Tag Archives: Inner ear

Meniere’s Disease

Definition:
Ménière’s disease is a disorder of the inner ear that can affect hearing and balance to a varying degree. It is characterized by episodes of vertigo — a sensation of a spinning motion — along with fluctuating hearing loss, ringing in the ear (tinnitus), and sometimes a feeling of fullness or pressure in your ear. In most cases, Meniere’s disease affects only one ear.
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People in their 40s and 50s are more likely than people in other age groups to develop Meniere’s disease, but it can occur in anyone, even children.
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Although Meniere’s disease is considered a chronic condition, there are various treatment strategies that can help relieve symptoms and minimize the disease’s long-term impact on your life.

It is named after the French physician Prosper Ménière, who, in an article published in 1861, first reported that vertigo was caused by inner ear disorders. The condition affects people differently; it can range in intensity from being a mild annoyance to a chronic, lifelong disability

Symptoms:
The symptoms of Ménière’s are variable; not all sufferers experience the same symptoms. However, so-called “classic Ménière’s” is considered to have the following four symptoms:
CLICK TO SEE THE POICTURE
*Periodic episodes of rotary vertigo or dizziness.

*Fluctuating, progressive, unilateral (in one ear) or bilateral (in both ears) hearing loss, usually in lower frequencies.

*Unilateral or bilateral tinnitus.

*A sensation of fullness or pressure in one or both ears.

Ménière’s often begins with one symptom, and gradually progresses. However, not all symptoms must be present for a doctor to make a diagnosis of the disease.  Several symptoms at once is more conclusive than different symptoms at separate times.

Attacks of rotational vertigo can be severe, incapacitating, and unpredictable and can last anywhere from minutes to hours,  but generally no longer than 24 hours. For some sufferers however, prolonged attacks can occur, lasting from several days to several weeks, often causing the sufferer to be severely incapacitated. This combines with an increase in volume of tinnitus and temporary, albeit significant, hearing loss. Hearing may improve after an attack, but often becomes progressively worse. Nausea, vomiting, and sweating sometimes accompany vertigo, but are symptoms of vertigo, and not of Ménière’s.

Some sufferers experience what are informally known as “drop attacks”—a sudden, severe attack of dizziness or vertigo that causes the sufferer, if not seated, to fall without warning. Drop attacks are likely to occur later in the disease, but can occur at any time.[10] Patients may also experience the feeling of being pushed or pulled. Some patients may find it impossible to get up for some time, until the attack passes or medication takes effect.

In addition to hearing loss, sounds can appear tinny or distorted, and patients can experience unusual sensitivity to noises.

Some sufferers also experience nystagmus, or uncontrollable rhythmical and jerky eye movements, usually in the horizontal plane, reflecting the essential role of non-visual balance in coordinating eye movements

Migraine:
There is an increased prevalence of migraine in patients with Ménière’s disease.  As well, migraine leads to a greater susceptibility of developing Ménière’s disease. The distinction between migraine-associated vertigo and Ménière’s is that migraine-associated vertigo may last for more than 24 hours

Causes:
Ménière’s disease is idiopathic, but it is believed to be linked to endolymphatic hydrops, an excess of fluid in the inner ear.

he inner ear is a cluster of connected passages and cavities called a labyrinth. The outside of the inner ear is made of bone (bony labyrinth). Inside is a soft structure of membrane (membranous labyrinth) that’s a slightly smaller, similarly shaped version of the bony labyrinth. The membranous labyrinth contains a fluid (endolymph) and is lined with hair-like sensors that respond to movement of the fluid.

In order for all of the sensors in the inner ear to function properly, the fluid needs to retain a certain volume, pressure and chemical composition. Factors that alter the properties of inner ear fluid may help cause Meniere’s disease. Scientists have proposed a number of potential causes or triggers, including:

*Improper fluid drainage, perhaps because of a blockage or anatomic abnormality

*Abnormal immune response

*Allergies

*Viral infection

*Genetic predisposition

*Head trauma

Because no single cause has been identified, it’s likely that Meniere’s disease is caused by a combination of factors.

