BION muscle stimulator research news

[Guest guest]

From the Los Angeles Times/Health, December 9, 2002

A bionic nerve's power

The experimental muscle stimulator offers new hope for recovery from

strokes and spinal cord injuries.

By Marsa, Times Staff Writer

It sounds like one of those fitness products peddled in late-night

infomercials -- an implantable stimulator that electrically exercises

muscles. But if current tests prove it effective, this miniature device

could revolutionize the treatment of strokes and spinal cord injuries.

In these conditions, nerve signals that spark normal muscle function are

blocked, causing paralysis. Over time, unused muscles atrophy, which can

make rehabilitation and recovery more difficult. The new device, called

a BION because it works like a bionic neuron, strengthens and retrains

these muscles by mimicking the nerve

impulses from the brain.

Scientists know that electricity can be used to activate nerves and

muscles

throughout the body, said Dr. Gerald E. Loeb, a biomedical engineer who

invented the muscle stimulator at USC's Alfred E. Mann Institute for

Biomedical Engineering. " But the trick was to create something that

worked inside the muscle without leaving wires dangling through the

skin. "

Encapsulated in glass with electrodes at each end, the tiny device (it's

the size of two grains of rice) is injected with a large needle directly

into the " motor spot " -- the place where nerve endings meet muscle. When

the muscles are ready to be

exercised, a magnetic transmitter coil is placed over that part of the

body. The coil sends power and command signals to the implant, prompting

it to emit electrical pulses that activate the muscles.

" This is a real advance over what we have to treat people with severe

muscle weakness, " said Dr. D. Bagg, a stroke specialist at

Queen's University in Canada who has studied the device. Because it

could be used at home, it is

expected to be more convenient and produce better patient compliance.

Although the technology won't make anyone buff, it can reverse muscle

atrophy, strengthen joints and enhance flexibility.

Therapeutic muscle stimulation is already used as part of physical

therapy in patients who have sustained nerve damage. But current methods

have drawbacks that limit their

widespread use.

The more common treatment is an electrical stimulator used on the

surface of the skin. However, the electrical jolts can be painful, too

high a charge can burn the skin, and the impulses may not hit the muscle

in the right place. On the other hand, devices inserted directly into

the muscles have to be surgically implanted, with electrical leads

protruding through the skin, which increases risks of infection and

breakage.

The new device seems to be just as effective, but without these

disadvantages. The first human tests of the bionic nerve began in 1999

in Canada, when the device was inserted into the shoulder muscles of 11

people who had recently suffered a stroke. The shoulder is a shallow

joint and is held together by the activity of the muscles. When the

muscles are flaccid, the weight of the muscles and the bone pulls the

arm out of its socket, a painful shoulder dislocation that afflicts many

stroke victims.

The study volunteers used the device, which can send up to 3,000

commands per second, at home for 20 to 30 minutes two to three times a

day. At the end of six weeks, X-rays

revealed that the therapy had strengthened muscles and that the shoulder

joint either remained aligned or, if it had already slipped out of

place, had returned to its normal position.

Italian researchers have also tested the bionic nerve on patients with

osteoarthritis in their knees. Because sufferers avoid bending their

knees because of the arthritis pain, the muscles often atrophy. In that

12-week study, the volunteers experienced a significant reduction in

pain and disability, and one even postponed a scheduled joint

replacement surgery, Loeb said.

Three new studies funded by the National Institutes of Health are

currently enrolling a small number of stroke patients at USC and Rancho

Los Amigos National Rehabilitation

Hospital. One will use the BION to treat chronic shoulder pain; another

will test whether the device can help restore muscle function in the

hands; and the third will determine whether it can prevent muscle

contractions in the hands, a condition known as claw hand deformity.

Although the technology is still in a relatively early stage, the bionic

nerve eventually may be used to treat all kinds of disabilities that

result from muscle paralysis, even serious spinal cord injuries, said

Dr. Sophia Chun, medical director

of outpatient clinical and rehabilitation services at Ranchos Los Amigos

National Rehabilitation Center in Downey. " There's a number of exciting

potential applications, " she says.

Stroke symptoms and current therapies

Each year, more than 750,000 Americans suffer strokes, which are

injuries to the brain caused by the blockage or rupture of blood vessels

ferrying vital nutrients and oxygen.

Strokes cause different symptoms depending on where the damage occurred.

When the brain region regulating specific movements is injured, it stops

sending nerve signals to animate different muscles. As a result, many

stroke victims suffer from speech and language difficulties, paralysis,

persistent problems with balance and walking, or they may develop a

condition known as spasticity, in which movement is difficult or

uncontrollable.

Traditional stroke treatments include surgery to treat or repair brain

damage, speech therapy and occupational therapy to relearn daily routine

activities. Botox injections

also are used to relax muscles stiffened by spasticity.

But physical therapy is the cornerstone of stroke rehabilitation.

Research has shown that the brain has great capacity to recover and

relearn, but the muscles must be

strengthened and retrained. Without therapy, muscles can deteriorate and

result in a permanent loss of function.