May 3, 2005 Features

Measuring and Monitoring Progress with Cochlear Implants

Audiologists and Speech-Language Pathologists Working Together

Cochlear implant programs provide the perfect setting for much-needed collaboration between audiologists and speech-language pathologists. Working together facilitates quality care for patients as well as lifelong learning experiences for both groups of professionals.

The Cochlear Implant Program at the University of Michigan was established in 1984 with surgical placement of a single-channel cochlear implant in an adult with a profound hearing loss. Since that time, over 1000 patients have received cochlear implants at our facility. Our Cochlear Implant Team consists of three surgeons, six full-time audiologists, and two full-time SLPs. Ancillary team members include professionals who participate in the medical, educational, and rehabilitative care of our patients.

It is challenging for large cochlear implant programs to provide quality care for existing patients while trying to attract and provide quality care for new patients. One aspect of patient care that has the potential to be overlooked is the evaluation of speech perception and speech and language skills that should take place annually. Such evaluations are needed to document the efficacy of the intervention, to identify problems and intervene, and to continue to advance the field of cochlear implants.

When cochlear implants were first introduced for the pediatric population, anticipated outcomes for performance were largely unknown and professionals remained guarded in their expectations for performance. Although it was believed that cochlear implants would provide improved detection of environmental sounds, improved speechreading skills, and "better" speech and language skills than those that could be obtained if the child with profound deafness continued to use a hearing aid, no one ever imagined that children with cochlear implants would demonstrate such great strides in their development of spoken language. Results being obtained by children with cochlear implants today have greatly exceeded early expectations.

Today, expectations for performance for a child who receives a cochlear implant will have great influence on the type of intervention that is recommended. Recent research has demonstrated that children with profound deafness who receive a cochlear implant have the potential to develop normal speech and language skills if provided with the right tools. These include early identification of hearing loss; appropriate and immediate follow-up; early implantation; excellent medical, audiological, rehabilitative, and educational management; and dedicated, informed, and involved parents.

Importantly, the success of the child is greatly influenced by the expectations of the child's parents and by the professionals who work with the child. If these factors are present, children have the potential to develop spoken language skills comparable to those of their peers with normal hearing. However, such great strides in performance will only occur if parents and professionals set appropriate goals for the child and take the many steps needed for the child to succeed.

Annual Evaluation and Review

One of the most important steps in providing quality care to patients with a cochlear implant is the annual evaluation of performance. In the early 1990s, cochlear implant programs were involved in U.S. Food and Drug Administration (FDA) clinical trials to evaluate new and upgraded cochlear implant technology. Although the test protocols for such trials were often cumbersome and time-consuming, these trials provided our profession with large sets of pediatric performance data.

In recent years, the FDA has not required such rigorous data collection, decreasing the availability of nationally collected pediatric performance data. Additionally, the hectic pace and heavy workload at many centers has resulted in a decrease in the amount of data collected from cochlear implant recipients.

In our clinic, adult and pediatric patients are scheduled to return at least annually to assess device integrity and to evaluate performance with the device. These evaluations include assessment of the recipient's psychophysical measures, soundfield detection thresholds, and speech perception. For adults, separate speech perception batteries are used for adults with pre- and post-lingual deafness. With children, the type of test used to evaluate speech perception will vary depending on the individual's skills and language level. Pediatric patients additionally participate in annual assessment of their speech and language skills. Sample speech perception and speech and language batteries used with various age groups in our clinic are provided in the sidebar.

The speech perception tests listed in the sidebar enable us to evaluate the ability of the implant recipient to identify words, sentences, and simple phrases using closed- and open-set test formats. Pediatric tests are easy to administer and involve simple picture-pointing or word-repetition tasks. Over time, we have observed that most children quickly reach high levels of performance on such tasks, decreasing their sensitivity to subtle differences in performance. We additionally noted that many patients were able to repeat speech stimuli, even though they were unaware of the meaning of some words and phrases.

