'Lightning Fast' Switch Increases Accuracy, Reduces Fatigue

Wireless switch with Bluetooth technology responds to the faintest muscle movement

by Alyssa Quintero on July 1, 2009 - 2:38pm

QUEST Vol. 16, No. 3

Jayne uses the Impulse sensor to start scanning the wheelchair-driving software, which displays the drive function and a directional grid on his wheelchair-mounted laptop.

As technology evolves, new adaptations for hands-free computer access tools help people with muscle diseases 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, Impulse detects and wirelessly transmits the EMG signal to a Bluetooth receiver. Specialized Impulse software then processes the muscle signal as a switch “click,” which activates the communication software, such as EZ Keys (manufactured by Words+; retail price $1,395), for complete computer control.

The switch can be used for 24 hours between charges, and the adjustable switch sensitivity makes it effective for users who only can manage the slightest muscle movement.

Joe Wright, Neural Signals’ vice president of product development, said the sensitivity of the switch to slight movements cuts down on user fatigue. The lack of wires makes it easier for caregivers to maneuver around the person.

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 “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.)

Previously, Jayne relied on a fiber optics switch attached to his eyeglasses to send commands to his laptop for communication access, 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, 71, of Marietta, Ga., has used the switch for more than a year, dating back to its early development and testing stages.

Jayne, 48, 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 been 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 technology (also called “eyegaze”) can be made to work faster by adjusting the settings, Jayne says he prefers the Impulse because he’s constantly changing lighting environments and is in direct sunlight. Light, or different light angles, can interfere with some eye-tracking systems.

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.”

The Impulse sensor snaps onto a small, disposable electrode pad that sticks to the skin. It’s attached to the left side of Jayne’s forehead and is activated by electrical activity in the muscle there.

(The sensor can be attached to virtually any part of the body with a working muscle, and is commonly placed on the face, jaw, forehead, arm or leg. It’s advisable to work with an occupational or physical therapist to determine the appropriate spot.)

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 correct line of commands is highlighted, he raises his eyebrows again to scan each icon in that 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

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, he 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 said via e-mail.

Jayne said he appreciates the switch’s wireless feature “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.”

“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/impulse, or call (800) 322-0956. The AbleNet site also features a three-minute video of David Jayne using the Impulse switch to drive his wheelchair, speak and help lead a business presentation. To learn more about the EZ Keys communication software, go to www.words-plus.com, or call (800) 869-8521.

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