Training and transfer-of-learning effects in disabled and normal readers: evidence of specific deficits

Multiple-component remediation for developmental reading disabilities: IQ, socioeconomic status, and race as factors in remedial outcome

Results from a controlled evaluation of remedial reading interventions are reported: 279 young disabled readers were randomly assigned to a program according to a 2 × 2 × 2 factorial design (IQ, socioeconomic status [SES], and race). The effectiveness of two multiple-component intervention programs for children with reading disabilities (PHAB + RAVE-O; PHAB + WIST) was evaluated against alternate (CSS, MATH) and phonological control programs. Interventions were taught an hour daily for 70 days on a 1:4 ratio at three different sites. Multiple-component programs showed significant improvements relative to control programs on all basic reading skills after 70 hours and at 1-year follow-up. Equivalent gains were observed for different racial, SES, and IQ groups. These factors did not systematically interact with program. Differential outcomes for word identification, fluency, comprehension, and vocabulary were found between the multidimensional programs, although equivalent long-term outcomes and equal continued growth confirmed that different pathways exist to effective reading remediation.

Transfer of auditory perceptual learning with spectrally reduced speech to speech and nonspeech tasks: implications for cochlear implants

OBJECTIVE

The objective of this study was to assess whether training on speech processed with an eight-channel noise vocoder to simulate the output of a cochlear implant would produce transfer of auditory perceptual learning to the recognition of nonspeech environmental sounds, the identification of speaker gender, and the discrimination of talkers by voice.

DESIGN

Twenty-four normal-hearing subjects were trained to transcribe meaningful English sentences processed with a noise vocoder simulation of a cochlear implant. An additional 24 subjects served as an untrained control group and transcribed the same sentences in their unprocessed form. All subjects completed pre- and post-test sessions in which they transcribed vocoded sentences to provide an assessment of training efficacy. Transfer of perceptual learning was assessed using a series of closed set, nonlinguistic tasks: subjects identified talker gender, discriminated the identity of pairs of talkers, and identified ecologically significant environmental sounds from a closed set of alternatives.

RESULTS

Although both groups of subjects showed significant pre- to post-test improvements, subjects who transcribed vocoded sentences during training performed significantly better at post-test than those in the control group. Both groups performed equally well on gender identification and talker discrimination. Subjects who received explicit training on the vocoded sentences, however, performed significantly better on environmental sound identification than the untrained subjects. Moreover, across both groups, pre-test speech performance and, to a higher degree, post-test speech performance, were significantly correlated with environmental sound identification. For both groups, environmental sounds that were characterized as having more salient temporal information were identified more often than environmental sounds that were characterized as having more salient spectral information.

CONCLUSIONS

Listeners trained to identify noise-vocoded sentences showed evidence of transfer of perceptual learning to the identification of environmental sounds. In addition, the correlation between environmental sound identification and sentence transcription indicates that subjects who were better able to use the degraded acoustic information to identify the environmental sounds were also better able to transcribe the linguistic content of novel sentences. Both trained and untrained groups performed equally well ( approximately 75% correct) on the gender-identification task, indicating that training did not have an effect on the ability to identify the gender of talkers. Although better than chance, performance on the talker discrimination task was poor overall ( approximately 55%), suggesting that either explicit training is required to discriminate talkers' voices reliably or that additional information (perhaps spectral in nature) not present in the vocoded speech is required to excel in such tasks. Taken together, the results suggest that although transfer of auditory perceptual learning with spectrally degraded speech does occur, explicit task-specific training may be necessary for tasks that cannot rely on temporal information alone.

Paired associate learning in Chinese children with dyslexia

A total of 82 Chinese 11- and 12-year-olds with and without dyslexia were tested on four paired associate learning (PAL) tasks, phonological awareness, morphological awareness, rapid naming, and verbal short-term memory in three different experiments. Experiment 1 demonstrated that children with dyslexia were significantly poorer in visual-verbal PAL than nondyslexic children but that these groups did not differ in visual-visual PAL performance. In Experiment 2, children with dyslexia had more difficulties in transferring rules to new stimuli in a rule-based visual-verbal PAL task as compared with children without dyslexia. Long-term retention of PAL was not impaired in dyslexic children across either experiment. In Experiment 3, rates of visual-verbal PAL deficits among children with dyslexia were all at or above 39%, the highest among all cognitive deficits tested. Moreover, rule-based visual-verbal PAL, in addition to morphological awareness and rapid naming ability, uniquely distinguished children with and without dyslexia even with other metalinguistic skills statistically controlled. Results underscore the importance of visual-verbal PAL for understanding reading impairment in Chinese children.