Complications:
The unpredictable episodes of vertigo are usually the most debilitating problem of Meniere’s disease. The episodes often force a person to lie down for several hours and lose time from work or leisure activities, and they can cause emotional stress.

Vertigo can also increase your risk of:

*Falls

*Accidents while driving a car or operating heavy machinery

*Depression or anxiety in dealing with the disease

*Permanent hearing loss

Diagnosis:
Doctors establish a diagnosis with complaints and medical history. However, a detailed otolaryngological examination, audiometry and head MRI scan should be performed to exclude a vestibular schwannoma or superior canal dehiscence which would cause similar symptoms. There is no definitive test for Ménière’s, it is only diagnosed when all other causes have been ruled out. If any cause had been discovered, this would eliminate Ménière’s disease, as by its very definition,  as an exclusively idiopathic disease, it has no known causes.

Treatment:
Because Ménière’s cannot be cured, treatments focus more on addressing symptoms. In extreme cases, it is necessary to destroy vestibular hair cells with the antibiotic streptomycin or to remove the affected labyrinth surgically in order to relieve severe vertigo. Patients are sometimes treated by the insertion of a shunt that diverts excess endolymph directly to the cerebrospinal fluid, a procedure that is not always effective. Typical remedies to improve symptoms may include:

*Antihistamines considered antiemetics such as meclozine and dimenhydrinate

*Antiemetic drugs such as trimethobenzamide.

*Antivertigo/antianxiety drugs such as betahistine and diazepam.

*Herbal remedies such as ginger root

Coping:
Sufferers tend to have high stress and anxiety due to the unpredictable nature of the disease. Healthy ways to combat this stress can include aromatherapy, yoga, T’ai chi., and meditation.

Surgery:
If symptoms do not improve with typical treatment, more permanent surgery is considered.  Unfortunately, because the inner ear deals with both balance and hearing, few surgeries guarantee no hearing loss.

Nondestructive:
Nondestructive surgeries include those which do not actively remove any functionality, but rather aim to improve the way the ear works.

Intratympanic steroid treatments involve injecting steroids (commonly dexamethasone) into the middle ear in order to reduce inflammation and alter inner ear circulation.

Surgery to decompress the endolymphatic sac has shown to be effective for temporary relief from symptoms. Most patients see a decrease in vertigo occurrence, while their hearing may be unaffected. This treatment, however, does not address the long-term course of vertigo in Ménière’s disease.  Danish studies even link this surgery to a very strong placebo effect, and that very little difference occurred in a 9-year followup, but could not deny the efficacy of the treatment

Destructive
Destructive surgeries are irreversible, and involve removing entire functionality of most, if not all, of the affected ear.

The inner ear itself can be surgically removed via labyrinthectomy. Hearing is always completely lost in the affected ear with this operation. Alternatively, a chemical labyrinthectomy, in which a drug (such as gentamicin) that “kills” the vestibular apparatus is injected into the middle ear can accomplish the same results while retaining hearing.

Alternatively, surgeons can cut the nerve to the balance portion of the inner ear in a vestibular neurectomy. Hearing is often mostly preserved, however the surgery involves cutting open into the lining of the brain, and a hospital stay of a few days for monitoring would be required.

Vertigo (and the associated nausea and vomiting) typically accompany the recovery from destructive surgeries as the brain learns to compensate

Physiotherapy:
Physiotherapists also have a role in the management of Meniere’s disease. In vestibular rehabilitation, physiotherapists use interventions aimed at stabilizing gaze, reducing dizziness and increasing postural balance within the context of activities of daily living. After a vestibular assessment is conducted, the physiotherapist tailors the treatment plan to the needs of that specific patient.

The central nervous system (CNS) can be re-trained because of its plasticity, or alterability, as well as its repetitious pathways. During vestibular rehabilitation, physiotherapists take advantage of this characteristic of the CNS by provoking symptoms of dizziness or unsteadiness with head movements while allowing the visual, somatosensory and vestibular systems to interpret the information. This leads to a continuous decrease in symptoms.

Although a significant amount of research has been done regarding vestibular rehabilitation in other disorders, substantially less has been done specifically on Meniere’s disease. However, vestibular physiotherapy is currently accepted as part of best practices in the management of this condition

Prognosis:
Ménière’s disease usually starts confined to one ear, but it often extends to involve both ears over time. The number of patients who end up with bilaterial Ménière’s is debated, with ranges spanning from 17% to 75%.

