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Factors Associated With Reading Development in Children With Cochlear

Implants

Article in Perspectives on Hearing and Hearing Disorders in Childhood · September 2007

DOI: 10.1044/hhdc17.2.17

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Ann E Geers
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 LSHSS

Clinical Forum

Factors Affecting the Development

of Speech, Language, and Literacy
in Children With
Early Cochlear Implantation
Ann E. Geers
Central Institute for the Deaf, St. Louis, MO

T he advent of cochlear implants has had a

dramatic effect on the achievements of young
profoundly deaf children. Spoken language
competence is now attainable by many children who
previously depended primarily on sign language for commu-
Geers, & Tobey, 2000). Fryauf-Bertschy, Tyler, Kelsay,
Gantz, and Woodworth (1997) reported that most children
demonstrated some improvement in speech perception after
receiving a cochlear implant: Some children demonstrated
dramatic improvement, and some children obtained only
nication. Children who receive an implant early in life, limited perceptual gains even after 3–4 years of cochlear
followed by a period of appropriate rehabilitation, typically implant use. Ten out of the 16 children in this study who
achieve speech intelligibility and conversational fluency that had been implanted before the age of 5 achieved greater
exceeds levels observed in profoundly deaf children with than 50% recognition of words in an open-set list (Phoneti-
hearing aids. However, there continues to be considerable cally Balanced Kindergarten Words). However, the 9
variability and large individual differences in the perfor- minimal and eventual nonusers in this study all scored less
mance outcomes of groups of children (Pisoni, Cleary, than 32% open-set word recognition. Possible reasons for

ABSTRACT: Purpose: This study investigated factors contrib- ing variables. A series of multiple regression analyses
uting to auditory, speech, language, and reading outcomes determined the amount of variance in each outcome
in children with prelingual deafness after 4–6 years of accounted for by the intervening variables and the amount of
multichannel cochlear implant use. The analysis controlled additional variance attributable to independent variables.
for the effects of child, family, and implant characteristics Results: Characteristics of the child and the family (primarily
so that educational factors most conducive to maximum nonverbal IQ) accounted for approximately 20% of the
implant benefit could be identified. variance in postimplant outcome. An additional 24% was
Method: The sample included 136 8- and 9-year-old children accounted for by implant characteristics and 12% by
from across the United States and Canada who were educational variables, particularly oral communication mode.
implanted by age 5 with the Nucleus 22-channel implant. Clinical Implications: Auditory, speech, language, and
Type and amount of educational intervention since implanta- reading skills achieved 4–6 years after cochlear implantation
tion constituted the independent variables. The dependent were most strongly associated with nonverbal IQ, implant
variable was performance on a battery of tests of speech functioning, and use of an oral communication mode.
perception, speech production, language, and reading
administered 4–6 years postimplant. Characteristics of the KEY WORDS: deaf, cochlear implant, deaf education,
child, the family, and the implant itself constituted interven- communication mode

