Irene Ablinger

Improved single-letter identification after whole-word training in pure alexia

Pure alexia is characterised by a very time-consuming letter-by-letter reading strategy due to an impaired identification or integration of single letters. So far, therapy interventions have addressed impaired letter identification using specific single-letter training approaches. In the present study, we report patient KA with pure alexia and letter-by-letter reading. Contrary to common approaches, we investigated whether a whole-word reading approach can be successful despite severe impairments at the level of single-letter identification. As a first step, auditory-visual verification tasks were used to familiarise the patient with the training items, which in a second step were read with limited exposure duration. After a four week intervention, KAs word reading performance improved significantly for trained and control items in terms of speed and accuracy. Although not specifically addressed during our training programme, even single-letter identification and text reading performance increased significantly. However, the patients reading was still based on a letter-by-letter strategy.

Deep dysphasia as a phonetic input deficit: Evidence from a single case

Background: The syndrome of deep dysphasia is characterised by an inability to repeat pseudowords and the production of semantic errors in word repetition. Several single case studies revealed that phonological decoding might be outstandingly impaired. Recovery of deep dysphasia has only been illustrated in detail for patient NC (Martin & Saffran, 1992). Dell, Schwartz, Martin, Saffran, and Gagnon (1997) tried to simulate NCs repetition performance in their connectionist lexical activation model, but it did not fit his error pattern as it assumes perfect recognition of auditory input. With admiration, we dedicate this study to John Marshall who is one of the pioneers in discovering the difference between deep and surface processing of lexical information. We would like to thank Gary Dell with whom we discussed many details of the study. We also would like to thank an anonymous reviewer who helped us to revise and to extend the first version of the manuscript. Aims: In this new single case study on recovery of deep dysphasia, we intended to collect further evidence for the assumption that impaired input processing is the crucial cause of the impairment. Moreover, we aimed to explain impairment and psycholinguistic parameter effects in the connectionist semantic‐phonological model (Foygel & Dell, 2000) by adding a phonetic input level. Methods & Procedures: JRs performance was repeatedly assessed in the course of recovery. Errors in naming and repetition were classified according to the taxonomy of Dell et al. (1997). JRs error patterns were simulated in the semantic‐phonological model to determine the naming disorder and to predict word repetition. In addition, we established an error modality analysis to disentangle input and output impairments in repetition. Thus, the source of each error could be subclassified as belonging to either expressive or receptive components of repetition. Outcomes & Results: Initially there was a sharp contrast between severely impaired word and pseudoword repetition and almost unimpaired reading aloud. During recovery, performance in naming and word repetition improved a great deal, while repetition of pseudowords remained impossible. The evolvement of real word repetition was characterised by psycholinguistic parameter effects at different points in time: concreteness before length, before frequency. The connectionist model over‐predicted correct responses in word repetition as for NC. There were only few expressive repetition errors; regarding receptive errors, nonwords and null responses decreased significantly while formal errors became the dominant error type in the course of recovery. Conclusions: The development of psycholinguistic parameter effects, dissociations in performance, the computer simulations, and results from error modality analysis as well as changes of error pattern are ample evidence for the primary decoding disorder in JR. We argue that deep dysphasia can be explained by an impairment of phonetic–phonological connections in an extended version of the connectionist one‐route model of repetition with four rather than three levels of auditory word processing. The improved real word repetition despite persisting failure on pseudowords is accounted for by an increase of both phonetic–phonological and lexical–phonological connection weights.

Recovery in a letter-by-letter reader: more efficiency at the expense of normal reading strategy

Although changes in reading performance of recovering letter-by-letter readers have been described in some detail, no prior research has provided an in-depth analysis of the underlying adaptive word processing strategies. Our work examined the reading performance of a letter-by-letter reader, FH, over a period of 15 months, using eye movement methodology to delineate the recovery process at two different time points (T1, T2). A central question is whether recovery is characterized either by moving back towards normal word processing or by refinement and possibly automatization of an existing pathological strategy that was developed in response to the impairment. More specifically, we hypothesized that letter-by-letter reading may be executed with at least four different strategies and our work sought to distinguish between these alternatives. During recovery significant improvements in reading performance were achieved. A shift of fixation positions from the far left to the extreme right of target words was combined with many small and very few longer regressive saccades. Apparently, ‘letter-by-letter reading’ took the form of local clustering, most likely corresponding to the formation of sublexical units of analysis. This pattern was more pronounced at T2, suggesting that improvements in reading efficiency may come at the expense of making it harder to eventually return to normal reading.

Eye movement analyses indicate the underlying reading strategy in the recovery of lexical readers

