Altered Interoceptive Perception and the Effects of Interoceptive Analgesia in Musculoskeletal, Primary, and Neuropathic Chronic Pain Conditions

Abstract

Chronic pain (CP) severely disrupts the daily life of millions. Interoception (i.e., sensing the physiological condition of the body) plays a pivotal role in the aetiology and maintenance of CP. As pain is inherently an interoceptive signal, interoceptive frameworks provide important, but underutilized, approaches to this condition. Here we first investigated three facets of interoceptive perception in CP, compared with pain-free controls. We then introduce a novel interoceptive treatment and demonstrate its capacity to reduce pain severity in CP, potentially providing complementary analgesic treatments. Study 1 measured interoceptive accuracy, confidence and sensibility in patients (N = 60) with primary, secondary musculoskeletal, and neuropathic CP. Compared with matched controls, CP participants exhibited significantly lower interoceptive accuracy and interoceptive confidence. Pain severity was predicted positively by interoceptive accuracy, anxiety and depression, and negatively by interoceptive confidence. Study 2 tested a promising new interoceptive treatment for CP, in a single-blind between-subjects design (N = 51) with primary, secondary musculoskeletal, and neuropathic CP patients. The treatment specifically activates the C-Tactile system, by means of controlled stimulation of interoceptive unmyelinated afferents, at 3 cm/s with a force of 2.5 mN. This treatment led to significant pain reduction (mean 23%) in the CP treatment group after only 11 min, while CP controls who received comparable but non-interoceptive stimulation reported no change in pain intensity. These studies highlight the importance of interoceptive approaches to CP and demonstrate the potential of this novel method of C-Tactile stimulation to provide complementary analgesic treatments.

Neural basis of affective touch and pain: A novel model suggests possible targets for pain amelioration

“…However, even before CT-fibres were discovered, it was suggested that Ab-fibres elicit allodynia following central sensitization in the dorsal horn, a notion that is also suggested by recent research (Liljencrantz & Olausson, 2014). This could explain why CT-optimal touch and skin vibration did not elicit a painful sensation in the study of Di Lernia et al (2020) and, more importantly, why CT-optimal touch reduced the experienced chronic pain. As described in the previous section and illustrated in Figure 3, pain modulation through the CT-system may depend on multiple neural mechanisms that may downregulate the possible overactivation of the ACC and PFC in chronic pain resulting in a decrease in experienced pain severity (Gursul et al, 2018;Krah e et al, 2016;Lu & Perl, 2003;Schmidt-Wilcke, 2015;von Mohr, Crowley, et al, 2018).…”

“…Participants suffered from primary chronic pain, secondary musculoskeletal pain and neuropathic pain and received either CT-optimal touch or vibration on the skin. The effect of CT-optimal touch was independent of pathological condition (Di Lernia et al, 2020). Even in central and peripheral neuropathic pain its severity appears reduced by CT-optimal touch.…”

“…Based on the presented research, CT-optimal touch could be a promising candidate in reducing chronic pain. Indeed, a recently published paper of Di Lernia, Lacerenza, Ainley, and Riva (2020) shows that CT-optimal touch significantly reduces the severity of reported pain in chronic pain patients by 23% after 11 min of stimulation. Participants suffered from primary chronic pain, secondary musculoskeletal pain and neuropathic pain and received either CT-optimal touch or vibration on the skin.…”

“…Overall, based on the aforementioned studies, CT-optimal touch may reduce pain in these patient groups and may therefore be useful as a new, alternative or supplementary pain intervention (Di Lernia et al, 2020;Gursul et al, 2018;Habig et al, 2017;Liljencrantz et al, 2017;von Mohr, Krah e, et al, 2018). If proven effective, it may be implemented in daily care routines in which a partner or caregiver provides CT-optimal touch, as this appears to increase its beneficial effects (von Mohr, Krah e, et al, 2018).…”

Co-Players in Chronic Pain: Neuroinflammation and the Tryptophan-Kynurenine Metabolic Pathway

“…Chronic pain is an unpleasant sensory and emotional experience that persists or recurs more than three months and may extend beyond the expected time of healing [1,2]. Chronic pain occurs as a part of symptoms due to an underlying medical condition or remains despite successful treatment of the condition that originally caused it [3].…”