172 LANGUAGE , SPEECH , AND H EARING SERVICES IN SCHOOLS • Vol. 33 • 172–183 • July 2002 © American Speech-Language-Hearing Association
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 poor performance included inadequate device fitting, form of Manually Coded English accompanies speech. The
insufficient cognitive skills, poor motivation, educational use of a sign system allows for easier assimilation of
and social environment emphasizing manual communica- language through the unimpaired visual modality. The child
tion, and limited parental support. is then able to associate what he or she hears through the
Implant benefit has been examined in relation to a implant with signed representations of language in order to
number of demographic variables. Onset of deafness at a support spoken language development. In practice, TC
later age and shorter length of auditory deprivation have programs range from those that rely heavily on signed
been associated with greater speech perception scores input with less emphasis on speech and English syntax to
(Osberger, Todd, Berry, Robbins, & Miyamoto, 1991; those that emphasize speech, audition, and lipreading and
Staller, Beiter, Brimacombe, Mecklenburg, & Arndt, 1991). maintain careful adherence to English syntax and morphol-
A younger age at implantation and longer duration of ogy. Although there is evidence that children enrolled in
implant use (Fryauf-Bertschy et al, 1997; Waltzman & OC programs demonstrate better speech perception and
Cohen, 1998) have also been associated with better speech language improvement postimplant than those in TC
perception scores. Other factors contributing to variability programs (Miyamoto, Kirk, Svirsky, & Sehgal, 1999), other
include preimplant residual hearing (Osberger & Fisher, studies indicate greater vocabulary improvement for
2000) and the type of processor used (Parkinson, Parkinson, children enrolled in TC programs (Connor, Hieber, Arts, &
Tyler, Lowder, & Gantz, 1998). Communication mode used Zwolan, 2000; Robbins, Bollard, & Green, 1999).
in the child’s educational setting has also been found to Documenting the effects of educational choices on
play an important role in postimplant outcome. Miyamoto speech and language outcomes is especially difficult when
et al. (1994) used multiple regression techniques to predict other factors that could also affect performance vary a
postimplant speech perception scores for 61 children who great deal. Factors such as the child’s age at onset of
used a Nucleus cochlear implant. Age at onset of hearing deafness, at implant, and at test; duration of implant use;
loss, duration of deafness, processor type, and communica- family characteristics; and intelligence can have a substan-
tion mode were all significant predictors, but the length of tial impact on test scores. Parents and children with
device use accounted for the largest amount of variance in particular characteristics may be drawn to certain kinds of
speech perception scores postimplant. programs, and programs emphasizing spoken or sign
Whereas establishing the effects of preexisting child and language may favor the admission of children with certain
implant characteristics on postimplant performance is useful other characteristics. Furthermore, factors such as type of
for addressing candidacy issues and establishing post- device and/or processing strategy and preimplant candi-
implant expectations, parents and educators are interested in dacy criteria are constantly changing, making control of
determining which educational choices will maximize their these factors difficult to achieve over time. Failure to
child’s ability to benefit from implantation. Educational control for any of these intervening variables may obscure
choices for children with hearing impairments include the underlying causes of exceptionally good or poor
factors such as mainstream or special education class performance with an implant (see Kirk, 2000 for a
placement; public or private school programs; speech, sign, discussion of these issues). It is important to undertake
or equal communication mode emphasis; amount of studies that control for as many of these factors as
individual speech and language therapy provided; and possible so that the relative benefits of specific educa-
characteristics of the clinicians providing the therapy. tional approaches can be documented. Parents and
One educational variable that is frequently examined educators can then interpret these results to make in-
in relation to implant benefit is the communication mode formed educational choices designed to maximize a child’s
used in the child’s classroom. This variable is most often postimplant hearing, speech, and language development.
dichotomized into oral communication (OC) approaches In 1996, the Center for Applied Research in Childhood
and total communication (TC) approaches. Proponents of Deafness at the Central Institute for the Deaf initiated the
the OC approach maintain that dependence on speech study that is reported here. This study, titled "Cochlear
and audition for communication is critical for achieving Implants and Education of the Deaf Child," was funded
maximum auditory benefit from any sensory aid. Con- by the U.S. National Institutes of Health and was de-
stant use of auditory input to monitor speech production signed to document the effects of various education and
and to comprehend spoken language provides the rehabilitation models on the ability of the child who is
concentrated practice needed for optimum benefit from a deaf to understand, produce, and read English while using
cochlear implant. Types of OC approaches differ in their a Nucleus 22-channel cochlear implant (Geers et al.,
emphasis on the auditory and visual channels for the 2000). This study was designed to reduce variability as
reception of spoken language. Methods range from the much as possible through sample selection criteria and to
cued speech approach, in which manual cues are used to include a sufficiently large number of children to control
complement lipreading, to the auditory–verbal approach, for intervening variables in the analysis. This report
in which lipreading is discouraged and the child learns examines the effects of communication mode, class
from an early age to make use of whatever auditory placement, and therapy on five outcome variables (speech
information is available through his or her sensory perception, speech production, spoken language, total
device to understand speech. language, and reading) after controlling for the effects of
Proponents of the TC approach maintain that the child intervening variables associated with the child, the family,
with severe-to-profound deafness benefits most when some and the implant device.

Geers: Education and Cochlear Implantation 173

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 ment postimplant independent of educational factors.
METHOD Controlling for child, family, and implant characteristics in
the analysis minimizes the chances that a difference in
Participants outcome will be mistakenly interpreted as being associated
with educational factors when they are caused by sample
Over a 4-year period, 180 8- and 9-year-old children differences on these variables.
from 33 different states and 5 Canadian provinces came to Child characteristics included age at test, age at onset of
St. Louis to attend the Cochlear Implant Summer Research deafness, age at implant, and nonverbal intelligence.
Camp. This preliminary report describes 136 children who Chronological age at testing was restricted to children aged
were tested during the first 3 years of data collection. 8;0 (years;months) to 8;11 (n = 62) and those aged 9;0 to
Participants were selected to be as homogeneous as 9;11 (n = 74). Age at onset of deafness was restricted in
possible on a number of key factors known to affect the sample selection process to less than 3;0. Most (n =
performance postimplant. Characteristics of these partici- 102) of the 136 children were known or presumed to be
pants are summarized in Table 1. These children all deaf from birth, 12 were deafened before 1 year of age, 15
received their implants when the candidacy requirements between 1 and 2 years of age, and 7 became deaf when
included no observable benefit from conventional amplifica- they were 2 years old. Age at implant was restricted at
tion. Thus, none of these children exhibited any open-set sample selection to less than 5 years of age: 41 were
speech perception ability with hearing aids before receiving implanted before age 3, 59 between 3 and 4 years of age,
an implant. The participants do not represent any single and 32 between ages 4 and 5. Four children were im-
educational program or method, but rather come from the planted by age 4 but did not complete hookup until they
full range of educational settings available across the had turned 5. Although sample selection criteria were
United States and Canada. designed to include only children with average or above-
average intelligence, 9 of the children obtained a Perfor-
Procedure mance IQ on the Wechsler Intelligence Scale for Children,
Third Edition (WISC–III; Wechsler, 1991) below the
Approximately 15 children, accompanied by a parent, average range for their age.
were included in each data collection camp session. All Measured family characteristics were education, income,
expenses were paid, including transportation, hotel accom- and size. More than half of the families included at least
modations for 4 nights, and daily entertainment activities. one college graduate as a parent. Parents were asked to
Testing took place 2 hours each day for 3 days. All select, from a choice of categories, the income range best
children were tested under similar conditions with a representing their family. The median family income was
consistent group of examiners on an identical battery of between $50,000 and $80,000, with 35 families reporting
tests. Children were tested individually in their hotel an income of more than $80,000 per year. Most of the
rooms, which were converted to testing suites each morn- children were being raised in two-parent families with an
ing. The parents attended educational seminars during this average of two children per family. Eleven of the children
time and completed questionnaires and signed release forms were from single-parent families.
for questionnaires sent to implant centers and clinicians. In Variables associated with the implant itself included
the afternoon, families participated in planned recreational duration of implant use and duration of use of the Spectra
activities. Three categories of measures were obtained: (a) speech processor with the updated Spectral Peak (SPeak)
intervening variables that were controlled in the analysis, coding strategy. The implant map includes parameters that
(b) independent educational variables that were the focus of are set by the audiologist to maximize the child’s percep-
the study, and (c) outcome measures that represented each tion of speech. The map was characterized by the number
child’s auditory, speech, language, and reading abilities. of currently active electrodes, the size of the dynamic
Intervening variables. These are factors that are either range from threshold to comfortable listening level, and
known or suspected to affect speech and language develop- the average range over which the child perceived growth
of loudness.
All 136 children had used the same electrode array, the
Table 1. Sample characteristics for 136 subjects.
Nucleus 22 from Cochlear Corporation, for between 4 and
7 years. Many of these children were first fitted with the
Mini speech processor and later received the newer SPeak
M SD Minimum Maximum
processor. All but 20 of the children had switched to the
SPeak coding strategy by the time of the study. Fifty of
Age at test (years;months) 9;0 0;6 8;0 9;11 them had used SPeak for 4 or more years. Almost half had
Age at onset 0;4 0;9 0 3;0 a fully active array with 20 or more electrodes in their
Age at implant 3;6 0;9 1;10 5;2
Performance IQ 102 15 65 136 map. Only 12 of the 136 children had fewer than 16 active
Duration of CI use 5;6 0;9 3;9 7;6 electrodes. More than half of the children exhibited a
Duration of SPeak use 3;0 1;8 0 5;2 dynamic range of greater than 60 clinical units per elec-
# of active electrodes 18 2.86 6 22 trode (M = 60.9; SD = 23.4). This indicates that a wide
range of loudness levels in speech was available to these
Note. CI = cochlear implant. children from their processor. An estimate of growth of

