Prevalence is estimated to be 0.005%. The age of onset has been found to be under 15 years in 40% of cases while it is between 10 and 14 years in one third of the cases. Females outnumber males, 4 to 1. Only 3% have attacks after age 52.

Sporadic hemiplegic migraine (SHM) is a form of hemiplegic migraine headache isolated cases of which are observed. It is a rare disease. It is considered to be a separate type of migraine.

Caprine arthritis encephalitis (CAE) is a viral disease of goats caused by a lentivirus called caprine arthritis encephalitis virus. The disease is found worldwide.

Two syndromes of CAE occur. Adult goats develop a chronic progressive arthritis, whereas young goats develop a neurological syndrome, with signs of paresis or paralysis. Less commonly, mastitis or pneumonia may occur.

Infection is life-long, and it may be years before signs of the disease occur. The reason for the long (and variable) period of dormancy of the virus is not known.

In goats which develop arthritis, the joints become inflamed and swollen, and the goats will slowly lose condition. In some cases the goat will not be able to stand.

In goats which develop the neurological form of the disease, the onset of signs is gradual over several weeks. The hind legs are most often affected. The goat will be uncoordinated, and unable to place its feet properly, so that it "knuckles", that is, it stands with the front of its fetlock on the ground, rather than its hoof. The goat has increased difficulty standing and eventually is unable to stand.

The disease is spread to goat kids when they drink colostrum or milk from infected goats. Separating goat kids from infected goats, and feeding the kids with cow's milk, or pasteurized goat milk, will prevent infection. The disease can be spread from goat to goat via direct contact and body fluids, such as saliva. Blood testing goats for CAE virus before moving them into a new herd will prevent the spread of the disease.

There is no known cure. To prevent spread of the disease, infected animals are separated from non-infected goats, or culled.

Proventricular dilatation disease (PDD) is a disease affecting psittacines (parrots). It was first recognized and described in 1978 by Dr. Hannis L. Stoddard. Since the first reported cases were involving species of macaw, the condition was termed macaw wasting syndrome.

Rabbits helped keep vegetation in their environments short through grazing and short grasses are conducive to habitation by the butterfly, "Plebejus argus""." When the population of rabbits experienced a decline due to Myxomatosis, grass lengths increased, limiting the environments in which "P. argus" could live, thereby contributing to the decline of the butterfly population.

In pet rabbits, myxomatosis can be misdiagnosed as pasteurellosis, a bacterial infection which can be treated with antibiotics. By contrast, there is no treatment for rabbits suffering from myxomatosis, other than palliative care to ease the suffering of individual animals, and the treatment of secondary and opportunistic infections, in the hopes the treated animal will survive. In practice, the owner is often urged to euthanize the animal to end its suffering.

In July 2008, a team of researchers at the University of California, San Francisco was able to identify a virus that may cause PDD, which they have named avian bornavirus. A member of the Bornaviridae family, avian bornavirus was isolated in 71 percent of samples from infected birds, but in none of the healthy birds. The researchers were able to clone a full-length genome of the virus from avian tissue. Later analyses revealed that numerous distinct avian bornaviruses exist - not all of them cause PDD. Gancz "et al." succeeded in inducing PDD in cockatiels by inoculation of brain tissue from avian bornavirus-positive birds while Gray "et al." caused PDD in Patagonian conures by inoculation of a tissue-culture derived isolate of avian bornavirus.

Despite many reports, avian bornaviruses should not be stated as the cause of PDD.

The cause of benign paroxysmal torticollis in infants is thought to be migrainous. More than 50% of infants have a family history of migraine in first degree relatives. The cause is likely to be genetic.

The prevalence of migraine and vertigo is 1.6 times higher in 200 dizziness clinic patients than in 200 age- and sex-matched controls from an orthopaedic clinic. Among the patients with unclassified or idiopathic vertigo, the prevalence of migraine was shown to be elevated. In another study, migraine patients reported 2.5 times more vertigo and also 2.5 more dizzy spells during headache-free periods than the controls.

MAV may occur at any age with a female:male ratio of between 1.5 and 5:1. Familial occurrence is not uncommon. In most patients, migraine headaches begin earlier in life than MAV with years of headache-free periods before MAV manifests.

In a diary study, the 1-month prevalence of MAV was 16%, frequency of MAV was higher and duration longer on days with headache, and MAV was a risk factor for co-morbid anxiety.

The mechanism of action of benign paroxysmal torticollis is not yet understood. It has been suggested that unilateral vestibular dysfunction or vascular disturbance in the brain stem may be responsible for the condition.

The actual incidence of this disease is not known, but only 243 cases have been reported in the scientific literature, suggesting an incidence of on the order of one affected person in ten million people.

Worster-Drought syndrome is a form of congenital suprabulbar paresis that occurs in some children with cerebral palsy. It is caused by inadequate development of the corticobulbar tracts and causes problems with the mouth and tongue including impaired swallowing. A similar syndrome in adults is called anterior opercular syndrome.

A 1986 study of a family in which multiple members had Worster-Drought Syndrome suggested it might be hereditary.

A 2000 review of cases classified Worster-Drought Syndrome as a form of cerebral palsy, caused by early damage to the brain, but identified no obvious causes during gestation or birth and found some families with a history of the condition.

The syndrome was named after Cecil Charles Worster-Drought, the doctor who discovered it in 1956.

