Running Head: Cochlear Implantation

Literacy Achievement and Early Cochlear Implantation in Deaf Children

Lawrence W. Sherman and Teri L. Cruse

Department of Educational Psychology

Miami University

 Available on the web at:

Abstract. Interest in the effect of cochlear implantation devices in deaf children has focused on their influence on literacy achievement.  Early learning and developmental theorists have suggested that the earlier this surgical procedure is done, the more positive the influence will be on children’s literacy learning.  Demographic data were obtained for 11 children attending a private school for the deaf.  These children had all received testing using the Woodcock/Johnson Letter Recognition Scale.  The children had received this surgical procedure at various developmental points in time ranging from 27 to 60 months.  The duration of use of the cochlear implant ranged from 27 to 70 months.  Pearson-Product-Moment correlations between age in months when the device was implanted and their total reading scores (r = -.89), as well as two subscales (letter/word recognition, r = -.91, and reading comprehension, r = -.93) were statistically significant (p < .01).  Likewise, the duration of time in months the device was in effect and their total reading scores (r = .79), as well as two subscales (letter/word recognition, r = .91, and reading comprehension, r = .88) were statistically significant (p < .01). Considering the small sample size of our study, we were especially impressed with the robust magnitudes of these relationships.  While acknowledging that there is some controversy among the deaf culture regarding the use of this surgical procedure, our data strongly suggest early use of the cochlear implant device enhances children’s literacy achievement.

Literacy Achievement and Early Cochlear Implantation in Deaf Children




     Many studies have been conducted on the benefits of cochlear implants.  There have been over 25,000 children fitted with cochlear implants in the last 20 years.  Rubinstein (2002) states that children fewer than 24 months of age were at one stage excluded as candidates for this procedure.  There were concerns about misdiagnosis, safety of the procedures and long-term reliability of the device.  In recent years, this view has shifted.  Children are being implanted earlier and the results are supporting the change in policy.  Research conducted by Ruben (1997) suggests there are critical periods for language development.  Pinker (1994) theories regarding the “Language Instinct,” would support the importance of early critical periods for language development.  Findings from Bollard et al. (1999) and Conner et al. (2000) describe age as a key variable for vocabulary development.

     Although the use of cochlear implant technology has opened doors for many deaf people, controversy regarding the technology remains. In 2001, the National Association of the Deaf (NAD) created a position paper addressing the Cochlear Implant Debate (Bloch, 2001). Throughout the deaf community, an outcry was heard stating the loss of a culture due to the new cochlear implant technology. This objection is similar to the fear present in the 1950's, when hearing aids were made available to younger children and technology had made them more useful (Pollard, 2001).  The Deaf community in the 1950’s feared the loss of its culture and its language, American Sign Language, just as it does now with the rise of cochlear implants.  The focus of the 2001 NAD position statement on cochlear implants was on preserving and promoting the psychosocial integrity of deaf and hard of hearing children and adults (Bloch, 2001). Many, outside the deaf community, believe deafness is a handicap that needs to be to be fixed. The cochlear implant is seen as the device that "fixes" the deaf person.  One important aspect detailing the popularity of implantation and oral language training is the notion that being deaf has "perceived burdens" in a hearing society. (Mayhill, 2001).   NAD has now shifted their position against cochlear implantation to one of accepting the rights of all individuals and individual differences.  The organization maintains the view of cultural diversity and the need for candidates and parents considering a cochlear implant to have as much information as possible on the advantages and disadvantages of this device.  One conceivable advantage for deaf children is the possibility of early implantation.

     Due to a change in the minimum age for implantation, the possibility for a longitudinal study on early implantation could be carried out.  Ertmer’s et al. (2003) study noted that children who were implanted during the preschool years tended to outperform those implanted later.   Bollard (1999) found that children implanted at a younger age (approximately 3:7 years) achieved an increase of 42 months in vocabulary age after 18 months of implant experience.

