Vertigo is a medically recognized term for the symptom of vestibular system disturbance. It may include a feeling of rotation or illusory sensations of motion or both. The general term dizziness is used by nonmedical people for those symptoms but often refers to a feeling of light-headedness, giddiness, drowsiness, or faintness, all of which must be differentiated from true vertigo, since the latter symptoms might have other causes.

Motion sickness occurs more frequently in migraine patients (30–50% more than in controls). Benign paroxysmal vertigo of childhood is an example of migraine-associated vertigo in which headache does not often occur. Basilar artery migraine (BAM) consists of two or more symptoms (vertigo, tinnitus, decreased hearing, ataxia, dysarthria, visual symptoms in both hemifields or both eyes, diplopia, bilateral paresthesias, paresis, decreased consciousness and/or loss of consciousness) followed by throbbing headache. Auditory symptoms are rare. However, a study showed a fluctuating low-tone sensorineural hearing loss in more than 50% of patients with BAM with a noticeable change in hearing just before the onset of a migraine headache. The attacks of vertigo are usually concurrent with the headache and the family history is usually positive. The diagnostician must rule out: TIAs, and paroxysmal vestibular disorder accompanied by headache.

There is also a familial vestibulopathy, familial benign recurrent vertigo (fBRV), where episodes of vertigo occur with or without migraine headache. Testing may show profound vestibular loss. The syndrome responds to acetazolamide. Familial hemiplegic migraine (FHM) has been linked to mutations in the calcium channel gene. (Ophoff et al. 1966 cf. Lempert et al.)

Ménière's is characterized by recurrent episodes of vertigo, hearing loss and tinnitus; episodes may be accompanied by headache and a feeling of fullness in the ears.

People may also experience additional symptoms related to irregular reactions of the autonomic nervous system. These symptoms are not symptoms of Meniere's disease per se, but rather are side effects resulting from failure of the organ of hearing and balance, and include nausea, vomiting, and sweating—which are typically symptoms of vertigo, and not of Ménière's. This includes a sensation of being pushed sharply to the floor from behind.

Sudden falls without loss of consciousness (drop attacks) may be experienced by some people.

Many patients will report a history of vertigo as a result of fast head movements. Many patients are also capable of describing the exact head movements that provoke their vertigo. Purely horizontal nystagmus and symptoms of vertigo lasting more than one minute can also indicate BPPV occurring in the horizontal semicircular canal.

Patients do not experience other neurological deficits such as numbness or weakness, and if these symptoms are present, a more serious etiology, such as posterior circulation stroke or ischemia, must be considered.

The spinning sensation experienced from BPPV is usually triggered by movement of the head, will have a sudden onset, and can last anywhere from a few seconds to several minutes. The most common movements patients report triggering a spinning sensation are tilting their heads upwards in order to look at something, and rolling over in bed.

There are two forms (also referred to as "classifications") of FCMS; bilateral and unilateral. The bilateral form is most common (also referred to as the "classical form") and is caused by the formation of lesions on both sides of the anterior or posterior region of the operculum. In contrast, the unilateral form is rare and is caused by the formation of lesions on one side of the anterior or posterior region of the operculum. Lesions located in the anterior regions of the operculum are associated with motor deficits and anarthria, a total absence of the ability to form speech or language. Lesions located in the posterior regions of the operculum are associated with parietal opercular functions. The two classifications of FCMS were established based on the location of the lesion, stroke, and trauma affecting the brain. Classifying FCMS based solely upon lesions yields five specific subtypes of FCMS currently known to fall into the bilateral and unilateral categories:

- Bilateral anterior opercular syndrome (lesion in both the anterior or in the frontal operculum)

- Opercular-subopercular syndrome (lesions in the opercular cortex on one side and the subopercular lesion in the contralateral side).

- Subopercular syndrome (lesions in the subcortical corticobulbar projections only).

- Unilateral anterior syndrome involving the frontal operculum.

- Posterior syndrome involving the junction between the frontal and the parietal lobe of the operculum.

The bilateral form of FCMS ("also known as facio-labio-pharyngo-glosso-laryngo-brachial paralysis)" is consistent with the classic presentation of bilateral corticobulbar involvement. It is characterized by well-preserved automatic and reflex movements. It is caused by lesions in the cortical or subcortical region of the anterior opercular area surrounding the insula forming the gyri of the frontal, temporal, and parietal lobes.

Benign paroxysmal positional vertigo - Migraine is commonly associated with BPPV, the most common vestibular disorder in patients presenting with dizziness. The two may be linked by genetic factors or by vascular damage to the labyrinth.

