Module 4 Flashcards
- At Inferior frontal lobe
- Tested using coffee or soap
- Volatile substances like perfume must be avoided
o Don’t use injurious stimuli!
o Don’t use ammonia, or ammonia like substances(volatile substances), it will stimulate CN V and give a false reading - BUT ACCORDING TO DEMEYER: Use aromatic, nonirritating substance (camphor, perfume, coffee powder)
- May be absent when patient has colds
- Or when there is an inferior frontal brain tumor
CN I - OLFACTORY
Proper way to test CN 1 (Olfactory Nerve)
o Proper way to test: close the patient’s eyes and waft the bottle. Don’t let the patient inhale directly from the bottle because small particles may be carried (i.e. when using coffee powder)
o Test one nostril at a time, giving a few minutes in between because smell develop tolerance very fast
Examination Proper: CN I
Examine Nostril Separately (Occlude the other) ↓ With the patient’s eyes closed and one nostril occluded bring the test substance near the open one ↓ Ask patient to sniff and identify ↓ Repeat on the other side ↓ Compare 2 sides
- At anterior frontal lobe
- Central vision/Visual acuity – use a Snellen or Jaeger chart testing eyes one at a time
- Peripheral Vision/Visual Fields – tested by visual confrontation
- Fundoscopic Examination
CN II: OPTIC
Testing of Visual Acuity
Test each eye separately. The Pt keeps eye glasses on. Although glasses improve acuity by correcting for a refractive error, they do not improve acuity impaired.
Examination Proper: CN II OPTIC
Central Vision/Visual Acuity – use a Snellen or Jaeger Chart
o Distance 20ft or 6m
o Jaeger chart held 14 inches or 35.5cm
o Use pinhole
Testing of Visual Fields (by confrontation)
- Confront the Pt by stationing yourself directly in front. Start with your left eye directly in line with the Pt’s right eye, at a distance of about 50 cm—eye to eye but not breath to breath. The Pt covers the left eye with the left hand
- Hold up your left index finger just outside your own peripheral field, in the inferior temporal quadrant. Hold the finger about equidistant between your eye and the Pt’s. Ideally the finger should extend beyond the perimeter of the field. Wiggle the finger slowly and move it very slowly toward the central field. Request the Pt to say “now” as soon as the wiggling finger is seen. Try to match the perimeter of the Pt’s visual field against your own. Test all quadrants of each eye separately, each time starting at the limit of the field.
Testing of Visual Fields (by confrontation) 2
- After surveying the visual field by the wiggling finger, you can refine the test by asking the Pt to count the number of fingers presented in each of the four quadrants of the visual field of each eye. Have the Pt close or cover the eye not being tested. Then randomly hold up one, two, or five digits (three or four is too complicated) in each quadrant for the Pt to count.
- Confrontational test: Detect the temporal visual field, making it possible to plot the visual eye fields of the patient.
Any reflex observed on one side of the body when the other side has been stimulated. (i.e. Constriction of the pupil when one eye was lighted)
Consensual reflex
Testing: Fundoscopy
- Inspect the cornea with and without the scope for opacities and for a circular ring near the limbus, which, if grayish-white, is an arcussenilis, or, if greenishbrown, a Kayser-Fleischer ring pathognomonic of Wilson hepatolenticular degeneration.
- Next focus on a retinal vessel by using whatever lens setting, from 0 to a strong plus or minus that is required to overcome refractive errors. After locating a retinal vessel, follow it along until you find the optic disc (optic papilla).
Testing: Fundoscopy 2
- Next, identify the pigment ring around the disc, note the disc color, and the presence or absence of a physiologic cup.
- Look for venous pulsations where the veins bend over the edge of the physiologic cup.
- Follow each artery out as far as possible. Locate the macula, a darker, avascular area two disc diameters lateral to the disc. Note the pearl of light reflecting from the fovea centralis, the center of the macula. This light reflection fades in older persons.
*Right eye of the patient will be seen by the right eye of the doctor. The doctor must be on the side of the patient para di magkiss
Examination Proper: CN II OPTIC (Fundoscope)
Use an Opthalmoscope ↓ Check if the gadget is in adequate setting ↓ Approach the patient from the side (you’ll see something red-orange reflex: those are your arteries and veins) ↓ Follow the red-orange reflex ↓ Look for hemorrhages
CN II and III: OPTIC AND OCCULOMOTOR (Pupillary light reflex (Use 2 lights))
- Ask the patient to look into the distance, and shine a bright light obliquely into each pupil in turn. Both the distant gaze and the oblique lighting help to prevent a near reaction.
