Angeliki Mouzaki

Development of Lexical Mediation in the Relation Between Reading Comprehension and Word Reading Skills in Greek

This study focuses on the shared variance between reading comprehension and word-level reading skills in a population of 534 Greek children in Grades 2 through 4. The correlations between measures of word and pseudoword accuracy and fluency, on the one hand, and vocabulary and comprehension skills, on the other, were sizeable and stable or increasing with grade. However, the unique contribution of word reading to comprehension became negligible after vocabulary measures were entered in hierarchical regression analyses, particularly for higher grades, suggesting that any effects of decoding on comprehension may be mediated by the lexicon, consistent with lexical quality hypothesis. Structural modeling with latent variables revealed an invariant path across grades in which vocabulary was defined by its covariation with reading accuracy and fluency and affected comprehension directly. It is argued that skilled word reading influences comprehension by strengthening lexical representations, at least when phonological decoding can be relatively effortless.

Age-related changes in regional brain activation during phonological decoding and printed word recognition.

Using magnetic source imaging, age-related changes in spatiotemporal brain activation profiles associated with printed word recognition and phonological decoding (pseudoword reading) were examined in 27 adults and 22 children without reading problems. Adults showed a distinct spatiotemporal profile during reading of both types of print consisting of bilateral activation of occipital cortices, followed by strongly left-predominant activation of basal temporal regions, and, finally, left hemisphere temporoparietal (including the angular gyrus) and inferior frontal activation. Children lacked the clear temporal distinction in the engagement of basal and temporoparietal areas and displayed significantly weaker activation of the left inferior frontal gyrus. In addition, the consistent hemispheric asymmetries in the degree of activation of basal temporal regions that were present in the adult readers were not apparent in the children. In contrast, the strong left hemisphere preponderance in the degree of activation of temporoparietal areas was present in children as well as adults, regardless of the type of print they were asked to read. The data suggest that the degree of specialization of cortical regions for reading, as well as the pattern of regional interactions that supports this specialization, may change with age.

CLASSIFICATION OF STUDENTS WITH READING COMPREHENSION DIFFICULTIES: THE ROLES OF MOTIVATION, AFFECT, AND PSYCHOPATHOLOGY

Attempts to evaluate the cognitive-motivational profiles of students with reading comprehension difficulties have been scarce. The purpose of the present study was twofold: (a) to assess the discriminatory validity of cognitive, motivational, affective, and psychopathological variables for identification of students with reading difficulties, and (b) to profile students with and without reading comprehension difficulties across those variables. Participants were 87 students who scored more than 1.3 SD below the mean on a standardized reading comprehension battery and 500 typical students in grades 2 through 4. Results using linear discriminant analyses indicated that students with reading comprehension difficulties could be accurately predicted by low cognitive skills and high competitiveness. Using cluster analysis, students with significant deficits in reading comprehension were mostly assigned to a low skill/low motivation group (termed helpless) or a low skill/high motivation group (termed motivated low achievers). Based on these findings, it was concluded that motivation, emotions, and psychopathology play a pivotal role in explaining the achievement tendencies of students with reading comprehension difficulties.

The Components of the Simple View of Reading: A Confirmatory Factor Analysis

The simple view of reading admits two components in accounting for individual differences in reading comprehension: a print-dependent component related to decoding and word identification, and a print-independent one related to oral language comprehension. It has been debated whether word or nonword reading is a better index of the print-dependent component and whether vocabulary measures fit within the print-independent component or constitute an additional factor. Here we apply a confirmatory factor analysis on a set of relevant measures from 488 Greek children in Grades 3–5 independently of reading comprehension. The results indicate that word and nonword reading do not constitute distinct factors but covary along the same two dimensions of accuracy and fluency. Oral vocabulary measures group with listening comprehension, resulting in excellent model fits. Strong correlations were observed between the latent factors of the purported print-dependent and print-independent components, consistent with an approach that focuses on the strong relations among semantic, orthographic, and phonological aspects of word representations.

The Role of Vocabulary in the Context of the Simple View of Reading

The simple view of reading posits that reading comprehension can be decomposed into a print-specific component (concerning decoding and sight word reading) and a language comprehension component (concerning verbal and metalinguistic skills not related to print). One might properly consider lexical skills, indexed by vocabulary measures, part of the language component; however, vocabulary measures end up taking up substantial amounts of print-dependent reading comprehension variance, presumably because of the interrelations among semantic, orthographic, and phonological specification of lexical entries. In the present study we examined the role of vocabulary in the prediction of reading comprehension by testing alternative formulations within the context of the simple view. We used cross-sectional and (1-year) longitudinal data from 436 children in Grades 3–6 attending regular classrooms. We quantified the proportion of variance accounting for reading comprehension that could be attributed to vocabulary measures. We then tested a latent variable model positing a mediating position for vocabulary against a model with lexically based covariation among the simple view components. We discuss the results in an attempt to bring together the simple view with the lexical quality hypothesis for reading comprehension.

Psychometric Evaluation of a Receptive Vocabulary Test for Greek Elementary Students.

