Digitimer DS5 - Electrode Selection and Placement

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DS5 Isolated Bipolar Constant Current Stimulator DS5 Operator's Manual 5.0

reads the safety precautions and warnings at the front of this operator's manual, fully appreciates their

meaning and is totally familiar with the operation of the stimulator and other equipment interfaced with it.

We recommend that the operator also carry out intended stimulation protocols with a dummy load before

carrying out any studies on human subjects.

On no account should a grounded oscilloscope or other monitoring device be connected to the

front panel output sockets of the DS5 while a patient is connected to the stimulator.

Selecting Appropriate Stimulation Electrodes

Digitimer does not supply any electrodes with the DS5 stimulator as it is expected that most operators will

already be familiar with the type of electrodes suitable for transcutaneous peripheral nerve/muscle

stimulation and will have a preferred supplier.

We do provide a range of optional accessories which include an output extension cable and these are more

thoroughly described in the Optional Accessories section of this manual.

We provide the following electrode selection guidance based on the experiences of those more familiar with

this form of electrical stimulation technique:-

Electrode Material – For patient safety, we recommend that electrodes should be of a non-polarizable

construction e.g Ag/AgCl.

Electrode Fixation – Electrodes may be of the disposable self adhesive type or reuseable taped or self

adhesive washer fixed type. Whichever method of fixation is used, the operator should ensure that the skin

is well abraded and cleaned prior to fixation to minimise impedance. The operator should also ensure that

there is low risk of the electrode becoming detached during a stimulation protocol. Regular visual inspection

of the electrodes in parallel with checking of the patient impedance during stimulation would be beneficial in

this regard.

Electrode Dimensions – The operator should take special care when the current density of any electrode

is greater than 2mA rms / cm

. While electrodes with a surface area of ~1cm

are routinely used for

peripheral nerve stimulation, we would recommend that the operator uses electrodes with the largest

surface area that still allows them to adequately stimulate particular nerves with precision.

Electrode Leadwires - Electrode leadwires should be kept as short as possible so as to reduce the chance

of inadvertent trans-thoracic stimulation. We recommend use of our D185-HB4 Electrode Extension

Cable as this brings a pair of DIN 42 802-1, 1.5mm Touch Proof sockets closer to the subject so that

electrode lead wire can be shorter.

Electrode Placement Protocols

Correct electrode placement is determined by the location of the nerve or muscle that is being studied and

as such the operator should have adequate anatomical knowledge to allow for the correct placement of

stimulation and recording electrodes before proceeding to use the DS5.

If necessary a search of recent publications on peripheral nerve stimulation should be conducted. A

bibliography is provided in this manual which may provide a good starting point for such a search, as it

includes papers by those who have used a prototype model of the DS5 stimulator.