Eliciting Dyslexic Symptoms in Proficient Readers by Simulating Deficits in Grapheme-to-Phoneme Conversion and Visuo-Magnocellular Processing
Among the cognitive causes of dyslexia, phonological and magnocellular deficits have attracted a substantial amount of research. Their role and their exact impact on reading ability are still a matter of debate, partly also because large samples of dyslexics are hard to recruit. Here, we report a new technique to simulate dyslexic symptoms in normal readers in two ways. Although difficulties in grapheme-to-phoneme conversion were elicited by manipulating the identifiability of written letters, visual-magnocellular processing deficits were generated by presenting letters moving dynamically on the screen. Both factors were embedded into a lexical word–pseudoword decision task with proficient German readers. Although both experimental variations systematically increased lexical decision times, they did not interact. Subjects successfully performed word–pseudoword distinctions at all levels of simulation, with consistently longer reaction times for pseudowords than for words. Interestingly, detecting a pseudoword was more difficult in the grapheme-to-phoneme conversion simulation as indicated by a significant interaction of word type and letter shape. These behavioural effects are consistent with those observed in ‘real’ dyslexics in the literature. The paradigm is thus a potential means of generating novel hypotheses about dyslexia, which can easily be tested with normal readers before screening and recruiting real dyslexics. Copyright © 2011 John Wiley & Sons, Ltd.
Skilled reading depends upon successfully integrating orthographic, phonological, and semantic information; however, the process of becoming a skilled reader with efficient neural circuitry is not fully understood. Short-term learning paradigms can provide insight into learning mechanisms by revealing differential responses to training approaches. To date, neuroimaging studies have primarily focused on effects of teaching novel words either in isolation or in context, without directly comparing the two. The current study compared the behavioral and neurobiological effects of learning novel pseudowords (i.e., pronouncing and attaching meaning) trained either in isolation or in sentential context. Behavioral results showed generally comparable pseudoword learning for both conditions, but sentential context-trained pseudowords were spoken and comprehended slightly more quickly. Neurobiologically, fMRI activity for reading trained pseudowords was similar to real words; however, an interaction between training approach and reading proficiency was observed. Specifically, highly skilled readers showed similar levels of activity regardless of training approach. However, less skilled readers differentiated between training conditions, showing comparable activity to highly skilled readers only for isolation-trained pseudowords. Overall, behavioral and neurobiological findings suggest that training approach may affect rate of learning and neural circuitry, and that less skilled readers may need explicit training to develop optimal neural pathways.
A total of 35 adults (24—77 years; 24 males and 11 females) with Asperger syndrome (AS) who were in, were waiting to get in, or had been in support groups participated in the study. In general, the adults were highly educated but unemployed or underemployed and living alone with family members as friends. The participants were interviewed, completed the Autism-Spectrum Quotient questionnaire and the UCLA Loneliness Scale, and rated group experiences. The results of qualitative and quantitative analyses can be interpreted to conclude that participants were lonely and perceived support groups as beneficial for providing (a) social skills and interaction, (b) information and advice, and (c) structure. Participants also reported that someone had encouraged them to attend a support group. This information can help practitioners gain insight into the content and structure of support groups for individuals with AS and may aid in the design of future research on services for adults with AS.
The influence of word extension and the position of speech disruption within the syllable structure in the speech of stuttering and fluent adolescents and adults
Overall, results suggest that speech disruptions occur at the beginning of words and syllables, thus indicating difficulty in synchronizing phonological selection and activation. This fact happens independently of word extension.
Documenting Changes in Adult Speakers’ Locus of Causality during Stuttering Treatment using Origin and Pawn Scaling
The concepts of locus of control and locus of causality are similar and refer to the degree to which a person perceives daily occurrences to be a consequence of his or her own behavior. Locus of control is considered to be a unidimensional construct indicating an inverse relationship between the polls of internality and externality. The locus of control is generally determined by using questionnaires with a limited number of items. Locus of causality is considered to be a two-dimensional construct where Origin and Pawn values, which are similar to internality and externality, respectively, are not necessarily inversely related. Locus of causality is determined by content analysis of freely spoken or written narratives. In the current study Origin and Pawn scores were obtained from twenty adults prior to and following a three-week intensive stuttering treatment program. Brief narratives written by the participants were analyzed to obtain Origin and Pawn values. These scores were compared with traditional measures of therapeutic outcome (Locus of Control, OASES, PSI, percentage of syllables stuttered). Results indicated statistically significant increases in pre- to post-treatment Origin scores (p = .001; Cohen’s d = 1.44) and statistically significant decreases in pre- to post-treatment Pawn scores (p = .003; Cohen’s d = 1.11). Origin and Pawn scores showed significant relationships with other measures of stuttering, indicating concurrent and construct validity. Origin and Pawn scaling procedures appear to provide a valid, sensitive, and nonreactive indicator of the speaker’s locus of causality and ability to develop an autonomous and agentic lifestyle.
Lexical content of stimulus materials impacts performance characteristics for dichotic speech recognition tasks in the normal-hearing young adult population. The use of nonsense CVC syllable material may provide a way to assess dichotic speech recognition performance while potentially lessening the effects of lexical content on performance.
