 The Use of the Tactilator With Children: A Pilot Study Submitted by: Introduction Research has demonstrated that tactile aids used in combination with hearing aids provide useful acoustic information. Tactile aid users are able to learn to discriminate suprasegmental information, recognize specific speech sounds, experience an improvement in speechreading abilities as well as identify environmental sounds (Brooks, Frost, Mason, & Gibson, 1986; Plant, 1988; Cowan, Galvin, Blamey, & Sarant, 1995; Eilers, Cobo-Lewis, Vergara, Oller, Dolan-Ash, 1995; Proctor, 1995, Weisenberger, 1995; Plant, Horan, & Reed, 1997). The Tactilator is a tactual device developed by Audiological Engineering. It is intended to simulate Tactiling (Söderlund, 1995), a method of tactually supplementing speechreading developed and used by Gustaf Söderlund. He lost his hearing at age seven and began to use Tactiling with his parents during daily rehabilitation sessions. While speechreading he supplemented visual information by placing his hand on the speaker's should er with his thumb resting on the neck. Numerous studies have demonstrated that with this approach he gains a significant amount of information about the speech code (Plant & Spens, 1986; Plant, Franklin, Franklin, & Steele, 1995). The Tactilator is designed to allow the user to gain the same information provided by Tactiling without the need of physical contact between the speaker and speechreader. The Tactilator is a two-channel vibrotactile aid equipped with high and low frequency vibrators. The low frequency vibrator is a wide-band vibrator which transmits both spectral and voicing cues while the high frequency vibrator transmits temporal information above 1500 Hz. The Tactilator can also be used as a single channel device in which case the full signal is provided through the low frequency vibrator. The Tactilator can be worn alone or in combination with hearing aids or a FM auditory training system. The purpose of this study was to conduct a preliminary investigation into the efficacy of the Tactilator as a supplement to audition and speechreading. Five children and one adult were administered speech perception tests then trained in the use of the Tactilator for a six-month period. The tests were administered again following a six-month training period and the results were analyzed. Test results obtained using the Tactaid 7 (Audiological Engineering, Somerville, MA), a seven channel tactual vocoder, were also obtained to provide a comparison between the two devices. Subjects The five pediatric subjects range in age from 5 years to 8 years and are all enrolled in the same educational program at the University of Miami/Miami-Dade County Public Schools Model Program the Deaf and Hard of Hearing. The hearing impairment of all five subjects is in the profound range. Each subject was prelingually deafened and identified and aided by three years of age. The children are all experienced tactile aid users having trained with the Tactaid 7 (Audiological Engineering, Somerville, MA) and the Digivoc 16 (Intelligent Hearing Systems, Miami, FL) while enrolled in the Model Program. The adult subject is a 26-year-old postlingually deafened woman with a profound hearing loss. She lost her hearing abruptly at the age of seventeen. She received a cochlear implant three months prior to the onset of this investigation. Methods Three speech perception tests were administered to the pediatric subjects in the pretest and posttest conditions. These included the Maximal Pairs Test (Vergara, Eilers, Oller, & Miskiel, 1991), the Monosyllable, Trochee, and Spondee Test (Erber and Alencewicz, 1976), and the Minimal Pairs Test (Robbins, Renshaw, Miyamoto, Osberger, & Pope, 1988). Information on these tests is available in Table I. An experienced research associate who did not participate in the training administered the tests. The tests were in administered in a variety of conditions including speechreading alone, the Tactaid II+ and speechreading, the Tactilator and speechreading, the Tactilator alone, the Tactilator and hearing aids, and the Tactaid 7 and hearing aids. See Table II. Table I: Tests Administered
Table II: Modalities
Following the pretest the students participated in six months of weekly thirty-minute training sessions conducted by a speech-language pathologist experienced with aural rehabilitation techniques and tactile training methods. Therapy was conducted following a training protocol designed specifically for the Tactilator (Vergara & Miskiel, In Press). The curriculum follows a hierarchy of domains that include receptive and expressive skills. Training was conducted in the Tactilator and hearing aid modality. The adult subject was administered the Connected Discourse Tracking procedure (De Filippo and Scott, 1978; De Filippo, 1988) in the speechreading alone condition, the Tactilator and speechreading condition, and the cochlear implant and speechreading condition. Like the pediatric subjects she received weekly intervention for six months then was tested again. All subjects held the Tactilator vibrators in their hands with the high frequency vibrator in the right hand and the low frequency vibrator in the left hand. The microphone was within 18 inches of the speaker's mouth. Results Pediatric Figures 1 through 3 compare the group pretest and posttest results in three conditions; speechreading alone (SR), the Tactaid II+ and speechreading (T2 + SR), and the Tactilator and speechreading (Tctl + SR), for each of the tests administered. The Maximal Pairs test results, Figure 1, indicate that on this test the children improve over time regardless of condition. They all achieved 100% on the posttest. The MTS test results, Figure 2, demonstrate greater improvement over time in the Tactilator and speechreading condition, a 25 point increase, as opposed to the Tactaid II+ and speechreading condition which resulted in only an 11 point increase in the score over time. Figure 3 represents the Minimal Pairs test results and indicates improvement over time in each condition with somewhat higher posttest scores in the Tactilator and speechreading condition, 76% correct, as compared to 70% correct in the Tactaid II+ and speechreading condition. Figures 4 and 5 represent the pretest and posttest results for two subjects in the speechreading alone condition as compared to the speechreading and Tactilator condition. The children show some advantage with the Tactilator in the posttest condition, particularly when the difficulty of the test increased. Subject 2 (Figure 4) demonstrated an increase from 21% correct on the MTS to 96% correct when he was using the Tactilator. Subject 3 (Figure 5) also demonstrates improvement over time with the Tactilator, going from 21% correct to 42% correct on the MTS. Figure 6 represents the group posttest results on the Maximal Pairs and Minimal Pairs tests without speechreading using the Tactilator alone (Tctl), as compared to using the Tactilator with hearing aids (Tctl + HA). This illustrates the benefit of having auditory cues available along with the tactile information. The results on both tests are higher in the Tactilator and hearing aid condition. Figure 7 represents the group posttest results without speechreading using the Tactaid 7 and hearing aids (T7 + HA) as compared to using the Tactilator and hearing aids (Tctl + HA). Scores obtained using the Tactilator were higher than those obtained with the Tactaid 7 on both the Maximal Pairs and Minimal Pairs tests, 24 percentage points and 18 percentage points, respectively.
