phonological language- and spatial processing abilities and reading ...

Journal of Speech and Hearing Disorders, Volume 53, 316--327, August 1988

PHONOLOGICAL LANGUAGE-

AND SPATIAL PROCESSING ABILITIES AND READING-IMPAIRED CHILDREN

IN

ALAN G. KAMHI Memphis State University, Memphis, TN HUGH W. CATTS University of Kansas, Lawrence DARIA MAUER Memphis State University, Memphis, TN KENN APEL Whittier College, Whittier, CA BETHOLYN F. GENTRY Memphis State University, Memphis, TN In the present study, we further examined (see Kamhi & Catts, 1986) the phonological processing abilities of language-impaired (LI) and reading-impaired (RI) children. We also evaluated these children's ability to process spatial information. Subjects were 10 LI, 10 RI, and 10 normal children between the ages of 6:8 and 8:10 years. Each subject was administered eight tasks: four word repetition tasks (monosyllabic, monosyllabic presented in noise, three-item, and multisyllabic), rapid naming, syllable segmentation, paper folding, and form completion. The normal children performed significantly better than both the LI and RI children on all but two tasks: syllable segmentation and repeating words presented in noise. The LI and RI children performed comparably on every task with the exception of the multisyllabic word repetition task. These findings were consistent with those from our previous study (Kamhi & Catts, 1986). The similarities and differences between LI and RI children are discussed. Share, 1983; Wagner & Torgesen, 1987). At the core of one body of literature is the notion of phonological awareness, that is, the awareness of the syllabic, phonemic, and phonetic units of speech. Tasks that assess phonological awareness include tapping out the number of sounds in a word, reversing the order of sounds in a word, and putting together isolated sounds to form words. Poor readers do not perform as well as good readers on such tasks (Bryant & Bradley, 1981; Fox & Routh, 1975; Liberman, Shankweiler, Fischer, & Carter, 1974; Treiman & Baron, 1981). A second body of research has compared the abiliW of good and poor readers to encode phonological information in short- and long-term memory (Bradey, Shankweiler, & Mann, 1983; Byrne & Shea, 1979; Vellutino, Steger, Harding, & Phillips, 1975; Torgesen, 1978, 1982). The term encoding, as used in this literature and throughout this article, refers to the process of translating sensory input into a representational form that can be stored in memory (Torgesen, 1985). Encoding thus involves perceptual, attentional, and representational processes. A variety of tasks have been used to show that poor readers have difficulty creating accurate representations of phonological information (see Stanovich, 1985; Torgesen, 1985; Wagner & Torgesen, 1987). In contrast, poor readers do not tend to have diffleulty processing nonverbal information (e.g., Katz, Shankweiler, & Liberman, 1981). A third body of research has considered children's

It has been about 10-15 years since reading theorists (e.g., Gough, 1972; Mattingly, 1972; Smith, 1979; Vellutino, 1977, 1979) began to emphasize the linguistically based cognitive processes associated with reading and reading disabilities. Although higher level text comprehension processes contribute to individual differences in reading ability, there is now considerable evidence that the processes associated with word recognition are very significant contributors to variance in early reading ability (Stanovich, 1985). The relationship between reading comprehension and the ability to recognize words is particularly strong in the early grades (e.g., Stanovich, Cunningham, & Freeman, 1984). For this reason, most current theories of reading disabilities have attempted to explain why young children might have deficient word recognition skills. The claim currently receiving the most attention is that deficient phonological processing abilities underlie early reading problems (Liberman & Shankweiler, 1985; Mann, 1986; Stanovich, 1985, 1987; Vellutino, 1979; Wagner & Torgesen, 1987). There is a large body of literature indicating that the ability to access the lexicon accurately and rapidly using a phonologic code is strongly related to reading skill and negatively associated with reading disability (Jorm & Share, 1983; Stanovich, 1985). Several attempts have been made to organize the diverse bodies of literature that have examined phonological processing abilities in good and poor readers (e.g., Jorm & © 1988, American Speech-Language-Hearing Association

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KAMHI ET AL.: Phonological and naming abilities (Denckla & Rudel, 1976; Denckla, Rudel, & Broman, 1981; Wolf, 1984, 1986; Wolf, Bally, & Morris, 1986). Naming abilities are most frequently measured by rapid naming tasks in which children are asked to name a series of objects, colors, numbers, or letters. Rapid naming is sometimes viewed as a retrieval task. However, the ability to rapidly name items may depend on how well the phonological information associated with these items is represented and stored in long-term memory. Low-level sequential scanning abilities also contribute to performance on this task. Higher level skills, such as attending to patterns (i.e., ABAAB and ABCABC), can facilitate performance on the alternating naming tasks. Wolf, in a series of longitudinal studies, has studied the relationship between continuous naming, alternating naming, and measures of reading. She found that poor readers could not complete the alternating naming tasks in kindergarten. Unlike the continuous naming task, which was only weakly correlated with reading after kindergarten, the alternating naming task continued to be moderately correlated to reading through second grade. In explaining this relationship, Wolf (1984, 1986) suggested that like reading, the alternating naming task represents an early integration of both controlled (noticing patterns) and automatic (naming) attentional processes (Wolf, 1986, p. 362). The literature thus indicates that poor readers do not perform as well as good readers on a variety of measures of phonological processing. In a recent study, we (Kamhi & Carts, 1986) questioned how children with developmental language impairments would perform on selected measures of phonological processing. Four measures of phonological awareness (elision, segmentation, bisyllabic word division, and monosyllabic word division) as well as a multisyllabic word repetition and sentence repetition task were used to evaluate phonological processing skills. Subjects were 12 language-impaired (LI) children, 12 reading-impaired (RI), and 12 normal children between 6 and 8 years of age. Subjects in the three groups were matched for performance mental age (MA) using the Test of Nonverbal Intelligence (TONI) (Brown, Sherbenou, & Johnsen, 1982). Because of their previous history of language impairment, we initially thought that LI children might perform more poorly than RI children on all of the measures of phonological processing. However, the LI children performed significantly worse than the RI children on only the word and sentence repetition tasks. No significant differences were found between the LI and RI children on the four phonological awareness tasks. In interpreting these findings, we argued that the repetition of multisyllabic words provided the most direct measure of phonological encoding abilities. In order to successfully produce the multisyllabic words, it was necessary to perceive all of the acoustic-phonetic information in the word and accurately represent this information in memory. Because the words were nonsense words, children could not rely on a previously stored lexical representation of the word to aid performance. The speech production component of the task was not thought to be a major contributing factor in the LI children's performance. The