174 L ANGUAGE, SPEECH, AND HEARING SERVICES IN SCHOOLS • Vol. 33 • 172–183 • July 2002

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 loudness for randomly presented stimuli representing three Figure 1. Amount of therapy over time averaged across 136
different noise bands at seven intensity levels between 55 children.
and 80 dB SPL was obtained for each child on a 5-point
scale from “nothing” to “too loud” (Davidson, Brenner, &
4
Geers, 2000). The average increment in ratings between

Hours per week (±1 SD)

loudness levels was 0.43, slightly less than half a rating
scale point. Variability was 0.53, or approximately half a 3
rating scale point.
Independent variables. These variables describe each 2
child’s therapy, class placement, and classroom communica-
tion mode. The effect of these variables is the focus of this 1
investigation. Because educational practices and placement
could change from year to year, values were recorded for 0
each of 3 years following implantation plus the year just Year 1 Year 2 Year 3 Current Year
completed before the child attended camp.
Variables used to assess the impact of therapy were
number of hours of therapy, clinician experience, and
parent participation in therapy. Parents identified all to those who had taught more than 10 deaf children,
clinicians who saw their child for individual or small group including those with implants (50%).
speech and/or auditory training (outside of classroom A questionnaire asked parents to estimate the frequency
instruction) since receiving the implant. A questionnaire with which they participated in activities designed to
was mailed to each clinician. The return rate on question- stimulate auditory and speech development at home.
naires after follow-up phone calls to nonrespondents was Results are summarized in Figure 3, where the average
87%. Number of hours of therapy per week averaged over parent responses over all questions over all respondents are
12 months for the entire sample is depicted in Figure 1. plotted along with the standard error of these values for
These children averaged almost 1.5 hours per week of each postimplant year. On average, parents reported that
therapy during each year postimplant. they worked with their child daily for the first 2 years
Clinicians varied in their level of experience teaching postimplant, and between daily and weekly for the third
deaf children and children with cochlear implants. These year postimplant and the year just completed.
differences are depicted in Figure 2, where clinicians are Variables used to assess the impact of educational
categorized by whether they had prior experience teaching setting included public or private school placement and
an implanted child before they began working with the special education or mainstream classroom. Parents reported
child in this study. Within each category, the distribution of their child’s school setting each year as none, public,
clinicians is plotted according to the number of deaf private, or both public and private. Figure 4 indicates an
children they had previously treated, regardless of sensory increase in public school placement over time. Type of
aid used. Responses ranged from no prior experience with class is depicted in Figure 5. The percentage of children
either deaf children or children with cochlear implants (5%) enrolled in full-time special education classes decreased

Figure 2. Clinicians returning therapy questionnaires described in terms of their prior experience
with children who are deaf and children who use cochlear implants (CIs).

