Neurological Assessment and Signs of Damage for Cranial Nerves

CN l - Olfactory

Neurological Assessment:

• Blindly identifying various scents

Damage:

• Affects sense of smell

• Abnormalities in flavor perception

CN ll - Optic

Neurological Assessment:

• Pupil dilation

• Visual field testing

• Snellen chart

Damage:

• Varying depending on location

• Involves visual defect

CN lll - Oculomotor

Neurological Assessment:

• Able to fully open eyes

• Pupils assessment/dilation

• Visual field testing

Damage:

• Eyelid droop

• Eye deviation

• Difficulty moving eyes

• Double vision (diplopia)

CN lV - Trochlear

Neurological Assessment:

• Visual field testing

• Observation

Damage:

• Eyes deviate upward

• Diplopia

CN V - Trigeminal

Neurological Assessment:

• Light touch to the face, testing V1,V2, and V3

• Palpating the masseter and temporalis muscles while patient clenches

Damage:

• Decreased sensation in the face

• Increased pain sensation in the face

• Paralysis/paresis of muscles of mastication

• Trigeminal neuralgia

CN Vl - Abducens

Neurological Assessment:

• Visual field testing

• Observation

Damage:

• Affected eye deviates laterally

• Diplopia

CN Vll - Facial

Neurological Assessment:

• Observe facial symmetry

• Smile

• Raise eyebrows

• Close eyes tightly

• Puff cheeks

Damage:

• Muscle paralysis

• Loss of taste

• Increased sensitivity to sound

• Facial droop

• Reduced eye closure

(Common causes of damage to this nerve are Bell’s Palsy, stroke, and tumor)

CN Vlll - Vestibulochoclear

Neurological Assessment:

• Finger rub/whisper

• Tuning fork

• Nystagmus

• Balance Problems

• Complaints of vertigo

Damage:

• Hearing loss

• Tinnitus

• Loss of balance

• nausea

(Common causes of damage to this nerve are acoustic neuroma, noise-induced hearing loss, ototoxic medications, viral infections, and trauma)

CN lX - Glossopharyngeal

Neurological Assessment:

• Test gag reflex

• Swallow evaluation

Damage:

• Loss of taste

• Dysphagia (reduced sensation to the base of the tongue, soft palate, and pharynx)

• Diminished gag reflex

• Contralateral deviation of the uvula

CN X - Vagus

Neurological Assessment:

• Test gag reflex

• Palatal evaluation

• Assess vocal quality

Damage:

• Dysphonia

• Dysphagia

• Reduced gag reflex

• Deviation of uvula

CN Xl - Accessory

Neurological Assessment:

• Shoulder shrug against resistance

• Head turn against resistance

Damage:

• Weakness in the shoulders and neck

• Difficulty with arm movement

• Neck pain and muscle fatigue

CN Xll - Hypoglossal

Neurological Assessment

• Protrude tongue

• Lingual range of motion and strength

Damage:

• Dysphagia (problems with swallowing, particularly in the oral phase of swallowing)

• Dysarthria

• Fasciculations