Reduced categorical learning of faces in dyslexia.

The perception of phonological categories in dyslexia is less refined than in typically developing (TD) individuals. Traditionally, this characteristic was considered unique to phonology, yet many studies showed non-phonological perceptual difficulties. Importantly, measuring the dynamics of cortical adaptation, associated with category acquisition, revealed a broadly distributed faster decay of cortical adaptation. Taken together, these observations suggest that the acquisition of perceptual categories in dyslexia may be slower across modalities. To test this, we tested adult individuals with developmental dyslexia (IDDs) and TDs on learning of two unknown faces, yielding face-specific categorization. Initial accuracy was similar in the two groups, yet practice-induced increase in accuracy was significantly larger in TDs. Modeling the learning process (using Drift Diffusion Model) revealed that TDs' steeper learning results from a larger increase in their effective face-specific signal. We propose that IDDs' slower item-specific categorical learning of unknown faces indicates that slower categorical learning in dyslexia is a core, domain-general difficulty.

Reading problems and their connection with visual search and attention.

Attention has been hypothesized to act as a sequential gating mechanism for the orderly processing of letters and words. These same visuoattentional processes are often assumed to partake in some but not all types of visual search. In the current study, 24 dyslexic and 36 typical readers completed an attentionally demanding visual conjunction search. Visual feature search served as an internal control. It has been suggested that reading problems should go hand in hand with specific problems in visual conjunction search-particularly elevated conjunction search slopes (time per search item)-often interpreted as a problem with visual attention. Results showed that reading problems were associated with slower visual search, especially conjunction search. However, reading deficits were not associated with increased conjunction search slopes but instead with increased search intercepts, traditionally not interpreted as reflecting attention. We discuss these results in the context of hypothesized visuoattentional problems in dyslexia. Remaining open to multiple interpretations of the data, the current study demonstrates that difficulties in visual search are associated with reading problems, in accordance with growing literature on visual cognition problems in developmental dyslexia.

Variability in auditory processing performance is associated with reading difficulties rather than with history of otitis media.

The nature and cause of auditory processing deficits in dyslexic individuals have been debated for decades. Auditory processing deficits were argued to be the first step in a causal chain of difficulties, leading to difficulties in speech perception and thereby phonological processing and literacy difficulties. More recently, it has been argued that auditory processing difficulties may not be causally related to language and literacy difficulties. This study compares two groups who have phonological processing impairments for different reasons: dyslexia and a history of otitis media (OM). We compared their discrimination thresholds and response variability to chronological age- and reading age-matched controls, across three auditory processing tasks: frequency discrimination, rise-time discrimination and speech perception. Dyslexic children showed raised frequency discrimination thresholds in comparison with age-matched controls but did not differ from reading age-matched controls or individuals with a history of OM. There were no group differences on speech perception or rise-time tasks. For the dyslexic children, there was an association between phonological awareness and frequency discrimination response variability, but no association with thresholds. These findings are not consistent with a 'causal chain' explanation but could be accounted for within a multiple deficits view of literacy difficulties.

The effects of rehabilitative interventions on reading disorders caused by homonymous visual field defects: a meta-analysis focusing on improvement in reading speed.

INTRODUCTION: Reading disorders caused by homonymous visual field defects (HVFDs) have a significant impact on a patient's quality of life. However, no review has been conducted to evaluate the available evidence on the effects of rehabilitative interventions on reading disorders caused by HVFDs. Thus, the aim of this study was to systematically evaluate the effects of rehabilitative interventions on reading disorders caused by HVFDs. METHODS: We searched the MEDLINE/PubMed, Cochrane Library, ClinicalTrials.gov, CINAHL, and ScienceDirect databases for relevant articles. Relevant search terms were used to identify reports of randomized controlled trials or randomized crossover trials published between January 1990 and December 2021. Only studies that included reading-speed-related outcomes were analyzed. Risk of bias was assessed using the PEDro scale. Meta-analysis was conducted using a random-effects model, and standardized mean differences (SMD) and 95% confidence intervals (CIs) were calculated. Heterogeneity was assessed using the Ι2 statistic. RESULTS: Nine studies were included in the meta-analysis. The results showed that rehabilitative interventions significantly improved reading disorders caused by HVFDs (SMD = 0.30; 95% CI 0.08-0.51; P < 0.01; Ι2 = 0.0%). Subgroup analysis showed that reading training significantly improved reading disorders (SMD = 0.35; 95% CI 0.05-0.66; P = 0.02; Ι2 = 0.0%). CONCLUSION: Reading disorders caused by HVFDs can be improved through rehabilitation. In addition, reading training for the improvement of eye movement and fixation to compensate for foveal and parafoveal visual field defects may improve reading speed.