Spatial ProcessingAbilities

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poorer performance of the LI children on this task was thus taken as evidence that they have more difficulty encoding phonological information than RI children. The purpose of the present investigation was to extend our comparison of LI and RI children's phonological processing abilities. We were specifically interested in determining the relative influence of perceptual, representational, retrieval, and speech production abilities on children's performance. We also questioned how LI and RI children would compare on tasks that involved processing nonlinguistic, spatial information. A total of eight tasks were administered. There were four word repetition tasks all involving nonsense words: monosyllabic, monosyllabic in noise, three-item monosyllabic, and multisyllabic. The other tasks were syllable segmentation, rapid naming, and two spatial tasks involving paper folding and form completion (The Minnesota Paper Form Board Test). The four repetition tasks had varying encoding demands as well as different speech production demands. Repeating monosyllabic nonsense words was clearly the easiest task, whereas repeating multisyllabic nonsense words seemed to be the most difficult. Repeating a series of three monosyllabic words is more difficult than repeating one monosyllabic word. Indeed, one of the most consistent findings from the study of RI children is that they perform poorly on tasks that require brief but verbatim retention of strings of verbal items (Cohen, 1982; Torgesen, 1978, 1982). Presenting monosyllabic nonsense words in background noise increased encoding demands by making the words more difficult to perceive. Bradey et al. (1983) have found that poor readers have difficulty on such a task. The syllable segmentation task was the only measure of phonological awareness in the present study. The measure of phoneme segmentation in the previous study revealed no group differences. We questioned whether a syllable segmentation task would better differentiate among the groups. Awareness and access of syllables is known to be easier than accessing phonemic information (e.g., Tunmer & Bowey, 1984). The naming tasks, as indicated above, tap scanning, retrieval, and control processes. They also may provide an indication of how well information is represented in long-term memory. The final two tasks, paper folding and form completion, assessed children's ability to process spatial information. Both of these tasks placed heavy demands on representational processes by requiring children to mentally manipulate complex spatial configurations. LI children have been found to make more errors than matched controls on both of these tasks (Murphy, 1978; Savich, 1984). All of these tasks are described in more detail in the next section. METHOD

Subjects Subjects were 30 children between the ages of 6:8 and 8:10 years. Specific subject data are presented in Table 1.

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TABLE 1. Group means (M) and standard deviations (SD) for chronological age (CA), mental age (MA), language, and reading.

Group

CA (in months)

Language impaired M 95.4 SD 9.8 Reading impaired M 91.8 SD 3.4 Normal M 91.7 SD 6.8

MA (in months)

TOLD a (SLQ)

Woodcockb WA WI

Gates-MacGinitie Reading Comprehension

96.0 12.7

79.0 7.6

43.6 21.7

16.0 11.7

-0.77 c 0.76

93.0 10.5

93.4 10.0

29.0 10.2

10.2 6.6

-0.90 0.35

98.5 10.6

aSpoken-language quotient, bWA = Word Attack; WI = Word Identification. °Difference between expected grade and grade score. Of the 30 children, 10 were poor readers with no history of speech-language impairment, 10 had a developmental language impairment, and 10 had normal language and reading abilities. There were 6 boys and 4 girls in each group. The group of poor readers (henceforth referred to as reading impaired--RI) were second-grade children (M age = 7:8) who had been identified as having a reading impairment by an educational team and who were enrolled in special classes for their problems. The reading impairment in these children was not the direct result of global intellectual, sensory, physical, or emotional deficits. To be included in this study, the RI children also had to perform at least 1 year below expected grade level on the Word Identification and/or the Word Attack subtest of the Woodcock Reading Mastery Tests (Woodcock, 1973) and perform within normal-age limits on the Wechsler Intelligence Scale for Children--Revised (WISC--R) (Wechsler, 1972) or the TONI. None of the RI children had any previous history of speech, language, or hearing disorders and were not currently enrolled in speechlanguage therapy. All of the RI children were reading below grade level according to the Gates-MacGinitie Comprehension Test (Gates & MacGinitie, 1965). The five principal subtests of the Test of Language Development--Primary (TOLD) (Newcomer & Hammill, 1982) were administered to ensure that expressive and receptive syntactic-semantic abilities of the poor readers were within normal limits. To be included in the study, an RI child had to perform within age limits on at least three of the five subtests from the TOLD. Although 3 children had to be excluded because their reading scores were too high, no RI child was excluded because of a low T O L D score. These RI children were thus representative of the general RI children without histories of speech-language impairment. The 10 language-impaired (LI) children (M age = 7:11) were all previously diagnosed as "language-impaired" by a certified speech-language pathologist and were currently enrolled in speech-language therapy. None of the LI children were currently being treated for speech problems. The language impairment w a s not the direct result of global intellectual, sensory, motor, emotional, or

