Abnormal Pain Processing in COPD Patients

Sujetos sanos

Pacientes con EPOC

Pressure pain thresholds

Pressure pain thresholds (PPT) was used to measure pressure pain sensitivity in muscles with an algometer. With the patient in a seated position, pressure was applied three times at five bilateral points of the body: the distal thumb phalangeal, the gracilis muscle tendon at the inside of the knee, the distal of the middle part of the clavicle, the supraspinous muscle and the trapezius muscle's second portion. When the participant reported that pressure changed to pain, the pressure was stopped, and the mean value was registered.

Temporal summation

Temporal summation (TS) was used to evaluated peripheral sensitization. First, the pressure was applied with gradually increasing pressure until the subject reported pain in the flexor digitorum muscle of each arm. Second, 15 stimuli were applicated to one arm at an interstimulus interval (ISI) of 3 s and then to the other arm at an ISI of 5 s. After a 5 min, the series of stimuli were repeated in reverse order. The evaluation of TS was measured with a standardized numerical scale for rating the magnitude of late sensations experienced during the first, fifth, tenth, and fifteenth stimuli, and 15 and 60 s after the last stimulus in each series to evaluated the temporal summation. The scale ranged from 0 (no pain) to 100 (intolerable pain).

Pain Sensitivity Questionnaire

The Pain Sensitivity Questionnaire (PSQ) measured general pain sensitivity. It consists of 17 items, each describing a daily life situation and asking the patients to rate how painful this situation would be for them on a numeric rating scale ranging from 0 (not painful) to 10 (worst pain imaginable). A major score in the questionnaire a higher pain sensitivity.

Borg scale

The Borg scale was used to assess the dyspnea, which is a comprehensive instrument designed to measure breathlessness in patients with respiratory pathology. Patients rated their dyspnoea from 0 to 10, where 0 represents "no dyspnoea" and 10 represents "maximum dyspnoea." A difference of 0.9 units was considered as the minimal clinically important difference (MCID), according to previous studies in patients with respiratory disease

International Physical Activity Questionnaire

The International Physical Activity Questionnaire (IPAQ) measures total physical activity (MET·minutes·days per week).

Hospital Anxiety and Depression Scale

The HADS is a self-rated questionnaire originally developed for minor depressive symptoms in general medical outpatients. It consists of 14 items, depression (seven items) and anxiety (seven times), each with four choices numbered alphabetically. Each of the subscales' scores ranges from 0 to 21, corresponding to total scores of 0 to 42, with higher scores indicating greater distress.

London Chest Activity of Daily Living

The London Chest Activity of Daily Living (LCADL) was used to assess the impact and severity of breathlessness on ADLs. The LCADL has been used as an outcome measure in COPD. Higher scores reflect greater breathlessness during daily activity and the tool includes an anchor question identifying an individual's overall perception of the impact of breathlessness on their daily life.