Instructions for participants

The following text may be useful in instructing participants and explaing to ethics/IRB panels what you propose.

What is the FAB device?

This device is designed to apply a safe but painful pressure to fingers on one or both of your hands.

The pressure is applied by a weight, attached to a plastic blade which rests on your fingers.

The weights can be lifted up and down by a computer to adjust the intensity of the pain you experience.

The machine has a failsafe which means it can never press with a force greater than the equivalent of 2kg. This makes it safe to use in our experiments.

Deciding whether to take part

The FAB machine will deliver a painful stimulus to one or both of your fingers. The maximum force which can be delivered is equivalent to 2kg applied to an area approximately 19mm:sup:2. This force is safe, but painful, and can leave some temporary indentations or marks on your fingers, although these will soon disappear.

You should NOT take part in this experiment if you have:

  • Any current or part skin or joint problems with your hands (e.g. excema or arthritis).
  • If you have recently injured or damaged any part of your hands.
  • If you bruise easily, or suffer from excessive bleeding. Also if you have thin or delicate skin, or are taking medications which might cause your skin to become thin (for example, oral corticosteroids taken for asthma).
  • Any form of restricted blood flow to your hands, poor circulation, or conditions like Raynaud’s disease.

You should also tell the experimenter if you:

  • Have a condition which affects your perception of pain
  • Have experienced long-term or chronic pain at any time in your life
  • Are anxious or worried about the procedure.

What will happen during the experiement?

The FAB machine works by lowering weights onto your finger, which press a plastic probe into the skin between your first and second knuckles.

Two fingers may be tested at once, although only one from each hand. You may undergo several trials in the course of the experiment.

The experimenter is likely to ask you to:

  • Tell them when the probe begins to hurt
  • Tell them when the pain is unbearable and you want to stop the trial
  • Ask you to rate how much the probe hurts and particular moments during the trial

Stopping and/or withdrawing

It is always your right as a participant to stop an experiment at any time. This is even more important when the experiment includes a pain stimulus. Please remember that:

  • You can tell the experimenter at any time you would like to stop the study.
  • You can stop any trial at any time by simply pulling your fingers backwards.

Note

You can remove your hands at any time by pulling backwards. This will not harm the machine or disrupt the experiment. The experimenter should show you how to do this before starting the study.