electrical stimulating part

7/23/2019 Electrical Stimulating Part

http://slidepdf.com/reader/full/electrical-stimulating-part 1/53

Electrical Stimulation of the

Neuromuscular system, part II



Outline

• Introduction• Neuro-muscular junction, myelin sheet

• Examples of neuromuscular prostheses – Upper extremity

– Loer extremity – !ladder stimulation

• "eri#ati#es $∇% and cross, dot products&

• 'athematical formulation of the effect of currentstimulation from electrode immersed in conducti#emedia&



(he )del* operator $na+la, or ∇%

radient of p $here p is a scalar field% a #ector field.



No e ant to multiply a #ector field # +y the /radient&

"ot product +eteen #ectors a$x,y,0% and +$x,y,0%

11111111111111111111111111111111111111111

2ross product +eteen same #ectors

1111111111111111111111111111111111111111



3% "ot product +eteen /radient and v$x,y,0%

"efined as the "I4E5EN2E of v $it6s a scalar.%

7% 2ross product +eteen /radient and v$x,y,0%"efined as the 2U5L of v $it6s a #ector.%



Laplacian operator $∇7% di#er/ence of the /radient&

Scalar field.



Quasi-static formulation of Maxwell’s equations

11111111111111

11111111111111

11111111111111 11111111111111

Equivalence between dielectric and conductive media:

It helps to loo8 in static fields $due to point char/es% and

relate to fields due to current sources and sin8s&



No let6s deri#e the #olta/e at a point alon/ the axon

of a neuron +ein/ stimulated +y an electrode ith a

monopolar current source&

$See notes%



I93m:



4olta/e alon/ the axon due to a +ipolar source&

2urrent throu/h one electrode has the same amplitude

$+ut opposite si/n% as current throu/h the otherelectrode&



I93m:,d9?&3mm

y93?mm

x9r



No plot +oth sides of an axon – orthodromic and

antidromic – for the +ipolar stimulation&



'ONOFOL:5 S(I'



:NO"I2 S(I'UL:(ION

2:(O"I2 S(I'UL:(ION

'ONOFOL:5 S(I'

EJ(5:2ELLUL:5 V

:LON (E KI!E5



Iel93m:,

rhoe93 8Ohm&m,

093?mm



Electrode-tissue interface

• 2onstant current x constant #olta/e

stimulation

• (issue dama/e

– Fassi#e presence of forei/n o+ject $mechanical%

– :cti#e passa/e of current $electrochemical%



"ama/e to +iolo/ical tissue

• Fassi#e #ascular or neural

– o to o#ercome this

• 2han/e electrode si0e, tip /eometry, su+strate,

anchorin/

• :cti#e

– primary $reaction products from

electrochemistry%< – secondary $physiolo/ical chan/es associated

ith neural excitation&



• Stren/th-duration cur#e $o+tained empirically%

– FM9 pulseidth

– Ith9threshold current

– Irh 9 rheo+ase current, minimum current amplitude

if FM&

– (ch 9 chronaxie time FM to excite neuron ith 7Irh&

– Ith9 IrhP$Ith(chAFM%

Effect of a#eform

: di th di ti l ti



:nodic #s cathodic stimulation



Introduction

- 5estorin/ function is not immediate in paralysis&

Ex& Kreeand $+y Neuro2ontrolQ%

- KES $functional electrical stimulation% stimulate

the neuromuscular junction, neuron is stimulated

first $less char/e needed%

- Fhrenic ner#e stimulation restore respiration

$#entilation%

N l th



Neuromuscular prostheses

Ner#ous system injury 9 impairment of motor functions&

'otor functions +ody functions< lim+ mo#ement&

Objectives of neuroprostheses restore lost function,

increase independence of disa+led indi#iduals< reduce

economic impact of disa+ility&

2urrent neuroprostheses use KES $functional electrical

stimulation% to acti#ate motoneurons&

Motoneurons neurons that inner#ate muscles& 'uscles arethe actuators $for the desired function%&

2urrent tar/et patients stro8e $R@?,???Ayear incidence%< S2I

$3?,???Ayear incidence, hi/her pre#alence%&

Nodes of 5an#ier



Unmyelinated axon

'yelinated axon

Nodes of 5an#ier

httpAA&nc+i&nlm&nih&/o#A+oo8sA+oo8res&fc/iAneurosciAch;f3>&/if



5ecruitment properties

'a/nitude of muscular contraction depends on $3% electrodetype< $7% stimulation a#eform shape, time, amplitude< $;%location

of electrode relati#e to motoneuron&

orce modulation can +e achie#ed +y $3% rate modulation $7%

recruitment

$3% rate modulation there6s summation of muscular

contraction if hi/h enou/h freuency is used, +ut the muscle ismore prone to fati/ue& i/her freuency leads to hi/her $faster%

fati/ue&

$7% recruitment num+er of motoneurons stimulated more

neurons means more muscles&



'US2LE 3

'US2LE 7

'O(ONEU5ON

'O(ONEU5ON

!