physical impairments. All of the LI children performed within normal age limits on the performance part of the W I S C - - R or the TONI. To be included in this study, the LI children had to perform at least 1 year below age level on at least four of the five T O L D subtests. Performance on the Woodcock Reading Mastery Tests and the GatesMacGinitie was not a criterion for the LI group. To substantiate further the different language abilities of the LI and RI groups, spoken language quotient (SLQ) scores were calculated (see Table 1). These scores are based on children's performance on the five language subtests of the TOLD. The mean SLQ scores for the two groups were significantly different, t(18) = 3.63, p < .01. Consistent with our previous study (Kamhi & Catts, 1986), there was not a significant difference in the reading abilities of the LI and RI children. Note, however, that the LI children performed slightly better than the RI children on the reading tests. The normal children (M age = 7:8) attended the same schools as the LI and RI children. These children had no history of speech, language, hearing, or reading problems. The three groups had comparable mental ages, as measured by the WISC--R, the TONI, the Columbia Mental Maturity Scale (Burgemeister, Blnm, & Lorge, 1972), or the Otis-Lennon School Ability Test (OLSAT) (Otis & Lennon, 1979). With the exception of 3 LI and 3 RI children, all of the children had been administered one of these tests within 6 months prior to the experiment. These 6 children were administered the TONI. The remaining disordered children had current scores on the W1SC--R or the Columbia. All of the normal children had current scores on the OLSAT. Children's chronological age (CA) at the time of the experiment rather than at the time of the intelligence test is reported in Table 1. Because there was a potential gap of 6 months between a child's MA level and current age, reported MA scores for all but the 6 children who received the T O N I might slightly underestimate cognitive level. To ensure that the MA scores of the 6 disordered children did not overly inflate group means, IQ scores that reflected age at the time of the IQ test were calculated. The mean scores for the three groups were 100.7 (LI),

KAMHI ET AL.: Phonological and Spatial Processing Abilities 101.4 (RI), and 107.6 (normal). These scores were not significantly different.

General Procedures Testing was conducted in two sessions for the LI and RI children. In the first session, children were administered the TOLD, the Word Identification and Word Attack subtests for the Woodcock Reading Mastery Tests, and the reading comprehension portion of the GatesMacGinitie. As indicated above, the TONI was administered to the 6 LI and RI children who did not have a current (within 6 months) measure of cognitive level. The normal children were generally tested in one session because they did not receive the language or reading tests. As noted earlier, there were eight experimental tasks. The tasks are described in detail below. Monosyllabic word repetition. This task 'measured children's ability to repeat monosyllabic nonsense words (e.g., var, dap, tiy9. Twenty-five words were presented via tape recorder. The number of correct responses was recorded. Phonological deviations other than distortions were scored as incorrect. Monosyllabic word repetition in noise. In this task, 25 monosyllabic consonant-vowel-consonant (CVC) nonsense words were presented with accompanying speech noise (15 dB signal/noise ratio). As in the previous task, the words were presented via tape recorder. The same scoring procedures were followed. Three-item monosyllabic word repetition. This task measured children's ability to recall a series of three monosyllabic CVC nonsense words similar to the ones used in the previous tasks. Three practice and 10 test lists were tape-recorded and presented to subjects. Responses were scored for the number of items correctly recalled. A score of 30 was possible (10 x 3-item lists). Phoneme substitutions, omissions, additions, and deletions were scored as errors. Articulatory distortions (e.g., lateralized /s/) were considered correct. MultisyUabic word repetition. In this task subjects repeated 40 multisyllabic nonsense words. Thirty of the words were similar to the ones used in our previous study (Kamhi & CaRs, 1986). An additional 10 words were created for the present study. The use of nonsense words rather than real words ensures that children must rely on their verbal short-term memory abilities to respond accurately. (Representations of real words in long-term memory can facilitate productions of real words.) Following the procedures outlined by Snowling (1981), all of the words were derived from real multisyllabic English words. For example, [so$af~si] was derived from philosophy, whereas [man~mzn] was derived from minimum. The 40 words appear in the Appendix. The 40 words were presented via tape recorder. Each child's word repetitions were immediately transcribed by the experimenter using broad phonetic transcription. Tape recordings of the word productions were then used to verify these live transcriptions. The experimenter

319

checked all of the transcriptions with the tape-recorded productions. Then a second judge independently transcribed all the words produced by 3 children from each group. Listener agreement was 94%. Children's word productions were scored as either correct or incorrect. Syllable segmentation. This task provided a measure of children's ability to segment successive syllables in spoken words. Children were given 21 nonsense words to segment. There were an equal number (7) of one-syllable words (e.g., [pu] and [maks]), two-syllable words (e.g, [nippa,] and [nepsI1], and three-syllable words (e.g., [l~tventain] and [s~pzkzl]). All 21 words appear in the Appendix. The following instructions were given to each child: "Now we're going to play a tapping game. I'm going to say something to you--some play words, and then tap them after I say them. You need to listen carefully, so you can learn how to play the game." The experimenter says, "boo," and taps one time; then says, "boo boo," and taps two times; and then says, "boo boo do," and taps three times. The child then is given the same 3 items and asked to tap them. Corrective feedback is given. The 3 items then are presented in a different order (e.g., boo boo, boo boo do, boo). Corrective feedback is again provided. Then the experimenter says, "Now we're going to play the real game. I'm going to say some play words, but I'm not going to tap because you know how to do that now." The child is then instructed to repeat the word and tap out the number of syllables in the word. The number of taps for each of the 21 words was recorded. Responses were scored as either correct or incorrect. The maximum score possible was 21. Rapid automatized naming. Children were administered two continuous naming tests from Denckla and Rudel (1974) and two alternating stimulus sets described in Wolf (1984). Each of the continuous naming charts consisted of five letters (a, d, o, s, p) or five numbers (2, 4, 6, 7, 9) repeated 10 times in a random sequence totaling 50 items. The letter and number alternating set consisted of five letters and five numbers, repeated in a fixed A-B-A-B pattern. The letter, number, color alternating set consisted of five letters, five numbers, and five colors (red, yellow, green, blue, black), repeated in a fixed A-B-C-A-B-C pattern. The materials and procedures were similar to those employed by Denckla and Rudel (1976) and Wolf (1984). All charts were made of V4" white 327-C formecor board, 11" x 14". Letters were made from V2" Normatype transfer letters, Haas-Helvetica Medium (#61 6022-48L); numbers were Has-Helvetica Medium (#61 6022-48N). Colors were represented by V2" x 1/2" color chips made of silk-screened, color-aid Rorhue paper of maximum hue intensity. Children were first asked to name five numbers, five colors, and five letters to assure that this information was stored in long-term memory. Children were then instructed to name each letter, number, or color on the chart, left to right and row to row, as quickly and accurately as possible. A stopwatch was used to measure (in 0.1 s) the time taken by each subject to name each of the

