Tests of vestibular system (balance) function include electronystagmography (ENG), Videonystagmograph (VNG), rotation tests, Computerized Dynamic Posturography (CDP), and Caloric reflex test.

Tests of auditory system (hearing) function include pure-tone audiometry, speech audiometry, acoustic-reflex, electrocochleography (ECoG), otoacoustic emissions (OAE), and auditory brainstem response test (ABR; also known as BER, BSER, or BAER).

Other diagnostic tests include magnetic resonance imaging (MRI) and computerized axial tomography (CAT, or CT).

The difficulty of making the right vestibular diagnosis is reflected in the fact that in some populations, more than one third of the patients with a vestibular disease consult more than one physician – in some cases up to more than fifteen.

Diagnosis of a balance disorder is complicated because there are many kinds of balance disorders and because other medical conditions—including ear infections, blood pressure changes, and some vision problems—and some medications may contribute to a balance disorder. A person experiencing dizziness should see a physiotherapist or physician for an evaluation. A physician can assess for a medical disorder, such as a stroke or infection, if indicated. A physiotherapist can assess balance or a dizziness disorder and provide specific treatment.

The primary physician may request the opinion of an otolaryngologist to help evaluate a balance problem. An otolaryngologist is a physician/surgeon who specializes in diseases and disorders of the ear, nose, throat, head, and neck, sometimes with expertise in balance disorders. He or she will usually obtain a detailed medical history and perform a physical examination to start to sort out possible causes of the balance disorder. The physician may require tests and make additional referrals to assess the cause and extent of the disruption of balance. The kinds of tests needed will vary based on the patient's symptoms and health status. Because there are so many variables, not all patients will require every test.

Evaluation of any suspected disease of the somatosensory system is included in a neurological examination of the peripheral nervous system. Modern techniques for testing somatosensory function are still quite crude compared to testing motor function. Evaluation of somatosensory stimuli are limited by the patient's interpretation of sensation in response to testing.

Tactile sensation is tested with a cotton wisp or light touch with a finger. Pain is assessed by pinprick or pinwheel (Wartenberg wheel). A 128 Hz tuning fork is used for testing vibrations.

A somatosensory disorder is an impairment of the somatosensory system.

Both taste and smell disorders are diagnosed by an otolaryngologist, a doctor of the ear, nose, throat, head, and neck. An otolaryngologist can determine the extent of your taste disorder by measuring the lowest concentration of a taste quality that you can detect or recognize. You may also be asked to compare the tastes of different substances or to note how the intensity of a taste grows when a substance’s concentration is increased.

Scientists have developed taste testing in which the patient responds to different chemical concentrations. This may involve a simple “sip, spit, and rinse” test, or chemicals may be applied directly to specific areas of the tongue.

About 20–30% of the population report to have experienced dizziness at some point in the previous year.

Ageusia ( ) is the loss of taste functions of the tongue, particularly the inability to detect sweetness, sourness, bitterness, saltiness, and umami (meaning "pleasant/savory taste"). It is sometimes confused with anosmia – a loss of the sense of smell. Because the tongue can only indicate texture and differentiate between sweet, sour, bitter, salty, and umami, most of what is perceived as the sense of taste is actually derived from smell. True ageusia is relatively rare compared to hypogeusia – a partial loss of taste – and dysgeusia – a distortion or alteration of taste.

The disease is an inherited autosomal dominant disease, but the physiological cause of the dysfunction is still unclear. An acidophyllic mucopolysaccharide-containing substance was discovered, especially in cochleas, maculas, and crista ampullaris of patients with DFNA9 (a chromosome locus), as well as severe degeneration of vestibular and cochlear sensory axons and dendrites. It is suggested that the mucopolysaccharide deposit could cause strangulation of nerve endings.

The maculas and crista ampullaris are what allow for non-visual sensation of head movements. The crista ampullaris resides in the semicircular canals of the inner ear and detects angular acceleration, while the maculas are housed within the vestibule of the inner ear and detect linear acceleration. When affected, these organs can lead to vertigo and nausea because the body would always feel off-balance.

Treatment with the steroid "prednisone" and the antiviral drug "acyclovir 800mg 5 times a day" is controversial, with some studies showing to achieve complete recovery in patients if started within the first three days of facial paralysis, with chances of recovery decreasing as treatment was delayed. Delay of treatment may result in permanent facial nerve paralysis. However, some studies demonstrate that even when steroids are started promptly, only 22% of all patient achieve full recovery of facial paralysis.