60

50
Percentage of Clinicians

40
No CI experience

30 CI experience

20

10

0
0 1–5 6–10 >10 1–5 6–10 >10

Number of Deaf Children Treated

Geers: Education and Cochlear Implantation 175

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 Figure 3. Median frequency of parent participation in therapy from approximately 60% before implant to approximately
and interquartile range of ratings obtained over 4 years 20% at the time of the study. By the time of the study,
postimplant.
more than half of the children were fully mainstreamed.
Classroom communication mode was assessed with a
rating scale completed by the parents that was intended to
5 Daily reflect the amount of emphasis on speech and auditory skill
development provided in the child’s classroom (see Table
4 Weekly 2). A rank between 1 and 6 was assigned to each instruc-
tional mode for each year. Ratings between 1 and 3 were
Median Rating

3 Monthly assigned to TC programs. In mostly sign programs, sign-

only was used for communication during some of each day.
In speech and sign programs, speech almost always
2 Rarely
occurred simultaneously with each signed word, and sign-
only or speech-only were rarely used. In speech emphasis
1 Never programs, speech-only was used for communication during
Year 1 Year 2 Year 3 Current Year some of each day. Ratings between 4 and 6 were applied to
OC programs. In cued speech programs, a formal system of

Figure 4. Percentage of children enrolled in no school program, public school program, private
school program, or both public and private school programs at the time a cochlear implant was
fitted (at CI) and each of 4 years thereafter.

100
Percentage of Children

80 None

Public
60
Private
40 Both

20

0
at CI Year 1 Year 2 Year 3 Current Year

Figure 5. Percentage of children enrolled in no program, special education class, part-day main-
stream (MS) class, or full-day mainstream class at the time a cochlear implant was fitted (at CI) and
each of 4 years thereafter.

80
Percentage of Children

None
60
Special Ed

40 Partial MS

Full MS
20

0
at CI Year 1 Year 2 Year 3 Current Year

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 Table 2. Classroom communication mode rating scale.

1 2 3 4 5 6
Mostly sign Speech & sign Speech emphasis Cued speech Auditory–oral Auditory–verbal

Total Communication Oral Communication

➜ Increasing speech emphasis ➜ Increasing auditory emphasis

manual cues was used to facilitate lipreading. In auditory– single score for the collection of original variable scores.
oral programs, the child was encouraged throughout the The approach is motivated by the belief that a collection of
day to both lipread and listen to the talker. In auditory– measures all tap the same ability or aptitude and that a
verbal programs, the child was taught to rely on listening single summary score would be more economical than
alone to understand speech. Classroom communication multiple scores. Principal components analysis forms this
mode scores were averaged across 5 years and are depicted summary score by creating a weighted linear combination
for individual children in Figure 6. The 67 children with of the original variables, which is no different in principle
average scores of 4 or higher had spent most of their years than the common practice of summing multiple items on a
in an oral setting. The 69 children with average mode questionnaire. However, in the case of principal compo-
scores of less than 4 had been mostly in TC settings. nents, the variables are weighted optimally so that the
Outcome measures. Five dependent variables were composite score best captures the information in the set of
selected to represent the areas most likely to be affected by original variables. When a single principal component
cochlear implantation: speech perception, speech produc- accounts for the majority of variability in the set of
tion, language (assessed in two ways: spoken only and total original variables, we can be assured of its validity as a
communication), and reading. It was anticipated that post- representative index. The proportion of original variable
implant therapy and education factors might explain variance that overlaps with the principal component
differences in the ultimate outcome level achieved for these provides an objective measure of the validity of the derived
variables once the impact of intervening variables associ- score. To say that a principal component accounts for 60%
ated with child, family, and implant characteristics had of the original variable variance means that 60% of the
been accounted for. Because each of these outcomes is information in the set of original variables is represented in
multifaceted and not readily quantified by a single test, the single principal component score. Generally, compo-
batteries of tests were administered to each child. Ulti- nents that account for more than 50% of the original
mately, performance on these measures was reduced to a variable variance are considered to be excellent summary
single factor score for each outcome by creating a weighted scores. The battery of tests used to measure each dependent
combination of scores from each test battery using principal variable is listed in Table 3, along with each test’s relative
components analysis. factor loading (FL) in the overall factor score.
Principal components analysis provides a means of All speech perception tests were administered using
summarizing a collection of measures by substituting a recorded stimuli presented at 70 dB SPL in the soundfield.

Figure 6. Classroom communication mode rating for each of 136 subjects averaged over 5 years plotted in order of increasing
emphasis on speech and auditory skill development.

5
Mode Average

3 Total Communication
Oral Communication
2

0
Subjects (N = 136)

Geers: Education and Cochlear Implantation 177

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 Table 3. Test battery and factor loadings (FL) for composite score on each outcome.

Speech Speech Spoken Total

perception FL production FL language FL language FL Reading FL

ESP .88 McG-HC .93 IPSyn NPa .87 IPSyn NP b .79 PIAT rec .95
WIPI .88 McG-LC .91 IPSyn VPa .95 IPSyn VP b .89 PIAT comp .90
LNT .93 % consonants .95 IPSyn QNa .67 IPSyn QN b .52 WRMT wa .88
MLNT .92 % vowels .68 IPSyn SSa .93 IPSyn SS b .89 RHYME .59
BKB .92 Dyalog .87 Typesa .96 Typesb .85 LD .65
VidSPAC .78 % plosives .73 Morpha .83 Morphb .82
CHIVE .94 SPQ .89 Wd/Utta .89 Wd/Uttb .89
ARQ .69 Fluencya .87 NAS .83
WISC-sim .79
TACL-wc .56
TACL-gm .62
TACL-es .77

