(1) To assess the effect of deafferentation on pain processing in the brain by task-fMRI(2) To assess the effect of deafferentation on reaction time (sedation) by task-fMRI(3) To assess the effect of deafferentation on endogenous pain modulation
ID
Source
Brief title
Condition
- Other condition
- Peripheral neuropathies
Synonym
Health condition
(chronische) neuropathische pijn
Research involving
Sponsors and support
Intervention
Outcome measures
Primary outcome
fMRI measures (BOLD signal)
pain intensity (VAS)in response to a noxious thermal stimulus
reaction time after a cognitive test
Secondary outcome
n.v.t.
Background summary
Spinal anesthesia induces several alterations in normal brain processes.
Firstly, loss of afferent information increases pain sensitivity. In our
previous study on the effects of spinal anesthesia (P11.221) we showed that
subjects felt more pain upon heat stimulation during spinal anesthesia. This
increase in pain sensitivity was explained by alterations in the endogenous
pain modulation system, which is an important regulator of pain perception.
Secondly, clinical evidence suggests that the loss of afferent information from
the spinal cord has significant effects on the maintenance of the arousal
state. For example, spinal anesthesia coincides with the development of a
decrease in the necessary dose of intravenous or inhalational anesthesia to
reach a defined level of sedation. Furthermore, an increased level of sedation
has been shown in healthy volunteers with spinal anesthesia.
Study objective
(1) To assess the effect of deafferentation on pain processing in the brain by
task-fMRI
(2) To assess the effect of deafferentation on reaction time (sedation) by
task-fMRI
(3) To assess the effect of deafferentation on endogenous pain modulation
Study design
The study will be performed using a single-blinded, placebo-controlled
cross-over design. After arrival in the MRI suite, the subjects will be
familiarized with the pain tests and cognitive test (reaction time and
stop-signal test). Baseline pain sensitivity and reaction time will be measured
and an intravenous access-line will be placed in the arm. Next, the first MRI
scan session will be performed, which includes a baseline anatomical scan and
baseline task-fMRI scans. The tasks that will be performed will be thermal pain
tests and cognitive reaction time tests. Spinal anesthesia will be induced by
intrathecal injection of the spinal anesthetic (bupivacaine) or a sham
procedure will be performed. The block level and haemodynamic parameters (blood
pressure and heart rate) will be determined at 5-minute intervals. 50 minutes
post-injection the second MRI scan session will be started in which the tasks
will be repeated. After the last scan, endogenous pain modulation will be
tested by 2 methods, conditioned pain modulation and offset analgesia. These
tests will be performed outside the MRI suite.
Intervention
spinal anesthesia
Study burden and risks
Small chance of post-spinal headache which will be treated where necessary
Albinusdreef 2
Leiden 2333 ZA
NL
Albinusdreef 2
Leiden 2333 ZA
NL
Listed location countries
Age
Inclusion criteria
Healthy male volunteers, aged 18 to 45 years, right-handed.
Exclusion criteria
- Obesity (BMI > 30);
- Significant history of any cardiac or vascular disorder, asthma or other pulmonary disease, major gastrointestinal abnormalities, peptic ulceration, hepatic, neurological, psychiatric, hematological (including bleeding disorders), endocrine, renal, or major genitourinary disease;
- History of illness, condition or medication use that, in the opinion of the investigator, might interfere with optimal participation, confound the results of the study or pose additional risk in administering spinal anesthesia to the subject;
- History of chronic alcohol or illicit drug use;
- Metal medical devices like pacemakers, knee or hip prosthesis, ear implants, vessel clips, subcutaneous insulin pumps or carries metal particles (e.g. metal splinter in the eye) inside the body;
- Claustrophobia;
- Allergy to study medications;
- Not able to maintain a regular diurnal rhythm.
Design
Recruitment
Followed up by the following (possibly more current) registration
No registrations found.
Other (possibly less up-to-date) registrations in this register
No registrations found.
In other registers
| Register | ID |
|---|---|
| CCMO | NL43966.058.13 |