Ménière's disease - There is an increased prevalence of migraine in patients with Ménière's disease and migraine leads to a greater susceptibility of developing Ménière’s disease. But they can be distinguished. Ménière's disease may go on for days or even years, while migraines typically do not last longer than 24 hours.

Motion sickness is more prevalent in patients with migraine.

Psychiatric syndromes Dizziness and spinning vertigo are the second most common symptom of panic attacks, and they can also present as a symptom of major depression. Migraine is a risk factor for developing major depression and panic disorder and vice versa.

Vertigo is a sensation of spinning while stationary. It is commonly associated with nausea or vomiting, unsteadiness (postural instability), falls, changes to a person's thoughts, and difficulties in walking. Recurrent episodes in those with vertigo are common and frequently impair the quality of life. Blurred vision, difficulty in speaking, a lowered level of consciousness, and hearing loss may also occur. The signs and symptoms of vertigo can present as a persistent (insidious) onset or an episodic (sudden) onset.

Persistent onset vertigo is characterized by symptoms lasting for longer than one day and is caused by degenerative changes that affect balance as people age. Naturally, the nerve conduction slows with aging and a decreased vibratory sensation is common.

Additionally, there is a degeneration of the ampulla and otolith organs with an increase in age. Persistent onset is commonly paired with central vertigo signs and symptoms.

The characteristics of an episodic onset vertigo is indicated by symptoms lasting for a smaller, more memorable amount of time, typically lasting for only seconds to minutes. Typically, episodic vertigo is correlated with peripheral symptoms and can be the result of but not limited to diabetic neuropathy or autoimmune disease.

Patients with unilateral hearing loss have difficulty in

- hearing conversation on their impaired side

- localizing sound

- understanding speech in the presence of background noise.

- interpersonal and social relations

- difficulty concentrating in large, open environments

In quiet conditions, speech discrimination is no worse than normal hearing in those with partial deafness; however, in noisy environments speech discrimination is almost always severe.

Darwin's tubercle (or auricular tubercle) is a congenital ear condition which often presents as a thickening on the helix at the junction of the upper and middle thirds.

Vertigo that arises from injury to the balance centers of the central nervous system (CNS), often from a lesion in the brainstem or cerebellum, is called "central" vertigo and is generally associated with less prominent movement illusion and nausea than vertigo of peripheral origin. Central vertigo may have accompanying neurologic deficits (such as slurred speech and double vision), and pathologic nystagmus (which is pure vertical/torsional). Central pathology can cause disequilibrium which is the sensation of being off balance. The balance disorder associated with central lesions causing vertigo is often so severe that many patients are unable to stand or walk.

A number of conditions that involve the central nervous system may lead to vertigo including: lesions caused by infarctions or hemorrhage, tumors present in the cerebellopontine angle such as a vestibular schwannoma or cerebellar tumors, epilepsy, cervical spine disorders such as cervical spondylosis, degenerative ataxia disorders, migraine headaches, lateral medullary syndrome, Chiari malformation, multiple sclerosis, parkinsonism, as well as cerebral dysfunction. Central vertigo may not improve or may do so more slowly than vertigo caused by disturbance to peripheral structures.

Ménière's disease (MD) is a disorder of the inner ear that is characterized by episodes of feeling like the world is spinning (vertigo), ringing in the ears (tinnitus), hearing loss, and a fullness in the ear. Typically only one ear is affected, at least initially; however, over time both ears may become involved. Episodes generally last from 20 minutes to a few hours. The time between episodes varies. The hearing loss and ringing in the ears may become constant over time.

The cause of Ménière's disease is unclear but likely involves both genetic and environmental factors. A number of theories exist for why it occurs including constrictions in blood vessels, viral infections, and autoimmune reactions. About 10% of cases run in families. Symptoms are believed to occur as the result of increased fluid build up in the labyrinth of the inner ear. Diagnosis is based on the symptoms and frequently a hearing test. Other conditions that may produce similar symptoms include vestibular migraine and transient ischemic attack.

There is no cure. Attacks are often treated with medications to help with the nausea and anxiety. Measures to prevent attacks are overall poorly supported by the evidence. A low salt diet, diuretics, and corticosteroids may be tried. Physical therapy may help with balance and counselling may help with anxiety. Injections into the ear or surgery may also be tried if other measures are not effective but are associated with risks. The use of tympanostomy tubes, while popular, is not supported.

Ménière's disease was first identified in the early 1800s by Prosper Ménière. It affects between 0.3 and 1.9 per 1,000 people. It most often starts in the 40s to 60s. Females are more commonly affected than males. After 5–15 years, the episodes of world spinning generally stop and the person is left with mild loss of balance, moderately poor hearing in the affected ear, and ringing in their ear.

