Monitor, a Vibrotactile Aid for Environmental Perception: A Field Evaluation by Four People with Severe Hearing and Vision Impairment

Parivash Ranjbar,Ingeborg Stenström

doi:10.1155/2013/206734

Parivash Ranjbar, Ingeborg Stenström

Open Access

https://doi.org/10.1155/2013/206734

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Abstract

Monitor is a portable vibrotactile aid to improve the ability of people with severe hearing impairment or deafblindness to detect, identify, and recognize the direction of sound-producing events. It transforms and adapts sounds to the frequency sensitivity range of the skin. The aid was evaluated in the field. Four females (44–54 years) with Usher Syndrome I (three with tunnel vision and one with only light perception) tested the aid at home and in traffic in three different field studies: without Monitor, with Monitor with an omnidirectional microphone, and with Monitor with a directional microphone. The tests were video-documented, and the two field studies with Monitor were initiated after five weeks of training. The detection scores with omnidirectional and directional microphones were 100% for three participants and above 57% for one, both in their home and traffic environments. In the home environment the identification scores with the omnidirectional microphone were 70%–97% and 58%–95% with the directional microphone. The corresponding values in traffic were 29%–100% and 65%–100%, respectively. Their direction perception was improved to some extent by both microphones. Monitor improved the ability of people with deafblindness to detect, identify, and recognize the direction of events producing sounds.

Highlights

Monitor is a device developed to give people with severe hearing impairment (HI) or deafblindness (DB) access to more information about events in their surroundings
The results showed that Monitor consistently improved the ability of blindfolded deaf people to detect, identify, and recognize the direction of ongoing events producing sounds at home and in traffic
P1, with the longest training period, was the first to begin the training at the end of November. She continued with the training even after completing her five training weeks while waiting for the test leader to organize a test opportunity, which took a long time due to unexpected delays including late equipment delivery and finding a common day convenient for all involved in the test

Summary

Introduction

Monitor is a device developed to give people with severe hearing impairment (HI) or deafblindness (DB) access to more information about events in their surroundings. The aid, Monitor, uses the vibratory sense and is programmed to handle environmental sounds in contrast to other vibratory aids designed for speech signals [1, 2]. It detects sounds from events picked up by a microphone, adapts the sound to the frequency sensitivity range of the skin using algorithms developed based on modulating, transposition, or filtering principles, and translates the signal as vibrations. Four different algorithms, based on modulating and transposing principles, were found to be good candidates to be implemented in a portable vibrotactile aid for persons with DB In this current study, Monitor’s design was made portable by implementing a specific algorithm (one of the four selected in the laboratory) in a cell phone for a specific person with DB. The three microphones in a headband are reduced to one microphone

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