Note. Speech Perception: ESP = Early Speech Perception Test for Profoundly Deaf Children (Moog & Geers, 1990); WIPI = Word Intelligi-
bility by Picture Identification (Ross & Lerman, 1971); LNT = Lexical Neighborhood Test (Kirk, Pisoni, & Osberger, 1995); MLNT =
Multisyllabic Lexical Neighborhood Test (Kirk, Pisoni, & Osberger, 1995); BKB = Bamford Kowal Bench Sentences (Bamford & Wilson,
1979); VidSPAC = Video Game Test of Speech Pattern Contrast Perception (Boothroyd, 1997); CHIVE = Children’s Visual Enhancement Test
(Tye-Murray & Geers, 1997); ARQ = Auditory Responsiveness Questionnaire.
Speech Production: McG = McGarr sentences (McGarr, 1983); HC = high context; LC = low context; Dyalog = Dyalog Communication
Analysis (Erber & Weiner, 1997); SPQ = Use of Speech Questionnaire.
Spoken/Total Language: IPSyn = Index of Productive Syntax (Scarborough, 1990); NP = noun phrases; VP = verb phrases; QN = questions/
negatives; SS = sentence structures; NAS = Narrative Ability Score (Crosson & Geers, 2001); WISC-III = Wechsler Intelligence Scale for
Children, Third Edition (Wechsler, 1991); TACL = Test for Auditory Comprehension of Language–Revised (Carrow, 1985); wc = word
classes; gm = grammatical morphemes; es = elaborated sentences.
Reading: PIAT = Peabody Individual Achievement Test–Revised (Dunn & Markwardt, 1989); Rec: = reading recognition; Comp = reading
comprehension; WRMT = Woodcock Reading Mastery Tests–Revised (Woodcock, 1987); wa = word attack; LD = lexical decision task.
a
Based on spoken language sample; bBased on spoken and signed language sample.

Measures of closed-set word identification included the established for consonants (% consonants) and vowels (%
Central Institute for the Deaf Early Speech Perception Test vowels) by comparing a phonetic transcription of these
(ESP; Moog & Geers, 1990) and the Word Intelligibility by sentences with the targeted production. Effective conversa-
Picture Identification test (WIPI; Ross & Lerman, 1971). tional use of speech was estimated by determining the
Open-set word recognition was assessed with the Lexical percentage of time that was spent in breakdown in a
Neighborhood Test and the Multisyllabic Lexical Neighbor- videotaped conversation using the Dyalog analysis proce-
hood Test (LNT/MLNT, Kirk, Pisoni, & Osberger, 1995). dure (Erber & Weiner, 1997). Correct manner of production
Open-set sentence recognition was assessed with the was established for plosive sounds in imitated sentences (%
Bamford Kowal Bench Sentences (BKB; Bamford & plosives; Uchanski, Torretta, Geers & Tobey, 1999). Speech
Wilson, 1979). Discrimination of phonetic contrasts intelligibility ratings were obtained from the child’s parent,
representing the features of place, manner, voicing, and who completed a “Use of Speech Questionnaire” (SPQ)
vowels was assessed with the Video Game Test of Speech developed for this study that reported how well the child’s
Pattern Contrast Perception (VidSPAC; Boothroyd, 1997). speech was understood by listeners with varying degrees of
Lipreading enhancement was assessed with the Children’s experience with deaf speech. The speech production
Visual Enhancement Test (CHIVE; Tye-Murray & Geers, outcome variable score accounts for 83% of the total
1997). An “Auditory Responsiveness Questionnaire” (ARQ) variance in the seven speech production measures, making
specifically developed for this study recorded the parents’ it a valid summary score.
observations of the child’s auditory behaviors while Spoken language competence was measured in a
wearing the implant. The speech perception outcome videotaped 20-minute conversation with an examiner who
variable score accounts for 76% of the total variance in the did not use sign language. The child’s spoken words were
eight speech perception measures, making it a valid transcribed orthographically and verified by trained teachers
summary score. of the deaf using the CHAT format of the CHILDES
The speech production battery included an estimate of system (MacWhinney, 1995). Each utterance was scored for
overall speech intelligibility based on word recognition by syntactic complexity (Index of Productive Syntax;
naive listeners for audio recordings of the 36 McGarr Scarborough, 1990) in four categories: noun phrase (IPSyn
sentences (McGarr, 1983; Tobey et al., 2000). The McGarr NP), verb phrase (IPSyn VP), question/negative (IPSyn
sentence list contains an equal representation of high- QN), and sentence structure (IPSyn SS). In addition, counts
context sentences (McG-HC; e.g., the flag is red, white, were made of the number of different words (TYPES),
and blue) and low-context sentences (McG-LC, e.g., the fat number of bound morphemes per word (MORPH/WD), and
baby cried). Percentage correct phoneme production was number of words per utterance (WD/UTT). An oral

