Vibrotactile Feedback in Exoskeletons

Rationale: People with motor-complete spinal cord injury (SCI) lack motor function below the lesion level and are, thus, wheelchair-dependent. In recent years, wearable exoskeletons have emerged as potential mobility devices for this population. Although exoskeletons generate the basic motions for ambulation, postural stability must be maintained by the user. People with motor-complete SCI miss essential somatosensory perception, which affects their ability to maintain postural stability. Hence, walking in an exoskeleton is demanding, and crutches are necessary.

When sensory information of a specific system is lost, the lack of sensory information can be substituted by providing feedback to another sensory system. As sensory feedback has been shown to improve postural control in people missing essential sensory information, such sensory substitution may also be effectively incorporated in people with complete SCI using an exoskeleton.

Objective: The study aims to investigate the effect of vibrotactile feedback on exoskeleton use in people with motor-complete SCI.

Study design: The proposed study is an experimental study. The study protocol includes six sessions of 90 minutes spread over three weeks. Sessions one to five are dedicated to training to assess the effect of vibrotactile feedback on exoskeleton motor learning. Session six is dedicated to evaluation to assess the effect of vibrotactile feedback on exoskeleton motor control.

Inclusion criteria

• SCI classification American Spinal Injury Association Impairment Scale (AIS) A or B
• Minimally six months post-injury
• Prior experience with the ReWalk Exoskeleton, able to walk independently

Exclusion criteria

• Pre-existing somatosensory problems before the SCI
• Visual or auditory issues that are not resolved with glasses or a hearing device
• Insufficient mastery of the Dutch language
• Contraindications related to the ABLE Exoskeleton