Executive functions underlie word reading and reading fluency in Chinese children with attention deficit/hyperactivity disorder, reading disabilities, and comorbid attention deficit/hyperactivity disorder and reading disabilities.

The current study examined the executive function (EF) deficits and their roles in reading in one hundred and four Cantonese-speaking children with typical development, reading disabilities (RD), ADHD, and comorbid ADHD and RD (ADHD + RD). Children's EF and reading skills were measured. Analysis of variance results showed that all children with disorders manifested deficits in verbal and visuospatial short-term and working memory and behavioral inhibition. Moreover, children with ADHD and ADHD + RD also exhibited deficits in inhibition (IC and BI) and cognitive flexibility. These findings demonstrated that the EF deficits in Chinese children with RD, ADHD, and ADHD + RD are similar to those in their counterparts using alphabetic languages. However, children with ADHD + RD displayed more severe deficits in visuospatial working memory compared to children with RD and ADHD, which was inconsistent with that observed in children using alphabetic languages. Regression analysis results showed that verbal short-term memory was a significant predictor for both word reading and reading fluency in children with RD and ADHD + RD. Moreover, behavioral inhibition significantly predicted reading fluency in children with ADHD. These findings also agreed with previous studies. Collectively, the results of the current study showed that the EF deficits and their roles in reading found in Chinese children with RD, ADHD, and ADHD + RD are mainly consistent with children using alphabetic languages. However, more studies are still needed to confirm these findings, especially comparing the severity of working memory among these three disorders.

Atypical function of auditory sensory gating in children with developmental dyslexia: Investigating its relationship with cognitive abilities.

Impairments of auditory processing are among frequent findings in dyslexia. However, it is unclear how auditory signals are gated from brainstem to higher central processing stages in these individuals. The present study was done to investigate auditory sensory gating in children with developmental dyslexia (DD), and to determine whether sensory gating correlates with performance on behavioural tasks. Auditory sensory gating at P50, N1 and P2 waves was evaluated in two groups including 20 children with DD and 19 children with typical reading development (TRD). Behavioural tests were used to evaluate phonological working memory (PWM) and selective attention abilities. Sensory gating in children with DD was significantly less efficient than their peers at P50, N1 and P2 waves. Lower auditory evoked potential (AEP) amplitudes were found in the DD group. The children with TRD scored better in all the behavioural tests. Relationships were reported between sensory gating at P50, N1, P2 and behavioural performance in the two groups. Children with dyslexia had deficient sensory gating in comparison with controls. In addition, children with dyslexia experienced problems with PWM and selective attention tasks. The function of sensory gating was associated with attentional and PWM performances in this group.

Associative gene networks reveal novel candidates important for ADHD and dyslexia comorbidity.

BACKGROUND: Attention deficit hyperactivity disorder (ADHD) is commonly associated with developmental dyslexia (DD), which are both prevalent and complicated pediatric neurodevelopmental disorders that have a significant influence on children's learning and development. Clinically, the comorbidity incidence of DD and ADHD is between 25 and 48%. Children with DD and ADHD may have more severe cognitive deficiencies, a poorer level of schooling, and a higher risk of social and emotional management disorders. Furthermore, patients with this comorbidity are frequently treated for a single condition in clinical settings, and the therapeutic outcome is poor. The development of effective treatment approaches against these diseases is complicated by their comorbidity features. This is often a major problem in diagnosis and treatment. In this study, we developed bioinformatical methodology for the analysis of the comorbidity of these two diseases. As such, the search for candidate genes related to the comorbid conditions of ADHD and DD can help in elucidating the molecular mechanisms underlying the comorbid condition, and can also be useful for genotyping and identifying new drug targets. RESULTS: Using the ANDSystem tool, the reconstruction and analysis of gene networks associated with ADHD and dyslexia was carried out. The gene network of ADHD included 599 genes/proteins and 148,978 interactions, while that of dyslexia included 167 genes/proteins and 27,083 interactions. When the ANDSystem and GeneCards data were combined, a total of 213 genes/proteins for ADHD and dyslexia were found. An approach for ranking genes implicated in the comorbid condition of the two diseases was proposed. The approach is based on ten criteria for ranking genes by their importance, including relevance scores of association between disease and genes, standard methods of gene prioritization, as well as original criteria that take into account the characteristics of an associative gene network and the presence of known polymorphisms in the analyzed genes. Among the top 20 genes with the highest priority DRD2, DRD4, CNTNAP2 and GRIN2B are mentioned in the literature as directly linked with the comorbidity of ADHD and dyslexia. According to the proposed approach, the genes OPRM1, CHRNA4 and SNCA had the highest priority in the development of comorbidity of these two diseases. Additionally, it was revealed that the most relevant genes are involved in biological processes related to signal transduction, positive regulation of transcription from RNA polymerase II promoters, chemical synaptic transmission, response to drugs, ion transmembrane transport, nervous system development, cell adhesion, and neuron migration. CONCLUSIONS: The application of methods of reconstruction and analysis of gene networks is a powerful tool for studying the molecular mechanisms of comorbid conditions. The method put forth to rank genes by their importance for the comorbid condition of ADHD and dyslexia was employed to predict genes that play key roles in the development of the comorbid condition. The results can be utilized to plan experiments for the identification of novel candidate genes and search for novel pharmacological targets.