- Look for: The direct reaction (pupillary constriction in the same eye) or the consensual reaction (pupillary constriction in the opposite eye)
CN III, IV and VI – OCULOMOTOR, TROCHLEAR and ABDUCENS
Test the extra ocular eye movements
o CN VI innervates the lateral recti (LR6)
o CN IV innervates the superior oblique muscles (SO4)
o CN III innervates all other muscles – the medial recti, superior and inferior recti and the inferior oblique muscle
- Weakness of the EOMs associated with ptosis may indicate myasthenia gravis
- Isolated CN VI palsy may occur in patients with diabetes
- CN III palsy associated with the headache is ominous and indicates a PCOM aneurysm
Examination Proper: CN III, IV, and VI
- Check and observe the eyelids
- (Look for ptosis, exopthalmos, enopthalmos)
- The target should slowly trace a large letter H for the patient to follow
Test both eyes ↓ Ask the patient to follow your finger ↓ Move your finger up, down and sideways ↓ Report whether the patient can’t look up, down or sideway
- At pons
- Facial sensation
- Also for mastication (Masseter and temporalis and pterygoids) - The most common ailment affecting this CN is trigeminal neuralgia (usually V1 & V2)
CN V - TRIGEMINAL
CN V: Trigeminal Nerve
Motor (Strength):
o Check chewing movements. (What are the muscles innervated? TIME! Temporalis, Internal pterygoid, Masseter, External pterygoid)
Sensation:
o Test the forehead (Opthalmic), cheeks (Maxillary), and jaw (Mandibular)on each side for pain sensation. If you find an abnormality, confirm it by testing temperature sensation. Two test tubes, filled with hot and ice-cold water, are the traditional stimuli.
Examination Proper: CN V Sensory
Ask patient to close the eyes ↓ Check for all part of face sensation ↓ Check if there are equal sensations (compare both sides)
- touch the cornea (not just the conjunctiva) lightly with a fine wisp of cotton.
Direct corneal: stimulate one side, blink on same side
Consensual corneal: stimulate one side, both eyes blink, equally forcefuL
Corneal (Blink) reflex
DIFFERENTIAL DIAGNOSIS
What if right side is stimulated but it is the left eye that blinks? Where is the problem (what part of the reflex arc has the problem – motor arc or sensory)? Motor! CN7!
What if the stimulation is applied but neither eye blinked? Sensory problem! CN5!
With the patient’s jaw sagging loosely open, the examiner rests a finger across the tip and strikes it a crisp blow.
Jaw Jerk
Exaggerated reaction in jaw jerk test may indicate problem in the __.
pons
Examination Proper: CN V Motor (jaw jerk)
Ask patient to bite hard ↓ Palpate the temporalis area ↓ Observe contraction of muscles
Motor: o Forehead wrinkling o Eyelid closure o Mouth retraction o Whistling or puffing out cheeks o Wrinkling of skin over the neck o Labial articulations
CN VII: FACIAL NERVE
- ”Wrinkle up your forehead” or “Look up at the ceiling”
- Inspect for asymmetry
- What muscle is tested?
Frontalis
- ”Close your eyes tight and don’t let me open them”
- Inspect for asymmetry of wrinkles; try to pull eyelids apart
- What muscle is tested?
Orbicularis oculi
- ”Pull back the corners of your mouth, as in smiling”
- Inspect for asymmetry of nasolabial fold
- What muscle is tested?
Buccinator
- “Wrinkle up the skin on your neck”or “Pull down hard on the corners of your mouth”
- Inspect for asymmetry
- What muscle is tested?
Platysma
CN VII: Facial (Sensory)
o Taste sensation in anterior 2/3 of the tongue
o Rarely assessed unless with peripheral VII nerve palsies. Use tongue depressor with single substances (e.g sugar crystals) applied to one side of the tongue. Instruct patient to protrude the tongue for application, then raise the hand once they have decided what the taste is.
- Can be tested grossly by rubbing fingers beside the ears one at a time
- Hearing: finger rub testing (if no tuning fork available).
- Tuning Fork Tests (Schwaback, Rinne, Webers)
CN VIII- VESTIBULO-COCHLEAR
Hearing: finger rub testing (if no tuning fork available).
o Rub your own thumb and index finger beginning 50cm from the test ear, bringing the stimulus closer to the patient’s head. Note the distance at which the stimulus is reliable perceived
Schwabach’s Test
o Here bone conduction (BC) of patient is compared with that of the normal hearing person (examiner) but meatus is not occluded.
o It has the same significanceas absolute bone conduction test.
o Schwabach is reduced in sensorineural deafness and lengthened in conductive deafness.
o Place the vibrating tuning fork on the patient’s mastoid bone. When patient can no longer hear the sound, place the tuning fork on your mastoid bone. If there is still sound subject is positive for the test
Compare patient bone conduction to that of the examiners’
Schwabach’s Test
Test for bone and air conduction.