Cobb syndrome is a rare congenital disorder characterized by visible skin lesions with underlying spinal angiomas or arteriovenous malformations (AVMs). The skin lesions of Cobb syndrome typically are present as port wine stains or angiomas, but reports exist of angiokeratomas, angiolipomas, and lymphangioma circumscriptum. The intraspinal lesions may be angiomas or AVMs and occur at levels of the spinal cord corresponding to the affected skin dermatomes. They may in turn produce spinal cord dysfunction and weakness or paralysis.

The disorder was first described by Berenbruch in 1890, but became widely known only after Cobb's report in 1915. Cobb syndrome is thought to be more common in males and have no racial predilection, but only a few dozen cases are known. It is believed to be due to a sporadic mutation, since parents of affected children usually have no evidence of the disease.

Adie's syndrome is not life-threatening or disabling. As such, there is no mortality rate relating to the condition; however, loss of deep tendon reflexes is permanent and may progress over time.

Inflammatory issues associated with contact granuloma include gastroesophageal reflux, allergy or infection. There is some disagreement among researchers as to whether inflammatory issues are a direct cause. Some researchers identify reflux and infection as indirect causes due to aggressive coughing that usually occurs as a result.

Across all posited aetiologies, contact granulomas are more commonly observed in male patients than in female patients, and more commonly in adult patients than in pediatric patients. In cases where gastroesophageal reflux disease is identified as the most likely cause of the granuloma, the patient is most commonly an adult man in his 30s or 40s. When contact granulomas do occur in female and pediatric patients, they usually occur post-intubation. There are no observable age or gender trends within the category of post-intubation patients suffering from contact granulomas, nor within the causation category of vocal abuse history.

Postoperative residual curarization (PORC) is a residual paresis after emergence from general anesthesia with neuromuscular-blocking drugs.

Most commonly caused by hypertension, continued stress on the walls of the artery will degrade the vessel wall by damaging and loosening the collagen and elastin meshwork which comprises the intima. Similarly, hypercholesterolemia or hyperlipidemia can also provide sufficient trauma to the vessel wall resulting in dolichoectasia. As the arrangement of connective tissue is disturbed, the vessel wall is no longer able to hold its original conformation and begins to unravel due to the continued hypertension. High blood pressure mold and force the artery to now take on an elongated, tortuous course to better withstand the higher pressures.

Most commonly affected is the Vertebral Basilar Artery (Vertebral Basilar Dolichoectasia or Vertebrobasillar Dolichoectasia). The Internal Carotid Artery is also at high risk to be affected. Patients with Autosomal Dominant Polycystic Kidney Disease (ADPKD) are more likely to be subject to dolichoectasias. Dolichoectasias are most common in elderly males.

In cases involving the basilar artery (VBD), the pathogenesis arises from direct compression of different cranial nerves. Additionally, ischemic effects on the brain stem and cerebellar hemispheres as well as symptoms related to hydrocephalus are common. Direct cranial nerve compression can lead to isolated cranial nerve dysfunction, usually associated with a normal-sized basilar artery that is tortuous and elongated. Cranial nerve dysfunction most commonly involves the VII cranial nerve and the V cranial nerve. Multiple cranial nerve dysfunction is far more likely to occur if there is dilation (ectasia) associated with a tortuous and elongated basilar artery. Cranial nerves affected in descending order of frequency include: VII, V, III, VIII, and VI.

Internal Carotid Artery dolichoectasia is particularly interesting because the artery normally already contains one hairpin turn. Seen in an MRI as two individual arteries at this hairpin, a carotid artery dolichoectasia can progress so far as to produce a second hairpin turn and appear as three individual arteries on an MRI. In the case of a dolichoectasia of the Internal Carotid Artery (ICD), the pathogenesis is primarily related to compression of the Optic Nerves at the Optic Chiasma (see Fig. 1 and 2).

ODD is typically an autosomal dominant condition, but can be inherited as a recessive trait. It is generally believed to be caused by a mutation in the gene GJA1, which codes for the gap junction protein connexin 43. Slightly different mutations in this gene may explain the different way the condition manifests in different families. Most people inherit this condition from one of their parents, but new cases do arise through novel mutations. The mutation has high penetrance and variable expression, which means that nearly all people with the gene show signs of the condition, but these signs can range from very mild to very obvious.

In 80% of cases, the parotid gland is affected. Lacrimal glands are also affected.

Benign lymphoepithelial lesion is a type of benign enlargement of the parotid and/or lacrimal glands. This pathologic state is sometimes, but not always, associated with Sjögren's syndrome.

Voice disorders are medical conditions involving abnormal pitch, loudness or quality of the sound produced by the larynx and thereby affecting speech production. These include:

- Puberphonia

- Chorditis

- Vocal fold nodules

- Vocal fold cysts

- Vocal cord paresis

- Reinke's edema

- Spasmodic dysphonia

- Foreign accent syndrome

- Bogart–Bacall syndrome

- Laryngeal papillomatosis

- Laryngitis

Jugular foramen syndrome, or Vernet's syndrome is characterized by the paresis of 9th–11th (with or without 12th) cranial nerves together.

A variety of surgeries have been performed including microvascular decompression (MVD) of the fifth, ninth, and tenth nerves; as well as partial cutting of the nervus intermedius, geniculate ganglion, chorda tympani and/or the ninth and tenth cranial nerves.