Cefar Basic Tips for NMES Treatment
NMES - Neuromuscular Electrical Stimulation:
Electrical muscle stimulation is an internationally well established clinical physiotherapy treatment in fields like orthopedic and neurological rehabilitation.
The method is a compliment to other physiotherapy and should be combined with active training of mobility, strength, co-ordination and functional training. The method is simple and suited for clinic based treatments and self treatment at home.
Electrode Placement:
The placement of the electrodes is significant for the best results. The muscle is activated by stimulation over the motor nerve. The motor point is the area on the skin that is closest to where the motor nerve enters the muscle. Thsi is the easiest place to trigger a contraction electronically. The NMES programs in Cefar's stimulators generate a symmetric biphasic waveform, which means that the polarity constantly shifts. This means that both electrodes are equally active.
What Size Electrodes Should I Use?:
Larger muscle groups require larger electrodes. You can target smaller muscle groups more specifically with small electrodes, which give a higher current density (mA/cm2). Large muscle groups may also require stimulation on 2 channels - with 4 electrodes at once.
What Frequency and Pulse Duration Should I Choose?:
NMES usually uses frequencies of 20-120 Hz. To enhance blood circulation, choose frequencies under 10 Hz. The goal is to create muscle vibrations, not contractions. Regulate the pulse duration according to how much energy you want each pulse to have. When stimulating small muscle groups, a short pulse duration (say 200 µs) is often sufficient, while a longer duration (perhaps 400 µs) is used for larger muscle groups.
 |
1. Ramp-Up Time 2. Stimulation Time 3. Ramp-Down Time 4. Pause Time |
The figure above shows how electrical muscle stimulation is built up. It starts with a Ramp-Up Time (1), during which the contraction gradually increases to reach maximum contraction during the Stimulation Time (2). During Ramp-Down Time (3), stimulation gradually decreases and goes into a resting phase, which may have no or a mild stimulation (Active Resting). Active Resting helps prevent sore muscles and prepares the muscle for the next contraction. Stimulation with regular pauses is called intermittent stimulation.
What Should the Stimulation Feel Like?:
The goal of NMES treatment is usually to create muscle contractions. Increase the amplitude above the somatosensory threshold until a motor response occurs. The patient often experiences an electrical contraction as stronger than a voluntary one. The contraction must not feel unpleasant.
How Long Should I Use the Stimulator?:
Depending on the muscle's status and where the patient is in the rehabilitation phase, treatment can last from 5 to 60 minutes and be repeated from 3 times a week to twice a day. To intensify the treatment, you can gradually extend the stimulation time in relation tothe Pause Time. You can also increase the amplitude, frequency and/or pulse duration.
Denervated Muscles:
Stimulating denervated muscles differs from stimulating innervated ones. If the muscle is innervated you can stimulate it via the motor nerve, while if it is denervated, you must stimulate the muscle fibres themselves to trigger a contraction. The purpose of stimulating denervated muscle fibres is to maintain their contractile units while awaiting a possible reinnervation. It takes a long pulse of 100-300 ms to generate a contraction. A rectangular pulse is used if the muscle is totally denervated, while a triangular or trapezoidal pulse is used for partial denervation. This separates out the innervated and denervated fibres.
Handswitch:
To manually regulate the length of the stimulation and pause times, you can use a handswitch during electrical muscle stimulation. The switch is especially practical when electronic muscle contractions are combined with voluntary ones. The result is an effective, individual, treatment.