Peripheral Sensory Input in Central Post Stroke Pain (CPSP)

Study Overview
=================
Brief Summary
-----------------
Prospective, open-label study in 10 patients with Central Post Stroke Pain (CPSP). The study will evaluate the effects of peripheral nerve blockade on spontaneous pain and evoked thermal and mechanical responses in CPSP, and assesses the associated local anesthetic pharmacokinetics.

Official Title
-----------------
How Central is Central Post-stroke Pain? Investigating the Role of Peripheral Sensory Input in Maintaining Central Pain

Conditions
-----------------
Central Post Stroke Pain

Intervention / Treatment
-----------------
* Drug: Ultrasound-guided peripheral nerve block with 2% lidocaine


Participation Criteria
=================
Eligibility Criteria
-----------------
Each subject must meet all of the following criteria: Age ≥18; CPSP affecting an upper or a lower limb, in a distribution that may be completely covered by a peripheral nerve block; Patient fulfills all mandatory criteria for CPSP, fulfills at least one supportive criteria, and has definite CPSP by probability grading. Pain duration at least 3 months; Spontaneous pain intensity (average pain in past week) of ≥ 4 on 0-10 Numerical Rating Scale (NRS). Exclusion Criteria Subjects will not be enrolled if any of the following criteria exist: Not giving consent to participate in the study; Significant psychiatric or cognitive impairment; Moderate to severe renal or liver failure; Concomitant treatment with warfarin or other anticoagulants; Pregnancy or lactation.

Ages Eligible for Study
-----------------
Minimum Age: 18 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
No

Study Plan
=================
How is the study designed?
-----------------

Design Details

Primary Purpose: Other
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Pain testing<br>Completion of NPSI questionnaire Sensory mapping of the affected limb Quantitative Sensory Testing Patients will have a peripheral nerve blockade | Drug: Ultrasound-guided peripheral nerve block with 2% lidocaine<br>* Patients will have a peripheral nerve blockade with a local anesthetic (lidocaine) Assessment of spontaneous and evoked pain responses Completion of NPSI questionnaire Mapping of the affected limb<br>|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Reduction in Spontaneous Pain Intensity After a Peripheral Nerve Block. | Reduction in spontaneous pain intensity in the painful extremity from baseline to 30 minutes after a peripheral nerve block.Spontaneous pain intensity was measured on 0-10 numerical rating scale (NRS), where 0 represents no pain, and 10 represents worst pain imaginable | baseline and 30 minutes | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in the Intensity of Cold Sensation | The intensity of cold sensation (application of roller cooled down to 20 degrees Celsius) was measured on 0-10 scale, where 5 represents normal sensation (comparable to contralateral non-painful extremity). Higher scores indicate increased sensitivity (10= painful cold); lower scores represent reduced sensitivity (0=no cold sensation) | baseline and 30 min | 
| Change in the Intensity of Warm Sensation | The intensity of warm sensation (application of roller heated up to 40 degrees Celsius) was measured on 0-10 scale, where 5 represents normal sensation (comparable to contralateral non-painful extremity). Higher scores indicate increased sensitivity (10= painful hot); lower scores represent reduced sensitivity (0=no warmth sensation) | baseline and 30 min | 
| Change in the Intensity of Pinprick Sensation | The intensity of pinprick sensation (application of Semmes-Weinstein monofilament #6.1,  100g target force) was measured on 0-10 scale, where 5 represents normal sensation (comparable to contralateral non-painful extremity). Higher scores indicate increased sensitivity (10= painful sharp); lower scores represent reduced sensitivity (0=no pricking sensation) | baseline and 30 min | 
| Change in the Intensity of Brush Sensation | The intensity of brush sensation (application of SENSELab Brush-05) was measured on 0-10 scale, where 5 represents normal sensation (comparable to contralateral non-painful extremity). Higher scores indicate increased sensitivity (10= painful brushing sensation); lower scores represent reduced sensitivity (0=no brushing sensation) | baseline and 30 min | 
| Reported Pain/Dysesthesia Descriptors on NPSI Questionnaire | Composite scores on NPSI (Neuropathic Pain Symptom Inventory) questionnaire before and 40 minutes after the peripheral nerve block. The NPSI assesses participant ranking of specific neuropathic pain descriptors, each ranked on a 0-10 scale, where 0 represents no burning/squeezing/electric shocks (etc), and 10 represents worst burning/squeezing/electric shocks (etc). The scores on individual questions are grouped (averaged) into the three following subscales (each subscale scores ranging from 0 to 10): Burning pain Paroxysmal pain Paresthesia/dysesthesia | baseline and 40 min | 

 Terms related to the study
=================
Keywords Provided by Centre Hospitalier Valida
-----------------
Central Post Stroke Pain, Nerve block