Eye Movements and Articulations During a Letter Naming Speed Task

Do Oral and Silent Word-Reading Fluency Rely on the Same Cognitive-Linguistic Skills? Evidence from a Cross-Sectional Study in Greek

Researchers tend to use oral- and silent-reading fluency measures interchangeably and to generalize research findings across reading modes, especially from oral to silent reading. In this study, we sought to examine if oral and silent word-reading fluency rely on the same cognitive-linguistic skills. Three hundred and forty-five Greek children (80 from Grade 2, 85 from Grade 4, 91 from Grade 6, and 89 from Grade 10) were assessed on measures of general cognitive ability, speed of processing, phonological awareness, rapid automatized naming, orthographic knowledge, articulation rate, and word-reading fluency (oral and silent). Results of hierarchical regression analyses revealed that phonological awareness was a unique predictor of both reading outcomes in Grade 2 and orthographic knowledge was a unique predictor of both reading outcomes in Grades 4, 6, and 10. However, rapid automatized naming predicted only oral word-reading fluency. These findings suggest that silent and oral word-reading fluency do not necessarily rely on the same cognitive-linguistic skills at the same grade level and we need to exercise some caution when we generalize the findings across reading modes.

Eye Movement Evidence for Simultaneous Cognitive Processing in Reading

Measuring simultaneous processing, a reliable predictor of reading development and reading difficulties (RDs), has traditionally involved cognitive tasks that test reaction or response time, which only capture the efficiency at the output processing stage and neglect the internal stages of information processing. However, with eye-tracking methodology, we can reveal the underlying temporal and spatial processes involved in simultaneous processing and investigate whether these processes are equivalent across chronological or reading age groups. This study used eye-tracking to investigate the simultaneous processing abilities of 15 Grade 6 and 15 Grade 3 children with RDs and their chronological-age controls (15 in each Grade). The Grade 3 typical readers were used as reading-level (RL) controls for the Grade 6 RD group. Participants were required to listen to a question and then point to a picture among four competing illustrations demonstrating the spatial relationship raised in the question. Two eye movements (fixations and saccades) were recorded using the EyeLink 1000 Plus eye-tracking system. The results showed that the Grade 3 RD group produced more and longer fixations than their CA controls, indicating that the pattern of eye movements of young children with RD is typically deficient compared to that of their typically developing counterparts when processing verbal and spatial stimuli simultaneously. However, no differences were observed between the Grade 6 groups in eye movement measures. Notably, the Grade 6 RD group outperformed the RL-matched Grade 3 group, yielding significantly fewer and shorter fixations. The discussion centers on the role of the eye-tracking method as a reliable means of deciphering the simultaneous cognitive processing involved in learning.

Pathogenesis of Comorbid ADHD and Chinese Developmental Dyslexia: Evidence From Eye-Movement Tracking and Rapid Automatized Naming

BACKGROUND

ADHD and Chinese developmental dyslexia (DD) have a very high comorbidity rate; however, which cognitive deficits characterize the comorbidity and when they occur during cognitive processing are still under debate.

METHODS

Rapid automatic naming (RAN) tasks with eye-movement tracking were conducted with 75 children who were typically developing, had comorbid ADHD and DD, had only ADHD, and had only DD.

RESULTS

The clinical groups had longer first fixation durations than the control for RAN digits. Temporal eye-movement measures, such as gaze duration and total reading time, were found to vary between the comorbidity and ADHD groups. Spatial eye-movement measures, such as regression probability and incoming saccade amplitude, differed between the comorbidity and DD groups.

CONCLUSIONS

These results indicate that investigation with eye-movement measures combined with RAN tasks can strengthen the understanding of the pathogenesis of comorbid ADHD and DD.

Fixation-related potentials in naming speed: A combined EEG and eye-tracking study on children with dyslexia

OBJECTIVE

We combined electroencephalography (EEG) and eye-tracking recordings to examine the underlying factors elicited during the serial Rapid-Automatized Naming (RAN) task that may differentiate between children with dyslexia (DYS) and chronological age controls (CAC).

METHODS

Thirty children with DYS and 30 CAC (M_age = 9.79 years; age range 7.6 through 12.1 years) performed a set of serial RAN tasks. We extracted fixation-related potentials (FRPs) under phonologically similar (rime-confound) or visually similar (resembling lowercase letters) and dissimilar (non-confounding and discrete uppercase letters, respectively) control tasks.