Alezzandrini syndrome is a very rare syndrome characterized by a unilateral degenerative retinitis, followed after several months by ipsilateral vitiligo on the face and ipsilateral poliosis. Deafness may also be present.

Benign paroxysmal positional vertigo (BPPV) is a disorder arising from a problem in the inner ear. Symptoms are repeated, brief periods of vertigo with movement, that is, of a spinning sensation upon changes in the position of the head. This can occur with turning in bed or changing position. Each episode of vertigo typically lasts less than one minute. Nausea is commonly associated. BPPV is one of the most common causes of vertigo.

BPPV can result from a head injury or simply occur among those who are older. A specific cause is often not found. The underlying mechanism involves a small calcified otolith moving around loose in the inner ear. It is a type of balance disorder along with labyrinthitis and Ménière's disease. Diagnosis is typically made when the Dix–Hallpike test results in nystagmus (a specific movement pattern of the eyes) and other possible causes have been ruled out. In typical cases medical imaging is not needed.

BPPV is often treated with a number of simple movements such as the Epley maneuver or Brandt–Daroff exercises. Medications may be used to help with nausea. There is tentative evidence that betahistine may help with the vertigo but its use is not generally needed. BPPV is not a serious condition. Typically it resolves in one to two weeks. It however may recur in some people.

The first medical description of the condition occurred in 1921 by Robert Barany. About 2.4% of people are affected at some point in time. Among those who live until their 80s, 10% have been affected. BPPV affects females twice as often as males. Onset is typically in the person's 50s to 70s.

Crossed dystopia (syn.unilateral fusion cross fused renal ectopia) is a rare form of renal ectopia where both kidneys are on the same side of the spine. In many cases, the two kidneys are fused together, yet retain their own vessels and ureters. The ureter of the lower kidney crosses the midline to enter the bladder on the contralateral side. Both renal pelvis can lie one above each other medial to the renal parenchyma (unilateral long kidney) or the pelvis of the crossed kidney faces laterally (unilateral "S" shaped kidney). Urogram is diagnostic.

The anomaly can be diagnosed through ultrasound of urography, but surgical intervention is only necessary if there are other complications, such as tumors or pyelonephritis.

Unilateral hearing loss (UHL) or single-sided deafness (SSD) is a type of hearing impairment where there is normal hearing in one ear and impaired hearing in the other ear.

This lesion is usually unilateral and affects several structures in the midbrain including:

It is caused by midbrain infarction as a result of occlusion of the paramedian branches of the posterior cerebral artery or of basilar bifurcation perforating arteries.

This atavistic feature is so called because its description was first published by Charles Darwin in the opening pages of "The Descent of Man, and Selection in Relation to Sex", as evidence of a vestigial feature indicating common ancestry among primates which have pointy ears. However, Darwin himself named it the Woolnerian tip, after Thomas Woolner, a British sculptor who had depicted it in one of his sculptures and had first theorised that it was an atavistic feature.

Patients who have malignant gliomas of the optic nerve have rapidly progressive, painful visual loss accompanied by signs of an optic neuropathy. Initial visual loss may be unilateral or bilateral (chiasmal involvement), but rapid progression to bilateral blindness and death are constant features. Depending on the initial location of the tumor, visual loss may be accompanied by exophthalmos, extraocular motility

Optic nerve melanocytoma does not usually produce symptoms or grow. If they slowly grow, optic nerve melanocytoma can produce afferent pupillary defects (30%), subretinal fluid (10%), and an enlarged blind spot (75%).

On fundoscopic exam, the optic disc may be swollen, atrophic, or even normal. Central retinal vein occlusion may occur.

If the tumor is next to the optic nerve, growth can compress the nerve and cause gradual loss of vision and unilateral proptosis. Dyschromatopsia may occur. Growth can also cause compressive vascular problems like central retinal vein occlusion. Lastly, growth also causes the tumor to exceed its blood supply. In these cases, necrotic areas form inside the tumor. Necrosis can (in turn) cause intraocular and rarely orbital inflammation.

Patients present with acute unilateral decreased vision, photopsias and central or paracentral scotoma. An antecedent viral prodrome occurs in approximately one-third of cases. Myopia is commonly seen in patients.

Eye exam during the acute phase of the disease reveals multiple discrete white to orange spots at the level of the RPE or deep retina, typically in a perifoveal location (around the fovea).

Michel aplasia, also known as complete labyrinthine aplasia (CLA), is a congenital abnormality of the inner ear. It is characterized by the bilateral absence of differentiated inner ear structures and results in complete deafness (anacusis).

Michel aplasia should not be confused with michel dysplasia. It may affect one or both ears.