Treatment apparently has no effect on the recovery of hearing loss. Diazepam is sometimes used to treat the vertigo.

Vestibulocochlear dysfunction progressive familial, known also as familial progressive vestibulocochlear dysfunction is an autosomal dominant disease that results in sensorineural hearing loss and vestibular areflexia. Patients report feelings of vague dissiness, blurred vision, dysequilibrium in the dark, and progressive hearing impairment.

Expensive and invasive, the above treatments are not guaranteed to work, and are not meeting the needs of patients. There is a need for a new, less expensive, less invasive form of treatment, two of which are postulated below.

- Spinal cord stimulation has been studied in the last couple of years. In a long case study, 8 patients were given spinal cord stimulation via insertion of a percutaneous lead at the appropriate level of the cervical or thoracic spine. Between 36 and 149 months after the stimulations, the patients were interviewed. 6 of the 8 had received initial pain relief, and three experienced long-term pain relief. Spinal cord stimulation is cheaper than brain stimulation and less invasive, and is thus a more promising option for pain treatment.

- In 2007, Dr. V. S. Ramachandran and his lab proposed that caloric stimulation might be effective in treating Dejerine–Roussy syndrome. They hypothesized that if cold water was streamed into the ear down the auditory canal, the symptoms associated with Dejerine–Roussy syndrome would be alleviated. Ramachandran stated that he had carried out provisional experiments on two patients and believed that their reactions supported his theory.

Dejerine-Roussy is a rare pain syndrome. Individuals with emerging Dejerine–Roussy syndrome usually report they are experiencing unusual pain or sensitivity that can be allodynic in nature or triggered by seemingly unrelated stimuli (sounds, tastes). Symptoms are typically lateralized and may include vision loss or loss of balance (position sense). Workup should be performed by a neurologist and brain imaging to look for evidence of infarction or tumor should be obtained.

Definitive treatment depends on the underlying cause of vertigo. Ménière's disease patients have a variety of treatment options to consider when receiving treatment for vertigo and tinnitus including: a low-salt diet and intratympanic injections of the antibiotic gentamicin or surgical measures such as a shunt or ablation of the labyrinth in refractory cases.

Common drug treatment options for vertigo may include the following:

- Anticholinergics such as hyoscine hydrobromide (scopolamine)

- Anticonvulsants such as topiramate or valproic acid for vestibular migraines

- Antihistamines such as betahistine, dimenhydrinate, or meclizine, which may have antiemetic properties

- Beta blockers such as metoprolol for vestibular migraine

- Corticosteroids such as methylprednisolone for inflammatory conditions such as vestibular neuritis or dexamethasone as a second-line agent for Ménière's disease

All cases of decompression sickness should be treated initially with 100% oxygen until hyperbaric oxygen therapy (100% oxygen delivered in a high-pressure chamber) can be provided. Several treatments may be necessary, and treatment will generally be repeated until either all symptoms resolve, or no further improvement is apparent.

Tests for vertigo often attempt to elicit nystagmus and to differentiate vertigo from other causes of dizziness such as presyncope, hyperventilation syndrome, disequilibrium, or psychiatric causes of lightheadedness. Tests of vestibular system (balance) function include: electronystagmography (ENG), Dix-Hallpike maneuver, rotation tests, head-thrust test, caloric reflex test, and computerized dynamic posturography (CDP).

The HINTS test, which is a combination of three physical exam tests that may be performed by physicians at the bedside has been deemed helpful in differentiating between central and peripheral causes of vertigo. The HINTS test involves: the horizontal head impulse test, observation of nystagmus on primary gaze, and the test of skew. CT scans or MRIs are sometimes used by physicians when diagnosing vertigo.

Tests of auditory system (hearing) function include pure tone audiometry, speech audiometry, acoustic reflex, electrocochleography (ECoG), otoacoustic emissions (OAE), and the auditory brainstem response test.

A number of specific conditions can cause vertigo. In the elderly, however, the condition is often multifactorial.

A recent history of underwater diving can indicate possibility of barotrauma or decompression sickness involvement, but does not exclude all other possibilities. The dive profile (which is frequently recorded by dive computer) can be useful to assess a probability for decompression sickness, which can be confirmed by therapeutic recompression.

