Structural and Functional Grey and White Matter Changes in Patients With Pain Disorders

"The QST is a standardized, internationally accepted test battery consisting of several well-established, non-invasive tests, measuring parameters, which reflect nearly all aspects of somatosensation.~1. Thermal detection threshold for the perception of cold, warm and paradoxical heat sensations~2. Thermal pain threshold~3. Mechanical detection thresholds for touch~4. Mechanical pain threshold for pinprick stimuli~5. Stimulus-response functions~6. Wind- up ratio: The wind- up ratio represents the quotient of the pain intensity evoked by 10 pin-prick stimuli and the pain intensity evoked by one single pin-prick stimulus~7. Vibration detection threshold~8. Pressure pain threshold"

"Functional and structural MRI data will be collected using a 3 Tesla Siemens Scanner with a multi-channel head coil.~For the resting state functional MRI the subjects will merely lie in the scanner for about 10 minutes.~A painful heat/cold stimulation will be performed to study the differences in pain processing between the three groups"

The pain characteristics will be assessed through a standardized questionnaire. The german pain questionnaire is a validated questionnaire that assesses various dimensions of pain. Patients will also get a complete neurological examination by an experienced clinician.

"Structured telephone interview with 3 Questionnaires~1. The german pain questionnaire~2. Questionnaire regarding clinical development since the last visit designed by the investigators~3. German translation of 12-item-allodynia symptom checklist (ASC-12)"