Transcript Slide 1
Interferential currents • Medium frequency alternating currents with frequency of 3000 – 6000Hz. • They stimulate sensory and motor nerves and meet with little skin resistance (4000 Hz = 40 Ω per 100cm2). • Low frequency currents have high skin resistance (50 Hz = 3200 Ω per 100cm2) and allow only small proportion of current to pass through the skin. • Negligible skin resistance is offered to high frequency currents and heat is produced in the tissues. Interferential therapy • Pass two medium frequency alternating currents which are slightly out of phase in to the tissues and make a low frequency current. • At the point where the two currents intersect, intensity of the combined current will increase and decrease rhythmically and it is called amplitude modulation. Interferential therapy • Physiological effects – Relief of pain – Motor stimulation – Absorption of exudate Interferential therapy • Indications – Pain – Muscle spasm – Oedema – Haematoma – Chronic ligament lesions – Trigger spots in myofascial syndromes – Stress incontinence Interferential therapy • Contraindications – – – – – – – – – – – Arterial disease DVT Infective conditions Pregnant uterus Danger of haemorrhage Malignant tumours Pace makers During menstruation over abdomen Open wounds Unreliable patients Dermatological conditions Interferential therapy • Dosage – Intensity – Beat frequency – Carrying frequency – Treatment time – Treatment schedule Types of electrodes • Metal plate electrodes and pads • Quadripolar electrodes and pads Types of electrodes • Suction cup electrodes • Quadripolar suction cup electrode Interferential therapy Types of application – Pain point or trigger point application: as a bipolar technique, anode over the pain point & cathode adjacent to it. – Nerve trunk application: two electrodes are placed along the course of the appropriate peripheral nerve where the nerve is superficial. Types of application – Paravertebral application: place the electrodes on both sides of the spine at the level of the nerve root supplying the painful area. If several nerve roots are involved , the electrodes may be applied alongside the spine at the highest and lowest nerve root levels. – Muscular application: two electrodes are placed on the either end of the muscle belly. – Transregional application: to treat a joint, electrodes are placed either side of the joint. Interferential therapy • Dangers – Burns – Shocks – Haematoma Advantages – Large doses of current can be passed to the body without chemical burns. – Decreased skin sensation is not a contraindication. – Current can be localized more effectively in a specific region. – Metal is not a contraindication. – It can not be given directly to cancer areas but the radiating pains can be treated. – It can combine with treatment like ultra sound.