RESULTS

Results revealed significant differences in FRP amplitudes between DYS and CAC groups under the phonologically similar and phonologically non-confounding conditions. No differences were observed in the case of the visual conditions. Moreover, regression analysis showed that the average amplitude of the extracted components significantly predicted RAN performance.

CONCLUSION

FRPs capture neural components during the serial RAN task informative of differences between DYS and CAC and establish a relationship between neurocognitive processes during serial RAN and dyslexia.

SIGNIFICANCE

We suggest our approach as a methodological model for the concurrent analysis of neurophysiological and eye-gaze data to decipher the role of RAN in reading.

Developmental Trends of Visual Processing of Letters and Objects Using Naming Speed Tasks

Studying the typical development of reading is key to understanding the precise deficits that underlie reading disabilities. An important correlate of efficient reading is the speed of naming arrays of simple stimuli such as letters and pictures. In this cross-sectional study, we examined developmental changes in visual processing that occurs during letter and object naming from childhood to early adulthood in terms of behavioral task efficiency, associated articulation and eye movement parameters, and the coordination between them, as measured by eye-voice span in both the spatial and temporal domains. We used naming speed (NS) tasks, in which participants were required to name sets of letters or simple objects as quickly and as accurately as possible. Single stimulus manipulations were made to these tasks to make the stimuli either more visually and/or phonologically similar to one another in order to examine how these manipulations affected task performance and the coordination between speech and eye movements. Across development there was an increased efficiency in speech and eye movement performance and their coordination in both the spatial and temporal domains. Furthermore, manipulations to the phonological and visual similarity of specific letter and object stimuli revealed that orthographic processing played a greater role than phonological processing in performance, with the contribution of phonological processing diminishing across development. This comprehensive typical developmental trajectory provides a benchmark for clinical populations to elucidate the nature of the cognitive dysfunction underlying reading difficulties.

Understanding the biological basis of dyslexia at a neural systems level

We examined the naming speed performance of 18 typically achieving and 16 dyslexic adults while simultaneously recording eye movements, articulations and fMRI data. Naming speed tasks, which require participants to name a list of letters or objects, have been proposed as a proxy for reading and are thought to recruit similar reading networks in the left hemisphere of the brain as more complex reading tasks. We employed letter and object naming speed tasks, with task manipulations to make the stimuli more or less phonologically and/or visually similar. Compared to typically achieving readers, readers with dyslexia had a poorer behavioural naming speed task performance, longer fixation durations, more regressions and increased activation in areas of the reading network in the left-hemisphere. Whereas increased network activation was positively associated with performance in dyslexics, it was negatively related to performance in typically achieving readers. Readers with dyslexia had greater bilateral activation and recruited additional regions involved with memory, namely the amygdala and hippocampus; in contrast, the typically achieving readers additionally activated the dorsolateral prefrontal cortex. Areas within the reading network were differentially activated by stimulus manipulations to the naming speed tasks. There was less efficient naming speed behavioural performance, longer fixation durations, more regressions and increased neural activity when letter stimuli were both phonologically and visually similar. Discussion focuses on the differences in activation within the reading network, how they are related to behavioural task differences, and how progress in furthering the understanding of the relationship between behavioural performance and brain activity can change the overall trajectories of children with reading difficulties by contributing to both early identification and remediation processes.

The Contribution of Oculomotor Functions to Rates of Visual Information Processing in Younger and Older Adults

Oculomotor functions are established surrogate measures of visual attention shifting and rate of information processing, however, the temporal characteristics of saccades and fixations have seldom been compared in healthy educated samples of younger and older adults. Thus, the current study aimed to compare duration of eye movement components in younger (18-25 years) and older (50-81 years) adults during text reading and during object/alphanumeric Rapid Automatic Naming (RAN) tasks. The current study also aimed to examine the contribution of oculomotor functions to threshold time needed for accurate performance on visually-driven cognitive tasks (Inspection Time [IT] and Change Detection [CD]). Results showed that younger adults fixated on individual stimuli for significantly longer than the older participants, while older adults demonstrated significantly longer saccade durations than the younger group. Results also demonstrated that older adults required longer threshold durations (i.e., performed slower) on the visually-driven cognitive tasks, however, the age-group time difference on the CD task was eradicated when the effects of saccade duration were covaried. Thus, these results suggest that age-related cognitive decline is also related to increased duration of saccades and hence, highlights the need to dissociate the age-related motor constraints on the temporal aspects of oculomotor function from visuo-cognitive speed of processing.

