Table 1.
Characteristics of participants.
| Characteristics | Controls | Chronic pain patients |
|---|---|---|
| Sample size; n | 42 | 42 |
| Gender (female); n (%) | 31 (74) | 31 (74) |
| Age [years]; mean (range) | 54.1 (35–66) | 54.0 (33–68) |
| Mean education∗ (SD) | 2.71 (1.0) | 2.05 (1.1) |
| Verbal IQ (SD) | 106.0 (9.5) | 98.0 (9.3) |
| Sleeping problems | 8 | 28 |
| Duration of pain [years]; mean (range) | / | 16.8 (1–50) |
| Pain intensity∗∗ (SD) | / | 5.9 (1.6) |
| Participants on opioid medication | / | 15 |
| Participants with depression (ADS-K score > 17) | 1 | 19 |
| Handedness (right, left, retrained left-handed) | 39, 1, 2 | 37, 1, 4 |
| (Main) pain syndromes† | Controls | Chronic pain |
| Fibromyalgia | / | 9 (7) |
| Musculoskeletal back pain | / | 20 (19) |
| Cervical/cervicobrachial pain | / | 7 (5) |
| Neuropathic pain | / | 3 (3) |
| Arthralgia | / | 9 (6) |
| Abdominal pain | / | 2 (2) |
| Myalgia | / | 1 (0) |
SD, standard deviation; ADS-K, General Depression Scale – Short form; ∗education refers to 0 = no degree, 1 = lower secondary education, 2 = secondary school, 3 = A-levels, 4 = university degree; ∗∗on an 11-point Numerical Rating Scale (0 = no pain; 10 = worst pain imaginable) on the day of testing. †The total amount of participants reporting different pain syndromes. In brackets, only the corresponding main pain category of each participant is listed.