The effect of pain on task persistence: mood-as-input as a possible predictor.

Researchers and clinicians are confronted with chronic pain patients who show
persistence of daily activities despite experiences of pain complaints, such as
patients with work related upper extremity pain (WRUEP). Biomedical models and
the prevailing Fear-Avoidance model, that is succesfully tested in patients
with chronic low backpain who are inclined to avoid activities due to fear of
movement, are insufficient in explaining development and maintenance of chronic
pain and disability when associated with task persistence. Instead of
explaining task performance as a consequence of main effects (pain, fear of
movement), it will be examined if task performance can be predicted by an
interaction effect. The Mood-as-Input model postulated by Martin (1993)
hypothesized dat the interaction between mood and goals (stop-rules) can lead
to different motivational effects during task performance. When individuals
adopt a goal directed stop-rule (or task-focused stop-rule), a negative mood
will lead to a motivation to continue with the task, because of an dissatisfied
feeling ("I have not done enough"), while a positive mood will lead to a
motivation to stop ("I have done enough"). When individuals adopt an enjoy
stop-rule, the opposite effect is seen, negative mood will lead to termination
of task performance ("I do not enjoy this task anymore"), while positive mood
will lead to task continuation ("I do enjoy this task). Significant results for
task persistence as a result of an interaction-effect between mood and
stop-rules are found in earlier studies with healthy subjects.
The aim of the present study is to test the Mood-as-Input model on the
performance of a cognitive task with administration of a painstimulus. It is
hypothesized that a combination between negative mood and a task-focused
stop-rule and positive mood and a enjoy stop-rule are leading to task
persistence compared to the opposite combinations of mood and stop-rules.

The aim of the study is to check if the mood-as-input model can give a possible
explanation for the persistence behaviour seen in patients with work related
upper extremity pain. Because of the fact that the mood-as-input model is only
tested in non-clinical samples with the use of cognitive tasks, it is important
to first test the mood-as-input model in healthy subjects using cognitive tasks
with administration of a painstimulus before studies on mood-as-input and
performance of physical tasks in chronic pain patients will be carried out.

Original study:
A 2 (mood: positive vs. negative) x 3 (stop-rule: no-stop-rule, task-focused,
enjoy) factorial design will be used. Mood is the between-subjects factor and
stop-rule is the within-subjects factor.
It is a double-blind experiment. First, to prevent for the fact that
participants will give desirable scores on mood-ratings, they will be told that
the experiment is about "Painful sensations affect your perspective on the
environment" (using this title, the aim of the distraction task and the
impression task are also covered). Second, the experimenter is unaware of the
stop-rule manipulation as well.

Amendment:
A 2 (mood: positive vs. negative) x 2 (stop-rule: task-focused, enjoy)
factorial design will be used. Mood and stop-rule are both between-subjects
factors.
It is a double-blind experiment. First, to prevent participants giving
desirable scores on mood-ratings, they will be told that the experiment is
about "Painful sensations affect your perspective on the environment" (using
this title, the aim of the distraction task and the impression task are also
covered). Second, the experimenter is unaware of the stop-rule manipulation as
well.

Original study:
Participants will be asked to complete some short questionnaires on the
internet and to visit the laboratory for one hour.
According to the mechanical stimulation: sensitization of the painstimulus can
appear, resulting in an increase of pain experiences during the task.
Participants have the ability to end the pain stimulus immediately at any time
by lifting the crowbar. Painstimulation will be terminated immediately. The
experimenter has the ability to hear and observe the participant and can
therefore intervene when necessary. Maximum duration of the task is 10 minutes.
According to the mood-induction: participants from the negative mood condition
could be left with a negative mood due to exposure to the filmfragments. At the
end of the experiment, they will receive a positive mood induction using a
positive filmfragment. Their mood will be checked before leaving the laboratory.
Taken into account these steps, execution of the experiment is, in our opinion,
justified.

Amendment: (parallel to original study, only the prevention of sensitization by
the use of different fingers for the different impression tasks won't be
necessary because participants need only to execute the impression task once)
Participants will be asked to complete some short questionnaires on the
internet and to visit the laboratory for one hour.
According to the mechanical stimulation: sensitization of the painstimulus can
appear, resulting in an increase of pain experiences during the task.
Participants have the ability to end the pain stimulus immediately at any time
by lifting the crowbar. Painstimulation will be terminated immediately. The
experimenter has the ability to hear and observe the participant and can
therefore intervene when necessary. Maximum duration of the task is 10 minutes.
According to the mood-induction: participants from the negative mood condition
could be left with a negative mood due to exposure to the filmfragments. At the
end of the experiment, they will receive a positive mood induction using a
positive filmfragment. Their mood will be checked before leaving the laboratory.
Taken into account these steps, execution of the experiment is, in our opinion,
justified.