Abstract

Introduction: Research has shown that dynamic force tracking tasks (FTT) rely on proprioception and in turn, sensorimotor integration (SMI) to accurately produce and track forces. Individuals with subclinical neck pain (SCNP) are known to have impaired upper limb proprioception as well as altered somatosensory processing as measured using somatosensory evoked potentials (SEPs). This suggests that they are also likely to have difficulties when trying to track forces using their upper limbs.

Objective: This study aims to validate a dynamic FTT in a young, healthy population by examining the neural (measured via SEPs) and performance changes in response to learning a novel dynamic FTT, in comparison to a motor tracing task (MT) previously shown to lead to motor learning and SEP peak changes.

Methods: SEPs were used to assess neural activity before and after learning a motor task from 12 (4 females and 8 males) right handed, healthy individuals between the ages of 18-35 years (21.6 ±3.01). Participants were allocated to either the FTT or the MT group. Participants in the FTT were asked to push against a force transducer to try to accurately track the force traces that were displayed on the computer, which were calibrated to the strength of their right thumb (aiming to utilize their abductor policis brevis (APB) muscle). Participants in the MT group were asked to trace sinusoidal waveforms using their right thumb as accurately as possible using an external tracking pad. Both of these motor tasks were made up of a pre-acquisition, acquisition, post-acquisition and a retention phase.  

Results: The N18 and N30 SEP peaks were higher in the FTT group whereas the N24, N11 and N60 SEP peaks demonstrated greater changes in the MT group. The MT group demonstrated greater decreases in motor performance error over time than the FTT group; however, both tasks demonstrated increased accuracy with practice.

Discussion and Conclusions: The increases in the N30 and N60 SEP peaks are in keeping with past work, while the differences between motor tasks likely reflects the great reliance on proprioception for the FTT and on vision for the MT. The findings demonstrate that the FTT produces similar or greater changes in neural activity and performance accuracy in comparison to the MT. Future research could use a FTT on a SCNP population to assess altered SMI because of their poor proprioceptive awareness.