Preparing participants for the use of the tongue visual sensory substitution device

Visual sensory substitution devices (SSDs) convey visual information to a blind person through another sensory modality. Using a visual SSD in various daily activities requires training prior to use the device independently. Yet, there is limited literature about procedures and outcomes of the training conducted for preparing users for practical use of SSDs in daily activities.

We trained 29 blind adults (9 with congenital and 20 with acquired blindness) in the use of a commercially available electro-tactile SSD, BrainPort. We describe a structured training protocol adapted from the previous studies, responses of participants, and we present retrospective qualitative data on the progress of participants during the training.

The length of the training was not a critical factor in reaching an advanced stage. Though performance in the first two sessions seems to be a good indicator of participants' ability to progress in the training protocol, there are large individual differences in how far and how fast each participant can progress in the training protocol. There are differences between congenital blind users and those blinded later in life.

The information on the training progression would be of interest to researchers preparing studies, and to eye care professionals, who may advise patients to use SSDs.IMPLICATIONS FOR REHABILITATIONThere are large individual differences in how far and how fast each participant can learn to use a visual-to-tactile sensory substitution device for a variety of tasks.Recognition is mainly achieved through top-down processing with prior knowledge about the possible responses. Therefore, the generalizability is still questionable.Users develop different strategies in order to succeed in training tasks.