Pain’s Adverse Impact on Training-Induced Performance and Neuroplasticity: A Systematic Review

Abstract

Motor training is a widely used therapy in many pain conditions. The brain’s capacity to undergo functional and structural changes i.e., neuroplasticity is fundamental to training-induced motor improvement and can be assessed by transcranial magnetic stimulation (TMS). The aim was to investigate the impact of pain on training-induced motor performance and neuroplasticity assessed by TMS. The review was carried out in accordance with the PRISMA-guidelines and a Prospero protocol (CRD42020168487). An electronic search in PubMed, Web of Science and Cochrane until December 13, 2019, identified studies focused on training-induced neuroplasticity in the presence of experimentally-induced pain, 'acute pain' or in a chronic pain condition, 'chronic pain'. Included studies were assessed by two authors for methodological quality using the TMS Quality checklist, and for risk of bias using the Newcastle–Ottawa Scale. The literature search identified 231 studies. After removal of 71 duplicates, 160 abstracts were screened, and 24 articles were reviewed in full text. Of these, 17 studies on acute pain (n = 7) or chronic pain (n = 10), including a total of 258 patients with different pain conditions and 248 healthy participants met the inclusion criteria. The most common types of motor training were different finger tasks (n = 6). Motor training was associated with motor cortex functional neuroplasticity and six of seven acute pain studies and five of ten chronic pain studies showed that, compared to controls, pain can impede such trainings-induced neuroplasticity. These findings may have implications for motor learning and performance and with putative impact on rehabilitative procedures such as physiotherapy.

Exploring pain interference with motor skill learning in humans: A systematic review

“…No studies have explored activity dependent plasticity using functional MRI. The findings in this review are consistent with a systematic review by Stanisic et al [ 23 ] who reported acute experimental pain may influence training induced neuroplasticity defined by TMS. The authors suggested the impact of pain on training induced neuroplasticity may be dependent on the motor learning paradigms utilised.…”

“…Two systematic reviews [ 22 , 23 ] have been recently published in this area. Izadi et al [ 22 ] investigated the impact of acute experimental pain on behavioural performance following motor learning.…”

“…Results were grouped based on the tissue where the pain was induced and investigated only experimental tonic pain paradigms. Stanisic et al [ 23 ] explored the impact of experimental and clinical pain on motor learning induced neuroplasticity, assessed using TMS. They reported both acute and clinical pain may impede neuroplasticity, resulting from motor learning, while highlighting a diversity of study findings.…”

Effect of standardized training in combination with masseter sensitization on corticomotor excitability in bruxer and control individuals: a proof of concept study

“…It could be speculated that pain caused by NGF-induced sensitization could help bruxers unlearn or “detrain” repetitive masticatory muscle activity, changing their oral behavior 11 . Indeed, our findings may have implications in motor learning and performance understanding, with a putative impact on rehabilitative procedures such as physiotherapy 26 . Since everyone has potential biological prerequisites and resources developed through the course of life our findings providing a better knowledge on orofacial pain and function and its assessment and strategies for management 8 .” The effect of pain on jaw-closing muscle performance has been a subject of interest in earlier experimental studies 10 , 23 , applying or not methods to distinguish bruxers or non-bruxers participants.…”

“…In the pain field, a rapid effect of pain on cortical motor plasticity has been observed in response to acute and chronic pain 25 , which may impede training-induced functional neuroplasticity manifested as decreased corticomotor excitability as defined by TMS 26 . Sensory-motor integration at a reflex such as a motor withdrawal reflex in response to noxious stimuli acts as a protective response to noxious stimulation 25 .…”