In terms of the diagnosis of radial neuropathy the following tests/exams can be done to ascertain the condition:

Mirror-touch synesthesia is a rare condition which causes individuals to experience the same sensation (such as touch) that another person feels. For example, if someone with this condition were to observe someone touching their cheek, they would feel the same sensation on their own cheek. Synesthesia, in general, is described as a condition in which a stimulus causes an individual to experience an additional sensation. Synesthesia is usually a developmental condition; however, recent research has shown that mirror touch synesthesia can be acquired after sensory loss following amputation.

Initial line of treatment is with anti-inflammatory drugs or cortisone injections. There have been trials with gloves which help protect the ulnar nerve from compression. The most radical treatment option is surgery to relieve tension in the volar carpal ligament which forms the roof of Guyon's canal, thereby reducing compression on the ulnar nerve.

The place of chiropractic-, physical-, occupational-, massage- and osteopathic therapy was not confirmed in scientific studies. These treatments can be both expensive as well as dangerous (causing permanent damage when performed wrongly).

It is advised to consult a physician beforehand starting any therapy, albeit an alternative approach, to avoid any permanent nerve damage.

In terms of prognosis radial neuropathy is not necessarily permanent, though sometimes there could be partial loss of movement/sensation.Complications may be possible deformity of the hand in some individuals.

If the injury is axonal (the underlying nerve fiber itself is damaged) then full recovery may take months or years ( or could be permanent). EMG and nerve conduction studies are typically performed to diagnose the extent and distribution of the damage, and to help with prognosis for recovery.

Intravenously administered penicillin is the treatment of choice. Associated pain can be treated with opiates, valproate, or carbamazepine. Those with tabes dorsalis may also require physical therapy to deal with muscle wasting and weakness. Preventive treatment for those who come into sexual contact with an individual with syphilis is important.

Hypoesthesia (or hypesthesia) refer to a reduced sense of touch or sensation, or a partial loss of sensitivity to sensory stimuli. In everyday speech this is sometimes referred to as "numbness".

Hypoesthesia is one of the negative sensory symptoms associated with cutaneous sensory disorder (CSD). In this condition, patients have abnormal disagreeable skin sensations that can be increased (stinging, itching or burning) or decreased (numbness or hypoesthesia). There are no other apparent medical diagnoses to explain these symptoms.

Cutaneous hyperesthesia has been associated with diagnosis of appendicitis in children but this symptom was not supported by the evidence.

Hypoesthesia originating in (and extending centrally from) the feet, fingers, navel, and/or lips is one of the common symptoms of beriberi, which is a set of symptoms caused by thiamine deficiency.

Hypoesthesia is also one of the more common manifestations of decompression sickness (DCS), along with joint pain, rash and generalized fatigue.

Peripheral neuropathy may first be considered when an individual reports symptoms of numbness, tingling, and pain in feet. After ruling out a lesion in the central nervous system as a cause, diagnosis may be made on the basis of symptoms, laboratory and additional testing, clinical history, and a detailed examination.

During physical examination, specifically a neurological examination, those with generalized peripheral neuropathies most commonly have distal sensory or motor and sensory loss, although those with a pathology (problem) of the nerves may be perfectly normal; may show proximal weakness, as in some inflammatory neuropathies, such as Guillain–Barré syndrome; or may show focal sensory disturbance or weakness, such as in mononeuropathies. Classically, ankle jerk reflex is absent in peripheral neuropathy.

A physical examination will involve testing the deep ankle reflex as well as examining the feet for any ulceration. For large fiber neuropathy, an exam will usually show an abnormally decreased sensation to vibration, which is tested with a 128-Hz tuning fork, and decreased sensation of light touch when touched by a nylon monofilament.

Diagnostic tests include electromyography (EMG) and nerve conduction studies (NCSs), which assess large myelinated nerve fibers. Testing for small-fiber peripheral neuropathies often relates to the autonomic nervous system function of small thinly- and unmyelinated fibers. These tests include a sweat test and a tilt table test. Diagnosis of small fiber involvement in peripheral neuropathy may also involve a skin biopsy in which a 3 mm-thick section of skin is removed from the calf by a punch biopsy, and is used to measure the skin intraepidermal nerve fiber density (IENFD), the density of nerves in the outer layer of the skin. Reduced density of the small nerves in the epidermis supports a diagnosis of small-fiber peripheral neuropathy.

