There are various FDA-cleared ES device forms for pain and wound therapy; this article will focus on one device called EQ Pro Therapy.
It differs from traditional 1 MHz and 3 MHz ultrasound devices by emitting low frequency (38kHz) longwave/low frequency ultrasound emissions with much deeper penetration into tissues, providing muscle stimulation benefits as well. The EQ Pro features enhanced muscle stimulation capabilities.
Low-Frequency TENS Units
TENS units are widely used to treat both neurologic and musculoskeletal pain. Used alongside other therapeutic modalities, they’re especially helpful for patients unable or unwilling to tolerate oral medications; TENS has also proven particularly successful at managing persistent discomfort that continues despite treatment with other medication.
Conventional TENS utilizes low frequency, low intensity stimulation to produce non-painful paraesthesia. For maximum effectiveness, the intensity should be tuned so as to produce a tingling sensation in the target area or muscle twitching; this stimulates large diameter non-noxious afferents related to pain areas in dermatomes related to it while simultaneously inhibiting second order nociceptive transmission neurones in the central nervous system (Fig 2a).
TENS is not recommended to be used near an artificial cardiac pacemaker or during pregnancy or epilepsy; however, in other conditions and circumstances it may provide effective pain treatment options. In such instances, seeking advice from a healthcare provider before undertaking TENS treatment and placing electrodes near wounds, broken skin areas or active tumours. Furthermore, as placing electrodes there could promote further cancerous cell growth.
First step of TENS treatment involves familiarizing patients with their equipment and machine. Next, participants should practice proper hand hygiene and expose areas for placement of electrode pads – these pads should then be covered in medical tape and hooked onto pin connectors on the TENS unit.
TENS therapy should only be applied for short durations – no more than 20 minutes at most – due to research suggesting that prolonged high-frequency TENS exposure may cause nerve adaptation and eventually reduce its effectiveness over time.
Review appointments should be scheduled periodically in order to assess whether TENS is helping a patient. During these appointments, it will provide them with the chance to ask any pertinent questions, identify issues that need attention or discuss possible TENS strategies that could work better for them.
Neuromuscular Electrical Stimulation (NMES)
NMES uses small electric impulses to stimulate denervated muscles or groups. It can help increase strength, blood flow and range of motion; decrease atrophy and spasticity; promote healing of damaged tissue; as well as increase atrophy prevention and spasticity reduction. NMES may be combined with physical therapy or movement pattern training for maximum effects.
NMES effectiveness depends on several variables, including frequency, pulse width, modulation of pulses, amplitude and electrode placement. Many EMS devices allow adjustments of these variables for maximum patient comfort and efficacy; generally lower amplitudes will produce less vibration and provide a softer more soothing sensation compared to higher ones; however, lower ones also tend to produce weaker contractions that need to be increased to effectively stimulate muscle fibres.
Frequency of NMES plays an integral part in creating muscle contractions as it determines how much force each contraction can generate. An increase in frequency has been shown to increase contraction force as more motor units (MUs) discharge synchronously with every stimulus pulse, while decreasing frequency results in decreased contractile responses. However, using high stimulation frequencies may result in neuromuscular fatigue by decreasing MU excitability and increasing metabolic demand on muscle fibers.
Research has also demonstrated the influence of NMES amplitude on muscle contraction. A low amplitude will cause only slight fluttering while increased NMES can result in stronger contractions that lead to stronger tetanus effects and also cause antidromic transmission through spinal cord of muscle activation, potentially blocking both sensory and motor impulses from motor pool.
Studies have also demonstrated that using NMES with other techniques such as local vibration, blood flow restriction (BFR), voluntary contractions or mental imagery can enhance its effects even further. For instance, using BFR and NMES together produced more rapid and larger strength adaptations in forearm extensor muscles than when either modality was used alone.
Functional Electrical Stimulation (FES)
FES (functional electrical stimulation) is an innovative treatment method that uses electric current to activate muscles and nerves, stimulating them to contract (tighten). FES is used to treat various conditions including foot drop, stroke-related weakness or illness that affects the brain or spinal cord, spasticity as well as muscular spasticity.
FES devices can be attached to either arm, hand, or leg to assist with finger and wrist function or prevent foot drop allowing someone to pedal a bicycle with or without motorised support. FES devices use electrodes which adhere directly to skin as small amounts of electricity stimulate muscle contraction – just as our body uses electrical impulses naturally to move muscles around our bodies.
As electrical stimuli reach neuron cells in damaged muscle tissue, they cause depolarisation of cell membranes, leading to the release of sodium ions into cells and creating less negative charges until a threshold is met and an action potential generated. Normal muscle activity follows the size principle with smaller diameter muscle fibers being activated first before larger ones when demand increases.
The amplitude and pulse width of electrical stimulation can be tailored to suit the clinical needs of each client, with force exerted being determined by total charge (the product of amplitude and pulse width). Though individual muscle reactions will differ, in general optimizing charge produces stronger contractions.
Be mindful that, even though stimulation therapy is designed not to harm muscle tissue, many may still experience some degree of discomfort when using it. Sensationss range from pins and needles at low settings to burning or tingling sensations at higher settings.
FES may not be appropriate for certain people due to complications that include uncontrolled epilepsy (the stimulation can trigger seizures) and severe osteoporosis, where fractures could result from bone weakening. It should also be avoided in situations involving open wounds, active infections or those who have had DVT/thrombophlebitis or chronic skin disorders in areas where electrodes would be placed.
H-Wave Device Stimulation (HWDS)
H-Wave technology has been FDA cleared for both pain relief and neuromuscular indications, and produces distinctive pain-relieving high frequency effects compared to TENS; its primary low frequency muscle effects differ significantly from NMES (it doesn’t cause weakness or tetany with extended use); plus it emits electrical pulses over orders of magnitude longer duration than TENS which could explain why clinical outcomes are often better with this device.
HWDS has been proven effective at treating rotator cuff tears and increasing work-readiness for first responders. It’s portable, user-friendly and offers customized self-adhesive electrode placement to meet individual patient needs – making a more active post-operative treatment regime to reduce pain and improve ROM possible, eliminating buildups of proteins at injury sites that contribute to inflammation.
H-wave devices have been shown to produce significant anaesthetic/analgesic effects by altering nerve sodium pump function and stimulating muscles non-fatiguingly with repetitive H-wave stimulation – ultimately increasing blood and lymph flow by way of increased nitric oxide production.
H-Wave Device Stimulation (HWDS) for shoulder rotator cuff tears was recently investigated, with results suggesting that patients using HWDS experienced significantly lower MRI scores and greater functional improvements versus a placebo control group. Researchers believe these effects were achieved through combination of analgesic/anti-inflammatory effects, improved range of motion, and active postoperative treatment strategies.
Training sessions to teach participants how to use the device were more likely to use it ten or more times; those who utilized it six or more times also reported greater benefits, including pain reduction, increased range of motion (ROM), better sleep quality and spending more time with family.
The H-Wave device can be found without prescription and serves as a non-drug alternative therapy to help speed recovery from neck and back injuries such as neck sprains, strains or disc disorders as well as lower back aches, sprains or degeneration.
