Pain Induced during Both the Acquisition and Retention Phases of Locomotor Adaptation Does Not Interfere with Improvements in Motor Performance

Abstract

Cutaneous pain experienced during locomotor training was previously reported to interfere with retention assessed in pain-free conditions. To determine whether this interference reflects consolidation deficits or a difficulty to transfer motor skills acquired in the presence of pain to a pain-free context, this study evaluated the effect of pain induced during both the acquisition and retention phases of locomotor learning. Healthy participants performed a locomotor adaptation task (robotized orthosis perturbing ankle movements during swing) on two consecutive days. Capsaicin cream was applied around participants' ankle on both days for the Pain group, while the Control group was always pain-free. Changes in movement errors caused by the perturbation were measured to assess global motor performance; temporal distribution of errors and electromyographic activity were used to characterize motor strategies. Pain did not interfere with global performance during the acquisition or the retention phases but was associated with a shift in movement error center of gravity to later in the swing phase, suggesting a reduction in anticipatory strategy. Therefore, previously reported retention deficits could be explained by contextual changes between acquisition and retention tests. This difficulty in transferring skills from one context to another could be due to pain-related changes in motor strategy.

Effect of movement‐related pain on behaviour and corticospinal excitability changes associated with arm movement preparation

“…Indeed, longer RTs have been reported during motor acquisition in the presence of experimental tonic pain when compared to a no-pain condition (Boudreau et al 2010). Moreover, an impact of pain on anticipatory aspects of motor strategies while learning to compensate for a force-field have been observed in previous studies (Lamothe et al 2014;Bouffard et al 2016).…”

Effect of Experimental Hand Pain on Training-Induced Changes in Motor Performance and Corticospinal Excitability

“…The spontaneous use of a different motor strategy in subjects training in the presence of pain has recently been reported in force-field adaptation studies involving either reaching [ 24 ] or gait [ 42 ], and does not necessarily impact on global performance [ 42 ]. The possibility that the presence of pain leads subjects to use a different strategy or to rely on different sensorimotor processes during learning, is also supported by recent observations showing differences in early cortical somatosensory-evoked potentials, following motor learning acquisition in subjects trained in the presence of pain (induced with capsaicin) vs. pain-free subjects [ 28 , 29 , 30 ].…”

“…Overall, these results suggest that subjects trained in the presence of pain employ different strategies or neural processes to support motor skill acquisition. It remains to be confirmed whether these alternative strategies/neural processes have carry-over effects in terms of retention or transfer, as only a few studies have investigated these questions, with variable patterns of results [ 23 , 24 , 29 , 30 , 42 ].…”

Motor Strategies Learned during Pain Are Sustained upon Pain-free Reexposure to Task

“…However, when movement accuracy was essential (e.g. avoiding falls during walking), results showed no differences in performance when learning a new task with or without pain (10,11).…”