Some Ménière’s disease sufferers, in severe cases, may end up losing their jobs, and will be on disability until the disease burns out.  However, a majority (60-80%) of sufferers will not need permanent disability and will recover with or without medical help.

Hearing loss usually fluctuates in the beginning stages and becomes more permanent in later stages, although hearing aids and cochlear implants can help remedy damage.  Tinnitus can be unpredictable, but patients usually get used to it over time.

Ménière’s disease, being unpredictable, has a variable prognosis. Attacks could come more frequently and more severely, less frequently and less severely, and anywhere in between.  However, Ménière’s is known to “burn out” when vestibular function has been destroyed to a stage where vertigo attacks cease.

Studies done on both right and left ear sufferers show that patients with their right ear affected tend to do significantly worse in cognitive performance.   General intelligence was not hindered, and it was concluded that declining performance was related to how long the patient had been suffering from the disease

Disclaimer: This information is not meant to be a substitute for professional medical advise or help. It is always best to consult with a Physician about serious health concerns. This information is in no way intended to diagnose or prescribe remedies.This is purely for educational purpose

Resources:
http://en.wikipedia.org/wiki/M%C3%A9ni%C3%A8re’s_disease
http://www.mayoclinic.com/health/menieres-disease/DS00535

http://www.dizziness-and-balance.com/disorders/menieres/menieres.html

http://www.360balance.com/hydrops.html

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Light May Bring Sound to the Deaf

Section through the spiral organ of Corti (mag...

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Researchers at Northwestern University in Chicago have made a new discovery that could lead to better cochlear implants for deaf people.
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Infrared light can stimulate neurons in the inner ear as precisely as sound waves, a discovery that could lead to better cochlear implants
They have found that infrared light can stimulate neurons in the inner ear as precisely as sound waves, reports New Scientist.

A healthy inner ear uses hair cells that respond to sound to stimulate neurons that send signals to the brain. However, hair cells can be destroyed by disease or injury, or can contain defects at birth, leading to deafness. In such cases, cochlear implants can directly stimulate neurons.

The hearing provided by implants is good enough to enable deaf children to develop speech skills that are remarkably similar to hearing children’s.

However, implant users still find it tough to appreciate music, communicate in a noisy environment and understand tonal languages like Mandarin and that’s because the implants use only 20 or so electrodes, a small number compared to the 3000-odd hair cells in a healthy ear.

More sources of stimulation should make hearing clearer but more electrodes cannot be packed in because tissue conducts electricity, so signals from different electrodes would interfere.

On the contrary, laser light targets nerves more precisely and doesn’t spread, which could allow an implant to transmit more information to the neurons.

In order to explore that idea, a research team led by Claus-Peter Richter at Northwestern University in Chicago shone infrared light directly onto the neurons in the inner ear of deaf guinea pigs.

At the same time, the researchers recorded electrical activity in the inferior colliculus, a relay between the inner ear and the brain cortex, producing a set of frequency “maps”.

These maps are a good indication of the quality of sound information sent to the brain.

Richter said that electrical stimulation of the inner ear by a cochlear implant produces blurred maps, but the light stimulation produced maps that were as sharp as those produced by sound in hearing guinea pigs.

While it’s a mystery how light stimulates the neurons, as they do not contain light-sensitive proteins, Richter hypothesizes the heat that accompanies the light may play a role, and his team is now investigating the long-term effects of heating neurons.

The findings were presented at the Medical Bionics conference in Lorne, in the Australian state of Victoria, earlier this week.

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Light-wave implant hope for deaf

Original Signal-Transmitting Science

Light may bring sound to the deaf

Light opens up a world of sound for the deaf

Sources: The Times Of India

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Bromelain

The cochlea and vestibule, viewed from above.Image via Wikipedia

Scientists have used gene therapy on mouse embryos to grow hair cells with the potential to reduce hearing loss in adult animals, according to a study.

The proof-of-concept experiments are a crucial step toward therapies that could one day treat deafness and inner-ear disease in humans, said the study, published in the British journal Nature on Wednesday.

