’Lightning Fast’ Switch Increases Accuracy, Reduces Fatigue

by Alyssa Quintero on Sun, 2009-02-01 14:31

Wireless switch with Bluetooth technology responds to the faintest muscle movement

David Jayne
Although single-switch scanning is considered a slow method for computer access, David Jayne is scanning faster and more accurately with the Impulse switch, which responds to slight muscle movements in his forehead.

In the January issue, we explored the technological wonder of a head mouse, or tracker, and its ability to facilitate hands-free computer access in conjunction with specialized communication software, onscreen keyboards and mouse-clicking solutions.

As technology evolves, new adaptations for hands-free computer access tools help people with ALS communicate, stay online and even drive a wheelchair — all with the slight movement of one working muscle.

More than a switch

For longtime ALS survivors David Jayne and Jack Hurst, AbleNet’s new Impulse computer-access device keeps them online and connected to the world.

Manufactured by Neural Signals for AbleNet, the Impulse switch ($2,100) is wireless and powered by Bluetooth technology. It uses an electrode to measure electromyography (EMG) impulses through small muscle contractions, providing a way to control computers and speech-generating devices with very small movements.

Used in conjunction with a Windows-based computer and the EZ Keys communication software (manufactured by Words+; retail price $1,395), the device provides complete computer control. The adjustable switch sensitivity makes it effective for users who only can manage the slightest muscle movement.

No visible muscle movement is necessary to set off the switch, reducing user fatigue, said Joe Wright, Neural Signals’ vice president of product development. The fact that it’s wireless makes it easier for caregivers to maneuver around the person, he added.

Staying on course

Disability-rights activist David Jayne of Rex, Ga., uses a single-switch scanning computer system for communication, environmental controls and driving his wheelchair. (See “Keep on Keepin’ On," MDA/ALS Newsmagazine, January 2008, and “On My Command,” Quest, May-June 2008.)

(Single-switch scanning is used by people who have one reliable movement to activate a switch. The switch prompts the computer/communication software to scan a variety of options, briefly highlighting each. Once the desired option is highlighted, the user again activates the switch to make the selection.)

Up until nine months ago, Jayne relied on a fiber optics switch attached to his eyeglasses to send commands to his laptop for communication, environmental controls and driving his wheelchair.

Always in search of the most functional and cutting-edge developments in assistive technology, Jayne was encouraged by fellow ALS survivor Jack Hurst to try the Impulse switch. Hurst, 70, of Marietta, Ga., has used the switch for more than a year, dating back to its early development and testing stages.

Jayne, 47, wasn’t excited about changing access methods, but he consulted with Neural Signals to make the switch more functional with an easy setup; compatible with his computer/communication system, particularly his specialized wheelchair-driving software; and able to reboot his computer independently, something he could do with his fiber optics switch system. He’s very happy with the result.

“The switch is lightning fast,” Jayne said via e-mail. “I am scanning faster and driving better than ever as a result of the switch. The adjustable sensitivity can be reduced to the point that sometimes it feels like I’m just thinking of moving the muscle.

“I’m doing everything faster, more accurately and with less effort than ever before.”

A wireless world

Although eye-tracking (also called “eyegaze”) technology can be made to work faster by adjusting the settings, Jayne asserts that the Impulse is the best option for single-switch users like him because he’s constantly changing lighting environments or is in direct sunlight. (Light can interfere with eye-tracking technology.)

Because his laptop controls virtually every aspect of his environment, Jayne demands a reliable system, and “eyegaze technology hasn’t advanced to meet my needs at this time.”

With adhesive strips, the Impulse switch is attached to the left side of Jayne’s forehead, and is activated by electrical activity in the muscle there. Jayne raises his eyebrows to activate the switch and begin scanning; when the desired option is highlighted, he raises his eyebrows again to make the selection.

For example, if Jayne wants to put his wheelchair in reverse, he raises his eyebrows to start scanning the driving software, and when the third line is highlighted, he raises his eyebrows again to scan each icon in the third line. When the down arrow is highlighted, he raises his eyebrows and holds them in position until he’s backed up the desired distance.

Highly responsive

AbleNet’s wireless Impulse switch uses Bluetooth technology to help provide computer access to people with limited movement. The device detects small muscle impulses and can be attached to virtually any part of the body, like the head or jaw, with a disposable sensor.

Like Jayne, Jack Hurst uses the Impulse switch and EZ Keys for full computer access. Hurst, who spends at least eight hours a day on his computer, uses his jaw muscle to activate the switch and send wireless signals to his computer. He bites down to start the scanning process, and when it reaches the desired letter or phrase, bites down again to select the option.

“I use my jaw muscle because it’s not tiring or fatiguing at all, it doesn’t require a lot of force to activate, and it keeps my jaw strong,” Hurst wrote via e-mail.

Jayne added, “The switch’s wireless feature is a wonderful benefit because there are no concerns about becoming disconnected by individuals who aren’t familiar with my equipment, and I thoroughly enjoy that my children and others can hug me without fear of disturbing my communication.”

Jayne said he didn’t realize how much effort he had been expending to trigger the fiber optics switch.

“I was anticipating when to activate the switch ahead of time,” he said. “Now, I activate the switch the instant the desired icon is highlighted [via scanning]. Eliminating the need to anticipate, combined with the minimal effort to activate, has increased my scanning rate and accuracy significantly.”

The switch’s sensitivity can be adjusted so low that it can be activated without any visible muscle movement, Jayne said, giving those who are almost completely paralyzed “hope of continued communication.”

For more information about the Impulse switch, visit www.ablenetinc.com, or call (800) 322-0956. To learn more about the EZ Keys communication software, go to www.words-plus.com, or call (800) 869-8521.

Alyssa Quintero
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