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 conversational fluency rating (FLCY) was obtained by 40 cards, each containing 2 printed words. The child sorted
subtracting the percentage of the last 10 minutes of the the cards into word pairs that “sound alike” and those that
conversation spent in breakdown (Erber & Weiner, 1997) “don’t sound alike.” Results are expressed as a percentage
from the percentage of child talk time. The speech produc- of errors on word pairs where auditory and visual cues
tion outcome variable score accounts for 78% of the total conflict and the child must use phonological skills to
variance in the eight spoken language measures, making it respond correctly. The lexical decision (LD) task consisted
a valid summary score. of 132 cards each containing a printed word that the child
Total English language competence in speech and sign sorted as a real word or a nonword. Half of the nonwords
was assessed using total communication with all children, were homophonic to their corresponding real word (e.g.,
whether or not they knew sign language. A 20-minute word, werd) and the remaining half were nonhomophonic
language sample was elicited on videotape. The examiner (e.g., some, somo). Results are expressed as the percentage
communicated with the children using simultaneous of errors in which homophonic nonwords are classified as
communication (speech and Signed English). All of the words. The reading outcome variable score accounts for
child’s recognizable utterances, whether spoken or signed, 65% of the total variance in the five reading measures,
were transcribed and scored for syntactic complexity using making it a valid summary score.
the four IPSyn categories, and counts were made of the
number of different words, number of bound morphemes
per word, and number of words per utterance. Use of
cohesive language was assessed with a picture sequence RESULTS
story from which a Narrative Ability Score was obtained
(NAS; Crosson & Geers, 2000). Verbal reasoning was The purpose of the analysis was to assess the effects of
assessed with the Similarities subtest of the WISC–III the independent (i.e., educational) variables on each of the
(WISC-sim; Wechsler, 1991). The Test for Auditory five dependent variables after variance as a result of
Comprehension of Language–Revised (TACL–R; Carrow, intervening variables had been removed. Linear regression
1985) was used to assess comprehension of language was used to partial out the variance in each outcome that
structures. Scores were obtained for the three subtests: was associated first with child and family characteristics,
Word Classes (TACL–wc), Grammatical Morphemes then with implant characteristics, and finally with the
(TACL–gm), and Elaborated Sentences (TACL–es). The remaining variance predicted by the educational variables.
total language outcome variable score accounts for 61% of Results for child and family characteristics are summarized
total variance in the 12 total language measures, making it in Table 4. Standardized coefficients represent the magni-
a valid summary score. tude of contribution of each intervening variable to an
The two reading subtests from the Peabody Individual outcome after variance as a result of all of the other listed
Achievement Test–Revised (Dunn & Markwardt, 1989) variables has been accounted for. The total variance
were administered: Reading Recognition (PIAT–rec) and accounted for by child and family characteristics ranged
Reading Comprehension (PIAT–comp). Responses could be from 11% for spoken language to 20% for reading.
either spoken or signed. The Word Attack subtest from the Performance IQ on the WISC–III (Wechsler, 1991) contrib-
Woodcock Reading Mastery Test (WRMT–wa; Woodcock, uted significant variance to all outcomes and was the only
1987) was used to determine grade-equivalent scores for significant independent predictor among the child and
phonic and structural analysis skills. This task required the family characteristics in speech perception, speech produc-
child to pronounce nonsense words using speech. Finally, tion, and spoken language. Older children (i.e., 9-year-olds)
two tasks were constructed to assess phonological coding achieved higher reading scores than younger children (i.e.,
skills. The rhyme recognition (RHYME) task consisted of 8-year-olds), and children who lost their hearing later

Table 4. Effect of child and family characteristics on each outcome variable.

Speech Speech Spoken Total

perception production language language Reading

Age –.10 –.09 .00 –.06 .19*

Age at onset –.03 .07 .11 .20* .17*
Age at implant –.07 –.10 –.07 –.05 –.08
Performance IQ .32*** .29*** .20* .21* .34***
Family size –.15 –.15 –.16 –.17* –.11
Parent’s education .08 .07 .13 .20* .13
Total variance (R2) 18% 15% 11% 17% 20%

(df 6,129)
*p < .05, **p < .01, ***p < .001

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 achieved higher reading scores than those who were deaf (i.e., there was no advantage exhibited by children from
from birth. In addition to IQ and age at onset, higher levels either oral or total communication programs). Higher
of total language performance were associated with smaller outcome scores in language and in reading were associated
family size and more highly educated parents. with placement in a mainstream classroom.
Added variance accounted for by implant characteristics Some of the independent variables that did not reach
(after variance as a result of child and family characteris- significance when all of them were considered together
tics was removed) is summarized in Table 5. Measures were significant when they were considered individually. A
derived from the implant and the map accounted for greater number of hours of therapy and parent participation
between 17% and 26% of variance in outcome factor in therapy were each independently associated with speech
scores. With the exception of loudness growth, all implant perception and speech production skill. However, when
characteristics contributed significant independent variance these factors were considered in combination with commu-
to every outcome. nication mode, the effects were no longer significant.
Table 6 identifies the educational variables that made a Children who achieved the most intelligible speech were
significant contribution to outcome performance after all more likely to be placed in private schools and in main-
intervening variables associated with the child, the family, stream classes. However, as with speech perception, when
and the implant were controlled. The amount of added these factors were combined with communication mode,
variance ranged from 5% for total language outcome to they no longer contributed significant additional variance.
18% for speech production outcome. With implant and When all outcomes were combined together into a single
family characteristics held constant, the consistently factor score, the predictor variables included in this
significant variable associated with performance on speech analysis accounted for 54% of the variance in overall post-
perception, speech production, spoken language, and implant outcome. The largest sources of variability were
reading outcome measures was classroom communication from child and family characteristics, which accounted for
mode. This variable represents the extent to which the 18%, and implant characteristics, which accounted for 24%.
child’s program emphasized speech and auditory input over Once the variance as a result of these intervening variables
signed input. Classroom communication mode made no was removed, educational factors, primarily communication
significant contribution to the total language factor score mode, accounted for 12% of additional variance.

Table 5. Effect of implant characteristics on each outcome variable.