"Aplasia" is the medical term for body parts that are absent or do not develop properly. In Michel aplasia, the undeveloped (anaplastic) body part is the bony labyrinth of the inner ear. Other nearby structures may be underdeveloped as well.

Multiple evanescent white dot syndrome (MEWDS) is an uncommon inflammatory condition of the retina that typically affects otherwise healthy young females in the second to fourth decades of life.

The typical patient with MEWDS is a healthy middle aged female age 15-50. There is a gender disparity as women are affected with MEWDS four times more often than men. Roughly 30% of patients have experienced an associated viral prodrome. Patients present with acute, painless, unilateral change in vision.

Individuals with exploding head syndrome hear or experience loud imagined noises as they are falling asleep or waking up, have a strong, often frightened emotional reaction to the sound, and do not report significant pain; around 10% of people also experience visual disturbances like perceiving visual static, lightning, or flashes of light. Some people may also experience heat, strange feelings in their torso, or a feeling of electrical tinglings that ascends to the head before the auditory hallucinations occur. With the heightened arousal, people experience distress, confusion, myoclonic jerks, tachycardia, sweating, and the sensation that felt as if they had stopped breathing and had to make a deliberate effort to breathe again.

The pattern of the auditory hallucinations is variable. Some people report having a total of two or four attacks followed by a prolonged or total remission, having attacks over the course of a few weeks or months before the attacks spontaneously disappear, or the attacks may even recur irregularly every few days, weeks, or months for much of a lifetime.

Some individuals believe that EHS episodes are not natural events, but are the effects of directed energy weapons which create an auditory effect. Thus, EHS has been worked into conspiracy theories, but there is no scientific evidence that EHS has non-natural origins.

Auditory verbal agnosia has been shown to form as a result of tumor formation, especially in the posterior third ventricle, trauma, lesions, cerebral infarction, encephalitis as a result of herpes simplex, and Landaui-Kleffner syndrome. The exact location of damage which results in pure word deafness is still under debate, but the planum temporale, posterior STG, and white matter damage to the acoustic radiations (AR) have all been implicated.

Auditory verbal agnosia is rarely diagnosed in its pure form. Auditory verbal agnosia can both present as the result of acute damage or as chronic, progressive degeneration over time. Cases have been documented that result from severe acute head trauma resulting in bilateral temporal lobe damage. In contrast, auditory verbal agnosia has also been documented to present progressively over several years. In one such case, the patient exhibited progressive word deafness over a 9-year period but did not exhibit any other cognitive of mental deterioration. MRIs showed cortical atrophy in the left superior temporal lobe region.

In childhood, auditory verbal agnosia can also be caused by Landau-Kleffner syndrome, also called acquired epileptic aphasia. It is often the first symptom of this disease. A review of 45 cases suggested a relationship between prognosis and age of onset with poorer prognosis for those with earlier onset. In extremely rare cases, auditory verbal agnosia has been known to present as a symptom of neurodegenerative disease, such as Alzheimer's disease. In such cases auditory verbal agnosia is a symptom that is typically followed by more severe neurological symptoms typical of Alzheimer's disease.

Weber's syndrome (superior alternating hemiplegia) is a form of stroke characterized by the presence of an ipsilateral oculomotor nerve palsy and contralateral hemiparesis or hemiplegia.

Auditory verbal agnosia can be referred to as a pure aphasia because it has a high degree of specificity. Despite an inability to comprehend speech, patients with auditory verbal agnosia typically retain the ability to hear and process non-speech auditory information, speak, read and write. This specificity suggests that there is a separation between speech perception, non-speech auditory processing, and central language processing. In support of this theory, there are cases in which speech and non-speech processing impairments have responded differentially to treatment. For example, some therapies have improved writing comprehension in patients over time, while speech remained critically impaired in those same patients.

The term "pure word deafness" is something of a misnomer. By definition, individuals with pure word deafness are not deaf – in the absence of other impairments, these individuals have normal hearing for all sounds, including speech. The term "deafness" originates from the fact that individuals with AVA are unable to "comprehend" speech that they hear. The term "pure word" refers to the fact that comprehension of verbal information is selectively impaired in AVA. For this reason, AVA is distinct from other auditory agnosias in which the recognition of nonspeech sounds is impaired. Classical (or pure) auditory agnosia is an inability to process environmental sounds. Interpretive or receptive agnosia (amusia) is an inability to understand music.

Patients with pure word deafness complain that speech sounds simply do not register, or that they tend not to come up. Other claims include speech sounding as if it were in a foreign language, the words having a tendency to run together, or the feeling that speech was simply not connected to the patient's voice.