faradic current and its effects and stimulations

Type of current used for muscles stimulation

1. FARADIC CURRENT

2. Contents of Lecture Effects of Current on body Faradic Current Production Modified Faradic Current Indication & Uses Methods of Application Contra-Indications

3. Electric current and body Tissue of body ___ capable of transmitting current because Tissue fluid contain ions. Conductivity of different tissues varies depend on amount of fluid that they contain Muscles___ Good blood supply Fat_____ poor conductor Epidermis ____ high resistance (1000 ohm or more) ___little fluid In applying electric treatment appropriate measures are used to reduce its resistance

4. True Faradic Current It is an unevenly direct current, with one phase of high amplitude and short duration and the other phase of low amplitude and longer duration Pulse duration__ 1ms Frequency __ 50 Hz

5. Faradic-Type Current Interrupted direct current Short duration Stimulate normal (innervated muscles) Frequency 50-100 per second Pulse duration 0.2-1 ms

6. Modified Direct current Faradic current can be modified by interruption and surging. In surging, surged duration, frequency, wave form and surged interval are used.

7. Tetanic contraction Near Normal tetanic like contraction and relaxation of muscle To produce a tetanic contraction by faradic type of current stimuli must be applied at a rate of at least 30 stimuli per second The strength of muscle contraction depend on the number of motor units bring about into action

8. Surged Current Intensity of successive impulses increases gradually, each impulse reaching a peak value greater than the preceding one, then falls either suddenly or gradually in surges

9. SURGES Surges varying in duration and waveform (Saw tooth, Triangular, Trapezoidal)

10. Advantages: It avoids fatigue It does not give surprise to patient as current is increases slowly Contraction of muscle is like physiological/voluntary contraction

11. Production Same principle as interrupted direct current Values of resistance is low to get short duration and high frequency 4 functional parts Power supply Oscillator circuit modulating circuit Amplifying circuit

12. Functional parts Power supply: battery or AC Oscillator circuit: Short duration pulses of 0.1 to 1ms with a frequency of 50 to 100 Hz) Modulating circuit: Give surged output varies frequency) Amplifying circuit : (increase the output voltage appropriately)

13. Originally/True Faradic Current Induction coil (Induction Coil, a device for converting low-voltage direct current (DC) into high-voltage alternating current (AC). Two unequal phases Low intensity and long duration High intensity and short duration

14. Electronic Stimulators Same physiological effect as original faradic current Different waveform

15. Physiological Effects

16. Stimulation of sensory nerves .. prickling like sensation due to stimulation of sensory nerves cause reflex vasodilation of superficial blood vessels leading to erythema.

17. Stimulation of motor nerves If sufficient intensity---cause muscle contraction, 50 times per second----muscle fatigue, surging-----fatigue is due to without intervals of relaxation)

18. Effects of muscle contraction Increased metabolism ad pumping action of muscles Electrical stimulation---Muscle contraction—increased metabolism----increase in demand for oxygen and food---- increase in waste products and metabolites-----dilates the capillaries and arterioles, increase in blood supply to muscle Muscle contract and relax---pumping action on venous and lymphatic return---direct fluid toward heart.

19. Stimulation of denervated muscle impulse lasting for 1ms and intensity of current required for producing contraction in denervated muscle with a faradic current is too great to be tolerated . So, its not satisfactory for stimulation of denervated muscles On the partially denervated muscles ( to stimulate partially denervated muscle; higher intensity than normal muscle is required)

20. Indications/Therapeutic Uses Facilitation of muscle contraction Re-education of muscle-action Training a new muscle action Neuropraxia of a motor nerve Diagnostic tool Improved venous and lymphatic drainage

21. Facilitation of muscle contraction Muscle contraction---facilitated by faradic current- --used when pt is unable to produce muscle contraction. Muscle contraction is inhibited by Trauma Inflammation pain surgery Faradic assists in voluntary contraction. Example: stimulation of quads after meniscectomy

22. Re-education of muscle-action Voluntary action lost---Prolonged disuse Incorrect use (Abductor Hallucis in Hallux Valgus)

23. Training a new muscle action After surgery ------ new movement pattern must be established During stimulation pt should attempt to perform voluntary contraction.

24. Neuropraxia of a motor nerve Impulses from the brain are unable to pass the site of the lesion Voluntary power is lost

25. Diagnostic Tool Innervated muscles will contract in response to faradic and faradic type of current at minimal intensity Partially innervated muscle will require more intensity of current then normal Completely denervated muscle will not respond even at higher intensity

26. Methods of application Motor point stimulation Labile Method Nerve Conduction Method Bath Method Faradism Under Pressure

27. Motor Point Stimulation Involves stimulation of individuals muscles Indifferent electrode is placed at the origin of muscle Active electrode (handle/pen electrode) is placed at the motor point

28. Advantages: Each muscle can be stimulated Effect of passive exercise can be given to each muscle Contraction of individual muscle can be obtained Every muscle can be stimulated and isolated muscle contraction Disadvantages : Tedious Time consuming Difficult to stimulate the deeply situated muscle

29. Labile Method It is for stimulation of large muscles with multiple nerve supply for example trunk muscles Indifferent electrode is placed at origin of muscle or muscles Active electrode in form of either disc or small plate electrode is moved over area to be treated

30. Nerve Conduction Method An indifferent electrode is placed at convenient place Active electrode to a point at which the nerve trunk is superficial Stimulate motor nerve trunk Contraction of all the muscles that it supplies

31. Bath Method Application of faradic current to the body parts in a tub, tray or tank containing water Application of faradic current to foot; faradic footbath Advantages: Skin resistance is lowered Perfect contact with tissues Disadvantages: It can not be localized Superficial muscles contract to a greater extent than deeper ones Chances of Electric Shocks

32. Faradism Under Pressure Treatment of edema to increase the venous and lymphatic drainage Faradic current is applied along with an elastic bandage such as elasto cerepe bandage Body part which is to be treated is kept elevated during the treatment 15-20 minutes

33. Uses Edema After knee surgeries Rheumatoid arthritis Tendon transplantation

34. Contra-Indications Cardiac Pacemakers Impaired sensation Impaired mentation (CP) Arterial disorders Danger of hemorrhage Area of defective supply Venous disorders (DVT)

35. Contra-indications Allergic Rash Varicose vein Acute Sepsis Tumor Cardiac patients Over the area of head Patient with epilepsy Open wound