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items on a chart. Time for errors and self-corrections was included in overall latency scores with one exception. When the error or correction resulted in serious faltering (over 10 s) or the subject's discomfiture, the procedure was stopped and the child was allowed to start again. Form completion. The Minnesota Paper Form Board-Revised (MPFB) (Likert & Quahsa, 1970) was used as one of the two measures of spatial processing. The MPFB is a multiple-choice task that requires the child to choose one of five configurations that best represents the assembly of several smaller constituent shapes. As Savich (1984, p. 496) notes, "The task is similar to predicting an assembled puzzle form by seeing the pieces and imaging their construction." In contrast to the previous tasks, the MPFB provides a measure of the facility with which children can encode and mentally manipulate nonlinguistie information. The encoding demands are minimized, however, by the presence of the visual configurations. Murphy (1978) and Savich (1984) both found that LI children made significantly more errors than matched controls on this task. The procedures used by Murphy and Savich were followed in the present study. Twenty of the less complex problems were chosen from the MPFB. The test was presented to children as "puzzles you can do in your head." In the pretraining session, children were asked to assemble a simple paper puzzle representing the shapes in the first practice problem. The child was then shown the sheet of practice problems. The shapes in the upper left corner of the first practice problem were pointed out and the child was asked to make an x on the one picture of the remaining five that showed the pieces of the puzzle after they had been put together. Three additional practice problems were administered. Errors made were discussed, and the correct answer demonstrated. Following the practice trials, the 20 test trials w e r e administered. Examples of test stimuli can be found in Savieh (1984, p. 501). Paper folding. This task was an adaptation of the one described initially by Piaget and Inhelder (1971). It provided a second measure of children's ability to encode nonlinguistic information. As was the case with the MPFB, LI children have been shown to make significantly more errors than normal children on this task (Savich, 1984). The procedures used in this study were identical to those used by Savich (1984, p. 496). In this task, the child observed a piece of paper being folded. The child then was asked to predict what the paper would look like when it was unfolded. The task was made increasingly difficult by increasing the number of folds (from one to three), adding marks to the paper, and cutting holes in the paper. The response format was a paper-and-pencil multiple-choice procedure. Holes were represented on the response sheet as darkened quarter, half, or complete circles. Folds were represented by dotted lines. After children observed the piece of paper being folded, they responded by marking one of four alternative two-dimensional representations of the unfolded piece of paper. The task consisted of five practice items and 22 test

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items. For the practice items, the child was asked to draw on another piece of white paper what the folded paper would look like when it was unfolded. A line on the paper indicated a fold or crease. The practice items were included to help the child understand the concept of predicting the outcome of folding and unfolding a piece of paper. Children had to respond correctly to two of the practice items before proceeding to the test items. The first 5 test items were the same as the practice items in order to ensure that the children understood the multiplechoice format. Examples of test stimuli can be found in Savich (1984, p. 501).

Reliability Reliability measures were discussed above for the word repetition task. The form completion and paper folding tasks were paper-pencil tasks. Children's responses to the five other tasks were initially recorded by three of the authors (DM, KA, or BG). An experimenter who did not do the initial recording independently listened to tape-recorded data from 3 children in each group and recorded and scored children's responses on the five tasks. Reliability checks were thus made on 9 of the 36 children tested. The total percentage agreement across the 10 tasks was 91%. Disagreements were resolved through discussion.

RESULTS

Group Differences The data were first analyzed to compare the performante of the three groups. Two multivariate analyses of variances and Tukey post hoe procedures were used to compare group performance on the 11 dependent measures. The means and standard deviations for each of these measures are presented in Tables 2 and 3. The first MANOVA procedure revealed that there was a significant difference among means for the four rapid automatized naming measures, Hotellings Ta(8, 46) = 4.14, p < .001. Tukey post hoe analyses (df = 2, 27, p < .05) indicated that the normal children had significantly shorter naming times than both the LI and RI groups on the two alternating naming tasks (letters and numbers; letters, numbers, and colors). The normal children also named letters more rapidly than LI children. There were no significant differences between the LI and RI children on any of the four rapid naming tasks. The see0nd MANOVA indicated that there was a significant difference among means for the seven remaining dependent measures, Hotellings Ie(14, 40) = 10.51, p < .001. Tukey post hoe analyses (df = 2, 27, p < .05) indicated that the normal children performed significantly better than the LI and RI children on all but two tasks, Syllable segmentation and monosyllabic word repetition in noise. On the segmentation task, the normal

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TABLE 2. Group means (M) and standard deviations (SD) for the four rapid naming measures (in seconds).

