Thursday, July 29, 2010

'Sniff Detector' Lets Those Lacking Mobility Drive a Wheelchair With Their Noses



 
 
The Sniff Detector By turning nasal pressure into electrical signals, the sniff detector lets those with "locked-in" syndrome communicate and paraplegics operate an electric wheelchair. PNAS
Israeli researchers have sniffed out what could become a way to give paraplegics and those suffering from "locked-in" syndrome a means to communicate with the outside world and even drive a wheelchair using their noses.

Using a device that converts nasal pressure into electrical signals, the team has successfully enabled locked-in patients to write messages independent of stimulus and allowed paraplegics to effectively navigate an electric wheelchair.
The "sniff controller," as it is known, is worn externally via a rubber tube not unlike the ones often used in hospitals for patients who need oxygen. The nasal device is not universal, as about a quarter of all people in a healthy control group were found to have insufficient volitional control over their soft palate, the part of your nasal passageway that lets you regulate the strength of your sniffs. But for those with sufficient soft palate control, the sniff controller gave test subjects a new degree of freedom.
The researchers started with a group of 36 healthy individuals on whom they tested the response time and precision with which humans can control their nasal pressure on a video game system that also measured their ability to with a mouse and a joystick. The team found that nasal control was just as reliable as mouse and joystick proficiency in those subject deemed to have good volitional control of their soft palates.

Encouraged, the team moved on to three patients suffering from "locked-in" syndrome, which allowed them to communicate using only their blinking eyes. Two of the three quickly learned to use a letter-choosing and word completion program that allowed them to initiate communication and expression (the third subject didn't take to the controller, though its unclear if the issue is soft palate-related or due to some other influence).


The team also created an interface for controlling an electric wheelchair using the sniff detector (two successive sniffs in = forward, two successive sniffs out = backward, etc.) and tested it on ten healthy patients. Again, they found that after a bit of practice the control group could easily navigate the wheelchair, so they put a man paralyzed from the neck down in the driver's seat. To their amazement, they found that after just 15 minutes a paraplegic can become quite skilled at navigating a wheelchair using the sniff detector.


Obviously these tests were conducted on a small group and further study and refinement is needed. But for those suffering from ailments that have denied them their mobility or their capacity to communicate, the sniff controller could provide a means for operating all kinds of devices that could improve quality of life.

Wednesday, July 28, 2010

Inhale, exhale and move forward

 
 
Quadriplegics like England’s Prof. Stephen Hawking who have difficulty even pressing buttons or moving a joystick will be able to navigate their wheelchairs and communicate with others more easily by inhaling or exhaling through the nose at a sniffing device invented at the Weizmann Institute of Science.

Prof. Noam Sobel, electronics engineers Dr. Anton Plotkin and Aharon Weissbrod, and research student Lee Sela developed the technology in the Rehovot institute’s neurobiology department, which announced the achievement on Tuesday.

The unique device could replace the more tedious technology of blinking one’s eyelids to choose letters and piece together words, use a computer or steer an electric wheelchair.

Sniffing technology, said the developers, might even be used in the future to create a sort of “third hand,” to assist healthy surgeons or pilots.

The new system identifies changes in air pressure inside the nostrils and translates these into electrical signals. After the device was tested on both healthy volunteers and quadriplegics, the results showed that the method is easily mastered.

Users were able to navigate a wheelchair around a complex path or play a computer game with nearly the speed and accuracy of a mouse or joystick.

“The most stirring tests were those we did with locked-in syndrome patients,” said Sobel.

“These are people with unimpaired cognitive function who are completely paralyzed – ‘locked into’ – their bodies.

With the new system, they were able to communicate with family members,and even initiate communication with the outside world. Some wrote poignant messages to their loved ones, sharing with them – for the first time in a very long time – their thoughts and feelings.”

Four of those who participated in the experiments are already using the new writing system, and the Weizmann Institute’s technology transfer arm, Yeda Research and Development Company, Ltd., is investigating the possibilities for developing and distributing the technology.

Sniffing is a precise motor skill that is controlled, in part, by the soft palate – the flexible divider that moves to direct air in or out through the mouth or nose. The soft palate is controlled by several nerves that connect to it directly through the skull. This close link led Sobel and his scientific team to theorize that the ability to sniff – that is, to control soft palate movement – might be preserved even in the most acute cases of paralysis.

Functional magnetic resonance imaging (fMRI) provided evidence behind the idea, showing that a number of brain areas contribute to softpalate control. This imaging revealed a significant overlap between soft palate control and the language areas of the brain, hinting to the scientists that the use of sniffing to communicate might be learned intuitively.

To test their theory, the researchers created a device with a sensor that fits on the nostril’s opening and measures changes in air pressure. For patients on respirators, they developed a different version of the device, which diverts airflow to the patient’s nostrils.

About three-quarters of the subjects on respirators were able to control their soft-palate movement to operate the device.

Initial tests, carried out with healthy volunteers, demonstrated that the device compared favorably with a mouse or joystick for playing computer games. In the next stage, carried out in collaboration with Prof. Nachum Soroker of Loewenstein Hospital Rehabilitation Center in Ra’anana, quadriplegics and locked-in patients tested the device.

One patient who had been locked in for seven months following a stroke learned to use the device over a period of several days, writing her first message to her family. Another, who had been locked in since a traffic accident 18 years earlier, wrote that the new device was much easier to use than one based on blinking. Another 10 quadriplegics succeeded in operating a computer and writing messages via sniffing.

The device can also function as a sort of steering mechanism for wheelchairs: Two successive sniffs in tell it to go forward, two out mean reverse, out and then in turn it left, and in and out turn it right. After 15 minutes of practice, a subject who is paralyzed from the neck down managed to navigate a wheelchair through a complex route – sharp turns and all.

