Neuropathy;Peripheral, Thermal Hypesthesia
Conditions
Keywords
Paradoxical Heat Sensations, Thermal Grill Illusion, Lidocaine
Brief summary
The purpose of the present study is to systematically test the occurrence of paradoxical and illusory responses to cold and warm stimuli in healthy volunteers with artificial sensory loss.
Detailed description
Efficient thermal sensation is important for adequate behavioral response to cold or warm stimuli and early signs of neuropathy can be changes in the thermal sensation. Alterations in thermal perception can results in paradoxical heat sensation (a warm perception when the skin is cooled) or a peculiar/burning sensation when the skin is stiumlated with simultaneous warm and cold (a thermal grill). Clarifying the occurrence of these paradoxical and illusory sensations, may help understanding early signs of peripheral neuropathy as well as thermal sensory perception. The investigators plan to conduct a study on thermal sensory perception using a model of sensory loss in healthy volunteers and systematically test the occurrence of paradoxical heat sensations and responses to the thermal grill.
Interventions
DIAGNOSTIC_TESTXylocaine spray 100mg/ml
Topical application
DIAGNOSTIC_TESTEthanol
Topical application
Sponsors
University of Aarhus
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
DIAGNOSTIC
Masking
DOUBLE (Subject, Investigator)
Eligibility
Sex/Gender
ALL
Age
18 Years to 40 Years
Healthy volunteers
Yes
Inclusion criteria
* Healthy subjects * Age between 18 and 40 years * Participant is able and willing to give informed consent.
Exclusion criteria
* Unable to understand and speak Danish * Non-cooperative * Chronic pain or acute pain the past week lasting more than 4 hours or pain on the day of investigation * Pain medication within the last week * Medication within the last week that can affect assessment * Psychiatric or neurological disease and diseases that may affect the assessment * Sensory disturbances * History or symptoms of significant diseases (e.g. psychiatric or neurological disease, diseases that may affect the assessment, sensory disturbances, cancer, diabetes mellitus, liver diseases, kidney diseases, cardiovascular diseases) * Pregnancy or lactation * Jetlag or sleep deprivation * Alcohol or drug abuse * Consumption of cannabis the last 4 weeks and consumption of alcohol in the last 48 hours * Any abnormality of the skin or of vascular origin at application site * History of hypersensitivity to lidocaine, other amide-type anesthetics, or other contents of the lidocaine or vehicle
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Paradoxical heat sensation (PHS) | 45 minutes | Number of PHS responders on arm treated with lidocaine 45 minutes after drug application and Number of PHS responders on arm treated with ethanol 45 minutes after drug application |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Quality of the Thermal Grill (TG) | 75 minutes | The participants are asked whether the stimulus is burning, hot, warm, neutral, cold, or freezing cold after the TG-condition (warm and cold), only warm or only cold on arm treated with lidocaine 75 minutes after drug application The participants are asked whether the stimulus is burning, hot, warm, neutral, cold, or freezing cold after the TG-condition (warm and cold) or only warm or only cold on arm treated with ethanol 75 minutes after drug application |
| Intensity of unpleasantness of the Thermal Grill (TG) | 95 minutes | The participants are asked to rate the intensity of unpleasantness on a VAS 0-100 (0 no unpleasantness; 100 worst unpleasantness imaginable) after the TG-condition (warm and cold), only warm or only cold on arm treated with lidocaine 95 minutes after drug application The participants are asked to rate the intensity of unpleasantness on a VAS 0-100 (0 no unpleasantness; 100 worst unpleasantness imaginable) after the TG-condition (warm and cold), only warm or only cold on arm treated with ethanol 95 minutes after drug application |
| Intensity of cold of the Thermal Grill (TG) | 95 minutes | The participants are asked to rate the intensity of unpleasantness on a VAS 0-100 (0 no cold; 100 extremely cold ) after the TG-condition (warm and cold), only warm or only cold on arm treated with lidocaine 95 minutes after drug application The participants are asked to rate the intensity of unpleasantness on a VAS 0-100 (0 no cold; 100 extremely cold ) after the TG-condition (warm and cold), only warm or only cold on arm treated with ethanol 95 minutes after drug application |
| Paradoxical heat sensation (PHS) | 30 minutes before drug application | Number of PHS responders at baseline without any treatment, 30 minutes before drug application |
| Intensity of warm of the Thermal Grill (TG) | 95 minutes | The participants are asked to rate the intensity of unpleasantness on a VAS 0-100 (0 no warm; 100 extremely warm ) after the TG-condition (warm and cold), only warm or only cold on arm treated with lidocaine 95 minutes after drug application The participants are asked to rate the intensity of unpleasantness on a VAS 0-100 (0 no warm; 100 extremely warm ) after the TG-condition (warm and cold), only warm or only cold on arm treated with ethanol 95 minutes after drug application |
| Thermal Grill (TG) | 75 minutes | Number of TG responders on arm treated with lidocaine 75 minutes after drug application and Number of TG responders on arm treated with ethanol 75 minutes after drug application |
| Pain intensity of the Thermal Grill (TG) | 90 minutes | The participants are asked to rate the intensity of pain on a visual analog scale (VAS) 0-100 (0 no pain; 100 worst pain imaginable) after the TG-condition (warm and cold), only warm or only cold on arm treated with lidocaine 90 minutes after drug application The participants are asked to rate the intensity of pain on a VAS 0-100 (0 no pain; 100 worst pain imaginable) after the TG-condition (warm and cold), only warm or only cold on arm treated with ethanol 90 minutes after drug application |
Other
| Measure | Time frame | Description |
|---|---|---|
| Mechanical thresholds | 45 minutes | Detection- and pain thresholds for mechanical (mNewton) stimuli at baseline without any treatment Detection- and pain thresholds for mechanical (mNewton) stimuli on arm treated with lidocaine 45 minutes after drug application Detection- and pain thresholds for mechanical (mNewton) stimuli on arm treated with ethanol 45 minutes after drug application |
| Thermal thresholds | 45 minutes | Detection- and pain thresholds for cold, warm (degrees) stimuli at baseline without any treatment Detection- and pain thresholds for cold, warm (degrees) stimuli on arm treated with lidocaine 45 minutes after drug application Detection- and pain thresholds for cold, warm (degrees) stimuli on arm treated with ethanol 45 minutes after drug application |
| Paradoxical heat sensation (PHS) using a modified protocol | 100 minutes | Number of PHS responders if the skin is heated or cooled prior the test at baseline without any treatment Number of PHS responders if the skin is heated or cooled prior the test on arm treated with lidocaine 100 minutes after drug application Number of PHS responders if the skin is heated or cooled prior the test on arm treated with ethanol 100 minutes after drug application |
Countries
Denmark
Contacts
Primary ContactEllen L Schaldemose, MD
Outcome results
None listed