Applications of E-Stim PDF

Electrical Stimulation for Pain and Edema Control  Review Define these terms: Draw the following waves – Coloumb’s Law and then label them. – Draw an open/closed circuit – Direct Current/Monophasic and a Seri...

Electrical Stimulation for Pain and Edema Control  Review Define these terms: Draw the following waves – Coloumb’s Law and then label them. – Draw an open/closed circuit – Direct Current/Monophasic and a Series/Parallel Circuit – Alternating Current/Biphasic – Ohms Law – Pulsed Current – Factors Influencing Resistance – Current Density  Review What are the different levels of electrical stimulation and what are they useful for? How can we effect different nerves and depth of tissue? What is the Strength Duration Curve and why is it important?  Review What are the indications for E-Stim? What are the contraindications for E-Stim? What is Joule’s Law? – How can we effect items within it?  Review What are the steps to the application of electrodes? What must you consider? Why may you choose different size pads? When trying to complete motor level stimulation why would we want to try to be over motor points?  Electrical Stimulation for Pain Control Transcutaneous Electrical Nerve Stimulation (TENS) – A method of nerve stimulation used to provide pain modulation – Not a specific type of device or stimulator – Typically, symmetrical or asymmetrical biphasic pulsed currents – However – any current that provides the appropriate parameters for stimulation can be used IFC, Premod, High Volt, VMS Electrical Stimulation for Pain Control TENS – Application of electrical stimulation via surface electrodes to stimulate nerve fibers – A method of activating nerves, not simply a type of device Fundamental parameters – Pulse frequency, pulse duration, and amplitude (or intensity)  Modes of TENS Four traditional modes – Conventional (high frequency/low intensity) Preferential activation of A-beta afferents Most commonly used mode of TENS – Motor Level (low frequency/high intensity) Activation of A-beta afferents and A-alpha – Burst train (combo of conventional and motor level) – Brief intense (high frequency, duration, and intensity)  Pain Control Parameters Conventional TENS Also called: – Sensory TENS – High-frequency/low intensity TENS Excites large A-beta and A- alpha sensory fibers – Gate Control Theory Stimulation at or above sensory level but below motor level  Pain Control Parameters Conventional TENS Amplitude – Strong, comfortable sensation without muscle contraction according to patient comfort and perception Pulse Duration – 60-100 µsec (must be < 100 µsec) Frequency – 60-100 pps  Pain Control Parameters Conventional TENS Treatment Time – As needed for analgesia – Typically, 30 minutes off if using up to 1 hour Electrode Placement – Around or over painful site – Over dermatome segmental area and painful site – Nerve root level  Pain Control Parameters Conventional TENS Onset of relief is usually within 10 min but it does not persist after stimulus is turned off Stimulus is typically perceived under the electrodes and throughout area of pain – Accommodation TENS unit, Asymmetrical Biphasic, Symmetrical Biphasic, IFC, PreMod  Pain Control Parameters Motor Level TENS Also called: – Low Frequency TENS – Low Rate TENS – Acupuncture-Like TENS – Low Frequency/High Intensity TENS Theorized to release endogenous opiates – Descending Mechanism of pain control Stimulation is at a motor level – Non painful – Visible muscle contractions  Pain Control Parameters Motor Level – Endogenous Opiates Stimulates the release of Endorphins from the pituitary and enkephalins from the spinal cord Some research indicates the intensity needs to be noxious or twice the intensity of motor threshold to recruit A-delta fibers  Pain Control Parameters Motor Level – Endogenous Opiate Amplitude – A strong, comfortable muscle contraction of the involved muscle Pulse Duration – 150-250 µsec (at least 200) Frequency – 2-4 pps  Pain Control Parameters Motor Level – Endogenous Opiate Treatment Time – 30 minutes Electrode Placement – Over myotomes – Over motor points - variation among individuals – Over acupuncture points - variation among individuals  Pain Control Parameters Motor Level – Endogenous Opiate Onset of relief is within 15-30 minutes of treatment and lasting 1-3 hours Can be achieved through use of: – Asymmetric Biphasic – Symmetric Biphasic – High Volt – IFC – Premod Are these last two the best options?  