Group Language impaired M SD Reading impaired M SD Normal M SD

Letters

Numbers

Letters and numbers

Letters, numbers, colors

38.9 7.9

38.7 6.9

47.1 8.9

55.1 10.1

35.8 4.6

36.4 8.7

49.2 7.9

57.7 9.4

29.3 6.4

32.7 6.5

37.5 7.1

39.3 8.5

children performed significantly better than the RI children; whereas on the noise task, the normal children performed significantly better than the LI children. The RI children performed significantly better than the LI children on the multisyllabic word repetition task. As in our previous study, this was the only task that significantly differentiated between the LI and RI children.

cesses or knowledge than the other tasks. Indeed, the segmentation task tapped specific awareness 0f syllable segments. Table 5 presents the correlation coefficients among the measures of language, reading, and the nine dependent variables. These coefficients were calculated from the scores of the 20 LI and Ri children; the normal children were not administered the reading or language tests. Reading performance was measured in this study by the Word Identification (WI) and Word Attack (WA) subtests of the Woodcock Reading Mastery Tests and the GatesMacGinitie Comprehension Test. Because there are Versions of the Gates-MacGinitie for each grade, difference scores rather than absolute scores were used in the correlational analysis. Language performance was measured by the five principal subtests of the TOLD. A spoken language quotient (SLQ) was derived from the children's performance on these five language subtests. The correlation coefficients that appear in Table 5 are not particularly revealing. As in our previous study, the expressive and receptive language abilities tapped by the T O L D were significantly related only to performance on the multisyllabic word repetition task. Word attack skills were significantly related only to letter naming. A significant correlation was found between the GatesMacGinitie and the ability to produce words presented

Correlational Analyses Pearson product-moment correlation coefficients were calculated between nine of the dependent measures. Because the four rapid naming measures were highly correlated (r ranged from .65 to .80}, only the coefficients involving one naming task (alternating letters, numbers, and colors) are reported in Table 4. AS can be seen in this table, the expected relationships among measures were generally found. The four repetition tasks were all significantly correlated at the .01 level. Performance on the naming task was significantly correlated to performance on three of the four repetition tasks. The strong relationship between these measures is not unexpected, given that all of these measures tap encoding processes. The segmentation task was not correlated with any other measure, indicating that this task involved different pro-

TABLE 3. Group means (M) and standard deviations (SD) for the four word repetition tasks, segmentation, paper folding, and form completion. Word repetition tasks

Group Language impaired M SD Reading impaired M SD Normal M SD

Monosyllabic (25)a

Multi- Segmen- Paper Noise 3-Item syllabic tation folding (25) (30) (40) (21) (22)

Form completion (20)

17.6 3.0

12.5 4.0

15.8 3.4

16.3 4.8

15.8 4.9

11:7 3.8

12.1 2.9

18.7 2.9

14.0 2.4

17.0 5.0

23.7 9.7

15.4 3.3

12.2 1.8

10.4 1.8

23.8 1.2

16.4 2.7

25.1 2.4

29.6 7.9

19.4 1.4

15.5 2.6

15.9 1.9

aNumbers in parentheses indicate possible correct.

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TABLE4. Pearson product-moment correlation coefficients between the experimental measures.

Word repetition tasks Experimental measure

Monosyllabic

Naming (L.N.C.)a Monosyllabic Noise 3-Item Multisyllabic Segmentation Paper folding

-.54**

Noise

3-Item

-.34 .62**

-.47* .61"* .52*

Multisyllabic

Segmentation

Paper folding

Form completion

-.56** .66** .57** .54**

-.27 .25 .04 .13 .15

-.48* .55** .52* .37 .38 .14

-.56** .52* .35 .41 .31 .25 .54**

~L.N.C. = letters, numbers, colors. *p < .01; r = .43. **p < .001, r = .53. with background noise. Also, consistent with our previous study, performance on the TOLD was not significantly correlated to any measure of reading (TOLD-WA, r = -.16; TOLD-WI, r = -.04; TOLD-Gates, r = ,13). As might be expected, the three reading measures were significantly related (p < .05): WA-WI, r = .45; WA-Gates, r = -.45; WI-Gates, r = -.57. Stepwise multiple regression analyses confirmed the pattern of correlation coefficients. Performance on the multisyllabic word repetition task was the best predictor of language abilities but only accounted for 20% of the variance on the TOLD. No measure significantly predicted word attack or word identification skills. Word repetition in noise accounted for 25% of the variance on the Gates-MacGinitie.

(Kamhi & CaRs, 1986), the only task that differentiated between RI and LI children was the multisyllabic word repetition task. Because performance on this task relied heavily on encoding processes, we speculated that LI children might have a more severe encoding problem than RI children. The findings from the present study were remarkably similar to those from our previous study, despite the use of different measures of phonological processing. As before, the LI and RI children performed comparably on every task with the exception of the multisyllabic word repetition task. The findings from each of the eight tasks are discussed below beginning with the syllable segmentation task.

S~lllable S e g m e n t a t i o n DISCUSSION The principal purpose of the present study was to extend our comparison of RI and LI children's phonological processing abilities. We were also interested in comparing the ability of these children to process nonlinguistic, spatial information. In our previous study

The similar performance of the two groups on the syllable segmentation task reaffirmed that LI children have no more difficulty than RI children explicitly accessing phonological information. Both disordered groups performed quite well on this task, accurately segmenting about 75% of the 21 stimulus words. The normal children

TABLE 5. Pearson product-moment correlation coefficients between the experimental measures and standardized measures of language and reading.

Word repetition tasks Standardized measure TOLD--SLQb Woodcock Word Identification Woodcock Word Attack Gates-MaeGinitie Reading Comprehension

Naming MonoMulti- Segmen- Paper Form (L.N.C.) a syllabic Noise 3-Item syllabic tation folding completion -. 13

.06

.33

.00

.45*

.23

.04

-.33

-.27

-.33

.16

.01

.16

-.16

-.41"

-.18

-.19

-.11

.09

.35

.14

.11

.22

.09

.34

.09

-.34

.10

.31

.50*

-.29 -.48*

aL.N.C. = letters, numbers, colors, bSpoken language quotient (SLQ) derived from performance on the five principal subtests of the Test of Language Development (TOLD) (Newcomer & Hammill, 1982). *p < .05; r = .40.

