)

Then shine the light into the other eye and it will constrict more

Then shine it back into the defect eye and it will appear to dilate because the normal eye constricts more

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What are causes of relative afferent pupillary defect?

Optic MS

Optic nerve lesion on the side of the defected pupil

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How do you test for accomodation reflex? What is the normal response?

Get them to look at something far and then something near Their pupil should constrict and converge

What are the tests for the optic nerve?

``` Inspect the pupils Visual acuity Visual inattention/neglect Visual fields Pupillary light reflex Accomodation reflex Colour vision Blind spot Fundoscopy ```

What chart is used to test colour vision?

Ishihara

Are CN III, IV and VI sensory or motor?

Motor

What are causes of ptosis?

3rd nerve palsy Horner's Neuromuscular eg myasthenia gravis Congenital

How do you test for CN III?

Observe the eyelid

How do you remember which nerve controls which eye muscle?

LR6SO4 Lateral rectus= CN VI Superior oblique= CN IV

If the 3rd nerve is damaged which eye muscles are left working and what does this cause?

Lateral rectus and superior oblique work= down and out

What may be seen in a partial 3rd nerve palsy?

Pupil may still dilate, ptosis may be less marked

What is nystagmus?

Flickering of the eyelid

What causes nystagmus?

Congenital Central (cerebellar lesion or midbrain) Peripheral (vestibular system) Physiological

What should you ask for before doing the H test?

Do they have double vision or pain?

Is CN V sensory or motor?

Both

How do you test for sensation of CN V?

Cotton wool on 6 spots on the face with eyes closed and tell them to say yes when they feel it Do it on the sternum first to show what it feels like

What are the 3 sensory components of CN V?

``` Ophthalmic= V1 Maxillary= V2 Mandibular= V3 ```

What muscles does CN V innervate?

Masseter and temporalis

What are the afferent and efferent nerves for the corneal reflex?

``` Aff= CN V Eff= CN VII ```

What reflexes does CN V control?

Corneal and jaw jerk

What are the afferent and efferent nerves for the jaw jerk reflex?

Both CN V

What reflexes are tested for when examining CN V?

Usually none as corneal and jaw jerk are uncomfortable

Is CN VII motor or sensory? How?

``` Motor= muscles of facial expression Sensation= taste and anterior 2/3 of the tongue ```

How do you test the motor components of CN VII

Raise your eyebrows Close your eyes and dont let me open them Blow out your cheeks and dont let me deflate them Do a big grin with teeth

If theres a facial nerve palsy how do you know if its and UMN or LMN lesion?

``` LMN= unilateral weakness of all ipsilateral facial muscle including the forehead (bell's palsy) UMN= unilateral weakness of contralateral facial muscles with forehead sparing ```

Why is the forehead spared in an UMN lesion in facial palsy?

There is double innervation so the forehead is innervated again below the original lesion

Is CN VIII sensory or motor?

Sensory

What is the function of CN VIII? How do you test for this?

Hearing and balance, ask about them

How do you do a gross hearing assessment for CN VIII?

Close one ear and then in the other ear whisper something or rub your fingers together and ask if they can hear it

What is Rinne's and Webber's test used for?

To see if hearing loss is conductive or sensorineural

Which tuning fork is used in Rinne's test if they give you 2?

The smaller one or 512

How do you do Rinne's test? What is a normal result

Make it vibrate and put it on the mastoid process (bone conduction) and ask them to tell you wen they can't hear it. Once they say yes lift it into the air outside their ear and ask if they can hear it. They should be able to as air conduction is better

How do you do Weber' test

Place a vibrating tuning fork on the patients forehead at the midline. Normally they should be able to hear the sound equally in both ears

In sensorineural hearing loss what will happen in Rinne and Weber's test?

``` Rinne= normal result Weber's= only normal ear will hear ```

In conductive hearing loss what will happen in Rinne and Weber's test?

``` Rinne= when tuning fork is in ear they will hear it less Weber's= normal ear hears it more ```

Are CN IX and X sensory or motor?

Both

What are the afferent and efferent components of the gag reflex?

``` Afferent= cn ix Efferent= cn x ```

How do you examine for CN IX and X?

Inspect soft palate and uvula Get them to say ahh and the uvula will deviate away from the affected side (theres also reduced elevation on the effected side) Ask them if they have any swallowing difficulty, changes in voice or cough

What muscles are effected by CN XI?

SCM and trapezius

How do you test for motor function of CN XI?

Get them to shrug their shoulders against resistance and then to turn against resistance

If you get a person to turn right against resistance what muscle specifically is being tested?

Left SCM

How do you test for CN XII?

Inspect tongue for wasting or fasciculations | Get them to stick their tongue out

What is an abnormal result when testing for CN XII?

Tongue deviates towards the lesion

What is the order of cranial nerves?

``` Olfactory Optic Oculomotor Trochlear Trigeminal Abducens Facial Vestibulocochlear Glossopharyngeal Vagus Accessory Hypoglossal ```

Neuro exam cranial nerves Flashcards

(66 cards)