Bodily Sensory Inputs and Anomalous Bodily Experiences in Complex Regional Pain Syndrome: Evaluation of the Potential Effects of Sound Feedback

Abstract

Neuroscientific studies have shown that human's mental body representations are not fixed but are constantly updated through sensory feedback, including sound feedback. This suggests potential new therapeutic sensory approaches for patients experiencing body-perception disturbances (BPD). BPD can occur in association with chronic pain, for example in Complex Regional Pain Syndrome (CRPS). BPD often impacts on emotional, social, and motor functioning. Here we present the results from a proof-of-principle pilot study investigating the potential value of using sound feedback for altering BPD and its related emotional state and motor behavior in those with CRPS. We build on previous findings that real-time alteration of the sounds produced by walking can alter healthy people's perception of their own body size, while also resulting in more active gait patterns and a more positive emotional state. In the present study we quantified the emotional state, BPD, pain levels and gait of twelve people with CRPS Type 1, who were exposed to real-time alteration of their walking sounds. Results confirm previous reports of the complexity of the BPD linked to CRPS, as participants could be classified into four BPD subgroups according to how they mentally visualize their body. Further, results suggest that sound feedback may affect the perceived size of the CRPS affected limb and the pain experienced, but that the effects may differ according to the type of BPD. Sound feedback affected CRPS descriptors and other bodily feelings and emotions including feelings of emotional dominance, limb detachment, position awareness, attention and negative feelings toward the limb. Gait also varied with sound feedback, affecting the foot contact time with the ground in a way consistent with experienced changes in body weight. Although, findings from this small pilot study should be interpreted with caution, they suggest potential applications for regenerating BDP and its related bodily feelings in a clinical setting for patients with chronic pain and BPD.

Enriching footsteps sounds in gait rehabilitation in chronic stroke patients: a pilot study

“…As revealed by previous research, auditory feedback can alter body perception in healthy controls, 15,16,[35][36][37] as well as in clinical populations. 22,23,[34][35][36][37] In this proof-of-principle pilot study, our main aim was to assess the possibility of modifying dysfunctional gait asymmetry patterns in chronic stroke patients with lower limb hemiparesis by providing manipulated auditory feedback of their walking sounds. While there are a number of applications for movement rehabilitation using sound with information about the actual body position or movement, our study is novel in that it shows the potential of using sound in gait rehabilitation by means of the introduction of changes in body perception in chronic stroke patients.…”

“…Participants were asked to wear a system, which will be referred to as "sonic shoes," previously described in detail in Tajadura-Jiménez et al [35][36][37] that allows the dynamic modification of footstep sounds while walking and measures behavioral changes. As shown in Figure 1A, the system is composed of a pair of strap sandals with hard rubber soles.…”

“…Further studies examining this relationship might reinforce previous findings linking changes in body perception, emotion, and gait. 24,36,37,60,61 Future studies could be performed addressing these issues by performing multicenter collaborations and randomized controlled trials for testing the feasibility of this new technology. like to thank our patients for their help, support, and willingness to collaborate in all cases during this project.…”

Characterising sensorimotor adaptation in Complex Regional Pain Syndrome

“…[9,32,34,51,81]) we found that participants with CRPS had distorted representations of their affected limbs. Tajadura-Jiménez and her colleagues recently showed that people with CRPS are able to update their bodily representations, because manipulating the frequency of auditory feedback during walking changed the perceived dimensions of the CRPS-affected limb [75]. However, they did not directly compare the performance of the people with CRPS to controls, meaning it is unclear from their results if the extent of this updating was normal.…”

Neuropsychological Changes in Complex Regional Pain Syndrome (CRPS)

“…Brun et al [44], N = 13; Bultitude et al [45], N = 24; Kotiuk et al [46], N = 50; Lewis and Schweinhardt [47], N = 22, HC; Tajadura-Jiménez et al [48], N = 12…”