Damage, paralysis, ect to a Cranial nerve

Hypoglossal Nerve

Damage to one nerve causes difficulties in speech, swallowing and the tongue points toward the affected side. Eventually the paralyzed side begins to atrophy If both nerves are damaged, the person can't protrude the tongue.

Vestibulocochlear Nerve

Damage to the cochlear nerve or its receptors results in central or nerve deafness. Damage to the vestibular nerve causes dizziness, rapid involuntary eye movements, loss of balance, nausea and vomiting.

Optic Nerve

Damage to the optic nerve results in blindness of the eye served by the nerve. Damage to the visual pathway beyond the optic chiasma results in partial visual losses; Visual defects are called anopsias.

Olfactory nerve

Fracture of the ethmoid bone or lesions of olfactory fibers may result in partial or total loss of smell - a condition known as anosmia

Oculomotor Nerve

In oculomoter nerve paralysis, the eye can't be moved up, down or inward. At rest, the eye rotates laterally (external strabismus), because the actions of the two extrinsic eye muscles not served by cranial nerve III are unopposed. The upper eyelid droops (ptosis), the person has double vision and trouble focusing on close objects.

Trigeminal Nerve

Inflammation of this nerve causes Trigeminal Neuralgia. This condition is known to produce the most intense pain known. The stabbing pain can last from a few seconds to a minute. Pain can occur many time a day. This is generally provoked by some sensory stimulus, such as brushing the teeth or even a passing breeze hitting the face. This is likely to be caused by pressure on the trigeminal nerve root. Analgesics and carbamazepine (an anticonvulsant) are only partially effective. In severe cases, the nerve is cut, proximal to the trigeminal ganglion. This relieves the pain but also results in loss of sensation to that side of the person's face

Glossopharyngeal Nerve

Injury or inflammation of this nerve compromises swallowing and taste.

Accessory Nerve

Injury to the spinal root of one accessory nerve causes paralysis to the sternocleidomastoid muscle, which subsequently causes the head to turn toward the side of the injury. Shrugging of the affected shoulder by the trapezius muscle on that side becomes difficult

Facial Nerve

Paralysis of facial muscles on affected side and partial loss of taste sensation causes a condition called Bell's palsy. This condition may develop overnight. This condition is most often caused by infection with Herpes Simplex I virus - infection of which causes inflammation of the facial nerve. The lower eyelid droops, corner of the mouth sags (making it difficult to eat or speak), tears drip continuously from the eye which can't be completely closed.

Abducens Nerve

Paralysis to this nerve, results in inability to rotate the eye laterally. The affected eyeball rotates medially - known as internal strabismus

Trochlear Nerve

Trauma to/paralysis of this nerve results in double vision. Person has reduced ability to rotate eye inferolaterally

Vagus Nerve

Vagus nerve paralysis can lead to hoarseness/loss of voice, difficulty swallowing, impaired digestive system motility. These signs/symptoms are apparent because nearly all muscles of the larynx are innervated by branches of this nerve. Total destruction of both vagus nerves is incompatible with life because these parasympathetic nerves are crucial in maintaining homeostasis of the visceral organs. Without the influence of the vagus nerves, the activity of the sympathetic nerves (which mobilize/accelerate vital body processes and shut down digestion) would be unopposed.