cranial n testing

olfactory n (CN I)

inspect each nostril

have PT close eyes

block PT nostril on opposite side being tested

present one odor at a time

a lesion of CN I (olfactory) is what

ansomia

why would pt with MS potentially have impaired smell

b/c MS can affect CN I & II b/c they are a part of the CNS

CN II (optic n) is afferent for

pupillary, convergence and accomodation reflexes

functional integrity of optic n tested by

visual acuity - central vision

visual fields - peripheral vision

light reflexes

accomodation reflexes

confrontation tests

checks 4 diagonal visual quadrants

test one eye at a time (occlude vision in opposite eye)

visual acuity test

Snellen chart

tests for myopia, hyperopia, presbyopia

visual field deficits reflect direction from which patient

cannot see

vertical deficit

superior and inferior peripheral vision

temporal deficit

right and left peripheral vision

bi-temporal hemianopsia may be associated with

pituitary tumors secondary to pressure midline optic chiasm

accommodation reflex

examiners finger is 2ft away and is advanced slowly towards pt nose

should see convergence and pupil construction

includes oculomotor pathway

pupillary light reflexes tests both eyes and is afferent of _____ and efferent of _____

afferent: CN II

efferent: CN III

direct pupillary light reflex

ipsilateral

light shined into eye, see if pupil constricts

indirect pupillary light reflex

consensual

look at pupillary constriction of eye

should constrict simultaneously and at the same rate

pupils that do not respond to light indicate

retina or optic n damage

CN II lesion

prevents pupillary reflex from occurring in both eyes when light is shined into affected eye bc the light is not detected

CN III lesion

ipsilateral eye looks lateral and down (pulled by unopposed m innervated by CNs IV and VI unopposed); diplopia

unilateral CN II lesion (one optic n)

ipsilateral blindness

bilateral CN II lesion

bilateral blindness

impaired CN II function pts have visual field deficits and are often

aware they cannot see objects in the compromised visual field

lateral rectus

abducts the eye

inferior rectus

depresses eye

superior rectus

eye looks up

medial rectus

adducts eye

superior oblique

adduct eye and moves eye downward

inferior oblique

adduct eye and move eye up

CN III innervates which extraoculuar eye m

superior and inferior rectus

inferior oblique

medial rectus

CN IV innervates which extraocular eye muscle

superior oblique

CN VI innervates which extraocular eye muscle

lateral rectus

oculomotor palsy

- Ptosis (drooping eyelid)

- Abducted and inferiorly directed pupil (down & out)

testing CN III, IV, and VI

smooth pursuit - tracking

H pattern

also test oculomotor centers and pathways that control

differential diagnosis for CN III, IV, and VI

CN 3, 4, 6 lesions v lesions affecting extraocular muscles, parieto-occipital cortex, cerebellum, or medial longitudinal fasciculus

CN IV lesion

ipsilateral eye looks slightly upward b/c of actions of muscles innervated by CN III and VI unopposed

CN VI lesion

ipsilateral eye to look medially b/c unopposed muscle that pulls medially, innervated by CN III

double vision is a result of

any cranial nerve lesion that innervates extraocular muscles

unilateral lesions involving motor of eye indicate

frontal lobe lesions Brodmann's Area 8

visual tracking problems indicate problems with

parieto occipital cortex that produces conjugate gaze away from the side of the lesion

3 divisions of trigeminal n

V1: opthalamic

V2: maxillary

V3: mandibular

CN V

mixed n

sensory fibers located in trigeminal ganglion near petrous part of temporal bone

what is the most sensitive test for sensory trigeminal n

corneal reflex

sensation of cornea relayed by

ophthalamic division

assessment of CN V sensory function

occlude vision

use cotton swab to stroke the pt's forehead, cheek, jaw and chin

test unaffected side first followed by affected side

testing motor division of CN V

Jaw Jerk reflex

innvervation muscles of mastication

trigeminal neuralgia

severe sharp, stabbing pain in the 1 or more branches of the trigeminal n

pain triggered by stimuli that normally are not noxious - talking, chewing, touching side of face

pain lasts

sensory component of CN VII

taste from anterior 2/3 of tongue and general sensation from oropharyngeal mucosa and palatine tonsils

motor component of CN VII

muscles of facial expression, platysma, stylohyoid, posterior belly of digastric and stapedius; corneal reflex (blink reflex)

motor assesment of CN VII

have pt raise eyebrows, squeeze eyes tighly shut, smile, and pucker their lips, looking for asymmetry of the face

lower motor neuron lesion

both forehead and lower face involved (bells palsy)

PNS problem

upper motor neuron lesion

muscles of the forehead remain intact

CNS problem

CN VIII

conveys auditory and vestibular information

afferent

hearing/auditory (cochlear branch)

vestibular (vestibular branch)

weber

rinne distinguishes conduction deficits

weber test

hit tuning fork then place on flat part of pts head

normally heard in center of head or equally in both ears

if there is a conductive hearing loss present

the vibration will be louder on the side with the conductive hearing loss

the Rinne test

compares air conduction to bone conduction

place butt of tuning fork on mastoid eminence

when pt can no longer hear the vibration, hold the U near ear and assess whether air or bone vibration is longer

normal response of Rinne test

air conduction > bone conduction

if there is sensorineural hearing loss

the vibration is heard in the air w/a reduced volume ipsilaterally

inability to hear the tuning fork outside the ear canal (impaired air condiction)

conductive hearing loss due to an auditory canal blockage or middle ear lesion

assessing vestibular branch of CN VIII

assessed for pt c/o dizziness

past pointing test

alternately touching nose and reach examiners finger

head impulse test: VOR

tests vestibular branch of CN VIII

assess cervical ROM, have pt look at your nose, gently shake head side to side then bring back to center

what does head impulse test test for

nystagmus

VOR: vestibuloocular reflex

stabilizes visual images during head movements

sensory portion of CN IX

taste on posterior aspect of tongue

lesion on CN IX sensory

loss of taste on posterior aspect of tongue

efferent portion of CN IX

swallowing

lesion of CN IX

lack of gag reflex or asymmetric elevation of the soft palate

function of CN IX and origin

origin: nucleus ambiguous and inferior salivary nucleus

carries information from tongue and larynx into CNS

afferent CN X

visceral sensations and motor to palae, pharynx, heart, and many glands

CN X motor comes from

motor nucleus ambiguous

CN X visceral

outside jugular foramen

lesion of CN X

hoarseness and asymmetric elevation of the soft palate, with the uvula deviating towards the unaffected side

testing CN IX and X

ask pt to say Ah

soft palate should rise symmetrically, uvula should remain midline and pharyn should constrict medially like a curtain

lesion of CN XI

unilateral paralysis or paresis of the 2 muscles

CN XI innervates

SCM and trapezius

CN XII innervates

intrinsics and extrinsics of tongue

assess CN XII by

having pt stick out tongue

in CN XII, with LMN or ALS will see

atrophy or fasciculations of tongue at rest

lesion of CN XII

tongue will deviate towards injured side, dysarthria, dysphagia