Effects of alphabeticality, practice and type of instruction on reading an artificial script: An fMRI study

In neuroimaging studies of word reading in natural scripts, the effect of alphabeticality is often confounded with the effect of practice. We used an artificial script to separately manipulate the effects of practice and alphabeticality following training with and without explicit letter instructions. Participants received multi-session training in reading nonsense words, written in an artificial script, wherein each phoneme was represented by 2 discrete symbols . Three training conditions were compared: alphabetical whole words with letter decoding instruction (explicit); alphabetical whole-words (implicit) and non-alphabetical whole-words (arbitrary). Each participant was trained on the arbitrary condition and on one of the alphabetical conditions (explicit or implicit). fMRI scans were acquired after training during reading of trained words and relatively novel words in the alphabetical and arbitrary conditions. Our results showed greater activation in the explicit compared to the arbitrary conditions, but only for relatively-novel words, in the left posterior inferior frontal gyrus (IFG). In the implicit condition, the left posterior IFG was active in both trained and relatively novel words. These results indicate the involvement of the left posterior IFG in letter decoding, and suggest that reading of explicitly well-trained words did not rely on letter decoding, while in implicitly trained words letter decoding persisted into later stages. The superior parietal lobules showed reduced activation for items that received more practice, across all training conditions. Altogether, our results suggest that the alphabeticality of the word, the amount of practice and type of instructions have independent and interacting effects on brain activation during reading.

Neural changes following remediation in adult developmental dyslexia

Brain imaging studies have explored the neural mechanisms of recovery in adults following acquired disorders and, more recently, childhood developmental disorders. However, the neural systems underlying adult rehabilitation of neurobiologically based learning disabilities remain unexplored, despite their high incidence. Here we characterize the differences in brain activity during a phonological manipulation task before and after a behavioral intervention in adults with developmental dyslexia. Phonologically targeted training resulted in performance improvements in tutored compared to nontutored dyslexics, and these gains were associated with signal increases in bilateral parietal and right perisylvian cortices. Our findings demonstrate that behavioral changes in tutored dyslexic adults are associated with (1) increased activity in those left-hemisphere regions engaged by normal readers and (2) compensatory activity in the right perisylvian cortex. Hence, behavioral plasticity in adult developmental dyslexia involves two distinct neural mechanisms, each of which has previously been observed either for remediation of developmental or acquired reading disorders.

Procedural and declarative knowledge of word recognition and letter decoding in reading an artificial script

In a previous study [Cogn. Brain Res. 16 (2003) 325], we found that letter knowledge did not evolve from implicit training on whole-word recognition in an artificial Morse-like script, although the participants were adults, experienced in alphabetical reading. Here we show minimal conditions in which letter knowledge may evolve in some individuals from training on whole-word recognition. Participants received multi-session training in reading nonsense words, written in an artificial script, in which each phoneme was represented by two discrete symbols. Three training conditions were compared: alphabetical whole words with letter decoding instruction (Explicit), alphabetical whole words (Implicit), and non-alphabetical whole words (Arbitrary). Subjects were assigned to training either on the explicit and arbitrary or on the implicit and arbitrary conditions. Our results show that: (a) Letter-decoding knowledge evolved implicitly from training on alphabetical whole-word recognition, in some individuals. However, (b) a clear double dissociation was found between effectively applied implicit letter knowledge and declarative letter knowledge. (c) There was no advantage of the implicitly derived over the explicitly instructed letter knowledge. (d) Long-term retention was more effective in the explicit compared to the arbitrary condition. (e) Word-specific recognition contributed significantly to performance in all three training conditions, i.e. even under conditions that presumably afford advantage for word segmentation. Altogether, our results suggest that both declarative and procedural knowledge contributed to letter decoding as well as to word-specific recognition performance. Moreover, a greater dependency on declarative knowledge may not be an inherent characteristic of word-specific recognition, but rather that both letter decoding and word-recognition routines can become proceduralized given sufficient practice.