Pain Control Parameters Burst Train TENS – Endogenous Opiate Combination of Conventional and Motor Level TENS Motor Level Bursts of pulses (100 Hz) delivered at a low frequency (1-4 Hz) Pulse duration of ~200 µsec 30 min, similar to Motor with different wave form. – Burst VMS, Asymmetric Biphasic, Symmetric Biphasic  Pain Control Parameters Brief Intense TENS Also called – Noxious Level TENS Typically used when pain relief is needed during a clinical procedure – Wound debridement, wound dressing changes, suture removal May produce a muscle contraction Used when other TENS modes have not resulted in pain modulation – Due to this, least commonly used  Pain Control Parameters Noxious Level – Castel Level II Amplitude – Highest tolerable intensity With or without muscle contractions Phase Duration – As high as possible; >200 µsec; typically, at least 1 ms Frequency – High Frequency - 100-150 pps.  Pain Control Parameters Brief-Intense Treatment Time – Each point stimulated for about 30 seconds. 8-10 points treated in a treatment session Electrode Placement – Typically use a point stimulator Asymmetrical biphasic, Symmetrical biphasic  Water Treatment Option Typically completed as sensory stimulation Good for irregular surfaces or large areas Cons? Electrode immersed in water – Make sure it is not going to exit the water What do we need to consider with the electrode on skin?  Interferential Current Sweep – Base treatment frequency is automatically and rhythmically increased and decreased. What does this sound like and what does it help with? Vector Scan – Amplitude modulation of the currents – Leads to greater area of effect by interferential current  Summary? What are your parameters for each type of pain control? – Frequency – Pulse Duration – Amplitude – Treatment time What is the pad placement for each?  Edema Control Sensory Level Stimulation Limits edema formation by preventing fluid from escaping to surrounding tissue Reduces capillary pressure and permeability Usually, a technique using HiVolt – Polarity adjustment – Need negative polarity  Edema Control Sensory Level Stimulation Parameters – Amplitude sensory level – Phase Duration 20-100 µsec – Frequency 60-120 pps  Edema Control Sensory Level Stimulation Parameters – Treatment Time 30 min repeated after 60 min of rest – Electrode Placement cathode (negative - black) over treatment site anode (positive - red) proximal (closer to trunk) – Polarity Negative – Negatively charged blood cells and plasma proteins are repelled from the cathode. Concentration gradient is created encouraging reabsorption of fluids  Edema Reduction Motor Level Stimulation Parameters – Amplitude Muscle contraction – Phase Duration 200+ sec – Frequency Very low 1-4 Hz if no duty cycle Tetany (>40 Hz) if duty cycle used  Edema Reduction Motor Level Stimulation Parameters – Duty Cycle 5-10 seconds on: 5-10 seconds off – Treatment Time 20 min repeated 2-5X daily – Electrode Placement Proximal and distal ends of muscle group near treatment area – Polarity Negative  Lab Time First work on getting use to the units and the parameters we can change. Answer the following questions: – What parameters can we change for the following wave forms? Asymmetric Biphasic Symmetric Biphasic IFC Premod High Volt – What do those parameters do? Physically put premod and interferential on your partner and feel what the parameters do. You should have a written list of parameters and explanations of what they do as a final product.  Edema Reduction and Pain Control Labs Lab Time!  