Explain Pain in Fibromyalgia Patients

On this continuous, horizontal scale used, where 0 is ''no pain" and 100 is ''worst possible pain" (0-100 mm line), subjects will be asked to mark the line with a cross somewhere between both extremes that best reflect their sensation

A validated self-reported questionnaire developed for FM (scores range from 0 to 100, average FM patients score about 50 and severely affected patients score >70) wich measures multidimensional function/health-related quality of life.

The Pressure Pain Threshold (PPT) is defined as the lowest pressure that, using standardized testing conditions, needs to be applied in order to cause the slightest sensation of pain. It is a reliable and widely used measure. PPTs will be the average intensity of three consecutive measurements, applied every 30 seconds, measured using an analogue Wagner algometer (Wagner Instruments, Greenwich, CT) fitted with a 1 cm2 pressure, with an approximate rate of pressure increase of 1 Kg/s.

The Physical Component Summary score of the Medical Outcomes Study Short Form 36 [SF-36] will be used. More than 10% improvement in SF-36 physical function has been identified as a responder-to-treatment definition for FM clinical trials

The patient global impression of change scale (PGIC) is recommended for evaluating participant ratings of overall improvement in pain treatment trials. The PGIC uses a 7-point Likert scale that varies from 1 "very much improved" to 7 "very much worse" to quantify patient global response to treatment and have been previously used in FM treatment trials.

The Depression subscale of the Hospital Anxiety and Depression Scale (HADS-D) includes 7 items to assess depressive symptoms, with each item answered on a four-point (0 to 3) scale so that possible scores range from 0 to 21 with higher scores indicating more severe symptoms. An analysis of data from three pregabalin FM trials supports diagnostic validity of the HADS by showing that, using a standard cutoff score of ≥11 on the HADS-D to identify patients with major depressive disorder

The Fatigue Severity Scale (FSS)20 is a 9-item unidimensional measure of fatigue that has been demonstrated to be valid and reliabile in FM patients. The FSS measures fatigue by quantifying the impact of fatigue on specific types of functioning. Each item is scored on a 7-point rating scale, and the FSS score is derived by averaging all items to yield a score from 1 to 7 with higher scores indicating more severe fatigue symptoms.

The Jenkins Sleep Scale (JSS) is a 4-item self-report questionnaire designed to measure how often a subject has experienced sleep problems in the past month and has been studied in FM patients and found to be valid, reliable, and able to detect change after treatment. JSS items evaluate trouble falling asleep, staying asleep, waking up several times, and awakening unrefreshed with each item scored on a 5-point Likert scale from 0 = "not at all" to 5 = "22-31 days." Scores vary from 0 to 20 with higher scores indicating more frequent sleep problems.

The Manual Tender Point Survey (MTPS) is a standardized approach to performing the tender point exam in which FM patients rate pain severity upon digital palpation of each tender point on a verbal 11 point number rating scale. Pain severity ratings from the 18 tender points are averaged to yield a Fibromyalgia Intensity Score (FIS) that varies from 0 to 10 with higher scores indicating more severe tenderness. Change in the severity of pain at tender point sites has been shown to be a better measure of tenderness than change in the number of tender points.

The Neurophysiology of Pain Test-patient version consists of 19 true-false choice items (scores ranging from 0 to 19, with high scores representing a better knowledge regarding pain neurophysiology). This test evaluates whether patients can understand currently accurate information about the neurophysiology of pain.