"#

$

$ here the electrode is located& If the stimulus intensity is lo, this is the

only acti#ated area&

" $hite area% if sli/htly hi/her current, only muscle 3 ould contract&# possi+ly hi/her force exerted +y +oth muscles no&

! e#ery+ody is stimulated $+oth muscles, throu/h acti#ation of +oth

motoneuron&

'uscular recruitment throu/h electrical stimulation

Journal of Rehabilitation Research and Development



httpAA&#ard&or/AjourA?3A;TA@Aliu-f?3&/if

Jou a o e ab tat o esea c a d e e op e t

Vol. 38 No. 5, September/ctober !""#

%electivit& of intramuscular stimulatin' electrodes in the lower limbs

(onald )* +riolo, h!. Ma& Q* /iu, M%. (udi 0obetic, M%. )ames * 1hlir, M%

httpAA&#ard&or/AjourA?3A;TA@Aliu;T@&htm



5ecruitment properties

Nonlinearities should +e dealt ith in the implant ho tomeasure and deal ith fati/ue&

(here are hi/h /ain re/ions, and plateau re/ions $hy%&

Spillo#er should also +e a#oided $they contri+ute to the

nonlinearities%



'uscle stimulation

• Mith rare exceptions, neuroprosthesesacti#ate paraly0ed neurons at different

le#els of the ner#ous system

– Spinal cord – Spinal roots

– Feripheral ner#es

– Intramuscular ner#e +ranches



Electrode types

• Surface

– S8in has hi/h resistance, and hi/h current

needs to +e passed +efore muscle is

acti#ated& $Lar/e area is stimulated,unpleasant side effects%&

• Implanta+le

– Epimysial $next slide% – Intramuscular



Epimysial #ersus intramuscular electrodes

• Epimysial and intramuscular are in#asi#e&

• Epim&sial touches the epimysia $outer

sheath of the muscle%, near the entry point

of the ner#e, and is su+cutaneously

secured&

• 2ntramuscular inserted throu/h a needle,

the needle is retracted, the +ar+ed tips of

the )ire* secure it in the muscle&



$ M1/+2#E3+E( %+1!4 O $3 2M/$3+E! 3E1(O(O%+5E%2%

O( (E%+O(236 5$3! 6($% 23 +E+($/E62$

F& unter Fec8ham, Fh"BV< 'ichael M& Weith, '"BV< We#in L& Wil/ore, Fh"BV<

Xulie & rill, 'SY< Wathy S& Muolle, O(5AL, 2(Y< eoffrey !& (hropeY< Feter orman, '"xxZ<

httpAA&ifess&or/Acdrom1tar/etAifess?3Aoral3Apec8hamF&htm



httpAA&case&eduA/roupsA:N2LApa/esA?@As?@1[7&/if

Fhoto/raph of to intramuscular electrodes

ith helical leads, mounted in hypodermic

needles, on ith multistranded lead ire $(op%

and ith sin/le strand ire $!ottom%

httpAA&case&eduA/roupsA:N2LApa/esA?@A?@1\3&htm



Upper extremity applications

• 5estorin/ hand /rasp and release

• andmaster $Ness, Israel%

• !ionic lo#e $Frocha08a%• Kreehand system $Neuro2ontrol%



httpAA&nessltd&comA

Neuromuscular Electrical Stimulation Systems



!ladder control implants

• Mhen the +ladder or8s – !ladder under lo pressure, sphincter ith

hi/h acti#ity&

– !ladder under hi/h pressure, sphincter in lo

acti#ity )mode*&

• 'ain pro+lems

– yperreflexia $too freuent%

– "yssyner/ia $asynchronous%

• Kour different types of implants

Urinary !ladder location and acti#ation



httpAA&polystim&polymtl&caAan/laisAurinaireAintrurin&html

Urinary !ladder location and acti#ation

Urinary !ladder histolo/y



+utorial 3ame: Neoplasia

#oncept3ame: In situ carcinoma

%lide 3ame: !ladder (ransitional Epithelium

2ma'e !escription: (ransitional epithelium is

found only in the conductin/ passa/es of theurinary system& Note the columnar surface cellsith their lar/e nuclei and prominent nucleoli&(hese are typical of transitional epithelium&

%tructures %tructure

!escriptions

lamina propria In the +ladder, this isthe rather denseconnecti#e tissuelayer +eneath theepithelium&

transitional epithelium Mhen the +ladder isnot distended $as in

this slide%, the line ofsollen cells at thesurface is particularlye#ident&

Urinary !ladder histolo/y



%lide 78 "ladder 9all

(he +ladder has transitional epithelium and a thic8 lamina propria to allo for expansion& Hou ill +e than8ful

for this on those lon/ days in la+& !ar 9 7@? 'icrons

httpAA&8umc&eduAinstructionAmedicineAanatomyAhistoe+AurinaryArenal3R&htm



$ri/ht% httpAA&delta/en&comAtar/etAhistolo/yatlasAatlas1filesA/enitourinaryAurinary1+ladder1>x&jp/

$left% httpAAli+rary&thin8uest&or/A3@>?3Aima/esAor/ans1urinary+ladder&jp/

Urinary !ladder ho does it really loo8

http://www.deltagen.com/target/histologyatlas/atlas_files/genitourinary/urinary_bladder_4x.jpg

http://library.thinkquest.org/15401/images/organs_urinarybladder.jpg

http://library.thinkquest.org/15401/images/organs_urinarybladder.jpg

http://www.deltagen.com/target/histologyatlas/atlas_files/genitourinary/urinary_bladder_4x.jpg



httpAA8idney&nidd8&nih&/o#A8udiseasesApu+sAner#ediseaseAima/esAstimulator&jp/

Urinary !ladder Implant& o ould you do it



httpAA&polystim&polymtl&caAan/laisAurinaireAimplant&html

Implanta+le +ladder stimulator



J-rays sho the sphincter contracted +efore stimulation $a%and loosen durin/ stimulation $+%& :lso, the /raph a+o#e shos

that the stimulation efficiency is enhanced +y more than @?=

ith selecti#e stimulation, leadin/ to an a#era/e residual

#olume of [=& (hese results are ta8en from studies on T

different su+jects&

httpAA&polystim&polymtl&caAan/laisAurinaireAimplant&html

'edtronic6s InterStim(' !ladder Stimulator



It measures 7&> inches $\cm% +y 7&7 $@&@cm% +y ?&> inches $3cm%,

ith a ei/ht of 3&@ ounces $>7 /rams%

electrical stimulating part

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