KAMHI ET AL.: Phonological and Spatial ProcessingAbilities 323 successfully segmented more than 90% of the words. Although the mean scores of the LI and RI children were almost identical, the LI children showed more variability on this task than the RI children.

Rapid Naming On the rapid naming task, the normal children performed significantly better than the LI and RI children on the two alternating naming tasks and significantly better than the LI children in naming letters. The performance of the RI children was consistent with the performance of the impaired readers in the studies by Wolf (1984, 1986). In these studies, Wolf found that the continuous naming tasks were only weakly correlated with reading performance after kindergarten, whereas alternating naming tasks remained moderately correlated with reading through the second grade. As noted earlier, alternating naming, like reading, requires an integration of lower level scanning, recognition, and retrieval skills with a higher level ability to attend to the broader context and patterns of the sets. The poorer performance of the LI and RI children on the alternating naming tasks thus might reflect some difficulty recognizing the pattern of the alternating sets or, more generally, some difficulty integrating automatic and controlled processes.

Word Repetition Tasks The easiest word repetition task involved repeating monosyllabic nonsense words. Success on this task depended largely on children's ability to accurately encode the phonological features of the nonsense words. The memory storage demands as well as the articulatory demands of this task were clearly minimal. Despite the relative simplicity of the task, both RI and LI children performed significantly worse than normal children. The presentation of the nonsense words with background noise increased the encoding demands of the task. The noise made the words more difficult to perceive and represent accurately, thereby making the words more difficult to repeat. One would expect the performance of all three groups to decrease, and indeed, all three groups did perform more poorly on this task. However, the reduction in performance was slightly higher for the normal children (31% reduction, 7.4-word decrease) and the LI children (29% reduction, 5.1-word decrease) than for the RI children (25% reduction, 4.7-word decrease). Only the difference between LI and normal children was significant on this task. The next word repetition task involved repeating a series of 3 nonsense words. Representing 3 words in short-term memory is clearly more difficult than representing only 1 word in short-term memory. Despite the increased processing demands of this task, the pattern of group performance was similar to the one for the monosyllabic word repetition task. The normal children recalled more than 80% of the 30 monosyllabic nonsense

words. In contrast, the LI and RI children recalled only about 50% of the words. The final word repetition task involved repeating multisyllabic words. As noted earlier, this task was the only one that differentiated between the RI and LI children. Of the four word repetition tasks, this one was clearly the most difficult one for LI children. On the other tasks, the LI children performed at around the 50% level, compared to 40% on the multisyllabic task. This task was not, however, the most difficult one for the other children. The RI children performed at approximately the same level on all tasks (55%-60% correct), whereas the normal children performed slightly more poorly in repeating words presented in background noise (66% correct) than they did in repeating the multisyllabic words (75% correct). The relatively poor performance of the LI children on this task can be explained most readily by either difficulties in encoding (i.e., perceiving and representing) the muhisyllabic words in memory or by difficulties in producing the words. The similar performance of the LI and RI children on the other tasks that tapped perceptual and representational processes does not totally rule out the encoding explanation. It might be that LI children will perform worse than RI children only on a task that taxes perceptual and representational processes. Support for this argument would require showing that the multisyllabic word repetition task placed the most demands on these processes. For example, perhaps the multisyllabic words that differentiated the performance of RI and LI children were more difficult to perceive than the words that did not differentiate among the groups. To consider this possibility, the number of RI and LI children who made errors on each of the 40 words was tabulated. The words that best differentiated between the LI and RI children were [god~kIk] and [pe0ot6obk]. Nine LI children misproduced [god~kIk] compared to only 3 RI children, whereas 8 LI children misproduced [pe0zt6ohk] compared to only 2 RI children. Three words showed a disparity of 5 children: [fobgdzdx], [brob6skxt], and [f~0zsls]. In contrast, some words caused difficulty for both groups (e.g., [soJ'~osi]), and others proved easy for both groups (e.g., [b~0oris], [w~t~fodI], [son~kolon]). Unstressed syllables that might prove difficult to perceive are well represented in all of the words above. There appear to be no obvious differences in the perceptual analyses required by these words. If the multisyllabic repetition task did place the most demands on perceptual and representational processes, then the performance levels of all three groups should have been lower on this task than on the other three word repetition tasks. This task, however, was the most difficult one only for the LI children. It appears, then, that the perceptual and representational demands involved in repeating multisyllabic words were no greater than those involved in the other three word repetition tasks, particularly, repeating words presented in noise. The only other hint of evidence in support of the encoding explanation is that the LI children performed slightly worse than the RI children on the three other