Sensory hair cells inside the cochlea, the auditory portion of the inner ear, convert sound waves into electrical impulses that are delivered to the brain.

The loss of these cells and the neurons they contain is the most common cause of hearing impairment and so-called nerve deafness. At birth, humans have about about 30,000 hair cells, which can be damaged by factors like infections, aging, genetic diseases, loud noise or treatment with certain drugs.

In most cases, damaged hair cells do not regrow in mature humans. But recent research has kindled hope that nerve deafness may one day be curable.

A team of scientists led by John Brigande at the Oregon Health and Science University, in Portland showed that implanting a gene known as Atoh1 into the inner ear of a mouse embryo coaxed non-sensory cells to become hair cells.

Earlier research had pointed to similar results, but this is the first study to show that the cells generated by the gene therapy are functional.

The production of extra, working hair cells in a mouse embryo could be an important step toward using similar therapies in human patients, the study by the researchers in US said.

Sources:The Times Of India

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Hearing Loss

 

 

Introduction:
The gradual hearing loss that occurs as you age (presbycusis) is a common condition. An estimated one-quarter of Americans between the ages of 65 and 75 and around three-quarters of those older than 75 have some degree of hearing loss.

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Over time, the wear and tear on your ears from noise contributes to hearing loss by damaging your inner ear. Doctors believe that heredity and chronic exposure to loud noises are the main factors that contribute to hearing loss. Other factors, such as earwax blockage, can prevent your ears from conducting sounds as well as they should.

You can’t reverse hearing loss. However, you don’t have to live in a world of quieter, less distinct sounds. You and your doctor or hearing specialist can deal with hearing loss by taking steps to improve what you hear.

Signs and symptoms
Signs and symptoms of hearing loss may include:

*Muffled quality of speech and other sounds
*Difficulty understanding words, especially against background noise or in a crowd of people
*Asking others to speak more slowly, clearly and loudly
*Needing to turn up the volume of the television or radio
*Withdrawal from conversations
*Avoidance of some social settings
How you hear:….click & see
Hearing occurs when sound waves reach the structures inside your ear, where the sound wave vibrations are converted into nerve signals that your brain recognizes as sound.

Your ear consists of three major areas: the outer ear, middle ear and inner ear. Sound waves pass through the outer ear and cause vibrations at the eardrum. The eardrum and three small bones of the middle ear  the hammer, anvil and stirrup   amplify the vibrations as they travel to the inner ear. There, the vibrations pass through fluid in the cochlea, a snail-shaped structure in the inner ear. Attached to nerve cells in the cochlea are thousands of tiny hairs that help translate sound vibrations into electrical signals that are transmitted to your brain. The vibrations of different sounds affect these tiny hairs in different ways, causing the nerve cells to send different signals to your brain. That’s how you distinguish one sound from another.

What causes hearing loss……....click & see
For some people, the cause of hearing loss is the result of a gradual buildup of earwax, which blocks the ear canal and prevents conduction of sound waves. Earwax blockage is a cause of hearing loss among people of all ages.

Most hearing loss results from damage to the cochlea. Tiny hairs in the cochlea may break or become bent, and nerve cells may degenerate. When the nerve cells or the hairs are damaged or missing, electrical signals aren’t transmitted as efficiently, and hearing loss occurs. Higher pitched tones may become muffled to you. It may become difficult for you to pick out words against background noise.

Ear infection and abnormal bone growths or tumors of the outer or middle ear can cause hearing loss. A ruptured eardrum also may result in loss of hearing.

Risk factors:
Factors that may damage or lead to loss of the hairs and nerve cells in your inner ear include:

Aging. The normal wear and tear from sounds over the years can damage the cells of your inner ear.

Loud noises. Occupational noise, such as from farming, construction or factory work, and recreational noise, such as from shooting firearms, snowmobiling, motorcycling, or listening to loud music, can contribute to the damage inside your ear.

Heredity. Your genetic makeup may make you more susceptible to ear damage.

