Effectiveness of Active Exploration of Simulated Textures for Sensorimotor Recovery

Stroke is one of the leading causes of long-term disability worldwide. In many cases, it results in persistent sensorimotor deficits in the upper limbs, including reduced tactile sensitivity, poor proprioception, and impaired fine motor skills. These deficits limit independence in daily activities such as grasping, dressing, or using utensils, and reduce the quality of life for stroke survivors.

Sensory rehabilitation is a critical but often under-addressed aspect of post-stroke recovery. Traditional approaches frequently focus on motor function alone, overlooking the importance of sensory input in guiding and refining movement. While methods such as sensory stimulation and retraining have shown some promise, their long-term effectiveness remains inconsistent, and they often lack patient engagement.

The present study investigates the efficacy of a novel method of active sensory rehabilitation based on simulated texture exploration using programmable transcutaneous electrical stimulation. This method is designed to combine active tactile exploration with real-time sensory feedback. Participants use their index finger to explore virtual textures on a tablet screen. Each time the finger crosses a virtual texture line, an electrical pulse is delivered to the finger via surface electrodes. This setup creates the sensation of moving across textures of different densities, which the participant must compare and identify.

The goal is to determine whether this approach improves tactile discrimination and supports motor recovery in the upper limb. The trial is conducted as a parallel-group, single-blinded controlled clinical study. Participants are adults aged 18 to 80 years, at least one month post-stroke, with sufficient cognitive and functional status (MoCA ≥ 20, Barthel Index ≥ 3). Participants are randomly assigned to either a control group or an experimental group.

The control group receives conventional rehabilitation prescribed by their physician.

The experimental group receives the same conventional therapy, plus 10 sessions of active sensory training using the programmable stimulation system.

Each session includes 5 blocks of 10 trials, during which the participant explores and compares pairs of virtual textures. Performance data, such as accuracy and response time, are recorded.

Before and after the intervention period, participants are assessed using standard clinical scales: Fugl-Meyer Assessment (FMA) for motor function, Action Research Arm Test (ARAT), Nine-Hole Peg Test (9HPT) for fine motor skills, Touch-Test monofilaments for tactile sensitivity

Results are expected to provide insight into the role of active sensory engagement in neurorehabilitation and help develop more effective strategies for upper limb recovery after stroke.

Inclusion criteria

• Episode of stroke confirmed by neuroimaging
• More than one month post-stroke
• Montreal Cognitive Assessment (MoCA) score ≥ 20
• Barthel Index score ≥ 3
• Ability to understand and follow instructions
• Informed consent for participation and data collection
• Age 18-80 years

Exclusion criteria

• Presence of depressive symptoms (HADS-Depression > 11)
• Upper limb paresis score below 35 on the Fugl-Meyer scale
• Sensory impairment score below 3 or above 10 on the Fugl-Meyer scale