     When hearing children begin to read, most are competent language users (Geers, 2003). Vocabulary and oral language skills have been strongly associated with reading and academic skills for children with normal hearing. The reading task for a deaf child is an extremely different type of language experience.  Often, low literacy levels are reported among students with hearing impairments and it is believed to be due in part to the difference between their incomplete spoken language system and the demands of reading a speech based system (Perfetti & Sandak, 2000).  It has been suggested that early implantation increases speech perception in young children (Baumgartner, 2002).  It has also been studied that children who receive a cochlear implant before three years of age exhibit higher vocabulary and word reading scores than children fitted after 5 years of age.  Early implantation, in turn, would assist in the acquisition of beginning reading skills (Geers, 2003). The goal of this study is to explore the effect of age of implantation, duration of experience with the device and academic success.

     In our sample of children their educational setting invites active participants in intense auditory training.  American Sign Language is not used as a form of communication.  They are taught to listen and understand what they hear.  Speech training is an integral part of the program.  This school services children ranging in age from two to nine years of age.  The question in need of answering is when the child is mainstreamed, what is their level of achievement.  Does early implantation offer a significant influence when addressing academic achievement?  Are these children ready to be integrated into the regular class?

     It is important to keep in mind children develop at different rates and there are outside factors that could influence the variables which we are examining.  These unexplored variables, for example, family support and quality of programs, may affect the results of the study.




     The 11 participants in our study received their cochlear implant at various times between the ages of 27 to 60 months and had an average duration of implant use of 49 months.  The children were in an auditory-oral educational setting. Most of the children were reportedly deaf from birth, but two children had a known etiology of deafness after birth. All the children were deafened under two years of age and all were implanted by the age of five years. 

The children had at least two annual testing records detailing their reading achievement.  Achievement testing occurred during the month of September 2003.   The average Intelligence Quotient was obtained from the Wechsler Intelligence Scale III (Wechsler, 1991). Ages were recorded in months for statistical purposes. All data was obtained anonymously with written permission from the school's director.    Approval for this study was granted from the Miami University Human Subject's Institutional Review Board.



     To obtain reading achievement scores two sub-tests were selected from diagnostic reading assessment batteries standardized on hearing children.  Scores are expressed as grade equivalents based on the normative sample.  General issues of reliability and validity are detailed in Burros (2001).

     Woodcock Johnson III Letter-Word.  This instrument identifies an aspect of reading decoding.  It requires identifying and pronouncing isolated letters and words.  It is constructed so students are only tested on those items within their operating range.  All the students began with test question one and the test was complete as soon as the student gave six incorrect responses.  The results of this test could be influenced by the children’s special production ability, because accurate articulation of each letter is required.  Continuous interval-like data was collected and used as grade equivalent scores.  For example, a 0.5 score would be equivalent to a Kindergarten child in his fifth month.

     Woodcock Johnson III Reading comprehension.  This sub-test measures reading comprehension of contextual information.  It requires reading a short passage and supplying a key missing word.  There are 47 questions.  There is no speech required for this test.  This will be used as a continuous interval-like value.  The scores were used as a grade equivalent values in a similar fashion as the “letter-word” score described above. 

      Wechsler Intelligence Scales for Children III.  The WISC III is used as a tool in school placement for determining the presence of a learning disability or a developmental delay and in tracking intellectual development.  All of the scales are divided into six verbal and five performance sub-tests.  A composite full-scale IQ score is computed with a mean of 100 and a standard deviation of 15.  The predictive validity shows a correlation with achievement for hearing-impaired-deaf categories.  Again, Burros (2001) report acceptable reliability and validity for this instrument.




     The results of this study are divided into two parts. The affect of early implantation and the duration of implant use are both hypothesized to be related to reading achievement. Our null hypothesis states that there will be no relationship between age of cochlear implantation and reading achievement ( Ho: r = 0).  This null hypothesis was tested using an alpha risk level of .01 with a one-tail test.  A series of simple linear regression analyses were used to assess these correlations.   Statview (1999) software was used to analyze the data.  Again, our research hypotheses predicted that age of implantation would be negatively correlated with achievement, and duration of implant would be positively related to achievement.