Eye Movements During RAN as an Operationalization of the RAN-Reading "Microcosm"

Rapid Automatized Naming (RAN) is a strong predictor of reading aloud, though there is little agreement on what underpins RAN or how it relates to reading. Some theorize phonological skills, while others suggest that RAN reflects the “microcosm” of cognitive and attentional processes also required for reading, with more recent research using eye movements in an attempt to study this relationship. In the current study, we aimed to extend previous investigations to identify whether the temporal patterns of eye movements predict RAN and can, therefore, be established as a method to study the cognitive processes underlying RAN that could then be utilized to elucidate the relationship of RAN to reading. A Gazepoint eye tracker was used to record the eye movements of 93 learner readers aged 5–8 years (M age = 7.00) while performing a custom computerized alphabetic RAN task. Text reading accuracy, comprehension and rate; nonverbal intelligence; and phonological awareness abilities were also assessed. Regression analyses showed that, independently of phonological awareness, eye movements [Fixation Count (FC) and Fixation Duration (FD)] measured during RAN tasks were highly reflective of children’s rapid naming performance (92.8%). Both mean FC and mean FD during RAN tasks also predicted text reading accuracy (36.3%), comprehension (31.6%), and rate (36.2%) scores, and in predicting these text reading skills there was a high level of shared variance with RAN performance. In a sub-sample of participants, longer average FDs and counts independently discriminated children with reading difficulties (n = 18; aged 7–9) from neurotypical children matched for age (n = 18), but not from younger neurotypical children matched for reading level (n = 18; aged 5–6). Together, these results suggest that the analysis of eye movements recorded during RAN allows for the operationalization of many of the spatially and temporally-bound cognitive and attentional processes that underpin the RAN, and a step towards elucidating its relationship to reading.

Examining the neural and cognitive processes that underlie reading through naming speed tasks

We combined fMRI with eye tracking and speech recording to examine the neural and cognitive mechanisms that underlie reading. To simplify the study of the complex processes involved during reading, we used naming speed (NS) tasks (also known as rapid automatized naming or RAN) as a focus for this study, in which average reading right-handed adults named sets of stimuli (letters or objects) as quickly and accurately as possible. Due to the possibility of spoken output during fMRI studies creating motion artifacts, we employed both an overt session and a covert session. When comparing the two sessions, there were no significant differences in behavioral performance, sensorimotor activation (except for regions involved in the motor aspects of speech production) or activation in regions within the left-hemisphere-dominant neural reading network. This established that differences found between the tasks within the reading network were not attributed to speech production motion artifacts or sensorimotor processes. Both behavioral and neuroimaging measures showed that letter naming was a more automatic and efficient task than object naming. Furthermore, specific manipulations to the NS tasks to make the stimuli more visually and/or phonologically similar differentially activated the reading network in the left hemisphere associated with phonological, orthographic and orthographic-to-phonological processing, but not articulatory/motor processing related to speech production. These findings further our understanding of the underlying neural processes that support reading by examining how activation within the reading network differs with both task performance and task characteristics.

