Graeme Clark Collection
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ItemWithin-subject comparison of speech perception benefits for congenitally deaf adolescents with an electrotactile speech processor and a cochlear implant( 1996)This study assessed speech perception benefits for three congenitally deaf adolescents who used an electrotactile speech processor (Tickle Talker™) and subsequently went on to use a Nucleus Minisystem 22 cochlear implant. Both devices provided significant and comparable benefits for all children in the device plus lipreading condition. All children benefited from the additional information provided by either the Tickle Talker™ or the cochlear implant, and were able to perceive speech information with these devices that was not available through either aided residual hearing or lipreading. None of the three children were able to understand open-set words or sentences using either hearing aids alone or Tickle Talker™ alone, without the aid of lipreading. Two of the children showed significant open-set speech perception benefits while using their cochlear implant alone.
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ItemIssues in the development of multichannel tactile devices for hearing-impaired children and adults( 1995)Levitt, Pickett and Houde (1980), in their landmark monograph, noted that the history of tactile aid development has been characterized by periodic bursts of enthusiasm and research, often culminating in identification of new avenues to be explored for improving tactile perception of speech. While several research groups have maintained long-term interest in tactile research (Boothroyd, 1985; Oller, Payne, & Gavin, 1980; Saunders, 1985), there was a marked increase in reports of new multichannel tactile devices during the 1980s (reviewed in McGarr, 1989). This upsurge may have been spurred in part by the rapid increase world-wide in the number of hearing-impaired children and adults using cochlear implants as everyday communication devices, and the perceived need for a non-surgical approach to assisting hearing-impaired children. Despite this increase in tactile research, no tactile device has yet achieved widespread commercial use by the hearing-impaired community. It is, therefore, of interest to question why cochlear implants have been more widely accepted than tactile devices.
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ItemArticulation accuracy of children using an electrotactile speech processor( 1995)Objective: Use of wearable tactile speech perception devices is suggested to help overcome the difficulties in speech production resulting from severe and profound hearing impairment in children. This suggestion is based on the assumption that subjects can use tactile input in isolation, or in combination with information from residual aided hearing, to monitor and modify their speech. The present study evaluated the benefits to articulation provided through use of a multichannel electrotactile device (“Tickle Talker™”). Design: Six profoundly hearing-impaired children were videotaped speaking with the Tickle Talker on and with the Tickle Talker off during conversations with their audiologist. Five of the subjects also wore their binaural hearing aids during all recorded conversations. The number of vowels, consonants, and overall phonemes correctly articulated by each child in the two conditions were compared. Results: One subject improved articulation of initial consonants and initial phonemes; one subject improved articulation of total vowels, total consonants, initial consonants, total phonemes, and initial phonemes; and a third subject improved articulation of total vowels and medial phonemes. Conclusions: Use of on-line tactile feedback from the Tickle Talker may benefit the articulation accuracy of some children, and the device may therefore be suitable to use with children who have not responded to more traditional speech training techniques.
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ItemWithin-subject comparison of speech perception benefits with a multiple-channel cochlear implant and tactile device( 1995)In order to adequately advise prospective cochlear implant patients and their families, a clinician must have a good knowledge of the potential for particular individuals to benefit from cochlear implants and other alternatives.
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ItemSpeech self-monitoring by children using an electrotactile speech processor( 1995)For the profoundly and severely-to-profoundly hearing impaired child, lipreading and hearing aids are not always sufficient to develop adequate speech perception and production skills. Tactile devices have been investigated as a source of supplementary speech information, with most research focusing on speech perception benefits. However, speech production difficulties are also a major issue for these children, and research into tactile devices should include investigation of the option to use them as speech production aids. This paper will present the results from an initial examination of the suitability of one tactile device for speech production monitoring.
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ItemImproved electrotactile speech processor: Tickle Talker( 1995)The Tickle Talker, an eight-channel electrotactile speech processor, has been developed from continuing research at the University of Melbourne. 'The development of the device has focused on production of reliable speech-processing hardware, design of cosmetically and ergonometrically acceptable electrode transducers, implementation of acute and chronic biomedical studies demonstrating device safety, design and testing of alternative speech-encoding strategies to provide benefit to speech perception and production, and design and testing of appropriate training methods for optimizing benefits. The Tickle Talker has been shown to provide benefits in supplementing lipreading or aided residual hearing for hearing-impaired adults and children. Improvements in speech processing have resulted in an increase in benefits to speech perception, and open the way for more flexible approaches to encoding speech input. Continuing development of the electrode circuitry has now produced a device that is robust and has an extended battery life. Safety studies have clearly demonstrated that there are no long-term contraindications to device use. The results suggest that the device has a role to play in rehabilitation programs for severely and profoundly hearing-impaired adults and children.
