Pain sensitivity in children with chronic pain and their mothers

The relationship between chronic pain in children and sensitivity to pain is
influenced by the way the mother deals with her childs' pain. Until now, pain
sensitivity in children with chronic pain has mainly been studied in children
recruited from tertiary health care clinics. Not all children with chronic pain
are referred to a hospital and chronic pain in the community is very common;
19% of children aged 4-7 and 23% of children aged 8-11.

The objectives of this study are:
1) assess the differences in pain sensitivity between children with and without
chronic pain
2) collecting normative data for pain sensitivity in children aged 8-12
3) investigate the relationship between parental factors, such as parenting
behavior and pain coping of the mother, and child pain sensitivity
4) investigate the relationship between the mothers' pain sensitivity and the
pain sensitivity of her child

Experimental study

Before testing the mother will be shown a short instruction video.

TSA
Thermal detection and pain thresholds will be measured in children and mothers.
All thermal stimuli will be induced with the Medoc Thermal Sensory Analyzer
(TSA) II. This is a precise, computer-controlled device capable of generating
and recording response to a highly repeatable thermal stimulus. A contact
thermode (30x30mm) will be used to apply cold or heat. The entire
thermode-stimulating surface will be placed in contact with the skin-testing
site. The minimum temperature is
-10°C and the maximum is 50°C. Starting from a baseline temperature of 32°C
warmth and cold the temperature will change at 1°C per second (warmer or
colder).
Before the thermal test is performed the subjects are instructed to press the
button when a cold sensation is first perceived. After this the thermode
returns to the baseline temperature of 32°C. This is repeated five times to
calculate the cold sensation detection threshold. The same procedure is carried
out for the warm sensation detection threshold. For detection of the cold
'pain' and heat 'pain' thresholds, subjects are instructed not to press the
button when they feel the warm or cold sensation but to press the button when
the cold or warm sensation gets painful. After they press the button the
thermode returns to the baseline temperature. If the subject does not press the
button before -10°C or 50°C the test will automatically terminate, returning to
the baseline temperature.

The published studies to date did not report any problems regarding the use of
the thermal test in children and children's willingness to participate is good
(Meier et al., 2001).


Neurometer
The detection and pain thresholds will be measured through electrical
stimulation, with the neurometer (Neurotron, Incorporated). This device is
capable of measuring the three different fibers (C fibers, A-delta fiber and
A-beta fibers). Because the neurometer can stimulate the different fibers
separately, we also want to use this. Different studies show that the different
methods to measure pain thresholds, show different results, although
inconsistently (Janal et al., 1994; Lautenbacher et al., 1994; Neddermeyer et
al., 2008).
With different frequencies (2000Hz, 250Hz, 5Hz) applied with a gold-plated
electrode with a 1cm diameter, the different fibers will be stimulated. The
measures will not be influenced by skin thickness, temperature or edema. Before
the beginning of the test the subjects will receive instructions. The electrode
will be coated with an electroconductive and taped to the skin. The stimulus
for the different frequencies will range from 0 to 9.99mA en will increase as
long as the subject presses a button. For the detection threshold the subject
will receive the instruction to release the button as soon as he or she feels
something. As soon as the button is released, the stimulus is stopped. For the
pain threshold the subject is instructed not to release the button as soon as
he feels anything, but when it becomes painful. With this button the subjects
will have full control over when they want to stop the test.

Experimental situation
The pain tolerance will not be measured, therefore the pain experienced will be
limited. To determine the influence of the mother's detection and pain
threshold, both tests will first be administered to the mother. The children
will do both tests twice, once in the mother's presence and once without. One
half will start with the mother present and the other half will start without
the mother.

Mothers and children will also fill out some questionnaires