324 Journal of Speech and Hearing Disorders word repetition tasks. The LI children also performed significantly worse than the normal children repeating words presented in noise. Taken together, the evidence in favor of the encoding explanation is thus relatively weak. The most obvious alternative explanation for the relatively poor performance of the LI children on the multisyllabie task centers on the speech production demands of the task. None of the other tasks required the production of complex phonological sequences. Although the string of three nonsense words in the three-item task was as long as many of the multisyllabic words, the words were all CVC monosyllables. In contrast, some of the multisyllabic words contained four syllables, and most had complex phonological sequences involving clusters and varying stress patterns. In our previous study we argued LI children's relatively poor performance on this task was not caused by articulation deficiencies. None of the children in the earlier study or in the present one made consistent speech errors involving substitutions, deletions, or additions. Categorizing errors in terms of phonological processes or distinctive features also revealed no qualitative differences between the two groups (Kamhi & CaRs, 1986). To explore further potential speech production differences, we looked again at the words that differentiated between the RI and LI children. The difficulty LI children had producing the five most discriminating words (e.g., [g~d~kIk] and [pe0ot6ohk])was clearly not the result of an inability to produce a particular phoneme. The phonemes in these five words occurred in several other words for which there were no group differences, such as [b~0~ns] and [wotgffodI]. Correct production of multisyllabic words, however, requires not only articulation proficiency hut also the ability to program complex phonological sequences. Consider, for example, why an adult might say [t~stfstIks] for statistics. The problem is not in articulating the individual speech segments, but in planning a complex phonological sequence (Shattuck-Hufnagel, 1987). It seems quite plausible that LI children might be less proficient than RI and normal children in planning complex phonological sequences. As indicated above, some words differentiated between LI and RI children. Other words differentiated between RI and normal children. The complexity of the phonological sequences in the 40 multisyllabic words thus differed, and these differences differentiated among normal, RI, and LI children. Importantly, there were several words (e.g., [szf(tfzsi], [spe0zstdpIk], and [ta~pz0ab,1]) that had such complex phonological sequences that even the normal children had difficultyproducing them. For example, only 5 children--1 LI, 2 RI, and 2 normal children-produced [s~fgfosx] correctly. In contrast, some words (e.g., [pr~lkhef~n], [wzt,4fgdl], and [s~n~ikolon]) caused litfie difficulty even for the LI children. For example, only 1 LI child misproduced [s~n~tkzlon]. The data suggest that the LI children's relatively poor performance on the multisyllabic word repetition task

53 316-327 August 1988 was not due to deficient articulation or encoding skills. The data are consistent with the claim that LI children might have poorer speech programming abilities than RI children. These points notwithstanding, we are not yet willing to conclude that RI and LI children have similar encoding (perceptual and representational) abilities. One possible way to sort out the relative effects of encoding and speech programming factors is to compare children's ability to recognize the multisyllabic nonsense words, thereby eliminating the (overt) speech production component. We are currently in the process of collecting such data.

Paper Folding and Form Completion The paper folding and form completion tasks assessed children's ability to process spatial information. As discussed earlier, both of these tasks place heavy demands on representational processes. For the form completion task, the memory demands were not very high because children had visual representations of the stimulus items in front of them. Accurately representing the spatial configurations was thus not as diflqcult as mentally manipulating these configurations. For the paper folding task, children had to make the symbolic association between folds and dotted lines and between darkened portions and holes. The most difficult part of the task was determining how marks and holes in a folded up paper would look when the paper was unfolded. The ability to mentally manipulate symbolic representations was thus an important aspect of this task as it was for the form completion task. Previous studies involving RI children (e.g., Katz et al., 1981) have shown that they do not have difficulty remembering nonverbal information. In the present study, however, the normal children performed significantly better than both the LI and RI children on the two spatial tasks. These findings indicate that the processing difficulties of RI children are not limited to difficulty processing phonological information. RI children might not have difficulty remembering nonverbal information, but like LI children, they have difficulty performing mental operations on complex spatial representations.

Developmental Language and Reading Disorders: Causes and Consequences At the conclusion of our previous study, we were left with the puzzle of how LI and RI children could perform similarly on the measures of phonological, lexical, and syntactic processing but have different language abilities. The findings from the present study indicate that the puzzle was not imagined. Its solution is also not as simple as we initially thought. As in the previous study, we are left with the question of what differentiates LI and RI children other than specific measures of language performance.

KAMHI ET AL.: Phonological and Spatial ProcessingAbilities 325 One possibility is that language differences between RI and LI children are relatively unsubstantial ones, perhaps even an experimental artifact, and thus not worthy of explanation. In support of this possibility are studies that document language deficits in the general population of learning-disabled children. Several researchers (e.g., Feagans & Short, 1984; Roth & Spekman, 1986) have found that RI children have deficiencies in higher level language functions, such as narrative discourse and figurative language. These are the same kinds of problems that have been documented in LI children (e.g., Lee & Kamhi, 1985; Liles, 1985, 1987). Concluding that the language abilities of LI and RI children are not distinctive is an attractive way to explain the similar performance of these children in our two studies. However, several studies have shown that many of the children who experience significant difficulties in learning to read do not have the types of language deficits (e.g., syntactic and semantic) that are identified by standardized language tests (Hessler & Kitchen, 1980; Newcomer & Magee, 1977). Moreover, studies that have directly compared the language abilities of LI and RI children have consistently found differences in favor of the RI children. Lee and Kamhi (1985), for example, found that LI children performed more poorly than matched RI children (M MA = 11:6) on a metaphor preference task and a metaphor production task. Masterson and Kamhi (1985) found that LI children were more susceptible than RI children (M MA = 7:0) to speech and language breakdowns as a function of increased processing demands. We are also not alone in finding a population of schoolage LI children who are distinct from the more general population of learning-disabled and reading-disabled children. There is a large body of literature that has identified a distinct group of school-age LI children for study (e.g., Johnston & Weismer, 1983; Liles, 1985, 1987; Savich, 1984; Weismer, 1985). Liles (1987), for example, in a recent study identified 20 LI children with a mean age of 8:7. These children, like ours, had an early history of language disorder, performed within normal limits on a nonverbal intelligence test, were currently enrolled in language therapy, and were not currently receiving therapy for articulation problems. Liles also notes that these children were not primarily identified as "learning disabled." If the language differences between LI and RI children are real, then they must be explained. There are two general approaches to explaining these differences. The first approach is to argue that the same processing deficiency underlies both developmental language and reading disorders, with the deficit being more severe in the LI children. Deficiencies in perceptual and representational processes seemed to be a good candidate for the nature of the processing deficit. However, the data from our two studies found that LI and RI children are not distinguishable in these areas. Our data also allow us to rule out other processing candidates, such as sequential scanning, memory storage and retrieval processes, and the repre-