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ItemIssues in long-term management of children with cochlear implants and tactile devices [Abstract]( 1994)For many children with severe and profound hearing losses, conventional hearing aids are unable to provide sufficient amplification to ensure good oral communication and/or in the case of very young children, development of speech and language. Traditionally a number of these children have opted for the use of sign language alone or in Total Communication approaches as a primary means of communication. The advent of multiple channel cochlear implants for children and the continuing development of multiple channel speech processing tactile devices provide auditory approaches to resolving communication difficulties for these children. The successful use of such devices depends on a number of factors including the information provided through the aid; the ease of use, convenience and reliability of the aid; the individual communication needs of the child; and the habilitation and management program used with the device. Long-term data has shown that children continue to show increased speech perception benefits from improvements in speech processing and from further experience with these devices. Habilitation and management programs must therefore be geared to meet the changing needs of children as they progress and of families as children mature and face new challenges. Habilitation must address specific individual needs in speech perception and in speech production. For very young children, benefits of improved speech perception should have an impact on the development of speech and language, and habilitation and management must emphasise the need for language growth.
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ItemHabilitation issues in the management of children using the cochlear multiple-channel cochlear prosthesis(Wien, 1994)Since 1985, a significant proportion of patients seen in the Melbourne cochlear implant clinic have been children. The children represent a diverse population, with both congenital and acquired hearing-impairments, a wide-range of hearing levels pre-implant, and an age range from 2 years to 18 years. The habilitation programme developed for the overall group must be flexible enough to be tailored to the individual needs of each child, and to adapt to the changing needs of children as they progress. Long-term data shows that children are continuing to show improvements after 5-7 years of device use, particularly in their perception of open-set words and sentences. Habilitation programs must therefore be geared to the long-term needs of children and their families. Both speech perception and speech production need to be addressed in the specific content of the habilitation program for any individual child. In addition, for young children, the benefits of improved speech perception should have an impact on development of speech and language, and the focus of the programme for this age child will reflect this difference in emphasis. Specific materials and approaches will vary for very young children, school-age and teenage children. In addition, educational setting will have a bearing on the integration of listening and device use into the classroom environment.
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ItemCochlear implants for congenitally deaf adolescents: is open-set speech perception a realistic expectation?( 1994)The prognosis for benefit from use of cochlear implants in congenitally deaf adolescents, who have a long duration of profound deafness prior to implantation, has typically been low. Speech perception results for two congenitally deaf patients implanted as adolescents at the University of Melbourne/Royal Victorian Eye and Ear Hospital Clinic show that, after 12 months of experience, both patients had significant open-set speech discrimination scores without lipreading. These results suggest that although benefits may in general be low for congenitally deaf adolescents, individuals may attain significant benefits to speech perception after a short period of experience. Prospective patients from this group should therefore be considered on an individual basis with regard to prognosis for benefit from cochlear implantation.
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ItemA review of the biological, psychophysical, and speech processing principles used to design the tickle talker( 1992)The Tickle Talker is a wearable electrotactile speech processor, designed to be used by profoundly hearing-impaired children and adults in conjunction with lipreading and residual hearing. The effectiveness of such a device is affected by an interaction between biological, human engineering, psychophysical, and speech processing considerations. The requirements, the design principles, and the performance of the Tickle Talker in each of these areas will be discussed. Electrical stimulation of the nerve bundles lying along the sides of the fingers was chosen to provide safe, comfortable, energy-efficient stimulation of a well-organised and sensitive part of the tactile sensory system. This is achieved at a small cost to the appearance and mobility of one hand when using the Tickle Talker. The biphasic pulse waveform used to stimulate the nerve bundles has been chosen to ensure a biologically safe stimulus. The electrical parameters (pulse duration, pulse rate, and electrode position) that are used to encode speech information are varied within ranges that are matched to the characteristics of the tactile sense. The usable ranges and information-carrying potential of each of these parameters have been assessed in psychophysical experiments. A comparison of these results with similar experimental data for cochlear implant and hearing aid users is instructive in assessing the possible limitations of tactile and auditory speech processors. The results discussed will include the discrimination and identification of stimuli differing in intensity, duration and pulse rate; the identification of different spatial patterns of stimulation, and the detection of gaps in stimuli. In most respects, the tactile results are similar to the corresponding auditory measures. The resolution of temporal differences such as pulse rate discrimination or gap detection are generally not as good as in the auditory case, but may be as good or better than the corresponding results for some profoundly hearing-impaired individuals. The speech processor used in the Tickle Talker is a "feature extraction" device that explicitly estimates the second formant frequency, amplitude envelope, and fundamental frequency of the voice and encodes them in terms of electrode position, pulse width and pulse rate of the electrical stimulation pattern. Consideration of the psychophysical results and the speech information available from these parameters allows optimization of the Tickle Talker's operation and a broad estimation of its potential performance in speech discrimination. The perception of duration and place of articulation (front/back) of vowels, and the manner and voicing of consonants are expected to be improved by the Tickle Talker. Prosodic variations conveyed by pulse rate are expected to be perceived by some users, but not all. High frequency consonants such as: /s/,/z/./?/, and /t?/ are encoded in a particularly salient manner by the Tickle Talker.