Speech Speech Spoken Total

perception production language language Reading

Duration of SPeak .23** .22** .19* .25** .20*

# of active electrodes .24*** .16* .22** .18* .16*
Dynamic range .27*** .21** .20** .21** .23**
Loudness growth .17* .24** .24** .18* .15
Added variance (∆R2) 26% 22% 23% 21% 17%

(df 4,131)
*p < .05, **p < .01, ***p < .001

Table 6. Effect of educational factors on each outcome variable.

Independent Speech Speech Spoken Total

variables perception production language language Reading

Hours of therapy .13 .13 .08 .12 .06

Therapist experience .03 .05 .01 –.02 –.02
Parent participation –.04 –.04 .06 .07 .05
School setting a .02 .12 .01 –.07 –.06
Type of class b .06 .13 .13* .18* .23**
Communication mode .37*** .30*** .30*** .14 .18*
Added variance (∆R2) 16% 18% 10% 5% 7%

(df 6,129)
a
Public/private; bMainstream/special education.
*p < .05, **p < .01, ***p < .001

180 L ANGUAGE, SPEECH, AND HEARING SERVICES IN SCHOOLS • Vol. 33 • 172–183 • July 2002

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 all of the reported data were derived from the only implant
CONCLUSION device available when these children were first implanted
(the Nucleus 22-electrode model from Cochlear Corpora-
Children who receive cochlear implants before 5 years tion) means that anything with fewer than 20 electrodes
of age are presented with auditory information at a crucial represents a less than optimal device. Alternative cochlear
time for speech and language development. The extent to implants that are currently available (e.g., the Clarion and
which a child will use this information to achieve speech, Med-El devices) use different speech processing strategies
language, and reading competence is affected by a variety on differing numbers of electrodes. A complete insertion of
of factors: (a) those that the child brings to the learning the electrode array and a map that activates all available
environment, (b) those that are provided by the implant electrodes will go a long way toward promoting optimal
itself, and (c) those that are provided by parents and performance.
professionals conducting the child’s rehabilitation program. The audiologist who programs the cochlear implant
The results of this study help us to understand the impor- makes a particularly important contribution to the child’s
tance of each of these components. potential successful outcome with the device. Once the
processing strategy and the number of active electrodes
have been maximized, it is the audiologist’s role to achieve
What the Child Brings to the
the most appropriate and balanced map possible for that
Learning Environment child. A well-fitted map, as evidenced by a wide dynamic
range and optimal growth of loudness characteristics,
Our findings indicate that the most important character-
contributed substantial variance for all outcomes. This is a
istic that a child brings to the task of learning from a
particularly important consideration in the mapping of
cochlear implant is good nonverbal intelligence. Once this
newly implanted infants, who may not be able to respond
variable is held constant, earlier age at implant (for
to traditional mapping techniques.
children implanted between 22 and 62 months of age) and
later age at onset of deafness (for children who lose
hearing before age 3) do not contribute significantly to What the Rehabilitation Program Provides
speech perception and production skill levels measured at
The primary rehabilitative factor associated with
ages 8–9. Although some period of normal hearing appears
desirable performance outcomes was educational emphasis
to affect overall language and reading skill development,
on oral–aural communication. Communication mode was
age at implant has no such effect on the development of
more important to auditory and spoken language develop-
speech perception, speech production, or language or
ment than any other rehabilitative factor examined, includ-
reading skills. This result suggests that the urgency to
ing classroom placement (public or private, special educa-
implant children in infancy deserves further evaluation.
tion, or mainstream), amount of therapy, experience of
Likewise, characteristics of the family do not seem to
therapist, or parent participation in therapy. Children whose
provide a particular advantage or disadvantage (given that
educational program emphasized dependence on speech and
an adequate motivation for implantation and follow-up
audition for communication were better able to use the
rehabilitation is present). Children of highly educated
information provided by the implant to hear, speak, and
parents did not achieve significantly better outcomes than
read. Use of sign communication with implanted children
those of less educated parents when intelligence was
did not promote auditory and speech skill development and
factored out. However, there was a tendency for smaller
did not result in an advantage for overall English language
families to have children who had somewhat better total
competence, even when the outcome measure included sign
language development.
language. Oral education appears to be an important
educational choice for children who have received a
What the Implant Contributes cochlear implant before 5 years of age.
This result appears to contradict results reported by
The overall functioning of the cochlear implant, particu- Connor et al. (2000) for 147 prelingually deafened children
larly duration of use of the updated SPeak coding strategy, who had used an implant for between 6 months and 10
had a substantial impact on all outcome areas examined. As years. The Connor et al. study compared consonant
engineering improvements in speech processing are made, it production and vocabulary development of children with
is important that children gain access to the technological cochlear implants who were enrolled in OC or TC settings
improvements provided as soon as they are available. throughout Michigan and parts of Ohio and Indiana.
Because the field of electronic speech processing is Results for 70 children implanted by age 5 showed no
evolving rapidly, upgrades in speech processors should be difference between OC and TC groups in consonant
considered on a relatively frequent basis. No child should production accuracy. However, relatively greater vocabulary
be left with an outdated processor. The benefits of im- growth was observed for the TC group. Differences
proved technology are apparent in these data. between the current study and the Conner et al. results may
Better outcomes were associated with a larger number of be related to the samples studied and the types of speech
active electrodes in the cochlear implant map. The impor- and language measures employed. Unlike in the present
tance of number of active electrodes should not be inter- study, the number of children followed for 4 to 6 years
preted to suggest that “more is always better.” The fact that after implantation in the Connor et al. study was small

