Comfort Strength Control™ is a new combination of Constant Current and Constant Voltage Strength Control designed to maximise the advantages of both forms - giving predictable, repeatable, and comfortable treatment.
Practical experience has shown that these features improve compliance and outcome in trials of TENS.
Comfort Strength Control™ monitors skin and pad condition to ensure that the stimulation remains constant – linked to intensity steps of 0.5mA for added comfort.
Why is current so important?
TENS is intended to stimulate nerves. It is the CURRENT flowing through the tissue along the nerve that does this.
What is the difference between Constant Current and Constant Voltage?
Ohms law states that VOLTAGE = CURRENT X RESISTANCE
Most standard TENS units are constant voltage. This means that as the resistance of the skin and electrode pads change, the current will change. Sometimes this will not affect the current as the pads absorb moisture from the skin the resistance will change.
The patient responds to this change in current by adjusting the strength control. However, if pressure is applied to the pads, the current can increase rapidly and there is a risk of causing pain to the patient.
With constant current, however, the unit measures the resistance and adjusts the voltage so that the current stays the same.
Advantages of Constant Current
- Output is fixed, predictable, and repeatable
- More comfortable for patient
- Allows the addition of the One Touch Memory Start feature which aids with patient compliance
- Quantified dosage numbers for research and recording for Evidence Based Practice
Disadvantages of Constant Current
- If the unit is not switched off before the pads are removed, it could cause discomfort
- As a pad loses contact, the output would be increased to maintain the current. This current would be concentrated into a smaller and smaller area, and could be a quite unpleasant sensation
Comfort Strength Control™ overcomes these disadvantages as it is able to automatically adjust voltage controls.
If the resistance becomes too high, the unit switches to Constant Voltage control, preventing the discomfort associated with constant current. This sophisticated combination of technologies ensures optimum patient comfort.
Comfort Strength Control™ is one of the main features of the iTouch Easy TENS unit.