Laboratory tests include blood tests for vitamin B-12 levels, a complete blood count, measurement of thyroid stimulating hormone levels, a comprehensive metabolic panel screening for diabetes and pre-diabetes, and a serum immunofixation test, which tests for antibodies in the blood.

Left untreated, tabes dorsalis can lead to paralysis, dementia, and blindness. Existing nerve damage cannot be reversed.

Treatment is directed at the pathology causing the paralysis. If it is because of trauma such as a gunshot or knife wound, there may be other life-threatening conditions such as bleeding or major organ damage which should be dealt with on an emergent basis. If the syndrome is caused by a spinal fracture, this should be identified and treated appropriately. Although steroids may be used to decrease cord swelling and inflammation, the usual therapy for spinal cord injury is expectant.

A doctor will base his or her diagnosis on the symptoms the patient has and the results of tests, including:

- An X-ray

- Magnetic resonance imaging (MRI), which usually provides the most information

- Computed tomography (CT) scan

Congenital insensitivity to pain with anhidrosis (CIPA), also known as hereditary sensory and autonomic neuropathy type IV (HSAN IV), is characterized by insensitivity to pain, anhidrosis (the inability to sweat), and intellectual disability. The ability to sense all pain (including visceral pain) is absent, resulting in repeated injuries including: oral self-mutilation (biting of tongue, lips, and buccal mucosa); biting of fingertips; bruising, scarring, and infection of the skin; multiple bone fractures (many of which fail to heal properly); and recurrent joint dislocations resulting in joint deformity. Sense of touch, vibration, and position are normal. Anhidrosis predisposes to recurrent febrile episodes that are often the initial manifestation of CIPA. Hypothermia in cold environments also occurs. Intellectual disability of varying degree is observed in most affected individuals; hyperactivity and emotional lability are common.

Hereditary sensory neuropathy type IV (HSN4) is a rare genetic disorder characterized by the loss of sensation (sensory loss), especially in the feet and legs and, less severely, in the hands and forearms. The sensory loss is due to abnormal functioning of small, unmyelinated nerve fibers and portions of the spinal cord that control responses to pain and temperature as well as other involuntary or automatic body processes. Sweating is almost completely absent with this disorder. Intellectual disability is usually present.

Type 4, congenital insensitivity to pain with anhidrosis (CIPA), is an autosomal recessive condition and affected infants present with episodes of hyperthermia unrelated to environmental temperature, anhidrosis and insensitivity to pain. Palmar skin is thickened and charcot joints are commonly present. NCV shows motor and sensory nerve action potentials to be normal. The histopathology of peripheral nerve biopsy reveals absent small unmyelinated fibers and mitochondria are abnormally enlarged.

Management of Hereditary sensory and autonomic neuropathy Type 4:

Treatment of manifestations: Treatment is supportive and is best provided by specialists in pediatrics, orthopedics, dentistry, ophthalmology, and dermatology. For anhidrosis: Monitoring body temperature helps to institute timely measures to prevent/manage hyperthermia or hypothermia. For insensitivity to pain: Modify as much as reasonable a child’s activities to prevent injuries. Inability to provide proper immobilization as a treatment for orthopedic injuries often delays healing; additionally, bracing and invasive orthopedic procedures increase the risk for infection. Methods used to prevent injuries to the lips, buccal mucosa, tongue, and teeth include tooth extraction, and/or filing (smoothing) of the sharp incisal edges of teeth, and/or use of a mouth guard. Skin care with moisturizers can help prevent palmar and plantar hyperkeratosis and cracking and secondary risk of infection; neurotrophic keratitis is best treated with routine care for dry eyes, prevention of corneal infection, and daily observation of the ocular surface. Interventions for behavioral, developmental, and motor delays as well as educational and social support for school-age children and adolescents are recommended.

Prevention of secondary complications: Regular dental examinations and restriction of sweets to prevent dental caries; early treatment of dental caries and periodontal disease to prevent osteomyelitis of the mandible. During and following surgical procedures, potential complications to identify and manage promptly include hyper- or hypothermia and inadequate sedation, which may trigger unexpected movement and result in secondary injuries.