Because of this, we added tests to our battery that would evaluate a higher level of perception-auditory comprehension. Thus, our speech perception battery now includes subtests from the Woodcock Johnson Test of Achievement-III. These tests enable us to identify discrepancies between the child's speech imitation skills and ability to understand and comprehend what has been said. A recent analysis of scores revealed that large numbers of children demonstrate discrepancies between these two skills (Heavner, Butler, & Zwolan, 2004). Importantly, the results of such test batteries have been used to develop goals and treatment plans to improve children's auditory comprehension skills.

The results of annual testing are reviewed with adult recipients immediately after testing. During this discussion, the results of the evaluation are compared to those obtained by the patient prior to receiving the implant, to those obtained at the patient's previous evaluations, and those obtained by other patients with similar histories and etiologies of deafness. In general, adults should obtain scores that are comparable to or better than those obtained at their previous test session. If scores have worsened, troubleshooting of the device and the speech processor map or program should occur to determine if remapping will result in improved speech recognition skills.

The results of pediatric testing are reviewed and discussed with the child's parents following testing. Similar to the comparison of the adults' results, the results obtained by the child are compared to those obtained by the child prior to implant, to those obtained at previous test sessions, and to other children with cochlear implants. The child's results are then compared to those of children with normal hearing. Because such children demonstrate speech and language delays prior to receiving the implant, they will need to make more than one year's worth of progress during each year of time if they are to close the gap that exists between their skills and those of children with normal hearing.

The review of the child's performance often includes discussion of the child's educational placement and rehabilitative needs. Parents are queried about the progress they feel their child is making toward the initial goals they set for their child's development of spoken language (an exercise regularly performed with parents before their child receives a cochlear implant). When needed, school personnel are contacted or are visited to discuss the results of the evaluation. Often, our SLPs assist the teachers and school clinicians with writing therapy or IEP goals and provide ideas for activities related to the child's skills based on the discussions we have had with the parents.

Decrements in performance noted during adult and pediatric evaluations are always taken seriously. Possible reasons for reduced performance are investigated and troubleshooting of the device, speech map or program, and internal device is performed. If no apparent reasons for decreased performance are identified, the cochlear implant manufacturer is contacted and integrity testing of the internal device is performed. In some instances, the results of this testing may indicate that the reduced performance is due to failure of the internal device and reimplantation is usually recommended. If the test results of the cochlear implant manufacturer are inconclusive, the results obtained during the annual speech perception and speech/language evaluations are important factors that will have great influence on a decision to recommend reimplantation of the internal device.

In our clinic, recommendations for a reimplant are not made lightly and are only given following careful consideration of different speech processing strategies and various speech processor program modifications. In order to closely monitor performance whe n considering a recommendation to reimplant, the child is seen regularly by one of our certified auditory-verbal therapists for ongoing treatment and assessment. The results of these appointments and the feedback provided by the SLP have great influence on our team's decision to recommend replacement of the internal device.

Sharing Knowledge

The interactions that have occurred between speech-language pathologists and audiologists in our program have been necessary components of the care we provide to our patients. We have learned a great deal from each other. Such knowledge is evident when one hears our pediatric audiologists discussing a child's potential for the development of spoken language or when one hears our SLPs describing speech processing strategies to a parent. Although our patient responsibilities differ, the professionals in our group share common goals related to our patients. Such collaboration has only become possible as we have come to appreciate and acknowledge each other's areas of expertise and to respect each other's contribution to patient care.

Lastly, the results of speech perception and speech and language evaluations are necessary if we are to continue to advance the field of cochlear implants. Results obtained with currently available devices have profound influence upon future candidacy recommendations for cochlear implants. Thus, it is important for clinics to regularly evaluate speech perception and speech and language skills of patients with cochlear implants as doing so will not only enhance the quality of the service provided to these patients, but will also enhance our understanding of present and future technology.

Terry Zwolan, is an associate professor in the department of Otolaryngology at the University of Michigan (UM) Medical Center. She has worked at UM since 1990 and has been director of the UM Cochlear Implant Program since 1994. Contact her by e-mail at zwolan@umich.edu. 

