A Brain Imaging Study of the Analgesic Effect of Lidocaine and the Hyperalgesic Effect of Capsaicin
Overview
- Phase
- Not Applicable
- Intervention
- Not specified
- Conditions
- Pain
- Sponsor
- Massachusetts General Hospital
- Enrollment
- 38
- Locations
- 1
- Primary Endpoint
- Subjective Response to Pain (0-20 Visual Analogue Scale)
- Status
- Completed
- Last Updated
- 8 years ago
Overview
Brief Summary
This study will use using fMRI (functional Magnetic Resonance Imaging) to elucidate how contextual learning/expectation relieves or aggravates pain experience in the same cohort of subjects and the same study session.
Investigators
Jian Kong
Assistant Professor
Massachusetts General Hospital
Eligibility Criteria
Inclusion Criteria
- •a) Healthy male and female adults aged 21-50
- •b) No contraindications to fMRI scanning
- •c) Right handed
Exclusion Criteria
- •a) Current or past history of major medical, neurological, or psychiatric illness
- •b) Pregnancy or breast feeding, menopause, and irregular menstrual cycles (length of cycle must be within 26 to 32 days)
- •c) Claustrophobia
- •d) History of head trauma
- •e) History of impaired elimination
- •f) Instability of responses to experimental pain (see Study Procedures Section)
- •g) Use of psychotropic drugs, hormone treatments (including hormonal birth control) within 1 year
- •h) Non-fluent speaker of English
Outcomes
Primary Outcomes
Subjective Response to Pain (0-20 Visual Analogue Scale)
Time Frame: Weeks 1-3
Subjects received heat pain before and after the application of a neutral cream (told one application of neutral cream was lidocaine, one was capsaicin, and one was neutral) and rated pain intensity on a 0-20 Visual Analogue Scale (0-no pain, 20-intolerable pain). We only measure this outcome measure in session 3. The pain intensity for each cream was averaged amongst all participants for both the pre and post treatment in session 3. Subjects have up to 3 weeks to complete the 3 sessions.
fMRI Signal Changes in the Dorsal Anterior Cingulate Cortex
Time Frame: Week 4
We used fMRI to investigate the signal changes associated with administration of identical pain stimuli before (pre) and after the treatment (post) with different creams in session 3. It is important to note that the subjects had multiple weeks to complete the study, but this measure was only taken during one session. The change was calculated from two time points as the value at the later time point (post treatment) minus the value at the earlier time point (pre treatment).