Rinne Test
Rinne Test
- In this test air conduction of the ear is compared with its bone conduction. o A vibrating tuning fork is placed on the patient’s mastoid and when he stops hearing, it is brought beside the meatus.
- When the patient can no longer hear the sound, quickly place the fork close to the ear canal and ascertain whether the sound can be heard again. Here the “U” of the fork should face forward, thus maximizing its sound for the patient. Normally the sound is heard longer through air than through bone (AC > BC)
- Rinne test is called positive when AC is longer or louder than BC. It is seen in normal persons or those having sensorineural deafness.
- A negative Rinne (BC > AC) is seen in conductive deafness.
Test for Lateralization.
Weber Test
Weber Test
- In this test, a Vibrating tuning fork is placed in the middle of the forehead or the vertex and the patient is asked in which ear the sound is heard.
- Normally, it is heard equally in both ears. It is lateralised to the worse ear in conductive deafness and to the better ear in sensorineural deafness
Examination Proper: Tuning Fork Tests
Check if gross hearing is intact then use a tuning fork
↓
Vibrate the tuning fork and put it near (parallel position) one ear
↓
Ask the patient to tell you when the sound ends
↓
Check for both bone conduction and air conduction
Examination Proper: CN VII
Use a tuning fork ↓ Vibrate the tuning fork ↓ Place if over the center of the forehead ↓ Ask the patient where he/she can hear the sound of the tuning fork more
CN IX supplies only one muscle exclusively, the stylopharyngeus. Because this muscle aids in swallowing, its isolated function cannot be tested clinically.
CN IX and X: GLOSSOPHARYNGEAL and VAGUS
Testing of Palatal elevation
- Observe palatal elevation when patients says “Ah”
- Ask the patient to say “ah” or to yawn as you watch the movements of the soft palate and the pharynx. The soft palate normally rises symmetrically, the uvula remains in the midline, and each side of the posterior pharynx moves medially, like a curtain. The slightly curved uvula seen occasionally as a normal variation should not be mistaken for a uvula deviated by a lesion of CN X
- Test swallowing and gag reflex (using a tongue depressor, touching the roof of the mouth, the back of the tongue, the area around the tonsils and the back of the throat)
- The remaining branchial efferent fibers of CNs IX and X supply the pharyngeal constrictors. Because they act as a unit in swallowing, the isolated function of the individual constrictors cannot be tested at the bedside.
Testing of Gag Reflex
o Stimulate the back of the throat lightly on each side in turn and note the gag reflex which consists of elevation of the tongue and soft palate and constriction of the pharyngeal muscles
o Gag reflex is often impaired in patients with stroke – supratentorial or infratentorial, especially when multiple strokes are present
CN XI: SPINAL ACCESSORY
- Ask the patient to raise his shoulder (trapezius), add resistance by pushing it down
- Ask the patient to resist head turning with his jaw (SCM) while letting the head with your hand, face the opposite side of the resistance
CN XII: HYPOGLOSSAL
- Ask the patient to stick his tongue out
- The presence atrophy and fasciculatons indicates a lesion in the nucleus or in the nerve
o Seen in patients with ALS
Testing Tongue Motility and Deviation
o Say to the Pt, “Stick your tongue straight out as far as possible and hold it there.” Check for alignment of the median raphe of the tongue with the crevice between the medial incisor teeth.
o Then, if the history or findings suggest a bulbar problem, ask the Pt to move the tongue alternately to the right and to the left and to try to touch the tip of the tongue to the tip of the nose and then to the tip of the chin. On protrusion the tongue tip should extend well beyond the teeth.
Testing Tongue Strength
o Have the Pt press the tongue against the cheek while you press your finger against the cheek.
Review of Cerebellum
- Located behind the dorsal aspect of pons and medulla
- Separated from occipital lobe by tentorium
- Fills most of the posterior fossa
- Vermis - Midline portion; Separates two lateral lobes or hemispheres
- Folia - narrow, ridge-like folds; oriented transversely onexternal surface; Adjacent to 4th Ventricles
CEREBELLAR FUNCTIONS
- Coordinate skilled voluntary movements
- Receive collateral input from sensory and special sensory systems.
o Cerebellum processes sensory information.
o Does not influence motor neurons directly
(cerebellar signs)
o It is related to a depression of gamma and alpha motor neuron activity
o The least evident of the cerebellar abnormalities
o More apparent with acute than with chronic lesions
o Failure to check a movement - a closely related phenomenon (impairment of the check reflex)
Hypotonia
(cerebellar signs)
o Cerebellar sign par excellence”
o May affect the limbs, trunk or gait
Ataxia or dystaxia