Assessment of lexical/semantic knowledge is performed with a variety of tests varying in response requirements. The present study exemplifies the application of modern statistical approaches in the adaptation and assessment of the psychometric properties of the Peabody Picture Vocabulary Test–Revised (PPVT-R) Greek. Confirmatory factor analyses applied to data from a large sample of elementary school students (N = 585) indicated the existence of a single vocabulary dimension and differential item functioning procedures pointed to minimal bias due to gender or ethnic group. Rasch model–derived indices of item difficulty and discrimination were used to develop a short form of the test, which was administered to a second sample of 900 students. Convergent and discriminant validity were assessed through comparisons with the Wechsler Intelligence Scales for Children–III Vocabulary and Block design subtests. Short- and long-term stability of individual scores over a 6-month period were very high, and the utility of the test as part of routine educational assessment is attested by its strong longitudinal predictive value with reading comprehension measures. It is concluded that the Greek version of the PPVT-R constitutes a reliable and valid assessment of vocabulary for Greek students and immigrants who speak Greek.

Age, gender, and education effects on vocabulary measures in Greek

Background: Assessment of lexical/semantic knowledge—the ability to retrieve phonological, lexical, and general (semantic) information from long term memory—can be performed with a variety of tests varying in response requirements. Aims: The present study explores the impact of demographic variables on three such tests. Methods & Procedures: The Peabody Picture Vocabulary Test-Revised (PPVT-R), the Vocabulary subtest from the Wechsler Abbreviated Scale of Intelligence (WASI), and the Boston Naming Test (BNT) were used in a representative sample of 500 Greek community-dwelling adults aged 50–84 years. Outcomes & Results: Education effects were generally stronger than age effects, and were strongest on the WASI. Age effects (independent of educational level) were highest for the BNT and lowest for the WASI Vocabulary. Relationships among tests and also between each vocabulary test and an index of non-verbal intelligence are also discussed.

Matthew Effects in Reading Comprehension: Myth or Reality?

The presence of Matthew effects was tested in students of varying reading, spelling, and vocabulary skills. A cross-sequential design was implemented, following 587 Grade 2 through 4 students across five measurement points (waves) over 2 years. Students were administered standardized assessments of reading, spelling, and vocabulary. Results indicated that the hypothesized fan-spread pattern for Matthew effects was not evident. Low and high ability groups were formed based on 25th and 75th percentile cutoffs on initial measures of spelling, reading accuracy and fluency, vocabulary, and reading comprehension. Multilevel modeling suggested that low and high ability groups had significantly different starting points (intercepts) and their pattern of growth on passage comprehension did not indicate that the gap would increase over time. Instead, some analyses, especially of the youngest cohorts, showed significant convergence. However, there was no evidence of eventually closing the gap. Thus, although the poor students may not be getting poorer, they do not get sufficiently richer either.

Reading Fluency Estimates of Current Intellectual Function: Demographic Factors and Effects of Type of Stimuli

The study explores the potential clinical value of reading fluency measures in complementing demographic variables as indices of current intellectual capacity. IQ estimates (based on the PPVT-R, WASI Vocabulary and Block Design subtests) were obtained from a representative, non-clinical sample of 386 Greek adults aged 48–87 years along with two measures of reading efficiency (one involving relatively high-frequency words—WRE—and the second comprised of phonotactically matched pseudowords—PsWRE). Both reading measures (number of items read correctly in 45 s) accounted for significant portions of variability in demographically adjusted verbal and performance IQ indices. Reading measures provided IQ estimates which were significantly closer to those predicted by demographic variables alone in up to 22% of individuals with fewer than 7 (across all ages) or 13 years of formal education (in the 70–87 year age range). PsWRE scores slightly outperformed WRE scores in predicting a person’s estimated verbal or performance IQ. Results are discussed in the context of previous findings using reading accuracy measures for low-frequency words with exceptional spellings in less transparent orthographic systems such as English.

Effects of demographic variables and health status on brief vocabulary measures in Greek

Background: Assessment of lexical/semantic knowledge is essential on a number of diagnostic situations. Since more than one test is typically required, brief assessments would be useful as part of an extensive neuropsychological battery. Aims: The present study reports the effects of demographic variables and reported health status on performance on the short forms of three such tests adapted into Greek. Methods & Procedures: Tests used were PPVT-R, WASI Vocabulary subtest, and BNT. The sample consisted of 468 community-dwelling adults aged 50–84 years. Outcomes & Results: Short forms consisted of 32 items for the PPVT-R, 15 items for WASI Vocabulary, and 20 items for BNT. Correlation coefficients between full and short forms ranged between .95 and .97. Total rate of inconsistent classification of persons with very low scores (lower than 2 SD below the population mean) based on the short forms was less than 3%, highlighting adequate potential sensitivity for clinical purposes. The equivalence of the two versions of each test was further attested by similar patterns of relationships with demographic variables. Indices of internal consistency and test–retest reliability were very good for each of the three tests. Finally, the sensitivity of the short forms of each test for detecting lexical/semantic deterioration as a function of systemic diseases is discussed.