Damage to the cranial nerves

Damage to the cranial nerves can have a range of effects depending on the nerve that is damaged and the location. Several diseases affecting cranial nerves VIII to XII will be discussed but there are also many more.

Acoustic Neuroma 

This affects the vestibulocochlear nerve and is caused by a benign tumour, this compresses the nerve and structures close to it in the cerebellopontine angle. This compression can lead to dizziness and deafness. The problems will become worse as the tumour expands with possible ataxia and paralysis of other cranial nerves and limbs. The inherited disease neurofibromatosis is a potential cause for these acoustic neuromas.

Glossopharyngeal neuralgia

This is a rare disorder potentially caused by an artery that is positioned wrongly so that it compresses the nerve near its exit from the brain stem, it can also be caused by a tumour in the brain or neck. The symptoms are normally brief and are not present all the time but cause severe pain in the back of the throat, tongue and ear. It can be triggered by certain actions such as talking or coughing and normally only affects one side.

Motor Neurone Disease

This is a degenerative disease which can occur in later life. It affects the nucleus ambiguus and hypoglossal nucleus by the degeneration of the corticobulbar tracts which project to them. This results in a variety of problems including problems with movement, and well as dysphonia, dysphagia, and dysarthria. For definitions see glossary. 

Nerve lesions

Nerves IX to XII are particularly susceptible to lesions caused by compression as they pass through the foramen in the skull. Tumours causing this compression can lead to dysphonia, weakness on the unilateral side, wasting of tongue and depression of gag reflex. 

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