Krista Heavner, completed her master's degree in speech-language pathology at the University of North Carolina at Chapel Hill in 1999. She received her Certification in Auditory-Verbal Therapy in 2003. Currently she works on the cochlear implant team at UM. Contact her by e-mail at heavner@umich.edu. 

cite as: Zwolan, T.  & Heavner, K. (2005, May 03). Measuring and Monitoring Progress with Cochlear Implants : Audiologists and Speech-Language Pathologists Working Together. The ASHA Leader.

Tests and Measures

The following tests are used to evaluate speech perception and speech/language skills at the University of Michigan Cochlear Implant Program. The precise test used with a recipient will vary depending on age, language skills, and attention span. Taped versions of the test are administered to a soundfield or administered monitored live voice using a presentation level of 60 dB SPL.

Speech Perception Tests: Adults With Postlingual Deafness

  • CNC Monosyllabic Words (Peterson & Lehiste, 1962)
  • Hearing in Noise Test (HINT) Sentences (Nilsson, Soli, & Sullivan, 1994)

Speech Perception Tests: Adults With Prelingual Deafness

  • CID Everyday Sentences (Silverman & Hirsh, 1955)-presented using hearing alone; hearing plus speechreading; and speechreading alone
  • CNC Monosyllabic Words (Peterson & Lehiste, 1962)

Speech Perception Tests: Children

  • Early Speech Perception Test (ESP; Moog & Geers, 1990)
  • Meaningful Auditory Integration Scale (MAIS; Robbins, Renshaw, & Berry, 1991)
  • Word Intelligibility by Picture Identification (WIPI) Test (Ross & Lerman, 1979)
  • Northwestern University-Children's Perception of Speech (NU-CHIPS) Test (Elliot & Katz, 1980)
  • Minimal Pairs Test (Robbins et al., 1988)
  • PBK-50 Word List (Haskins, 1949)
  • Bamford-Kowel-Bench Sentences (BKB; Bamford, Kowal & Bench, 1979)
  • The Common Phrases Test (Robbins, Renshaw, & Osberger, 1995)
  • Glendonald Auditory Screening Procedure (GASP; Words and Sentences; Erber, 1982)
  • Lexical Neighborhood Test (LNT; Kirk, Pisoni, & Osberger, 1995)
  • Multi-Lexical Neighborhood Test (MLNT; Kirk, Pisoni, & Osberger, 1995)
  • Hearing in Noise Test (HINT-C) Sentences for Children
  • Woodcock Johnson Test of Achievement-III, Oral Directions Subtest, Oral Comprehension Subtest (Woodcock, McGrew, & Mat her, 2001).

Speech and Language Measures: Children

  • Peabody Picture Vocabulary Test-III (Dunn & Dunn, 2001)
  • Expressive Vocabulary Test (Williams, 1997)
  • Oral and Written Language Scales (Carrow-Woolfolk, 1995)
  • Bracken Basic Concept Scale (Bracken, 1998)
  • Preschool Language Scale-4 (Zimmerman, Steiner, & Pond, 2002)
  • Clinical Evaluation of Language Fundamentals-3 (Semel, Wiig, & Secord, 1995)
  • Clinical Evaluation of Language Fundamentals-Preschool 2 (Wiig, Secord, & Semel, 2004)
  • Arizona Articulation Proficiency Scale, Third Revision (Fudala, 2000)
  • The Token Test for Children (DiSimoni, 1978)
  • Woodcock Johnson Test of Achievement-III, Passage Comprehension Subtest (Woodcock, McGrew, & Mather, 2001)
  • The Rosetti Infant-Toddler Language Scale (Rossetti, 1990)
  • Cottage Acquisition Scales for Listening, Language, and Speech (Wilkes, 2001)
  • CID Picture SPINE (Speech Intelligibility Evaluation; Monsen, Moog, & Geers, 1988)


References

Bench, J., Kowal, A., & Bamford, J. (1979). The BKB (Bamford Kowal-Bench) sentence lists for partially-hearing children. British Journal of Audiology, 13, 108–112.

Bracken, B. A. (1998). Bracken Basic Concept Scale-Revised. San Antonio, TX: The Psychological Corporation.

Carrow-Woolfolk, E. (1995). Oral and Written Language Scales. Circle Pines, MN: American Guidance Service.