Sniffs can be in or out, strong or shallow, long or short; and this gives the device’s developers the opportunity to create a complex “language” with multiple signals.

The new system is relatively inexpensive to produce, Sobel suggests, and simple and quick to learn to operate in comparison with other brainmachine interfaces.




Inhale, exhale and move forward

Friday, July 16, 2010

General Information about the Disease

Amyotrophic lateral sclerosis

Definition

Amyotrophic lateral sclerosis, or ALS, is a disease of the nerve cells in the brain and spinal cord that control voluntary muscle movement.
ALS is also known as Lou Gehrig's disease.

Alternative Names

Lou Gehrig's disease; ALS; Upper and lower motor neuron disease; Motor neuron disease

Causes

In about 10% of cases, ALS is caused by a genetic defect. In other cases, the cause is unknown.
In ALS, nerve cells (neurons) waste away or die, and can no longer send messages to muscles. This eventually leads to muscle weakening, twitching, and an inability to move the arms, legs, and body. The condition slowly gets worse. When the muscles in the chest area stop working, it becomes hard or impossible to breathe on one's own.
ALS affects approximately 1 out of every 100,000 people.
Except for having a family member who has a hereditary form of the disease, there are no known risk factors.

Symptoms

Symptoms usually do not develop until after age 50. Persons with ALS have a loss of muscle strength and coordination that eventually gets worse. This eventually makes one unable to do routine tasks such as going up steps, getting out of a chair, or swallowing.
Breathing or swallowing muscles may be the first muscles affected. As the disease gets worse, more muscle groups develop problems.
ALS does not affect the senses (sight, smell, taste, hearing, touch), bladder or bowel function, or a person's ability to think or reason.
Symptoms include:
  • Difficulty breathing
  • Difficulty swallowing
    • Gagging
    • Chokes easily
  • Head drop due to weak spinal and neck muscles
  • Muscle cramps
  • Muscle weakness that slowly gets worse
    • Commonly involves one part of the body first, such as the arm or hand
    • Eventually leads to difficulty lifting, climbing stairs, and walking
  • Paralysis
  • Speech problems, such as a slow or abnormal speech pattern
  • Voice changes, hoarseness
Additional symptoms that may be associated with this disease:

Exams and Tests

An exam of the nerves and muscles shows weakness, often beginning in one area. There may be muscle tremors, spasms, twitching, or loss of muscle tissue (atrophy). Atrophy and twitching of the tongue are common.
The person's walk may be stiff or clumsy. Reflexes may be abnormal and may include loss of the gag reflex. Some patients have trouble controlling crying or laughing. This is sometimes called "emotional incontinence."
Tests that may be done include:
  • Blood tests to rule out other conditions
  • Breathing test to see if lung muscles are affected
  • EMG to see which nerves do not work properly
  • Genetic testing, if there is a family history of ALS
  • Head CT or MRI of head to rule out other conditions
  • Swallowing studies
  • Spinal tap (lumbar puncture)
CELIAC DISEASE can mimic ALS symptoms:
In this Case Study, the patient's initial presentation consisted of a progressive motor syndrome in the absence of sensory signs, with clinical evidence of upper and lower motor neuron degeneration, electromyographic evidence of widespread acute denervation, and hyperintensity in the corticospinal tracts revealed by MRI. In view of these findings, while acknowledging the unusual hemiparetic presentation and strikingly territorial nature of the white matter changes seen on MRI, a diagnosis of amyotrophic lateral sclerosis (ALS) was initially considered by the referring neurologist. The apparent presentation of a rare ALS variant in association with celiac disease—a condition with various neurological manifestations—made it entirely appropriate, however, to review the initial diagnosis and institute treatment for celiac disease. Ultimately, improvement in the patient's symptoms following treatment for celiac disease rendered the diagnosis of ALS untenable.
see study:
http://www.nature.com/ncpneuro/journal/v3/n10/full/ncpneuro0631.html

Celiac disease symptoms can be eliminated by maintaining a strict gluten free diet. A simple blood test, or a small biopsy can determine whether you do, or do not have celiac disease.

Treatment

There is no known cure for ALS. The first drug treatment for the disease is a medicine called riluzole. Riluzole may prolong life, but does not reverse or stop the disease from getting worse.
The goal of treatment is to control symptoms. Baclofen or diazepam may be used to control spasticity that interferes with activities of daily living. Trihexyphenidyl or amitriptyline may be prescribed for people with problems swallowing their own saliva.
Physical therapy, rehabilitation, use of braces or a wheelchair, or other orthopedic measures may be needed to maximize muscle function and general health.
Choking is common. Patients may decide to have a tube placed into their stomach for feeding. This is called a gastrostomy.
A nutritionist is very important to help prevent weight loss. The illness itself appears to increase the need for food and there is usually limited ability to swallow.
The use of devices to assist in breathing includes machines that are only used at night as well as constant mechanical ventilation. Patients should discuss their wishes regarding artificial ventilation with their families and doctors.

Support Groups

Emotional support is vital in coping with the disorder, because mental functioning is not affected. Groups such as the ALS Association may be available to assist in coping with the disorder.

Outlook (Prognosis)

There is progressive loss of ability to function or care for oneself. Death often occurs within 3 to 5 years of diagnosis, about 20% of patients survive more than 5 years after diagnosis.

Possible Complications

When to Contact a Medical Professional

Call your health care provider if symptoms suggest ALS, particularly if there is a family history of the disorder.
Call your health care provider if ALS has been diagnosed and symptoms worsen or new symptoms develop. Increased difficulty swallowing, difficulty breathing, and episodes of apnea are symptoms that require immediate attention.

Prevention

Genetic counseling may be advised if there is a family history of ALS.