sentational processes involved in mentally manipulating complex symbolic representations. The second approach is to acknowledge that the skills involved in talking and understanding are different than those involved in learning to read. Although the language bases of reading have been well documented, there are some very obvious differences between oral language and early reading skills (see Perara, 1984, or Kamhi & Catts, in press, for a discussion or these differences). The most obvious differences are between expressive language abilities and written word recognition processes. As we have stated before, written word recognition problems are attributed primarily to difficulty processing phonological information. In contrast, expressive language problems can be caused by deficits in syntactic, semantic, phonological, or pragmatic knowledge and processes. An intriguing speculation is that the difficulty LI children seem to have in programming complex phonological sequences might reflect a more basic difficulty in programming or formulating grammatically well-formed utterances. Comprehension processes involved in oral and written languages are also different. Understanding oral language requires rapid processing of temporal auditory information. Written language is not temporal; it can be read over and over again until it is understood. Although similar higher level language processes are involved in understanding texts and discourse, the problem most children have in learning to read involves word recognition not text comprehension (Perfetti, 1985). Deficient text-comprehension processes thus cannot account for the word recognition problems encountered by children learning to read. In light of the differences between oral and early reading skills, it is perhaps unreasonable to think that the same processing deficit or even pattern of deficits should be able to explain oral language deficits and reading problems involving word recognition.

Conclusions The distinctiveness of LI and RI children has been seriously challenged by the findings from our two studies. Indeed, we have been somewhat surprised to find that school-age children with a history of preschool language impairments performed at the same level as poor readers with no history of language learning problems on measures of phonological, lexical, syntactic, and spatial processing. The similar performance of the two groups invites the conclusion that LI and RI children are essentially the same children disguised by a different label. As discussed above, however, such a conclusion ignores the very real language differences that exist between the two groups. Future studies need to identify the factors that underlie and maintain these differences. ACKNOWLEDGMENTS The authors wish to thank the Auburndale School System and Marion County Schools for graciously allowing us to disrupt the

326 Journal of Speech and Hearing Disorders children's daily routines for a few months. A special word of thanks goes to Amy Dietrich and Ann Carpenter for the help they provided in identifying children and making space available to carry out the research. Thanks also to Pat Savage for providing some of the materials and instructions for the form completion and paper folding tasks. An earlier version of this paper was presented at the 1986 Annual Convention of the American Speech-Language-Hearing Association, Detroit.

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APPEN

Word Repetition Task 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25. 26. 27. 28. 29. 30. 31. 32. 33.

b~60zris son~zlzn pr~hefon tJ'ofdstitJ" 9~da~kik fobgodI tJ'zl~Is m~omom sokfslp wsflzzet trfbzbl~ rzb6slt faS0osls kosz6bon pe0otOohk pl~ntmfjud3 bok~topi rfdleJ'~n bos~l~ned sp~pfstIks sok,~vit fetzsgoon

SOf~f~sI klfstroflob~s w~tftfod~ brob6skIt dosfpolo sontimonon vosfJ'os t~somtol r'z6bzli sp~zstop~k b~nofod

34. 35. 36. 37. 38. 39. 40.

ta6pogab! dosfbos sosfktob! m~kown fesov6J'os lfsotosin stosaSfik

Short-Term Memory 1. 2. 3. 4. 5. 6. 7. 8. 9. 10.

tab 9ulflv kIr vm3 n~ez sar zze0 dok vae9lore ms zel bod rap tff vat mze~3 sI9 peb zol f~emser gib pA0 dar bIs dap won 9ef

Segmentation Task 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11.

pu nIddw mpp~ kaos s~okol 6nep l~tventain maks pok g3~0bel s~podent

327

Verbal vs. non-verbal paired-associates learning in poor and normal readers. Neuropsychologia, 13, 75-82. WAGNER,R., & TORGESEN,J. (1987). The nature of phonological processing and its causal role in the acquisition of reading skills. Psychological Bulletin, 101,192-212. WECHSLER, D. (1972). Wechsler Intelligence Scale for Children-Revised. New York: The Psychological Corporation. WEISMER,S. (1985). Constructive comprehensive abilities exhibited by language-disordered children. Journal of Speech and Hearing Research, 28, 175-184. WOLF, M. (1984). Naming, reading, and the dyslexias: A longitudinal overview. Annals of Dyslexia, 34, 87-115. WOLF, M. (1986). Rapid alternating stimulus naming in the developmental dyslexias. Brain and Language, 27, 360--379. WOLF, M., BALLY, H., & MOB.mS, R. (1986). Automaticity, retrieval processes, and reading in average and impaired readers. Child Development, 57, 988-1000. WOODCOCK,R. (1973). Woodcock Reading Mastery Tests. Circle Pines, MN: American Guidance Service. Received July 17, 1987 Accepted October 21, 1987 Requests for reprints should be sent to Alan G. Kamhi, Ph.D., Department of Audiology and Speech Pathology, Memphis State University, 807 Jefferson Avenue, Memphis, TN 38105.

DIX 12. 13. 14. 15. 16. 17. 18. 19. 20. 21.

mnldron sa~golin kera~ famp nepsd wag mtip~daen b~tadi loot lubXrnkw

Perceptual Task Quiet 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19.

fat mar sIg pum riv kel vzeg ms gef lap zaerj let biz dok ser wn9 tIf vat dap

20. 21. 22. 23. 24. 25.

fun kIz dzef tan sIb zol

Noise 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25.

fnp kIr mzer3 peb sar lom tab won rap zel bls 9ab fzem z~k dar nob VArJ n~ez 9~b nnd tIV seb gul mff bod