What causes dyslexia? Identifying the causes and effective compensatory therapy

BackgroundChildren are diagnosed as dyslexic when their reading performance is much below that which could be expected for their educational level and cannot be explained by a sensory, neurological or psychiatric deficit or by a low IQ. Although poor reading is a major obstacle to school and career achievement, the causes of dyslexia are unclear and traditional therapies are often unsuccessful. To determine the causes of dyslexia, experiments must demonstrate under which conditions a reading disorder occurs and whether the reading performance improves if these conditions are abolished or compensated. To avoid irreproducible results, experiments must be repeated and the effect size must be calculated.ObjectivesThe aims of the study were to investigate the rate and location of misread letters within pseudowords, prove the effectiveness of compensatory reading therapy and demonstrate the reproducibility of the experimental results. The influence of reading therapy on the rate of eye movements opposite to the reading direction was investigated and causes of a poor reading performance were identified.MethodsThe rate and location of misread letters were investigated by tachystoscopic presentation of pseudowords containing between three and six letters. Presentation time, fixation time, and the time it takes to begin pronouncing the words (speech onset latency) were changed until 95% of the pseudowords were recognized correctly. On the basis of these results, the children learned a reading strategy that compensated the causes of the reading disorder. The therapy was demonstrated to be highly effective and it was shown that the results of the therapy were reproducible.ResultsIt was shown that misread letters occurred at all locations in pseudowords, regardless of the word's length. Inadequate fixation, excessively large saccadic amplitudes, reduced ability to simultaneously recognize a sequence of letters, a longer required fixation time and a longer required speech onset latency were all identified as causes of dyslexia. Each of the studies included in the meta-analysis were much more efficient than conventional therapeutic methods. The overall effect size with a value of Hedges' G = 1.72 showed that the therapy had a reproducible and stable effect.ConclusionsThe causes of dyslexia can be revealed by a dual-intervention approach consisting of a pseudoword experiment and learning a compensatory reading strategy. Reading performance improves immediately if the identified causes of dyslexia are compensated by an appropriate reading therapy.

Are RAN deficits in university students with dyslexia due to defective lexical access, impaired anchoring, or slow articulation?

The purpose of this study was to examine different hypotheses in relation to RAN deficits in dyslexia. Thirty university students with dyslexia and 32 chronological-age controls were assessed on RAN Digits and Colors as well as on two versions of RAN Letters and Objects (one with five items repeated 16 times and one with 20 items repeated four times). In addition, participants were tested on discrete letter and object naming, phonological awareness, orthographic knowledge, and speed of processing, and the RAN Letters and Objects total times were partitioned into pause times and articulation times. Results showed first that the dyslexia group was slower than the control group on all RAN tasks and the differences remained significant after controlling for discrete naming time. Second, both groups were slower in the large item set condition (20 × 4) than in the small set condition (5 × 16). Third, the dyslexia group was slower than the control group in both the pause and the articulation times. Although none of the processing skills was sufficient on its own to eliminate group differences in RAN Letters components, phonological awareness, and orthographic processing were sufficient on their own to eliminate group differences in the RAN Objects pause time. Taken together, our findings suggest that the deficits in RAN are not due to impaired anchoring, but rather due to subtle impairments in lexical access (specific to alphanumeric RAN), serial processing, and articulation.

Real-time coordination of visual and linguistic processes in novice readers

Skilled reading requires coordinating real-time visual fixations, orthographic analyses, and phonological encoding across multiple words in sentences. These procedures are well studied in experienced readers, but less is known about their status during development. To investigate how visual properties influence the origins of coordinated processing, the current study combined rapid automatized naming (RAN) with an eye-tracking paradigm and compared the timing of fixations and vocalizations in typically developing adults and 6-year-old children. Within RAN displays, sequences varied visual features of items (i.e., similar such as p-q vs. dissimilar such as p-t) and their locations in rows (i.e., row-initial vs. row-medial positions). Adults and children accessed parafoveal preview of subsequent items when fixating on current items, leading to longer latency to speak for similar items compared with dissimilar ones. Both groups also vocalized previous items while fixating on current items, leading to longer eye-voice overlap for row-medial items compared with row-initial ones. Yet, relative to adults, children exhibited exaggerated delays in latency to speak from parafoveal preview and reduced eye-voice overlap due to row transitions. Together, this suggests that coordinated processing is present at the earliest points of development but that greater inexperience increases susceptibility to momentary visual hurdles. Relationships to previous work on real-time RAN performance in dyslexic adults and children are discussed.

Nominación rápida y automática en alumnos de cuarto de Educación Primaria

En este trabajo se aplicó una prueba de nominación a 25 alumnos disléxicos y 25 lectores normales de 4º de Educación Primaria. La prueba incluye elementos alfanuméricos, elementos de un mismo campo semántico, familiares y no familiares, y elemento de distintas categorías. Se encontró que los disléxicos son más lentos y más inexactos en la nominación de los diferentes elementos, siendo los estímulos menos frecuentes y los pertenecientes a campos semánticos diferenes donde se observan mayores diferencias. Estos resultados coinciden con los encontrados en otros estudios.