Digitimer DS5 - Patient Connection and Electrodes

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

stimulator output. This procedure ensures that any baseline voltage offset at the input socket is

nulled and does not result in a DS5 stimulus output.

Monitor Output Connections

When connected to a suitable data acquisition device, the monitor outputs allows the operator to make a

continuous record of the stimulation current and voltage. These records can be used to relate the stimulus

time course to events observed within an evoked response. With appropriate analysis, this data would also

allow the operator to record the output impedance throughout a study.

1. Before proceeding, the operator should confirm that the analogue input connection of the

monitoring equipment is able to accept an input voltage of up to ±10V. If it is unclear whether the

equipment will accept this voltage range, the manufacturer of the equipment should be consulted

before any further use of the monitor feature.

2. If the operator of the DS5 is interested in monitoring the stimulus current, then the monitor output

scaling is 1V/10mA i.e a +1V signal at the current monitor output will equate to a +10mA

stimulation current. If the stimulus voltage is of more interest, then the voltage monitor output

scaling is 1V/20V. Using these scaling factors it may be possible to calibrate the data acquisition

software being used so that the computer displays a recording of the actual stimulus current and/or

voltage.

3. Once the data acquisition system has been configured, the DS5 monitor output(s) can be connected

to the appropriate analogue input(s) of the acquisition system.

USB Connection

Digitimer provide freely downloadable DS5 User Interface (DS5 UI) software which allows the operator to

update the DS5 firmware, adjust, save and recall stimulator settings or view a “virtual DS5 front panel” on a

computer during stimulation. Perhaps more importantly for some users, the USB connection also makes it

possible for other software to modify DS5 settings via COM Interface.

Further details on how to download, install and use the DS5 UI are given in Chapter 4, Annex 2.

NOTE: The DS5 should NOT be connected to a computer via the USB cable until the DS5 UI Software has

been successfully installed.

Connecting to a Dummy Load

We advise all new operators of the DS5 to simulate a protocol before a human subject is used. To do this

we suggest that the operator fabricates a “dummy load circuit” by placing a 1kohm (11 Watt) resistor

between the stimulus output sockets of the DS5 and applying a voltage waveform at the DS5 Voltage Input.

The resulting pulse current, energy and pulse duration information will be displayed on the main operating

screen. The operator should take care in handling the resistor after a pulse protocol has been applied, as it

may heat up considerably during a protocol.

Patient Connection

Before proceeding with patient connection to the stimulator output it is critically important that the operator