Adult Figure 8 represents the adult subject pretest and posttest results on the Connected Discourse Tracking Procedure in the speechreading alone condition (SR), the speechreading and Tactilator condition (Tctl + SR), and the speechreading and cochlear implant condition (CI + SR). These scores are represented in words per minute. The highest scores are obtained with the cochlear implant but some improvement over time is evident in the Tactilator condition, going from 19 words per minute to 25 words per minute. This is the only condition where the subject demonstrated improvement.
Summary The Tactilator appears to enhance the speechreading abilities of profoundly deafened individuals. Specific training is necessary to achieve optimal use of the device. Further research should be conducted on a larger group to investigate the full potential of the Tactilator and to confirm the results presented here. Specific questions that should be explored include placement of the vibrators and additional comparisons to other tactile devices. Abstract This paper describes a preliminary investigation into the efficacy of the Tactilator, a vibrotactile device designed by Audiological Engineering, as a supplement to audition and speechreading. Five children and one adult were administered speech perception tests then trained in the use of the Tactilator for a six month period. The tests were administered again following the training period. Results indicate that the Tactilator appears to enhance the speechreading abilities of profoundly deafened individuals. References Brooks, P.L., Frost, B.J., Mason, J.L., & Gibson, D.M. (1986). Continuing evaluation of the Queen's University tactile vocoder. II: Identification of open set sentences and tracking narrative. Journal of Rehabilitation Research and Development, 23, 129-138. Cowan, R.S.C., Galvin, K.L., Blamey, P.J., & Sarant, J.Z. (1995). Design fundamentals for electrotactile devices. The tickle talker case study. In G. Plant & K.E. Spens (Eds.) Profound Deafness and Speech Communication. London: Whurr. De Filippo, C.L. (1988). Tracking for speechreading training. The Volta Review, 90(5), 215-239. De Filippo, C.L. & Scott, B.L.(1978). A method for training and evaluating the reception of ongoing speech. Journal of the Acoustical Society of America, 63, 1186-1192. Eilers, R.E., Cobo-Lewis, A.B., Vergara, K.C., Oller D.K., & Dolan-Ash, M.M. (1995). A cohort study of children using multichannel tactile aids and cochlear implants. Seminars in Hearing, 16(4), 382-393. Erber, N.P., & Alencewicz, C.M. (1976). Audiologic evaluation of deaf children. Journal of Speech and Hearing Disorders, 41, 256-267. Plant, G., Franklin, D., Franklin, L., & Steele, M.(1995). Lipreaading with tactile supplements: a case study with an experienced subject. Seminars in Hearing, 16 (4), 296-304. Plant, G. (1988). Speechreading with tactile supplements. The Volta Review, 90, 149-160. Plant, G., Horan, M., & Reed, H. (1997). Speech teaching for deaf children in the age of bilingual/bicultural programs: the role of tactile aids. Scandinavian Audiology, 26, (47), 19-23. Plant, G. & Spens, K.E., (1986). An experienced user of tactile information as a supplement to lipreading. An evaluation study. STL-QPSR, 1/1986, 87-110. Proctor, A. (1995). Tactile aid usage in young deaf children. In G. Plant & K.E. Spens (Eds.) Profound Deafness and Speech Communication. London: Whurr. Robbins, A.M., Renshaw, J.J., Miyamoto, R.T., Osberger, M.J., & Pope, M.L. (1988). Minimal Pairs Test, Indianapolis: Indiana University School of Medicine. Söderlund, G. (1995). Tactiling and tactile aids: a user's viewpoint. In G. Plant & K.E. Spens (Eds.) Profound Deafness and Speech Communication. London: Whurr. Weisenberger, J.M. (1995). Factors influencing benefit from tactile aids. Seminars in Hearing, 16 (4), 343-355. Vergara, K.C., Eilers, R.E., Oller, D.K., & Miskiel, L.W. (1991). Maximal Pairs Test. Miami: University of Miami. Vergara, K.C. & Miskiel, L.W. (In Press). Tactilator Training Manual. Acknowledgements The authors appreciate the collaboration with Audiological Engineering Corporation. This work has been generously supported by Austin and Marta Weeks and Rita and Jerome Cohen. We also acknowledge the collaboration of the Miami-Dade County Public Schools in the implementation of the program with special thanks to Ronald K. Felton and Dennis Hoffman. *Presented at the International Sensory Aids Conference, Portland, Maine, May 10-May 14, 1998. |
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