Combating Locked-In Syndrome: New Methods of Communication for ALS Patients

Biology 202
2006 First Web Paper
On Serendip

Combating Locked-In Syndrome: New Methods of Communication for ALS Patients

Andrea Goldstein

Imagine having a fully-functional brain trapped within a non-functioning body. The brain would be conscious and aware of its surroundings; it could think and process stimuli, but it would be unable to translate thought into action. Locked-In Syndrome is a rare disorder that results in just that; all of the body's voluntary muscles, with the exception of those that control eye movement, become completely paralyzed. There are no treatments available, nor is there a cure. (1) While Locked-In Syndrome is most commonly caused by damage to the pons (2), numerous other events or disorders can lead to this tragic locked-in state. Perhaps the most well-known disease that causes Locked-In Syndrome is Amyotrophic Lateral Sclerosis (ALS), known colloquially as Lou Gehrig's disease.

ALS is a progressive neurodegenerative disorder that causes the death of motor neurons. With no motor neurons to receive signals from the brain and cause movement, patients become completely paralyzed. After a period of no input from motor neurons, the muscles themselves atrophy and become weak. Finally, the brain loses the ability to start signals that cause voluntary movement altogether. Many ALS patients die from respiratory failure when their diaphragms and chest wall muscles fail to contract any longer. (3) The majority of ALS patients die within 3-5 years of diagnosis, but about 10% survive for ten years or more past their diagnosis, and 5% survive for twenty years after being diagnosed (4).

People are living longer with ALS due to several therapies. The newest treatment is a drug called riluzole, which reduces motor neuron damage by decreasing the release of glutamate, a neurotransmitter which may cause the degeneration of motor neurons in the first place. Riluzole has been clinically proven to prolong life for at least several months. Other treatments include speech and physical therapy and drugs that reduce symptoms that accompany ALS, such as fatigue, muscle spasms, and excess salivation. (3)

Because ALS destroys motor neurons, its effects are irreversible. Unlike the proportion of people with Locked-In Syndrome that eventually recover some motor function (2), ALS patients can never be freed from the prison of their minds. Despite the promising research being done to find more effective treatments and a cure, the more immediately pertinent research deals with how best to combat the imprisonment of the mind that comes with ALS. Most communication methods use eye movement to convey information, while some more experimental technologies use electrical impulses directly from the brain (5).

The simplest method of communication for ALS patients who are no longer able to move anything but their eyes involves no sophisticated technology at all. With the help of an assistant, patients can use eye blinks to signify which letters or syllables they would like to select from a chart, slowly and methodically putting together words and sentences. Eye response technologies are a more complicated method of communication that allows ALS patients to communicate significantly faster and independent of others. Eye-gaze Response Interface Computer Aid (ERICA), for example, uses a camera and infrared light to detect the position of a person's gaze on a computer screen. In this way, a person can essentially type with his or her eyes, performing computer tasks normally. In addition, the software that ERICA uses can produce a computerized voice, allowing the patient to "talk" to others. (6) This technology can provide a highly effective means of communication for as long as voluntary muscles in the eye remain intact.

In most cases, control of the eye muscles is retained throughout the span of ALS, but researchers are currently looking into devices that will allow ALS patients in advanced stages of the disease to communicate without using the eyes. In one method, an electrode is implanted directly into the brain. The electrode picks up electrical impulses and translates them into instructions for the control of a computer cursor, which in turn allows the patient to communicate via computer. Another method involves electrodes on the scalp that yield much the same result as the electrode in the brain itself. These devices take a relatively long amount of time to process information and create words (about 30 seconds per letter), but for patients whose eye movements are not under voluntary control, it is the only option. (5) Other experimental devices translate EEG activity to translate signals into words through biofeedback (7).

These new technologies give people with ALS hope for more normal lives. With more efficient communication technology, patients with ALS would no longer suffer from the most devastating mental effects of Locked-In Syndrome. Despite the fact that the motor neuron degeneration cannot currently be reversed, patients no longer have to remain imprisoned in their own minds. Eye response technologies and new experimental devices in the future can allow ALS patients to communicate effectively, freeing them from their personal jails. Perhaps this new technology that uses computers translating signals into speech will shed light on what "thoughts" really are and what produces speech. Further research can only lead to new ideas and more information about ALS and the Locked-In Syndrome that it produces.

Resources:
1)Locked-In Syndrome Information Page, from the National Institute of Neurological Disorders and Stroke website
2)A clinical review of Locked-In Syndrome by Eimear Smith and Mark Delargy
3)Amyotrophic Lateral Sclerosis Fact Sheet, from the National Institute of Neurological Disorders and Stroke website
4) Facts You Should Know About ALS, from the ALS Association website
5) Unlocking Locked-In Syndrome, from the Society for Neuroscience website
6)Eye-gaze technology, from the University of Minnesota Duluth website
7)Biofeedback and Locked-In Syndrome in ALS, from the Futurehealth Inc. website