Background: Psycholinguistic error analysis of dyslexic responses in various reading tasks provides the primary basis for clinically discriminating subtypes of pathological reading. Within this framework, phonology-related errors are indicative of a sequential word processing strategy, whereas lexical and semantic errors are associated with a lexical reading strategy. Despite the large number of published intervention studies, relatively little is known about changes in error distributions during recovery in dyslexic patients. Aims: The main purpose of the present work was to extend the scope of research on the time course of recovery in readers with acquired dyslexia, using eye tracking methodology to examine word processing in real time. The guiding hypothesis was that in lexical readers a reduction of lexical errors and an emerging predominant production of phonological errors should be associated with a change to a more segmental moment-to-moment reading behaviour. Methods & Procedures: Five patients participated in an eye movement supported reading intervention, where both lexical and segmental reading was facilitated. Reading performance was assessed before (T1) and after (T2) therapy intervention via recording of eye movements. Analyses included a novel way to examine the spatiotemporal dynamics of processing using distributions of fixation positions as different time intervals. These subdistributions reveal the gradual shifting of fixation positions during word processing, providing an adequate metric for objective classification of online reading strategies. Outcome & Results: Therapy intervention led to improved reading accuracy in all subjects. In three of five participants, analyses revealed a restructuring in the underlying reading mechanisms from predominantly lexical to more segmental word processing. In contrast, two subjects maintained their lexical reading procedures. Importantly, the fundamental assumption that a high number of phonologically based reading errors must be associated with segmental word processing routines, while the production of lexical errors is indicative of a holistic reading strategy could not be verified. Conclusions: Our results indicate that despite general improvements in reading performance, only some patients reorganised their word identification process. Contradictive data raise doubts on the validity of psycholinguistic error analysis as an exclusive indicator of changes in reading strategy. We suggest this traditional approach to combine with innovative eye tracking methodology in the interest of more comprehensive diagnostic strategies.

Treating number transcoding difficulties in a chronic aphasic patient

Background : Number transcoding comprises the ability to read and write Arabic numerals and number words. Although number transcoding and counting are frequently impaired in aphasic patients, little attention has been given to the development of specific treatment methods and the evaluation of their efficiency. We report the treatment of the chronic aphasic patient PK who had severe difficulties in reading Arabic numerals. Number words could only be produced with an automatic counting strategy, always beginning with one. Aims : The therapy study was aimed at examining whether PKs numeral transcoding abilities could be improved by an intensive remediation programme that comprised tasks in which Arabic numerals had to be transcoded into number words. Methods & Procedures : Treatment consisted of specific training blocks of gradually increasing complexity. Therapy started with reading one-digit Arabic numerals, followed by teens, decades, and two- to five-digit numerals, which were divided into different subgroups according to complexity. Outcomes & Results : After an 8-week therapy period significant improvement in the processing of one- to five-digit numbers was observed. PK was able to read 49.4% of the Arabic numerals as compared to 2.2% before treatment. Performance was influenced significantly by number length and number word structure. Transcoding abilities improved remarkably for two- and three-digit numbers containing a zero or ending with two zeros. Stability of the treatment effects was assessed in a follow-up study 6 months after termination of the treatment programme. PK was still able to read 48.3% of the Arabic numerals successfully. Conclusions : In a single-case study of patient PK, suffering from chronic severe aphasia that was also characterised by severe transcoding and calculation impairments it could be demonstrated that these transcoding problems could be remedied to a substantial degree when employing a carefully graded intensive retraining programme for Arabic number naming.

The relationship between verbal and nonverbal auditory signal processing in conduction aphasia: behavioral and anatomical evidence for common decoding mechanisms

The processing of nonverbal auditory stimuli has not yet been sufficiently investigated in patients with aphasia. On the basis of a duration discrimination task, we examined whether patients with left-sided cerebrovascular lesions were able to perceive time differences in the scale of approximately 150 ms. Further linguistic and memory-related tasks were used to characterize more exactly the relationships in the performances between auditory nonverbal task and selective linguistic or mnemonic disturbances. All examined conduction aphasics showed increased thresholds in the duration discrimination task. The low thresholds on this task were in a strong correlative relation to the reduced performances in repetition and working memory task. This was interpreted as an indication of a pronounced disturbance in integrating auditory verbal information into a long-term window (sampling disturbance) resulting in an additional load of working memory. In order to determine the lesion topography of patients with sampling disturbances, the anatomical and psychophysical data were correlated on the basis of a voxelwise statistical approach. It was found that tissue damage extending through the insula, the posterior superior temporal gyrus, and the supramarginal gyrus causes impairments in sequencing of time-sensitive information.

A combined lexical and segmental therapy approach in a participant with pure alexia

ABSTRACT Background: Pure alexia is characterized by effortful left-to-right word processing, leading to a pathological length effect during reading aloud. Results of previous therapy outcome research suggest that patients with pure alexia tend to develop and maintain an adaptive sequential reading strategy in an effort to cope with their severe deficit and at least master a slow and laborious reading mode. Aim: We applied a theory-based, strategy-driven and eye-movement-supported therapy approach on HC, a participant with pure alexia. Our intention was to help optimizing his very persistent sequential reading strategy, while concurrently facilitating fast parallel word processing. Methods & Procedures: Therapy included a systematic combination of segmental and holistic reading as well as text reading components. Exposure duration and font size were gradually reduced. Following a single case experimental reading design with follow-up testing, we assessed reading performance at four testing points focusing on analyses of linguistic errors and word viewing patterns. Outcomes & Results: With respect to reading accuracy and oculomotor measures, the combined therapy approach resulted in sustained training effects evident in significant improvements for trained and untrained word materials. Text reading intervention only led to therapy specific improvements. Spatio-temporal analyses of eye fixation positions revealed a more and more efficient adaptive strategy to compensate for reading difficulties. However, spatial changes in fixation position were less pronounced at T4, suggesting some diminishing of success at follow-up. Conclusions: Our results underscore the need for a continuous systematic training of underlying reading strategies in pure alexia to develop and sustain more economic reading procedures.