Electrotherapy II Lecture 1

1-Electrical stimulation is the application of stimulation by using electrical currents. The general 3 uses of electrical stimulation (ES) is : 1- Activate skeletal muscle for strengthening or improving volitional movement 2- Decreasing (control) pain 3- Facilitating or accelerating tissue heal...

1-Electrical stimulation is the application of stimulation by using electrical currents. The general 3 uses of electrical stimulation (ES) is : 1- Activate skeletal muscle for strengthening or improving volitional movement 2- Decreasing (control) pain 3- Facilitating or accelerating tissue healing -In physical therapy clinical practice the electrical stimulation is conducted by using an external stimulator to deliver current through external, surface, transcutaneous electrodes. --------------------------------------------------------------------------------------------------------------------- 2-Electrical Current is the movement of ions or electrons in a conductor in response to a voltage force. -The international unit for current is the ampere (amp or A). - most therapeutic applications of current use milliamperes (mA, or thousandths of an ampere) or microamperes (A or millionths of an ampere). --------------------------------------------------------------------------------------------------------------------- 3- Electrical current waveforms can be considered to be of three types: 1-direct current (DC) 2-alternating current (AC). 3-pulsed current (PC). --------------------------------------------------------------------------------------------------------------------- 4- The waveform is simply a depiction or representation of the characteristics that represent a given current. All currents have parameters in the vertical (y coordinate) and horizontal (x coordinate) directions.  ‫ وبعدين قعد فترة فيه وبعدين التيار نزل فجأة‬peak ‫ التيار زاد فجأة ووصل لل‬: square ‫ وبعدين قعد فترة أطول فيه وبعدين نزل فجأة‬Peak ‫التيار زاد فجأة ووصل لل‬: Rectangular )‫ خالص‬Peak ‫ ونزل تدرجيا تاني ( مقعدشي في ال‬Peak ‫ التيار زاد تدريجيا ووصل لل‬triangular --------------------------------------------------------------------------------------------------------------------- 6-Direct Current (DC) " galvanic" current is the continuous unidirectional flow of ions or electrons for at least 1 second. -The most common clinical uses of DC are for iontophoresis and wound care. -Iontophoresis is the process of passing a weak electrical current through the skin. Direct current - Variations of DC exist, but to accurately be called DC, they must remain unidirectional and uninterrupted for a period of time. 1- Interrupted DC: where the direction of flow ceases after 1 second before resuming in the same direction for at least 1 second. 2- Reversed DC: where the flow ceases after 1 second before resuming in the opposite direction for at least 1 second. 3- Interrupted reversed DC: which is a combination of both. ‫التيار مستمر وفي اتجاه واحد‬ ‫التيار مستمر ووقف وبعدين كمل في نفس االتجاه‬ ‫التيار مستمر وكمل ولكن في عكس االتجاه‬ ‫التيار مستمر ووقف وبعدين كمل ولكن في عكس االتجاه‬ --------------------------------------------------------------------------------------------------------------------- 7- Alternating current (AC) is the uninterrupted bidirectional flow of ions or electrons and must change direction at least one time per second. - The rate at which AC switches direction is termed Frequency and is described with the international unit hertz (Hz) or in the unit cycles per second. --------------------------------------------------------------------------------------------------------------------- 8- Pulsed current, sometimes termed pulsatile current, is the unidirectional- or bidirectional flow of ions or electrons that periodically ceases for a period of time before the next electrical event. - Pulse is an isolated electrical event separated from the next by a period of time termed the interpulse interval. --------------------------------------------------------------------------------------------------------------------- 9-Electrical current parameters: 1- Waveform 4- Amplitude 2- Pulse and Phase 5- Frequency 3- Pulse duration --------------------------------------------------------------------------------------------------------------------- 1-waveform 1-Sine wave: It usually offers equal energy levels under positive and negative phases. 