The Effect of Multi-Sensory Training on sEMG Activity in Lower-Limb Muscles, Balance, and Sensory Function in Patients With Diabetic Neuropathy: A Randomized Controlled Trial

Introduction Diabetes mellitus is a group of chronic metabolic disorders characterized by persistent hyperglycemia due to defects in insulin secretion, insulin action, or both(1).

With the world's population aged over 60 projected to increase from 12% to 22% between 2015 and 2050, the burden of diabetes among the elderly is expected to rise substantially. In Iran, the prevalence of diabetes in individuals over 65 is estimated to reach 6.5 million by 2030, and approximately 53% of type 2 diabetic patients develop peripheral neuropathy(2, 3).

Diabetic peripheral neuropathy (DPN) is a progressive neurodegenerative disorder involving both peripheral nerve damage and maladaptive central sensory processing(4). This dual pathology impairs the integration of vestibular, visual, and proprioceptive inputs critical for postural stabilit (5). Older adults with DPN exhibit increased postural sway and higher fall incidence compared to their non-neuropathic counterparts(6, 7). Damage to large-diameter afferent fibers and microangiopathic nerve alterations further disrupt joint proprioception, resulting in impaired anticipatory and compensatory postural adjustments(8).

Given these challenges, targeted interventions are crucial to mitigate fall risk and enhance functional outcomes in this vulnerable population(9). In addition to sensory deficits, muscle weakness-particularly a 17% reduction in ankle dorsiflexor strength and a 14% decrease in plantarflexor strength-further compromises postural stability and increases fall risk among DPN patients(8). Recent evidence demonstrates that focused strength training and neuromuscular rehabilitation can significantly improve postural control and reduce fall incidence in this population(10).

Exercise-based interventions-including whole-body vibration training(11), vestibular exercises(12), lower-limb strength training(13), and ankle-strategy drills(14) - have demonstrated significant benefits for balance and neuromuscular function. However, most protocols target only a single sensory modality and may not adequately address the multisystem impairments characteristic of DPN(12, 15, 16). Emerging evidence indicates that combined multisensory or sensorimotor-gait training can improve proprioception, nerve function, and muscle activation in DPN patients (17). Notably, Ahmad et al. (2020) reported in a randomized controlled trial that an 8-week sensorimotor and gait training program significantly enhanced proprioception, nerve conduction velocity, and muscle activation-particularly in the medial gastrocnemius and multifidus-during postural tasks and gait in DPN patients(17). Similarly, Malwanage et al. (2024) found that a 12-week ankle-focused proprioceptive training program significantly improved ankle reaction strategies and postural stability (18). Despite these promising results, no study has specifically investigated the effects of a structured 12-week selected multisensory training on neuromuscular activation and sensory function in older women with DPN-a population at particularly high risk of falls. Targeting multisensory integration pathways may offer novel neurorehabilitative strategies to counteract CNS maladaptation in DPN.