The Theory Behind It
A GSR Meter measures a client's Galvanic Skin Response (also known as
Electrodermal Response or EDR). This is simply the electrical conductivity
of the skin. To measure this, a very small electrical current (unnoticeable
to the client) is passed through the skin from one finger electrode to the
The electrical conductivity of the skin is affected by changes in the salt
and water in the sweat gland ducts. These changes occur almost
instantaneously in response to certain emotional reactions, the fight or
flight response (electrical conductivity increases), and when relaxed
(electrical conductivity decreases). Thus the GSR Meter is able to measure
and display a client's general state of relaxation and immediate emotional
reactions. The depth of relaxation or intensity of emotional response is
indicated by the change in reading on the digital display.
How it works
The sensor lead: The velcro finger straps are fitted securely to the
client's first and second fingers. The straps should be positioned in the
middle of the end section of the fingers, orientated so the copper
electrodes are in good contact with the fingerprints (not the fingernails).
If the finger straps are not fitted well, for example if they are too loose,
or too near the tips of the fingers so the electrodes don't make good
contact, then the reading will tend to be too low.
It doesn't matter which hand is used, but it is important to continue using
the same hand from session to session in order to get comparable readings.
The front panel: Connect the sensor lead to the socket in the bottom right
corner. The rocker switch on the left turns the meter on, and the push
button on the right toggles between 2 and 3 digit mode. The first 2 digits
of the reading are the same in both modes - 3 digit mode simply adds more
accuracy. More accuracy can be useful in seeing more quickly which direction
the reading is moving in (e.g. during analysis), whereas the 2 digit mode is
less distracting to read (e.g. during hypnosis).
Since the readings will vary from person to person regardless of their
mental state (due to variations in skin type, etc). it is a good idea to
record a reading of a client before any therapy is carried out. This will
give you a reference to work from. It is best to take this reading after
your client has been sitting relaxed for a while. Perhaps attach the
electrodes at the beginning of the initial consultation but record the
reading near the end of the consultation. Typical readings at this stage
tend to be between 50 and 75.
Note that use of certain prescribed drugs or even herbal medication
(anti-depressants, tranquillisers, etc) may result in an unusually low
reading. This low reading does not matter as it is still a valid reference
It is also worth noting that if a client is particularly hot or cold this
will affect the reading, making it higher or lower respectively. This should
not normally be a problem since the environmental conditions of your
treatment room are most likely fairly stable. In any case it is the changes
in reading during a session that are of most interest.
Hypnosis: When you have your client comfortably settled, attach the GSR
Meter electrodes to their fingers. Take a note of the display reading as you
begin your induction. Normally as your client enters hypnosis the reading
will fall and continue to fall as they become more and more relaxed.
Occasionally a client's reading will rise even though they have entered
trance - this tends to be indicative of subconscious anxiety. It is
recommended to continue deepening suggestions until the reading stops
falling, or at least slows right down.
Analysis: As your client begins to talk during analysis (e.g. free
association, regression to cause, etc) the reading will tend to rise
somewhat as their trance lightens. This is normal, but when they enter a 'no
go' area (anxious thoughts, etc) the reading will rise more significantly,
often very quickly, even though they may appear visibly relaxed. This is the
time when you may decide to gently probe. Reduced reactions in particular
areas from session to session will give you good feedback of your client's
Suggestion: With the GSR Meter you can monitor your client's emotional
reactions to your suggestions during hypnosis and thereby pace your
suggestions. You can also get a good indication of progress made by
observing their response to a fear or phobia before and after hypnosis.
Ultimately as you use the GSR Meter you will gain specific experience
relevant to your particular methods of therapy and most likely you will find
it an invaluable tool.
If you would like to feel reassured that your client is in an altered state
before commencing analysis or suggestion therapy then we believe that the
GSR Meter is invaluable for effective client treatment.