Post-amputation pain is associated with the recall of an impaired body representation in dreams-results from a nation-wide survey on limb amputees.

Robin Bekrater-Bodmann,Xaver Fuchs,Martin Diers,Michael Schredl,Iris Reinhard,Jens Foell,Jörg Trojan,Herta Flor,Matthew Longo

doi:10.1371/journal.pone.0119552

Abstract

The experience of post-amputation pain such as phantom limb pain (PLP) and residual limb pain (RLP), is a common consequence of limb amputation, and its presence has negative effects on a person’s well-being. The continuity hypothesis of dreams suggests that the presence of such aversive experiences in the waking state should be reflected in dream content, with the recalled body representation reflecting a cognitive proxy of negative impact. In the present study, we epidemiologically assessed the presence of post-amputation pain and other amputation-related information as well as recalled body representation in dreams in a sample of 3,234 unilateral limb amputees. Data on the site and time of amputation, residual limb length, prosthesis use, lifetime prevalence of mental disorders, presence of post-amputation pain, and presence of non-painful phantom phenomena were included in logistic regression analyses using recalled body representation in dreams (impaired, intact, no memory) as dependent variable. The effects of age, sex, and frequency of dream recall were controlled for. About 22% of the subjects indicated that they were not able to remember their body representation in dreams, another 24% of the amputees recalled themselves as always intact, and only a minority of less than 3% recalled themselves as always impaired. Almost 35% of the amputees dreamed of themselves in a mixed fashion. We found that lower-limb amputation as well as the presence of PLP and RLP was positively associated with the recall of an impaired body representation in dreams. The presence of non-painful phantom phenomena, however, had no influence. These results complement previous findings and indicate complex interactions of physical body appearance and mental body representation, probably modulated by distress in the waking state. The findings are discussed against the background of alterations in cognitive processes after amputation and hypotheses suggesting an innate body model.

Highlights

The amputation of a limb represents the most serious breach of one’s body integrity
The regression analyses in the sample of amputees indicated that certain amputation-related sensations as well as a lifetime history of mental disorders were associated with higher dream recall frequency
We found a significant effect of amputation site on remembered body representation in dreams, i.e., lower-limb amputations were associated with higher frequency of dreams with an impaired body than upper-limb amputations

Summary

Introduction

The majority of limb amputees report awareness of a phantom limb [1], [2], i.e., the perceived presence of the missing limb. Beside the mere awareness of a phantom limb, amputees report various kinds of non-painful phantom sensations, such as tingling sensations or thermal perceptions [1], [2], or telescopic distortions, i.e., the sensation that the phantom limb has changed its length, most often shortened, over time [3]. Many amputees complain of phantom limb pain (PLP), which describes a painful sensation perceived in the removed limb. About 61% of the limb amputees reported residual limb pain (RLP), i.e., pain in the still present portion of the limb close to the amputation line [1], [2], [4], [5], [11]. PLP and RLP account for a significant reduction of health-related quality of life [12], highlighting the clinical importance of post-amputation pain

Methods

Results

Discussion

Conclusion