High-performing adults with compensated dyslexia pose particular challenges to dyslexia diagnostics. We compared the performance of 20 multilingual Finnish university students with suspected dyslexia with 20 age-matched and education-matched controls on an extensive test battery. The battery tapped various aspects of reading, writing, word retrieval, phonological processing and other cognitive functions relevant for dyslexia. Reading and writing were examined in the two domestic languages, Swedish and Finnish. The most prominent group differences in reading and writing emerged on accuracy measures in both languages (reading text aloud, proofreading, writing to dictation, free writing). The dyslexia group also performed less well on speeded segmentation of written input, complex speeded naming and complex phoneme manipulation. The pattern of results fits the phonological deficit hypothesis of dyslexia and indicates the presence of pervasive underlying defects in compensated dyslexia.
CONCLUSION: children and adults with AIDS present alterations in audiological assessment and Auditory Brainstem Response. This suggests the involvement of peripheral and central auditory pathways. Findings of the present study emphasize the effectiveness of using electrophysiological hearing measures in order to better identify the brain injury level in patients with AIDS, besides allowing the monitoring of the development rate of the disease.
An Experimental Investigation of the Effect of Altered Auditory Feedback on the Conversational Speech of Adults Who Stutter
Conclusions: Participants’ varying responses to differing AAF settings likely accounted for the failure to find group differences between conditions. These results suggest that studies that use standard DAF and FAF settings for all participants are likely to underestimate any AAF effect. It is not yet possible to predict who will benefit from AAF devices in everyday situations and the extent of those benefits.
Perceptual organization, phonological awareness, and reading comprehension in adults with and without learning disabilities
The aim of the present study was to investigate executive functions in adults with intellectual disability, and compare them to a closely matched control group longitudinally for 5 years. In the Betula database, a group of adults with intellectual disability (ID, n = 46) was defined from measures of verbal and non-verbal IQ. A control group, with two people for every person with intellectual disability (n = 92), was chosen by matching on the following criterion in order of priority: IQ higher than 85, age, sex, sample, level of education, and years of education. Three types of tasks of executive functions were included on two occasions, with 5 years between testing sessions: The Tower of Hanoi, executively loaded dual task versions of word recall, and verbal fluency. Adults with ID showed significant impairments on verbal fluency and on the executively loaded dual task word recall task (at encoding but not at recall). There were no group differences on the Tower of Hanoi. No significant differences between the two test occasions were found. The results are interpreted in terms of individuals with ID having problems with speed of accessing lexical items and difficulties with working memory-related executive control at encoding, which includes shifting between tasks. There are, however, not necessarily problems with inhibition. The dual task results additionally imply that the adults with intellectual disability were more sensitive to strategy interruptions at encoding, but that dividing attention at recall did not have such detrimental effects.
Cognitive and affective disturbances following focal cerebellar damage in adults: A neuropsychological and SPECT study
The traditional view on cerebellar functioning has recently been challenged by results from neuroanatomical, neuroimaging and clinical studies. In this contribution, eighteen patients with primary cerebellar lesions (vascular: n=13; neoplastic: n=5) were systematically investigated by means of an extensive neuropsychological test battery. Fifteen patients (83%) presented with a broad variety of cognitive and linguistic deficits following cerebellar damage. Disturbances of attention (72%), executive functioning (50%) and memory (50%) were most commonly found. Analyses of our results tend to support the hypothesis of a lateralization of cognitive modulation within the cerebellum, the right cerebellar hemisphere being associated with logical reasoning and language processing and the left cerebellum mediating right-hemispheric functions including attentional and visuo-spatial skills. In addition, nine patients (50%) presented with frontal-like behavioural and affective alterations. In an attempt to determine the working-mechanism underlying cerebellar-induced cognitive and affective disturbances, all patients were investigated by means of quantified Tc-99m-ethylenecysteine dimer (ECD) single photon emission computerized tomography (SPECT) studies. From a semiological point of view, damage to the cerebellum can cause a broad spectrum of clinically significant cognitive and affective disturbances. From a pathophysiological point of view, quantified SPECT data, reflecting the phenomenon of cerebello-cerebral diaschisis, support the functional impact of the cerebellar lesion on cortical functioning through disruption of cerebello-cerebral connections.
Replicated evidence of satisfactory 1- and 2-year post-treatment outcomes has been reported for the Comprehensive Stuttering Program (CSP). However, little is known about longer-term outcomes of the CSP. Yearly follow-up measures were obtained from 18 participants for 5 consecutive years. At 5-years follow-up, participants were maintaining clinically and statistically significant reductions in stuttering and increases in rates of speech relative to pre-treatment measures. Standardized effect sizes were large. There were no significant differences among the immediate post-treatment and five follow-up measures, indicating that speech gains achieved by the end of the treatment program were stable over the 5-year follow-up period. Insufficient return rates for self-report data for the third to fifth follow-up measurement occasions prohibited analyzing these data. However, non-significant differences among the immediate post-treatment and two follow-up measures indicated that improvements achieved by the end of treatment in speech related confidence, and perceptions of struggle, avoidance, and expectancy to stutter were stable over the 2-year follow-up period. Significant differences among the speech related communication attitudes scores indicated that improvements in attitudes made at the end of the treatment program were less stable. Taken together, these results provide further and longer-term evidence of the effectiveness of the CSP.
Conclusions: The results suggest that SLI persists into adulthood and that effective clinical markers of this disorder are similar to those used to identify SLI in children. Refinement of these tasks to increase their likelihood ratios will improve their usefulness in diagnosing SLI in adults.