Some medications. Drugs such as the antibiotic gentamicin and certain chemotherapy drugs can damage the inner ear. Temporary effects on your hearing — ringing in the ear (tinnitus) or hearing loss — can occur if you take very high doses of aspirin or nonsteroidal anti-inflammatory drugs (NSAIDs), antimalarial drugs or loop diuretics.

Some illnesses. Diseases or illnesses that result in high fever, such as meningitis, may damage the cochlea.

Comparing loudness of common sounds
What kind of decibel levels are you exposed to during a typical workday? To give you an idea, compare noises around you to these specific sounds and their corresponding decibel levels:

  • drugs can damage the inner ear. Temporary effects on your hearing — ringing in the ear (tinnitus) or hearing loss — can occur if you take very high doses of aspirin or nonsteroidal anti-inflammatory drugs (NSAIDs), antimalarial drugs or loop diuretics.
  • Some illnesses. Diseases or illnesses that result in high fever, such as meningitis, may damage the cochlea.

Comparing loudness of common sounds
What kind of decibel levels are you exposed to during a typical workday? To give you an idea, compare noises around you to these specific sounds and their corresponding decibel levels:


Sound levels of common noises
30 Whisper
60 Normal conversation
80 Heavy traffic, garbage disposal
85 to 90 Motorcycle, snowmobile, lawn mower
90 Belt sander, tractor
95 to 105 Hand drill, bulldozer, impact wrench
110 Chain saw, jack hammer
120 Ambulance siren
140 (pain threshold) Jet engine at takeoff
165 Shotgun blast
180 Rocket launch

Maximum sound exposure durations
Below are the maximum noise levels on the job to which you should be exposed without hearing protection — and for how long.

Maximum job-noise exposure allowed by law
90 8 hours
95 4 hours
100 2 hours
105 1 hour
115 15 minutes

When to seek medical advice:
Talk to your doctor if you have difficulty hearing. Your hearing may have deteriorated if you find that it’s harder to understand everything that’s said in conversation, especially when there’s background noise, if sounds seem muffled, or if you find yourself having to turn the volume higher when you listen to music, the radio or television.

Screening and diagnosis:
At first, your doctor may perform a general screening test to get an overall idea of how well you can hear. Your doctor may ask you to cover one ear at a time to see how well you hear words spoken at various volumes and how you respond to other sounds.

To determine your ability to hear and the extent of your hearing loss, your doctor may refer you to a hearing specialist (audiologist) for hearing tests.

During more thorough testing conducted by an audiologist, you wear earphones and hear sounds directed to one ear at a time. The audiologist presents a range of sounds of various tones and asks you to indicate each time you hear the sound. Each tone is repeated at faint levels to find out when you can barely hear. The audiologist will also present various words to determine your hearing ability.

Treatment:
Hearing loss treatment depends on the cause and severity of your hearing loss.

If your hearing loss is due to damage to your inner ear, a hearing aid can be helpful by making sounds stronger and easier for you to hear. If you can’t hear well because of earwax blockage, your doctor can remove the wax and improve your hearing. If you have severe hearing loss, a cochlear implant may be an option for you.

Removing wax blockage……...click & see
Earwax blockage is a common reversible cause of hearing loss. Your doctor may remove earwax by:

*Loosening the wax. Your doctor uses an eyedropper to place a few drops of baby oil, mineral oil or glycerin in your ear to loosen the wax, then squirts warm water into your ear using a bulb syringe. As you tilt your ear, the water drains out. Your doctor may need to repeat the process several times before the wax eventually falls out.

*Scooping out the wax. Your doctor may loosen the wax, and then scoop it out with a small instrument called a curette.

*Suctioning out the wax. Your doctor uses a suction deviceto remove the softened wax.

Hearing Aids:

An audiologist can discuss with you the potential benefits of using a hearing aid, recommend a device and fit you with it.

Hearing aids can’t help everyone with hearing loss, but they can improve hearing for many people. The components of a hearing aid include:

*A microphone to gather in the sounds around you
*An amplifier to make sounds louder
*An earpiece to transmit sounds to your ear
*A battery to power the device
The louder sounds help stimulate nerve cells in the cochlea so that you can hear better. Getting used to a hearing aid takes time. The sound you hear is different because it’s amplified. You may need to try more than one device to find one that works well for you. Most states have laws requiring a trial period before you buy a hearing aid, making it easier for you to decide if the hearing aid helps.

