Our primary objective is to examine the effects of two expectation manipulations (verbal suggestions with regard to an inert substance and an imagery exercise) on self-reported sensitivity to physical sensations of pain, itch, and fatigue.…
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Brief title
Condition
- Other condition
Synonym
Health condition
Op dit moment wordt het onderzoek bij gezonde proefpersonen uitgevoerd. In de toekomst zullen de interventies mogelijk toegepast kunnen worden bij de behandeling van een breed scala aan lichamelijke symptomen, waaronder pijn, jeuk en lichamelijke vermoeidheid
Research involving
Sponsors and support
Intervention
Outcome measures
Primary outcome
The primary endpoint of this study is the effectiveness of the expectation
manipulations in affecting sensitivity to pain, itch, and fatigue, i.e. the
difference between the conditions in sensitivity to pain, itch, and fatigue
after the expectation manipulations, as rated on Visual Analogue Scales (VAS).
Secondary outcome
The secondary endpoints of this study are to explore the effects of the
expectation manipulations on autonomic (heart rate, alpha amylase) and
endocrine responses (cortisol), as well as to explore the influence of
individual characteristics (e.g., general expectations) on the effectiveness of
the expectation manipulations.
Background summary
The potential relevance of expectations with regard to treatment outcome for
the effectiveness of medical interventions has only sparsely been attended to.
This is surprising, given that expectation effects can strongly influence, for
example, experienced pain (e.g., Price et al., 1999). Eliciting or enhancing
positive expectations might thus be a promising pathway for treating physical
symptoms with enhanced effectiveness. Previous research provides evidence that
inducing positive outcome expectations of symptom relief, for example pain
relief, via verbal suggestions could be a successful method to reduce physical
symptoms, such as pain (e.g., Vase et al., 2001; Van Laarhoven et al., 2011).
However, these effects have not been found consistently (e.g., Colloca et al.,
2008). Alternatively, one can enhance general positive expectations with
imagery, as in the Best Possible Self exercise (King, 2001), in which
participants write about and imagine their best possible future self. This
exercise proved to be successful in increasing positive future expectations
(Peters et al., 2010) and reducing sensitivity to pain (Hanssen et al., in
preparation). However, the effects of both verbal suggestions and the imagery
exercise on multiple physical symptoms simultaneously have not yet been
studied, nor have the effects of these methods been compared.
Study objective
Our primary objective is to examine the effects of two expectation
manipulations (verbal suggestions with regard to an inert substance and an
imagery exercise) on self-reported sensitivity to physical sensations of pain,
itch, and fatigue. Additionally, the effects on autonomic and endocrine
responses and the role of individual characteristics will be explored. The
results may contribute to the development of innovative therapeutic methods
that are intended to enhance the effectiveness of various medical treatments
for physical symptoms via altering positive outcome expectations.
Study design
Expectations are induced by verbal suggestions regarding an inert substance
(positive versus neutral) and/or an imagery exercise (positive versus neutral).
Using a 2x2 factorial design, participants are randomly allocated to 1 of 4
conditions. Participants in condition 1 will receive positive verbal
suggestions regarding the substance, after which they will do a neutral imagery
exercise (Positive Verbal Suggestions Condition). Participants in condition 2
will receive neutral verbal suggestions regarding the substance, after which
they will do a positive imagery exercise (Positive Imagery Condition).
Participants in condition 3 will receive both positive verbal suggestions and
they will do the positive imagery exercise (Combination Condition).
Participants in condition 4 will receive neutral verbal suggestions, after
which they do the neutral imagery exercise (Control Condition). Sensations of
pain, itch, and fatigue will subsequently be induced with stimuli of short
duration that previously have been validated by the research group and that are
safe and not burdensome (cold pressor test to induce pain, histamine
iontophoresis and electrical stimulation to induce itch, and Åstrand cycle test
to induce fatigue). Participants will indicate the intensity and unpleasantness
of the experienced sensations on visual analogue scales. The autonomic heart
rate response, the salivary autonomic alpha amylase response and the salivary
endocrine cortisol response will be assessed noninvasively.
Intervention
Expectation effects are induced by means of (1) positive versus neutral verbal
suggestions (that it is effective for 95% versus 5% of people) of the
effectiveness of a substance that is, unknown to the participants, inert, and
(2) a positive versus neutral imagery exercise in which participants focus on
either their best possible health in the future or on a typical day.
Study burden and risks
Participants will complete a series of validated questionnaires via internet to
assess relevant individual characteristics (30 minutes). Participants will then
visit the Department of Medical Psychology of the Radboud University Nijmegen
Medical Center once for approximately two and a half hours. The verbal
suggestions and imagination exercise will be given. The substance used is
inert, i.e., it does not contain any active ingredients. The stimuli used to
induce pain, itch, and fatigue have been validated by the research group, are
safe and not burdensome. The autonomic and endocrine responses are assessed
noninvasively. No risks are involved with participation in this study.
Postibs 9101
6500 HB Nijmegen
NL
Postibs 9101
6500 HB Nijmegen
NL
Listed location countries
Age
Inclusion criteria
Age >= 18 years
fluent in Dutch language
Exclusion criteria
1) Severe physical or psychological morbidity (e.g., heart and lung diseases, or DSM-IV psychiatric disorders) that would adversely affect participation
2) Chronic pain, itch, or fatigue complaints at present or in the past
3) Use of beta-blockers or other medication that influence heart rate, use of pacemaker
4) Inadequate health for physical exercise as indicated by 1 or more positive responses on the PAR-Q (Physical Activity Readiness Questionnaire)
5) Participants are required not to consume coffee, tea or cola within a 2 hour period prior to the experiment. Nor should they have smoked in the last two hours or consumed alcohol or other drugs in the last 24 hours. Additionally they are required to refrain from heavy physical exercise 24 hours prior to the experimental session
Design
Recruitment
Followed up by the following (possibly more current) registration
No registrations found.
Other (possibly less up-to-date) registrations in this register
In other registers
| Register | ID |
|---|---|
| CCMO | NL38953.091.12 |
| OMON | NL-OMON20989 |