Geers: Education and Cochlear Implantation 181

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 (<30) and included even fewer children implanted under Boothroyd, A. (1997). Video Game Test of Speech Pattern
the age of 5. Furthermore, the group in the present study Contrast Perception. New York: City University of New York
was much more homogeneous in chronological age and Graduate Center.
heterogeneous in the geographical distribution of educa- Carrow, E. (1985). Test for Auditory Comprehension of Language–
tional programs sampled and the breadth of measures used Revised. Allen, TX: DLM Teaching Resources.
to assess speech and language abilities. Conner et al. Connor, C., Hieber, S., Arts, H., & Zwolan, T. (2000). Speech,
pointed out that most of the children in their sample were vocabulary and the education of children using cochlear
from Michigan, a state that may provide an emphasis on implants: Oral or total communication? Journal of Speech,
quality TC programming. In the present study, the speech Language, and Hearing Research, 43, 1185–1204.
outcome was heavily weighted for intelligibility and the Crosson, J., & Geers, A. (2001). Analysis of narrative ability in
language outcome for English syntax. In contrast, the children with cochlear implants. Ear and Hearing, 22, 381–394.
findings of the Conner et al. study were based on pho- Davidson. L., Brenner, C., & Geers, A. (2000). Predicting speech
neme production and single-word vocabulary. Clearly, perception benefit from loudness growth measures and other
each study examined critical, yet different, components of map characteristics of the Nucleus 22 implant. Annals of
OC. Additional studies are needed to achieve a compre- Otology, Rhinology & Laryngology, 109(Suppl. 185), 56–58.
hensive picture of the influences of communication Dunn, L. M., & Markwardt, F. C. (1989). Peabody Individual
modalities on the development of all oral language Achievement Test–Revised. Circle Pines, MN: American
components for children with cochlear implants. Guidance Service.
Parents and clinicians can do little to change their
Erber, N., & Weiner, F. (1997). Dyalog Communication Analysis
child’s intelligence or electrode array. However, they can Plus. West Bloomfield, MI: Parrot Software.
ensure that the child acquires the most up-to-date process-
ing strategy with a well-fitted map that permits maximum Fryauf-Bertschy, H., Tyler, R., Kelsay, D., Gantz, B., &
Woodworth, G. (1997). Cochlear implant use by prelingually
dynamic range and loudness growth. They can also strive
deafened children: The influences of age at implant and length
for a consistent emphasis on speech and auditory skill of device use. Journal of Speech, Language, and Hearing
development in their chosen educational program and in Research, 40, 183–199.
communication interactions throughout the day. Results of
Geers, A., Nicholas, J., Tye-Murray, N., Uchanski, R., Brenner,
this study indicate that attention to these factors can make
C., Davidson, L., et al. (2000). Effects of communication mode
a significant difference in the overall benefit children on skills of long-term cochlear implant users. Annals of Otology,
obtain from cochlear implantation. Rhinology & Laryngology, 109(Suppl. 185), 89–91.
Kirk, K. I. (2000). Challenges in the clinical investigation of
cochlear implant outcomes. In J. K. Niparko, K. I. Kirk, N. K.
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ACKNOWLEDGMENTS Cochlear implants, principles & practices (pp. 225–259).
Philadelphia: Lippincott, Williams & Wilkins.
This study was supported by Grant No. DC03100 from the
National Institute on Deafness and other Communication Disorders Kirk, K. I., Pisoni, D. B., & Osberger, M. J. (1995). Lexical
(NIDCD) of the National Institutes of Health (NIH) to the Central effects of spoken word recognition by pediatric cochlear implant
users. Ear & Hearing, 16, 470–481.
Institute for the Deaf (CID). We gratefully acknowledge the
families of children with implants from across the United States MacWhinney, B. (1995). The CHILDES Project: Tools for
and Canada who enthusiastically participated in this study, as well analyzing talk (2nd ed.). Hillsdale, NJ: Lawrence Erlbaum
as the staff of Cochlear Corporation and implant centers across the Associates.
United States and Canada for their role in disseminating informa- McGarr, N. (1983). The intelligibility of deaf speech to experi-
tion about the study to potential participants. Michael J. Strube,
enced and inexperienced listeners. Journal of Speech and
PhD, conducted the statistical analysis. Data collection and Hearing Research, 26, 451–459.
preparation was coordinated by Christine Brenner, MS. Other
investigators who participated in designing and implementing the Miyamoto, R., Kirk, K., Svirsky, M., & Sehgal, S. (1999).
test battery include (in alphabetical order) Jean Moog, MS, from Communication skills in pediatric cochlear implant recipients.
the Moog Center for Deaf Education; Johanna Nicholas, PhD, from Acta Otolaryngologica, 119, 219–224.
CID; Allison Sedey, PhD, from the University of Colorado at Miyamoto, R. T., Osberger, M. J., Todd, S. L., Robbins, A. M.,
Boulder; Emily Tobey, PhD, from the Callier Center at the Karasek, A., Dettman, D., et al. (1994). Variables affecting
University of Texas at Dallas; Nancy Tye-Murray, PhD, from CID; implant performance in children. Laryngoscope, 9, 154–157.
and Rosalie Uchanski, PhD, from CID.
Moog, J. S., & Geers, A. E. (1990). Early Speech Perception Test
for Profoundly Deaf Children. St. Louis, MO: Central Institute
for the Deaf.
Osberger, M., & Fisher, L. (2000). Preoperative predictors of
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