DIADYNAMIC CURRENTS BY ABDULLAH RADWAN Diadynamic currents They

DIADYNAMIC CURRENTS BY ABDULLAH RADWAN

Diadynamic currents - They are basically a variation of sinusoidal current (which is an alternating current, with a frequency of 50 Hz and a pulse duration of 10 ms).

Gate control hypothesis by melzack and wall, 1965. • This hypothesis postulated that increased activity in the large afferent fibers of a peripheral nerve, will block the transmission of pain impulses in the small afferent fibers. • This is because the large diameter myelinated axons have lower electrical thresholds for externally applied currents than smaller diameter axons and don’t produce pain when activated so it is possible to stimulate them selectively without discomfort.

Mode of action • The main effect of diadynamic currents is relief of pain by increasing the pain threshold. This specific property is based on the following physiological phenomena: 1. Masking 2. Vasomotor effects 3. Direct effect on skeletal muscles 4. Stimulation of the vibration sense

1. Masking of pain - Masking is localized in the central nervous system. - It is the increase in the stimulation threshold (so that the pain stimulus no longer reaches this stimulation threshold).

2. Vasomotor effects • It is the vasodilatation and hyperemia that occur in the vicinity of the applied current as a result of release of certain substances in the tissues (e. g. histamine). • This explains the disappearance of inflammatory edema after few sessions of treatment.

3. Direct effect on the skeletal muscles • During diadynamic therapy the intensity is increased to the extent that in the 50 Hz phase of (CP & LP), muscle contraction occurs and in the 100 Hz phase, muscle relaxation results. • This muscular exercise will ensure good blood supply with subsequent relief of pain.

4. Stimulation of the vibration sense • This stimulation will cause general masking and thus it will lead to increase in the stimulation threshold.

Selection of current quality This depends upon the indication: 1. 2. 3. 4. 5. The fixed diphase (DF), The fixed monophase (MF), Short Period (Courtes Periods CP), Long period (Longue Periods LP), Rhythmic Syncope (RS).

1. The fixed diphase (DF) - This is a full wave rectified alternating current with a frequency of 50 Hz. - It is primarily used for initial treatment before the application of other currents. - It is also used in the treatment of circulatory disorders. - Patient feels a prickling sensation.

2. The fixed monophase (MF) • This is a half wave rectified alternating current with a frequency of 50 Hz. • Suitable for treatment of spastic conditions of pain after preliminary application of DF. • In MF, patient feels vibration.

3. Short Period (Courtes Periods CP) • Equal phases of DF and MF are alternated without interval pause (e. g. 1 sec MF and 1 sec DF). • It is used for treatment of traumatic pains. • Patient clearly feels the difference between the MF and DF periods.

4. Long period (Longue Periods LP) • This consists of 10 seconds of MF, followed by a 5 seconds of DF. • It has good and long standing analgesic effects. • In LP, patient does not feel difference between the diphasic and monophasic period. • It is used mainly for myalgia.

5. Rhythmic Syncope (RS) • This consists of 1 second MF followed by a 1 second rest phase. • It is used for faradic stimulation and faradic diagnostic testing of motor nerves and muscles.

Types of application It depends on the clinical picture: 1. Pain spot application , 2. Nerve trunk application, 3. Para vertebral application, 4. Specific gangliotropic application, 5. Vasotropic application, 6. Myo-energitic application, 7. Trans regional technique.

1. Pain spot application: • A small electrode is placed directly on the pain spot and the electrode is preferentially connected to the negative pole of the apparatus. The other electrode is placed on the same side about 2 -3 cm apart from the first or on the opposite side of the first. 2. Nerve trunk application: According to the course of the peripheral nerve the electrodes are placed on various points where the nerve is superficial.

3. Paravertebral application: -The electrodes are applied to both sides of the vertebral column at the level of nerve root. 4. Specific ganglionic application: -The electrodes are placed close to each other (2 -5 cm) on the skin over the treated ganglion. 5. Vasotropic application: -In peripheral vascular insufficiency, the electrodes are placed in accordance with vascular path.

6. Myoenergetic application: - Bipolar technique: in which the electrodes are placed at each end of the muscle in such a manner that the whole muscle is permeated with the current. - Mono-polar technique: in which a small active electrode is placed over the motor point of the muscle and a large inactive one is placed proximally to this. 7. Trans-regional application: As in joint treatment, the large plate electrodes are placed on either side of the joint.

Indications of diadynamic therapy 1. Relief of pain (acute and chronic) and edema 2. Soft tissue injuries as sprains , strains and contusions 3. Joint disorders, post-immobilization and arthritis 4. Circulatory disorders- Raynaud disease, migraine 5. Peripheral vascular disorders as neuralgia, neuritis, herpes zoster and radiculopathy

Contraindications of diadynamic therapy 1. Skin lesions and dermatological disorders 2. Infection 3. Inflammation 4. Thrombosis 5. Marked loss of skin sensation 6. Active T B or cancer 7. Cardiac pace makers (faradic current is not used in area of shoulder or thorax) 8. Thrombophlebitis 9. Unreliable patients 10. Metal implant

Precautions 1. special attention must be paid to the correct selection of the application site, the current quality and dosage. 2. It must be ensured that the sponge rubber padding is saturated with water. 3. The strength of the current must be switched to zero before applying the electrodes or before changing the application site.

Precautions ﺗﺎﺑﻊ 4. In plate electrode, the padding should protrude on all sides at least 1 cm to prevent direct contact between electrodes and skin (burn). 5. The time interval between sessions should not longer than 48 hours. 6. Further Two or three sessions are needed after complete improvement to stabilize the effect.

Duration and Frequency Duration - Treatment should not exceed 10 to 12 minutes. - Most single applications are given for 3 minutes Frequency - Generally 6 or 7 treatments are given daily or every other day

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