Alphabetical knowledge from whole words training: effects of explicit instruction and implicit experience on learning script segmentation

We investigated the possibility that pattern segmentation skills, specifically, phonological decoding, evolve implicitly in adult readers given training in an artificial script. In this Morse-like script each phoneme was represented by 2-3 discrete symbols. Subjects were trained in five consecutive sessions, on reading six nonsense words using a forced choice task that required translating symbol strings to sound patterns written in Latin letters. Three training conditions were compared within subject in terms of the time-course of learning and the ability to generalize the acquired knowledge (transfer): alphabetical whole words with letter decoding instruction (Explicit); alphabetical whole words (Implicit), and non-alphabetical whole words (Arbitrary). In separate blocks in each training session, a visual-matching task was administered using the same stimuli. Our results show: (a). that while all three training conditions were equally effective in terms of magnitude and time-course of learning accurate translation, each training condition resulted in a different type of knowledge (i.e. differential transfer). (b). Declarative knowledge of letters evolved from training on whole words only in subjects with previous experience in Explicit training. However, even with declarative knowledge of the specific letters subjects did not develop general letter segmentation skills. (c). Contrary to the robust transfer of learning gains to different stimuli within a given task, there was no significant transfer across tasks indicating that the locus of learning was task dependent. Altogether our results suggest that even given explicit letter instruction, training on word decoding may result in letter recognition rather than in alphabetic segmentation skills.

Putting struggling readers on the PHAST track: a program to integrate phonological and strategy-based remedial reading instruction and maximize outcomes

PHAST (for Phonological and Strategy Training) is a research-based remedial reading program that attempts to capitalize upon current research on reading disabilities and their remediation. The focus of the program is on the primary obstacles to word identification learning and independent decoding that most disabled readers face and the steps necessary to help these children achieve independent reading skills. A framework of phonologically based remediation was used as a foundation upon which a set of flexible and effective word identification strategies were scaffolded in an integrated developmental sequence. The program uses a combination of direct instruction and dialogue-based metacognitive training, with the pedagogical emphasis shifting from an initial direct instruction, remedial focus to increasingly metacognitive-strategy-based methods. A continuum of intervention over 70 hours provides both (a) remediation of the basic phonological awareness and letter-sound-learning deficits of disabled readers and (b) specific training of five word identification strategies that offer different approaches to the decoding of unfamiliar words and exposure to different levels of subsyllabic segmentation. Explicit instruction in the application and monitoring of multiple word identification strategies and their application to text-reading activities continues throughout the PHAST Program. PHAST training provides the disabled reader with the opportunity to become a flexible reader who approaches new words in or out of context with multiple strategies and has the ability to evaluate the success of their application. The PHAST Program was developed following the controlled evaluation of its components in laboratory classroom settings and recent positive results from their sequential combination. PHAST represents a new integrated approach to programming in this area using instructional components that have already demonstrated their efficacy with children with severe reading disabilities.

A comparison of two reading interventions for children with reading disabilities

This study compared the effectiveness of two reading interventions in a public school setting. Forty-five second-grade children with reading disabilities were randomly assigned to a 6-week phonological awareness, word analogy, or math-training program. The two reading interventions differed from each other in (a) the unit of word analysis (phoneme versus onset-rime), (b) the approach to intervention (contextualized versus decontextualized), and (c) the primary domain of reading instruction (oral versus written language). Results indicate that children in both reading programs achieved significant gains in beginning reading skills, learning the specific skills taught in their respective programs, and applying what they had learned to uninstructed material on several transfer-of-learning measures, in comparison to children in the control group. For children in both reading intervention groups, the most significant mediator of growth in oral reading fluency was a child's initial level of word identification skill. Implications of these findings are that systematic, high quality reading intervention can occur in a small group, public school setting and that there are several different paths to the remediation of children with reading disabilities.