FDA Clears Device to Aid Walking in Stroke, CNS Disorders.... Emma Hitt, PhD

May 13, 2011 — The US Food and Drug Administration (FDA) has given 510(k) clearance to the NESS L300 Plus System (Bioness Inc), which facilitates walking in patients with stroke or central nervous system disorders.
According to the manufacturer, the NESS L300 Plus device stimulates knee flexion and extension along with ankle dorsiflexion during each step. The system includes a wireless, software-driven functional electrical stimulation system that targets the peroneal nerve with low levels of electrical stimulation to enable foot dorsiflexion and facilitate motor recovery.

NESS L300 Plus device

A wireless heel sensor detects gait variations while navigating uneven surfaces and changes in elevation and walking speeds. Together with a synchronized thigh stimulation cuff, this device controls the knee and facilitates walking.
The system is indicated for patients with a motor deficit in the lower limb(s) caused by conditions such as stroke, multiple sclerosis, traumatic brain injury, or spinal cord injury. Historically, rigid plastic braces that restrict thigh and ankle movements have been used. However, these can lead to additional problems, such as loss of range of motion.
Patients with central nervous system injuries or diseases are often affected by gait movement disorders, such as foot drop, which results from partial leg paralysis that prevents the foot from lifting. In addition to making walking difficult, gait movement disorders may also lead to mental and physical fatigue, falls, or abnormal walking patterns that can result in additional injury.
"An estimated 12.5 million Americans live with the effects of central nervous system injuries and disorders, and many of these individuals have gait disorders that make it difficult if not impossible for them to walk with freedom," noted Thomas G. Fogarty, president and chief executive officer of Bioness Inc, in a written release.
"The NESS L300 Plus will provide physical therapists an additional modality to optimize the patient's course of therapy and allow home users better control over their knee and foot, making it easier to walk," he adds.
The company anticipates that the NESS L300 Plus system will be commercially available to both neurorehabilitation hospitals and to patients for home use within the next few weeks.

More on This Topic

• Stroke/Cerebrovascular Disease News & Perspectives
• Trauma News & Perspectives
• Multiple Sclerosis (MS) News & Perspectives

Nervous System: Neurons

Nervous System: Neurons

I). Function

A). Sensory input 
B). Integration:
C). Response  

II). Division of the Nervous System

A). Central Nervous System: (CNS)

Brain and Spinal Cord only

B). Peripheral Nervous System

Outside CNS

1). Sensory or afferent division:

Carries impulses to CNS

2). Motor or efferent division

Carries impulses from the CNS.

i). Somatic Nervous System

voluntary

ii). Autonomic Nervous System

involuntary

a.  Parasympathetic
b.  Sympathetic

III). Types of cells

A). Non nervous or glial cells.

1). Astrocytes
2). Microglia
3). Ependymal
4). Oliodendrocytes
5). Satellite cells
6). Schwann cells form myelin sheaths 

B). Neurons

1). Structure

i). cell body or soma

endoplasmic reticulum called the nissl body.

ii). Processes or tracts (nerves)

a). Dendrites: input region
b). Axon: Carries information away
c). Synaptic knobs or Axonal terminals Releases neurotransmitters.

2). Axons

a). myelin sheath  

	protects and electrically insulates fibers
	conduct nerve impulses faster than nonmylenated fibers.

b). nodes of Ranvier:  

spaces between the sheaths

The action potential skips to the nodes

IV). Nerve Impulse

A). Terms

1). Resting membrane Potential: 

Polarized

2). Depolarization: 

Change in ion concentration

3). Hyperpolarization

Change in ion concentration inside becomes more negative

4). Graded Potential

Localized change in ion; subthreshold

5). Action Potential  

Change in ion concentration that does not decrease over distance.

B). Action Potential

Stages  of an Action Potential

polarized resting potential		depolarizes
repolarizes		undershoot phase

Undershoot : the K+ channels stay open once resting potential is reached;

hyperpolarizing the cell.

C). Propagation

	Cannot be depolarized again until the membrane has reached resting potential.
	The action potential moves at a constant velocity

D). All or none phenomenon

	Not all depolarizations result in action potentials
	The depolarization must reach the threshold point

E). Refractory period

absolute refractory period cannot respond to another stimuli.

relative refractory period  The threshold is higher

F). Impulse Velocity

	Strong stimuli result in more nerve impulses
	Not stronger impulses or faster

V). Synapse

junction that carries information between neurons.

A). Types

1). Electrical synapse: ions to cross junction
2). Chemical synapse

neurotransmitters

Impulse		releases Ca++ (in neuron)
±  neurotransmitter released ± binds to receptors±			ion channels open on postsynaptic membrane

B). Termination of neurotransmitter

1). Degradation enzymes
2). Neurotransmitter reabsorbed
3). Diffusion of the neurotransmitter 

VI). Types of Neurotransmitters

A). Excitatory Synapses

	neurotransmitters results in the depolarization of postsynaptic membrane.
	Creating localized graded response.

(dendrites do not have action potentials)

IF THE GRADED RESPONSE IS STRONG ENOUGH TO BE CARRIED TO THE AXON A FULL ACTION POTENTIAL WILL RESULT

B). Inhibitory Synapses

	Binding neurotransmitters reduces the postsynaptic membranes ability to create an action potential.
	Induces hyperpolarization.

C). Integration or Summation of Synaptic Events

It takes more than one synaptic event to create an action potential.

Presynaptic inhibition =

excitatory neurotransmitter by one neuron +

inhibitory neurotransmitter of another neuron

VII) Neurotransmitters

A). Acetylcholine (ACh)
B). Biogenic Amines

1). Dopamine
2). Norepinephrine
3). Epinephrine
4). Serotonin

C). Amino Acids
D). Peptides

1). endorphins

E). Novel or Miscellaneous

AP Song Book

The Brain Song
(sung to the tune of "Camptown Races")

by Pinky and the Brain

Hear the  Song:  http://www.youtube.com/watch?v=Li5nMsXg1Lk

Pinky: And now...the parts of the Brain...presented by the Brain Brain: Yes! Brain: Neo-cortex, frontal lobe Pinky: Brainstem! Brainstem! Brain: Hippocampus, neural node, Right hemisphere Brain: Pons and cortex visual Pinky: Brainstem! Brainstem! Brain: Sylvian fissure, pineal, Left hemisphere. Brain: Cer-e-bellum left! Cer-e-bellum right! Synapse, hypothalamus, Striatum, dendrite. [Brain dances with tambourine] Brain: Axon fibers, matter gray Pinky: Brainstem! Brainstem! Brain: Central tegmental pathway, Temporal lobe. Brain: White core matter, forebrain, skull Pinky: Brainstem! Brainstem! Brain: Central fissure, cord spinal, Parietal. Brain: Pia mater! Menengeal vein! Medulla oblongata and lobe limbic Micro-electrodes... Pinky: Naaarf! P+B: THE BRAIN!!! Brain: That ought to keep the little squirts happy. Ye-e-s

Song:  http://www.youtube.com/watch?v=Li5nMsXg1Lk