     Our results are presented in Table 1 and Figures 1 to 6.  [Table 1 and the six figures are not presented here, but will be shown and distributed during the presentation.]  As can be seen in the inter-correlation matrix of Table 1, Age of Implant was significantly (p<.01) and inversely related to reading achievement on both Woodcock/Johnson subscales (Letter/word recognition, r = -.91,; Reading Comprehension, r = -.93), as well as on the total reading score (r = -.89).  The duration of use of the cochlear implant was likewise significantly (p<.01)and positively correlated to reading achievement on both Woodcock/Johnson subscales (Letter/word recognition, r = .91,; Reading Comprehension, r = .88)as well as on the total score (r = -.89).  The magnitude of these relationships is particularly impressive given that our sample was only 11 children. 

     Figure 1,2 and 3 show a high negative correlation regression line plots between Age of implantation and reading achievement scores. A correlation for the data revealed that age of implantation and reading achievement scores were significantly related.  There is a significant negative correlation, thus the null hypothesis is rejected and the research hypotheses predicting an inverse relationship between age of implantation and achievement was supported.  The earlier the implantation the higher the achievement.  Figures 4,5,and 6 show a positive correlation.  Duration of implant use and reading achievement are also significantly (p<.01) related.  With this significant positive correlation, the null hypothesis was rejected.  The longer the cochlear implant is in use the higher is the achievement.  The WISC III Performance IQ was not a significant variable in these relationships.  However it should be noted that these children do fall well within the range of “normal” intelligence (Mean Performance IG = 107, SD = 7.9, with I.Q’s ranging from a low of 92 to a high of 118).




     While the data suggests an advantage for using the technology of a cochlear implant at any age, the obtained levels of achievement show a significant benefit for early implantation.  Given this small sample our correlations are particularly impressive and robust.  These advances in cochlear implant technology have far exceeded the expectations of just a decade ago.   Ten years ago, the results were less significant and deaf children did not achieve the feats written about today.  The age of implantation has a correlation with Reading scores.  Children in this sample implanted at an early age were at the average grade equivalent of 2.1.  The normed grade equivalent average was 2.2.  These results suggest children can have possible normal literacy development when given an implant early in their lives. No one could have predicted the outcomes of children reading at grade level or better.

     It is important to keep in mind that the development of abilities in children depend on many variables.  In an ideal world, children would be educated in the educational setting that best fits their learning style. Recent data demonstrate the possibilities for deaf children who have a cochlear implant with early intervention in an ideal school program.  Our sample came from a private school where the children’s teachers as well as their parents are highly motivated.  Future research should attempt to confirm our findings in public school settings, especially with a larger sample.  For deaf children, achieving levels of achievement performance such as we obtained in our study may affect everything about their future lives.



Table 1. Inter-correlation matrix (with Effect Sizes in parentheses), Means, Standard Deviations and Ranges for 11 children.1





Age of



Age at Implant



of use





Letter Word ID G.E


Reading Comprehension G.E.





















Age in Months















Age of diagnosis















Age at implant























Duration of use



















Performance IQ
















Letter Word G.E.




















Comprehension G.E.



































1Note at df=9 (n=11 students), correlations greater than .74 are significant at p<.01.  Figures in parentheses are Effect Sizes reported as z, from r to z transformations.





Figure 1. Age at implantation in months predicting Letter/Word identification Grade Equivalent Score.





Figure 2. Age at implantation in months predicting Reading Comprehension Grade Equivalent Score

Figure 3. Age at implantation in months predicting Total Reading Grade Equivalent Scores.




Figure 4.  Duration of Implant use in months predicting Letter/Word Identification Grade Equivalent Score.



Figure 5.  Duration of Implant Use in months predicting Reading Comprehension Grade Equivalent Score.








Figure 6.Duration of Implant use in months predicting Total Reading Grade Equivalent Score.






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