Wound Healing Use low intensity DC generators – polarity is important Monophasic waveform (HiVolt) can be used Inflammatory mediators are attracted or repelled from the area  Wound Healing Electrical current encourages: – Increased rate of collagen formation – Stimulated growth of fibroblasts and granulation tissue – Migration of leukocytes  Wound Healing Parameters – Amplitude Sensory level, but subsensory can be effective – Phase Duration As long as possible – Frequency Maximum machine allows – Polarity Negative – attract fibroblasts Positive – attract macrophages  Wound Healing Parameters – Treatment Time 2 hrs followed by a 4-hour rest time; bouts of 2-3 treatments per day – Electrode Placement Typically, negative electrode is placed over wound Positive electrode is placed proximal to wound (about 25 cm) Electrodes can be reversed after 3 days  Fracture Healing Assist in healing of non- union fractures Bone growth generators – Attempt to mimic electrical signals produced by bone – Encourages calcium to be deposited through osteoblasts – Transcutaneous AC or implanted electrodes using DC – Usefulness is debatable and may actually delay fracture healing  Positive Polarity Hardens tissue – Chemical mediators force a coagulation of protein Contracts tissue Stops hemorrhage – Coagulation  Positive Polarity Diminishes congestion Sedating Relieves pain in acute conditions by reducing congestion Scars formed are hard and firm Attracts macrophages Promotes epithelial growth  Negative Polarity Softens tissue Dilates tissue Increases hemorrhage Increases congestion  Negative Polarity Stimulating Reduces pain in chronic conditions because of softening effect – Decrease nerve irritability Scars are soft and pliable Increases vascularity Stimulates fibroblastic growth Produces collagen Inhibits bacterial growth  Polarity Effects Positive Negative Hardens Tissues Softens Tissues Stops Hemorrhage Dilates Tissue Diminishes Congestion Increased Hemorrhage Sedating Increased Congestion Scar formed is hard and firm Stimulating Scars are soft and pliable Relieves pain in acute conditions by reducing Reduces pain in chronic congestion conditions because of softening effect. Electrical Stimulation for Strength ATGR 531  General Overview Neuromuscular Electrical Stimulation (NMES) Performed on muscles with intact nerve innervation Stimulation of alpha motor nerves Maximally tolerated contraction – Some studies as high as 70% of maximal voluntary contractions  Goals Muscle re-education – Increase the number of motor units recruited – Increase the frequency that motor units are recruited – Recruit motor units in a more synchronized manner (at the same time) Strengthening Prevent disuse atrophy Decrease muscle spasm Decrease edema  Muscle Contraction There are differences between physiologic muscle contraction and electrically induced muscle contraction – Muscle fiber recruitment Small to large – Predictable Variability in motor units and frequency – Synchrony of firing  Physiologic Muscle Contraction Muscle fiber recruitment – Small, slow-twitch units recruited first Isometric, postural motor units Fatigue resistant fibers – Large, fast twitch units recruited second Isotonic, high-tension muscles Fast fatiguing fibers  Physiologic Muscle Contraction Voluntary Muscle Contraction – Synchrony of Firing Small to large – Asynchronous Motor Activity Rotates which fibers are contracted to allow for rest Results – Maintains tension while minimizing fatigue – Reduces energy demands – Reduces potential for fatigue  Electrically Produced Muscle Contraction (Exogenous) Muscle fiber recruitment – large-diameter, fast- twitch muscle fibers recruited first – small-diameter, slow- twitch muscle fibers recruited second May occur at the same time as well – Unpredictable  Electrically Produced Muscle Contraction (Exogenous) Synchronous Motor Activity – All motor units are activated – Motor unit activation is not cycled Results in: – Faster rate of fatigue – Use of a duty cycle decreases fatigue  Applications/Indications for NMES Muscle Re-education Reduce Disuse Atrophy Muscle Pump Contractions Muscle Strengthening Muscle Spasm  Muscle Re-education Retraining muscle that has inhibitions post-surgery or injury Ability of the muscle to contract is enhanced Procedure: – Patient tries to actively contract with stimulation – Sees the muscle contract and attempts to duplicate the muscular response  Reduce Disuse Atrophy Prevent fast weakening Helps to maintain normal muscle functioning  Muscle Pump Contractions Helps stimulate circulation and reestablish proper circulatory pattern while keeping injured part protected Reduces edema  Muscle Strengthening Literature limited in evidence stating NMES alone improves strength. Some evidence has indicated that early initiation of NMES with an exercise plan may increases strength gains over exercise alone. – What do you think this looks like?  