Objective Assessment of Vibrotactile Mislocalization Using a Haptic Glove

There is growing evidence for distortions of somatotopic sensory maps of the hand after neurological injuries such as stroke. However, routine somatosensory assessments are administered manually, leading to poor control over stimuli, inability to capture somatotopic mismatches, and generating only qualitative results. To address these limitations, an automated tool was developed to assess vibrotactile mislocalization on the hand. The ReHaptic Glove includes 24 independently controlled vibration motors distributed on the volar side of the hand. The setup allows the development of novel, refined outcome measures based on which objective distortion maps are proposed. To validate these methods, a vibrotactile localization study was conducted with six healthy young subjects. Correct detection rates were 70% for the distal phalanges and 50% for the base of the proximal phalanges (or metacarpal bone for the thumb). These differences were significant for the right hand (p = 0.018) and marginally significant for the left hand (p = 0.052). The detection rates are in accordance with the known densities of rapidly adapting cutaneous mechanoreceptors. Ergonomics of the glove, such as fit and ease of donning and doffing, were well rated despite large variations of hand size across subjects. Such an objective tool has the potential of assessing somatotopic mismatch in neurological patients, providing a basis for deficit-oriented therapies tailored to the individual patient.