Hearing aids come in a variety of sizes, shapes and styles. Some hearing aids rest behind your ear with a small tube delivering the amplified sound to the ear canal. Other styles fit in your outer ear or within your ear canal.

Cochlear implants
If your hearing loss is more severe, often due to damage to your inner ear, an electronic device called a cochlear implant may be an option. Unlike a hearing aid that amplifies sound and directs it into your ear canal, a cochlear implant compensates for damaged or nonworking parts of your inner ear. If you’re considering a cochlear implant, your audiologist, along with a medical doctor who specializes in disorders of the ears, nose and throat (ENT), will likely discuss the risks and benefits with you

The components of a hearing aid are held in a small plastic container called the casing. All hearing aids use these common parts to help conduct sound from your environment into your ear. But different styles and different technologies make for many different types of hearing aids from which to choose.

Hearing aid styles vary by size. Though smaller styles may be less noticeable, they’re generally more expensive and have a shorter battery life. An audiologist can show you the various styles of hearing aids to help you decide which is best for you.

A microphone (1) picks up sounds. The sounds travel through a thin cable to a speech processor (2). You can wear the processor on a belt, in a pocket, or behind the ear. The processor converts the signal into an electrical code and sends the code back up the cable to the transmitter (3) fastened to your head. The transmitter sends the code through your skin to a receiver-stimulator (4 and 5) implanted in bone directly beneath the transmitter. The stimulator sends the code down a tiny bundle of wires threaded directly into your cochlea, the snail-shaped primary hearing organ. Nerve fibers are activated by electrode bands on this bundle of wires. Your auditory nerve carries the signal to your brain, which interprets the signal as a form of hearing.

Newer cochlear implants use an externally worn computerized speech processor that you can conceal behind your ear. The speech processor sends signals to a surgically implanted electronic chip that stimulates the hearing nerve of deaf people.

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causes of hearing loss

Hearing loss prevention consists of steps you can take to help you prevent noise-induced hearing loss and avoid worsening of age-related hearing loss:

  • Protect your ears in the workplace. Specially designed earmuffs that resemble earphones can protect your ears by bringing most loud sounds down to an acceptable level. Foam, pre-formed, or custom-molded earplugs made of plastic or rubber also can effectively protect your ears from damaging noise.
  • Have your hearing tested. Consider regular hearing tests if you work in a noisy environment. Regular testing of your ears can provide early detection of hearing loss. Knowing you’ve lost some hearing means you’re in a position to take steps to prevent further hearing loss.
  • Avoid recreational risks. Activities such as riding a snowmobile, hunting, and listening to extremely loud music for long periods of time can damage your ears. Wearing hearing protectors or taking breaks from the noise during loud recreational activities can protect your ears. Turning down the volume when listening to music can help you avoid damage to your hearing.

Coping skills

Try these tips to communicate more easily despite your hearing loss:

  • Position yourself to hear. Face the person with whom you’re having a conversation.
  • Turn off background noise. For example, noise from a television may interfere with conversation.
  • Ask others to speak clearly. Most people will be helpful if they know you’re having trouble hearing them.
  • Choose quiet settings. In public, such as in a restaurant or at a social gathering, choose a place to talk that’s away from noisy areas.
  • Consider using an assistive listening device. Hearing devices, such as TV-listening systems or telephone-amplifying devices, can help you hear better while decreasing other noises around you.

Click for Information from NIH about Hearing Loss

Hearing Loss Association Of America

Information abour Hearing Loss & Hearing Aids

What is Hearing Loss

Hearing impairment

Chinese herbs for improving hearing loss due to natural aging, ear …

How to Improve Hearing With Ear Candles

Conductive hearing loss can be treated with alternative therapies that are specific to the particular condition.

Hearing Loss: Alternative treatment

Disclaimer: This information is not meant to be a substitute for professional medical advise or help. It is always best to consult with a Physician about serious health concerns. This information is in no way intended to diagnose or prescribe remedies.This is purely for educational purpose

Resources:http://www.mayoclinic.com/health/hearing-loss/DS00172

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SID and SAD

Death is the end of life, when all brain activity ceases permanently. We all expect to die. But in Nature, the old die before the young, parents before their children. A disruption of this normal sequence results in distress, depression and an inability to cope.