Contraindications to NMES Damage to muscle or tendon where a muscle contraction would further damage muscle tissue or tendon fibers In cases where there is no bony attachment of the muscle (avulsion fracture)  Concerns with NMES Muscle fatigue due to reversed order of muscle fiber recruitment – Must allow for rest! 50 sec rest to start 30 second as patient accommodates to training No protective function of the Golgi Tendon Organs  Parameters Pulsatile or burst-modulated AC – VMS – biphasic – VMS - burst – TENS units - good for NMES in small muscle groups (biphasic) – Russian (burst-modulated AC - polyphasic) – Asymmetrical Biphasic – Symmetrical Biphasic  General Parameters Phase Duration – > 200 microseconds Frequency – Medium – Tetany – 30-50 pps Amplitude – Strong muscle contraction – Maximally tolerated Ramp – At least 2 seconds Duty Cycle – Minimize fatigue – 10-15 seconds on with 50 seconds to 2 minutes off – 10:50, 10:30, 4:12 Electrode placement?  Muscle Strengthening As high as tolerated with muscle Amplitude contraction Phase Duration > 200 microseconds Medium Frequency 30-50 pps Duty Cycle 10:50 Ramp At least 2 seconds Treatment Time 3 sets of 10 contractions  Muscle Strengthening Parameters Treatment Frequency and Duration – 3-5 times/week – 4-8 weeks If using burst modulated current (eg. Russian), use a relative duty cycle of 10-50%  Muscle Re-education Amplitude Strong Muscle Contraction Phase Duration > 200 microseconds Medium Frequency 30-50 pps Duty Cycle 10:50 (10:30 later) Ramp At least 2 sec 20-30 minutes Treatment Time 20-30 contractions  Reduce Disuse Atrophy Amplitude Strong Muscle Contraction Phase Duration > 200 microseconds Medium Frequency 30-50 pps Duty Cycle 10:50 (10:30 later) Ramp At least 2 sec 15-20 minutes Treatment Time Allow 10 Muscle Contractions  Muscle Pump Contractions Amplitude Strong Muscle Contraction Phase Duration > 200 microseconds Frequency Medium 30-50 pps Duty Cycle 5:5; 10:10 Ramp Minimum -.5 seconds Treatment Time 10-20 minutes  Muscle Spasm Amplitude Strong Muscle Contraction Phase Duration > 200 microseconds Medium Frequency 30-50 pps Duty Cycle 10:10 Ramp At least 1 second Treatment Time 10-20 minutes  Electrode Placement Bipolar configuration unless working agonist and antagonist then quadripolar Over motor points Strength of muscle contraction increases as size of electrode increases More generalized contraction is elicited with larger electrodes Use of probe to stimulate smaller muscle groups  Stimulating Denervated Muscle No longer called NMES Attempting to directly activate the muscle through depolarization of the sarcolemma Longer pulse durations are needed >1msec – Commercially available stimulators typically do not have this long of a pulse duration – Use of direct current stimulators  Parameters for Stimulating Denervated Muscles Pulse duration Duty Cycle – As long as possible – Not clearly identified in the literature Frequency Treatment Duration – Tetany – 4-7 days per week – 1-500 pps – 4 days to 4 years (per literature) Amplitude – Muscle contraction Treatment Time – Care taken to prevent burns – 30 minutes to 8 hours per day Let’s Practice With a Lab Biofeedback  Definition Use of instrumentation to bring physiological events to conscious awareness Permits awareness of neural recruitment of muscles A teaching aid with regards to muscle activation or relaxation Also referred to as EMG (Electromyography)  Purpose Increase or decrease the activity of skeletal muscle – Facilitatory or Inhibitory  Examples of Facilitatory EMG Increase muscle activity after surgery or injury when volitional contraction is impaired Normalize the balance of muscles acting at a joint where one muscle group may be insufficient Improve volitional motor control following dysfunction of the CNS Increase volitional control of pelvic floor muscles for rehabilitation of urinary incontinence  Examples of Inhibitory EMG Decrease activity in muscles demonstrating spasticity caused by dysfunction of the CNS Decrease activity in muscles demonstrating increased activity caused by postural stress or anxiety Decrease muscle activity associated with chronic pain  Instrumentation Electrodes – Two active leads and a ground – May be self-adhesive with a single three-pole attachment Once electrical activity of muscle is detected at the electrode, the signal is conducted to the EMG machine Electrodes are placed over the muscle  Instrumentation The signal is: – Filtered “Noise" removed – Amplified – Rectified Made positive or negative – Integrated Smoothes the signal  Instrumentation The signal is used to power lights or noise to provide feedback about the muscle activity The electrical activity of the muscle contraction is monitored, not the actual force of contraction – This means what? What are we getting information about physiologically?  