3. Current pulses and (IDC)
Flow which is less than 1 sec
and it allow to flow after a pause of
determined duration ,the current is
said to be interrupted direct
current.`
4. PULSE DURATION:
the time or duration of flow and
no flow can be from a fraction of a sec to less
than 1 sec.
the time for which the current flow is termed
as pulse duration
INTERPHASE:
The time for which the current
is not allowed to flow is called inter-pulse
duration.
5. ON TIME:
the length of time an impulse is
allowed to flow
Same as pulse duration
OFF TIME:
The duration of no flow ,is the same
as inter pulse duration
6. RISE TIME OR ON RAMP:
The duration of current that
takes to reach the desired intensity from (0 to desired
intensity)
DECAY TIME OR OFF TIME:
THE TIME TAKEN FOR
THE CURRENT TO COME DOWN TO BASE LINE
(ZERO)
• If the decay time follows an exponental pattern ,it is
possible to describe the decay in time contant ,that is
the time required for the signal to decrease to
approximately one third of its magnitude.
7. EFFECT OF IDC
• MOST COMMON AND CLASSICAL
PURPUSE OF IDC IS TO CAUSE TWICHES
A DENERVATED MUSCLE
• ALSO USED FOR THE PURPUSE OF
TREATMENT AND ELECTRODIAGNOSIS
8. ELECTRICAL EXCITABILITY
• Nerve and muscles can be excited by a electrical stimulus
• The response of a motor neuron to the electrical stimulus can be
measured either by the strength of contraction or by the conduction
process expressed by its action potential .In a resting state a neuron is a
charged cell not conducting a nerve impulse.
• To excite to conduct the an impulse,a nerve cell should have a potential
difference of (50 to 100milivolt) b/w inside and out side the cell.
• Resting membrane potential is (70-100milivolt)
• The intensity of current ,duration of current flow ,and speed at which the
current reaches peak intensity govern the excitability of the nerve and
muscle.
9. NERVE FIBER
• Short duration pulses from (0.02 ms-1ms
)interrupted current will cause depolarization
generation of action potential and induce a muscle
contraction
• When longer duration pulses are used the
intensity of current required to produce muscle
contraction is reduce
• More current will be required if an impulse
duration of shorter than 0.1 ms is used
10. MUSCLE FIBER
• Muscle fiber do not respond to shorter duration
stimulus at a torerable intensity of current
• Pulse duration of (0.02 to 1ms) do not cause
excitation and muscle contraction unless very
high intensity of current is given
• Thus shorter the duration of impulse the higher
the intensity needed to produce muscle
contraction.
11. POLARITY
CATHODE
• Used as an active electrode
to stimulate a nerve ,
• it causes decrease of
potential difference rapidly
causing depolarization
• Irritation of nerve impulse
resulting in muscle
contraction
ANODE
• An active electrode to
stimulate a nerve it would
not be as effective as
cathode
• because the potential
difference will increase
across the membrane
12. ACCOMODATION
• The nerve and muscle tissue posses the
property to adapt to slowly increasing
intensities
• This cause a decrease of excitability of the
membrane ,and thus requiring more intensity
of stimulating current
• Nerve fiber has high accommodation rate .
13. PHYSICAL EFFECT OF IDC
A charge in the concentration of
ion is caused at the cell membrane
when an electric current is passed.
The ionic concentration occurring
at the nerve membrane causes a
muscle contraction
14. 1-SENSORY NERVE STIMULATION
• IDC of fairly long pulse duration stimulate the
sensory nerve and cause stabbing or burning
sensation .
• The sensory nerve irritation bring about an
increase in dilation of superficial blood vessels
which is manifested in the form of erythema
15. • MOTOR NERVE STIMULATION:
• Stimulation of motor nerve cause contration in
the muscle that it supplies ,in the form of brisk
twitches.
• DENERVATED MUSCLE STIMULATION:
• Muscle can only appreciate longer duration of
pulses IDC of sufficiently long pulse duration
(100ms)produce sluggish muscle twitches
followed by immediate relaxation .
16. IDC USED IN
• To re educate muscle
• To gain range
• Facilitate muscle contraction
• Exercise for paralyzed muscle
• Increase strength
• Improve circulation
• Prevent and loosen adhesion
17. Case study
• A 48 year old woman come with right side
effected with partially damage of facial nerve
also effect the expression of that side .
dropping of eye lid ,impaired taste and also
difficulty in chewing.
18. Equipment preparation
• No current leaking on to the casing
• Polarity is marked
• Duration of impulse and frequency of impulse
controls are available desired
• Keep all control at zero
• Connect wire and electrode
• Select the appropriate probe if used
• Make appropriate size if indifferent electrode
19. Patient preparation
• Pt position is comfortable ,the part is adequately
supported
• Explain the patient in simple words about the treatment
(procedure and sensation)
• Explain Pt characteristics of muscle twitches
• Warn the patient not to touch the machine and not to
manipulate any control(when both electrode are tried to
Pt part
• Report any other sensation
20. Cont..
• Expose only that area to be treated cover the rest of the
body.
• Test skin sensation for ‘’pin –prick’’
• Inspect the skin , avoid stimulation when the skin has rashes
• Wash the area with soap and water then dry and then soak
the area with warn saline for 5 mint
• Place the indifferent electrode to appropriate area and
secure with bandage
21. treatment
• Inform Patient That You Are
Going To Commence The
Treatment Obtain Content
• Before Switching On The Mains
And The Apparatus Check To See
That All Controls Are At Zero
• Turn The Main Switch And
Control Switch On.
• Increase The Intensity Very
Slowly Till You Get The Desired
Strength Of Muscle Contraction
22. Cont,…
• note the sensation reported by the patient
• set the duration (time )of treatment
• remain with in the calling distance from the
patient a call bell can be gives to patient
• At the end of the treatment time turn the intensity
control slowly to zero then switch the apparatus
and the mains off
• Remove terminals from the apparatus
• Undo bandage to remove electrodes
• Inspect the skin and make a note of any reaction