CLICK & SEE....>…...SIDS………..SAD

SAD victims who simply drop dead in the middle of action may have unrecognized underlying risk factors

The unexpected death of a healthy child can be the result of SIDS (Sudden Infant Death Syndrome), also known as  cot death or  crib death  It occurs in a seemingly normal child, usually a male, under the age of one year, who goes to sleep in the night and fails to wake up in the morning.

The immature brains of children do not regulate the heart rate or breathing very efficiently, especially at night. This may be further compromised by exposure to cigarette smoke. Also, the child may be accidentally smothered when parents roll over in their sleep, or it could be that its nose and mouth get blocked by soft, fluffy sheets or pillows.

Parents are, therefore, advised to avoid sleeping in the same bed as the child and to always place the child on the back instead of the stomach. These measures appear to significantly reduce the number of SIDs.

Death in healthy young adults between the ages of 16 and 60 years may be due to accidents or violence. Some like the SIDS infants just  drop dead  or die during their sleep. Their death is sudden, unexpected, tragic and inexplicable.

These unexplained deaths have been grouped together and given the expressive acronym SAD (Sudden Adult Death). More men than women die this way. Some families are even considered cursed, with many economically productive young men in the family dying in the prime of their life.

Autopsies on SAD victims have shown that some of them actually did have unrecognized underlying risk factors. This is particularly true in India where we have many young undiagnosed diabetics and others with metabolic abnormalities of syndrome X (insulin resistance, hypertension, lipid abnormalities). Despite their youth, some had coronary arteries partially blocked with fatty deposits and plaques. In others, the vessels supplying the muscles of the heart arose from abnormal locations. The congenital heart diseases may have been mild enough to remain unrecognized and undiagnosed until it was too late. The efficient functioning of the heart may have been affected by a group of diseases called cardiomyopathies. Infection of the heart muscle (myocardium) with viruses and bacteria may have caused myocarditis. The infection can trigger arrhythmia and death. Some prescription drugs like terfenadine can also set off similar fatal reactions. Unfortunately, as such people appeared healthy and had no symptoms, they were never investigated for risk factors prior to the sudden death.

SAD has been in the news recently because of the discovery that many affected individuals had a  long QT  in their ECG (electrocardiograph). Even if the initial resting ECG is normal, the abnormality shows up on an ECG taken after exercise. These ECG changes are caused by disturbances in the electrical conduction currents of the heart and are inherited. The genetic defects causing this are of various types. The percentage of genetic carriers in the population is probably around 5 to 10 for 100,000 persons. This has lead to speculation that SID and SAD are two spectrums of the same disease.

The defects are commoner in Southeast Asia than in the western countries. The syndrome even has local names bangungutin the Philippines,  pokkuri in Japan and  lai tai in Thailand. It has been known for many centuries, although the precise defect was identified only recently.

About 60 per cent of people with hereditary long QT syndrome has non-specific symptoms like fainting spells or seizures during childhood and adolescence. Around 40 per cent has no symptoms at all and the condition may just present itself with sudden death. Many die in front of family and friends. Unfortunately, from the time the heart stops beating, irreversible brain damage occurs in three to six minutes, followed by coma and death. Cardio-pulmonary resuscitation (CPR) may have saved the lives of a few of these people. However, most people do not learn CPR, and others are too stunned by the occurrences to initiate it in time.

Once the long QT is picked up on an ECG, measures can be taken to prevent sudden death. Medications belonging to the beta-blocker group can be started. Certain prescription drugs that prolong the QT can be avoided. Potassium levels in blood need to be monitored as low levels can precipitate death. Some patients may need pacemakers.

Symptoms in persons with a long QT syndrome can be precipitated by physical exertion. The long QT has been implicated in the sudden death of trained Olympic-level athletes. Competitive sports, therefore, are risky and better avoided.

Exercise is good for health, well being, diabetic control and lipid abnormalities, but vigorous action should be undertaken only after medical advice in those with risk factors.

Source: The Telegraph (Kolkata, India)