DiSimoni, F. (1978). The Token Test for Children. Austin, TX: Pro-Ed.

Dunn, L. M., & Dunn, L. M. (1997). Peabody Picture Vocabulary Test-Third Edition. Circle Pines, MN: American Guidance Service.

Elliott, L., & Katz, D. (1980) Development of a new children’s test of speech discrimination. St. Louis: Auditec.

Erber, N. P. (1982) Auditory training. Washington, D.C.: Alexander Graham Bell Association for the Deaf.

Fudala, J. B. (2000). Arizona Articulation Proficiency Scale, Third Revision. Los Angeles, CA: Western Psychological Services.

Haskins, H. A. (1949) A phonetically balanced test of speech discrimination for children. Unpublished master’s thesis, Northwestern University, Evanston, IL.

Heavner, K., Butler, B., & Zwolan, T. (2004).  Bridging the gap between speech perception and language comprehension. Presented at the 2004 Alexander Graham Bell Association for the Deaf and Hard-of-Hearing National Convention, Anaheim, CA.

Kirk, K. I., Pisoni, D. B, & Osberger, M. J. (1995). Lexical effects on spoken word recognition by pediatric cochlear implant users. Ear and Hearing, 16, 470–481.

Monsen, R., Moog, J. S., & Geers, A. E. (1988). CID Picture SPINE Speech Intelligibility Evaluation. St. Louis, MO: Central Institute for the Deaf.

Moog, J. S., & Geers, A. E. (1990). Early speech perception test for profoundly hearing-impaired children. St. Louis: Central Institute for the Deaf.

Nilsson, M. J., Soli, S. D., & Sullivan, J. A. (1994). Development of the Hearing in Noise Test for the measurement of speech reception thresholds in quiet and in noise. Journal of the Acoustical Society of America, 95(2), 1085–1099.

Peterson, G. E., & Lehiste, I. (1962). Revised CNC lists for auditory tests. Journal of Speech and Hearing Disorders, 27, 62–70.

Robbins, A. M., Renshaw, J. J., & Berry, S. W. (1991). Evaluating meaningful auditory integration in profoundly hearing-impaired children. American Journal of Otology, 12 Suppl, 144–150.

Robbins, A. M., Renshaw, J. J., Miyamoto, R. T., Osberger, M. J., & Pope, M. L. (1988) Minimal Pairs Test. Indianapolis, IN: Indiana University School of Medicine.

Robbins, A. M., Renshaw, J. J., & Osberger, M. J. (1995) Common Phrases Test. Indianapolis, IN: Indiana School of Medicine.

Ross, M., & Lerman, J. (1979). Word intelligibility by picture identification. Pittsburgh, PA: Stanwix House, Inc.

Rossetti, L. (1990). The Rossetti Infant-Toddler Language Scale. East Moline, IL: LinguiSystems, Inc.

Semel, E., Wiig, E. H., & Secord, W. A. (1995). Clinical Evaluation of Language Fundamentals Third Edition. San Antonio, TX: The Psychological Corporation.

Silverman, S. R., & Hirsh, I. J. (1955). Problems related to the use of speech in clinical audiometry. Annals of Otology, Rhinology, and Laryngology, 64(4), 1234–1244.

Wiig, E. H., Secord, W. A., & Semel, E. (2004). Clinical Evaluation of Language Fundamentals Preschool-Second Edition. San Antonio, TX: Harcourt Assessment.

Wilkes, E. M. (2001). Cottage Acquisition Scales for Listening, Language, and Speech. San Antonio, TX: Sunshine Cottage School for Deaf Children.

Williams, K. T. (1997). Expressive Vocabulary Test. Circle Pines, MN: American Guidance Service.

Woodcock, R. W., McGrew, K. S., & Mather, N. (2001). Woodcock-Johnson III Tests of Achievement. Itasca, IL: Riverside Publishing.

Zimmerman, I. L., Steiner, V. G., & Pond, R. E. (2002). Preschool Language Scale Fourth Edition. San Antonio, TX: The Psychological Corporation. 



  

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