Instrumentation Biofeedback can be used with learning strategies, goal setting, and external clinician feedback Used as an adjunct to muscle re-education  Instrumentation Sensitivity – Ability to detect the electrical activity associated with a muscle contraction – On the machine – called Gain 1, 10, 100, 1000 µV – The smallest amount of muscle activity that can be detected is 1 µV – As the need for sensitivity decreases, gain is increased  Restoring Control Over Volitional Contraction Used for patellofemoral conditions Used for rotator cuff inhibition Used for glenohumeral instability Used for scapular stabilization  Patient Strategies Threshold – The level of muscle activity a patient is able to reach, whether it is increased or decreased activity To increase volitional muscle activation – With increased muscle activity, audio or visual feedback is provided To decrease volitional muscle activation – When muscle activity is decreased, audio or visual feedback is provided  Patient Strategies As the patient is able to increase volitional activity, sensitivity can be decreased As the patient is able to relax or quiet an active muscle, sensitivity may need to be increased  Methods to Facilitate Muscle Contraction Contract the muscle on the opposite limb, then contract muscle on the involved limb Apply biofeedback to opposite limb so that patient will “learn” the biofeedback technique Watch and/or touch the contracting muscle Using NMES to create a muscle contraction before using biofeedback  Functional Progression Used with open chain activities and then progressing to closed chain activities Once appropriate pattern is established, biofeedback is not needed  Teaching Relaxation Tension and stress Overactivation/Guarding Trigger points TMJ Lab 2 Microcurrent  Microcurrent - Basics Also called Low-Intensity Direct Current (LIDC) Either DC or monophasic pulsed current Amplitude less than 1 mA Does not excite peripheral nerves – Sensory – Motor Nerve – Pain  Uses Wound Healing – Increased ATP production Increased protein synthesis – Increased collagen Does not correlate to increased tensile strength – Negative polarity – Direct electrode placement with negative over the wound Phase Duration typically 500 msec Frequency varies between 1- 1,000Hz Iontophoresis  What is Iontophoresis? Use of electrical current to move charged particles across the skin – Hair follicles – Sweat glands Use of Direct Current to do so – Iontophoresor – Patches (12 or 24 hour)  How it Works Premise of like charges repel, opposite charges attract – Coulomb’s Law – Positive electrode (red) is used to deliver positive charged medications – Negative electrode (black) is used to deliver negative charged medications Monopolar electrode configuration  Indications Chronic inflammation and pain Trigger point treatment to treat myofascial pain Edema Neuralgia Calcific tendinitis Scar tissue Plantar warts Hyperhidrosis Gouty arthritis  Contraindications Skin wounds – Open wounds Allergic to medications Over a pacemaker Sensation Issues  Adverse Effects of Iontophoresis Skin irritation and redness Tingling Itching Types of Medications Used Anti-inflammatories – Dexamethasone Negative polarity – Salicylate Negative polarity – Hydrocortisone Positive polarity Analgesics – Lidocaine Positive polarity  Medications Skeletal Muscle Spasm – Magnesium sulfate Positive polarity Calcific tendinitis – Acetate Negative polarity  Advantages of Transdermal Medications Bypass liver which decreases metabolic breakdown of medication Concentrated medication in treatment area – Non systemic No needles No risk of infection  Treatment Procedures Current – Direct current Frequency, phase duration, ramp do not apply –