2-Rectangular (square) wave: This form of wave describes usually the direct current with a rapid instantaneous rise, prolonged duration and a sharp drop-off. 3-Spike wave: During such a waveform, the rise rate is rapid but not instantaneous, falling back rapidly to zero immediately after reaching the maximum. 4- Twin-spiked forms: With this waveform, more penetration is administered because of the extremely short pulse width (microseconds), as in high-voltage galvanic stimulation --------------------------------------------------------------------------------------------------------------------- 2- Pulse and Phase - A monophasic pulse deviates from the isoelectric line in only one direction. - It is produced by intermittently interrupting a DC current source. Some sources commonly use the term pulsed DC. -A biphasic pulse is one that deviates from the isoelectric line first in one direction, then in the other direction. -The biggest difference in the effects of biphasic and monophasic currents is the ability of monophasic current to cause polarity effect and chemical changes. polarity effect : ‫معناها ان التيار بيجمع ايونات موجبه الشحنه في منطقه اإلصابة عشان تسريع عملية الشفاء‬ ---------------------------------------------------------------------------------------------------------------------  3-Pulse duration & Phase duration ------------------------------------------------------------------------------------------------------------------- 4-Phase and Pulse Charge --------------------------------------------------------------------------------------------------------------------- 5-Amplitude - Most uses of ES use milliampere amplitude. - The highest current or voltage reached in a phase of a monophasic pulse or in any one phase of a biphasic waveform is termed the peak amplitude. --------------------------------------------------------------------------------------------------------------------- 6-Frequency - Frequency is the term used to describe the number of pulses occurring in 1 second and is reported as pulses per second. -Hertz (Hz): is used to describe the number of times AC switches direction in 1 second. Frequency pulse duration Frequency depth modulation ‫مثال لو المنطقه الي عايزين نشتغل عليها ديب‬ ‫قوي فحنا ممكن نستخدم تردد عالي عشان نوصل‬ ‫للنقطة ده وبعدين لما نوصلها نقلل التردد عن‬ ‫طريق تيار تاني مثال لحد ما نوصل للترد الي احنا‬ 1-Low Frequency Current: Current with frequency of 1- 1000 Hz. -Low frequency currents can stimulate both sensory and motor nerves, with the best effect form 1-100 Hz. Examples of low frequency currents are faradic current (FC), diadynamic current (DD), High voltage galvanic (HVG) current. 2-Medium Frequency Currents: Current with frequency of 1 KHz. - These currents can only stimulate sensory and motor nerves to after modulation. 3-High frequency currents: current of 1000,000 Hz or more. At this frequency the current has no effect on sensory and motor nerve. --------------------------------------------------------------------------------------------------------------------- 10- Burst: The generation of two or more consecutive pulses separated from the next series of consecutive pulses is termed a burst, and the time between bursts is the interburst interval. ‫ هيرتز‬120 ‫عباره من حزم من الترددات يعني لو التيار التردد بتاعه‬ burst ‫ هيرتز يعمله حزمه مع بعض ويبقي اسمهم‬30 ‫فمثال كل‬ --------------------------------------------------------------------------------------------------------------------- 11- Symmetrical & asymmetrical waveforms and Balanced & unbalanced have equal phase charges --------------------------------------------------------------------------------------------------------------------- ‫‪12- Red & black electrode and polarity‬‬ ‫باختصار ده عبارة عن جهاز بتحدد فيه انهي الكاثود‬ ‫السالب وانهي االنود الموجب من السلكين األحمر‬ ‫واألسود و وبعد لما تثبتهم حول منطقه اإلصابة بتشغل‬ ‫الجهاز ولما يمر التيار بيقوم الكاثود بتجميع االيونات‬ ‫الموجبه الي هي مثال زي بعض أنواع كرات الدم‬ ‫البيضاء والخاليا المناعيه عند منطقه االصابه فتقوم‬ ‫بتسريع عملية الشفاء‬ ‫‪------------------------------------------------------------------------------------------------------------------------------------------------‬‬ ‫‪Direct current‬‬ ‫التلت أنواع دول يفرق معايا أي احدد الكاثود‬ ‫‪polarity effect‬‬ ‫‪Monophasic pulsed‬‬ ‫من االنود اما باقي األنواع عادي مش مشكله‬ ‫‪Unbalanced asymmetrical‬‬