Pain in torture victims
From the present analysis it appears that little discriminates pain mechanisms in torture victims who have been exposed to trauma from torture on different parts of the body. Rather, it seems as if there are important overriding mechanisms, manifested by the hyperalgesia to pressure pain in the QST analysis, which is usually considered a sign of centralization
 and is also present in fibromyalgia and whiplash associated disorders
[28, 29]. In addition there were frequently signs of cutaneous hypoesthesia, but since there was no obvious correlation to the localization of trauma, it may be speculated that these findings also indicate centrally evoked disturbances in sensory transmission, that is, central inhibition
. In fact, other researchers found, in a large study of Complex Regional Pain Syndromes, that a combination of sensory loss and deep mechanical hyperalgesia was present in the majority of the patients (66 -69%;
). Like in their study, the large inter-individual variation of our QST findings makes it important to present data individually rather than as group means.
Regarding torture victims, our findings are on one hand similar to those of Olsen et al.
, who found that the pain was predominantly located where the trauma had hit the body (‘a local sign’); similarly, our patients who had been exposed to falanga had more intense foot pain and larger pain areas in the feet than those exposed to generalized torture. However, comparing the two tortured groups (generalized torture vs. falanga with generalized torture) we had expected that there would be substantial local differences, also in their sensory functions as examined by QST. This was not the case. Rather, we found indications that central, more than peripheral, mechanisms seem to play a critical role in these pain conditions.
Regarding the use of QST in medico-legal matters, such practice is not applicable, since the size of the effects of non-organic factors on the QST method is currently unresolved
. On the other hand, QST can assess both large and small fiber function as illustrated in the individual profiles.
The high side-to-side correlations of all QST parameters predict that short-term test-retest reliability within the same day should be high. However, formal determination of test-retest reliability over different time ranges of 1 day, 1 month or 1 year are not available
The patients were refugees with residence permits in Denmark and had been referred by their general practitioner to our specialized clinic, making our sample highly selected, and thus it may not be representative of all torture victims.
With our traumatized patients, it was unfortunately not possible to collect exact information on the extent of torture. Attempts to retrieve such information may produce intense anxiety and flash backs. Moreover, all patients had been subjected to various forms of torture, increasing the risk of brain injuries
, which may contribute to the pain reported. Torture victims are vulnerable, often forget and have difficulties in focusing attention
. Using QST requires cooperation from the patients and the dimensions of cognitive effects on QST findings are not resolved
[30, 33]. Indeed, there are recent indications that chronic widespread pain is associated with lower cognitive processing speed
. Furthermore, the need to use interpreters in a psychophysical study, especially in a population with high levels of anxiety and depression, may present certain problems
Since many of these patients have been imprisoned for long time periods, it is important to distinguish the present findings from those elicited by peripheral neuropathy, whether from toxic, nutritional or infectious causes. However, the victims were carefully examined for such comorbidities during the medical assessment (see Methods) and secondly, motor deficits, typical for severe polyneuropathies, were never found among the included patients. Furthermore, the combination often seen in our patients, cutaneous hypoesthesia, normal nociceptive transmission and deep mechanical hyperalgesia, is not typical for peripheral neuropathies but has been reported without signs of nerve injury in, for example, chronic regional pain syndrome [11; Appendix A in 27]. However it is difficult to completely exclude the possibility of nerve injury here.
For patients with neuropathic pain, some of the QST procedures may be briefly painful, for example the Wind-up test. In our study design, we have considered this problem, and as is obvious from our methods, the patients were always in control. In fact, we only had to discontinue one of the sensory examination sessions due to pain.