What are the cognitive-linguistic profiles and subtypes of Chinese adolescents with dyslexia?

While research has identified multiple deficits that may lead to dyslexia, the profiles of adolescents with dyslexia and dyslexia subtypes are yet fully understood. This study examined the profiles of Chinese adolescents with dyslexia and identified dyslexia subtypes. Adolescents from grades 7 to 9 (n = 184, 92 with dyslexia) were evaluated on morphological skills, visual-orthographic knowledge, rapid naming, working memory, word reading, word spelling, reading fluency and reading comprehension. The results revealed that adolescents with dyslexia performed less well on the cognitive-linguistic and literacy measures than typically developing adolescents. A logistic regression analysis also showed that morphological skills, visual-orthographic knowledge and rapid naming were significantly predictive of dyslexia status. Using cluster analysis and guided by the multiple deficit hypothesis, this study identified four dyslexia subtypes: morphological deficit, visual-orthographic knowledge deficit, rapid naming deficit and global deficit showing multiple cognitive-linguistic and literacy problems. Understanding the profiles and subtypes of dyslexia could enable educational psychologists and educators to select appropriate assessment measures and develop intervention strategies to support the learning of Chinese adolescents with dyslexia.

Properties of white matter tract diffusivity in children with developmental dyslexia and comorbid attention deficit/hyperactivity disorder.

BACKGROUND: Developmental dyslexia (DD) and attention deficit/hyperactivity disorder (ADHD) are highly comorbid neurodevelopmental disorders. Individuals with DD or ADHD have both been shown to have deficits in white matter tracts associated with reading and attentional control networks. However, white matter diffusivity in individuals comorbid with both DD and ADHD (DD + ADHD) has not been specifically explored. METHODS: Participants were 3rd and 4th graders (age range = 7 to 11 years; SD = 0.69) from three diagnostic groups ((DD (n = 40), DD + ADHD (n = 22), and typical developing (TD) (n = 20)). Behavioral measures of reading and attention alongside measures of white matter diffusivity were collected for all participants. RESULTS: DD + ADHD and TD groups differed in mean fractional anisotropy (FA) for the left and right Superior Longitudinal Fasciculus (SLF)-Parietal Terminations and SLF-Temporal Terminations. Mean FA for the DD group across these SLF tracts fell between the lower DD + ADHD and higher TD averages. No differences in mean diffusivity nor significant brain-behavior relations were found. CONCLUSIONS: Findings suggest that WM diffusivity in the SLF increases along a continuum across DD + ADHD, DD, and TD.

The Role of Choline in Neurodevelopmental Disorders-A Narrative Review Focusing on ASC, ADHD and Dyslexia.

Neurodevelopmental disorders appear to be rising in prevalence, according to the recent Global Burden of Disease Study. This rise is likely to be multi-factorial, but the role of certain nutrients known to facilitate neurodevelopment should be considered. One possible contributing factor could be attributed to deficits in choline intake, particularly during key stages of neurodevelopment, which includes the first 1000 days of life and childhood. Choline, a key micronutrient, is crucial for optimal neurodevelopment and brain functioning of offspring. The present narrative review discusses the main research, describing the effect of choline in neurodevelopmental disorders, to better understand its role in the etiology and management of these disorders. In terms of findings, low choline intakes and reduced or altered choline status have been reported in relevant population subgroups: pregnancy (in utero), children with autism spectrum disorders, people with attention deficit hyperactivity disorder and those with dyslexia. In conclusion, an optimal choline provision may offer some neuronal protection in early life and help to mitigate some cognitive effects in later life attributed to neurodevelopmental conditions. Research indicates that choline may act as a modifiable risk factor for certain neurodevelopmental conditions. Ongoing research is needed to unravel the mechanisms and explanations.

Heterogeneity of short-term memory deficits in children with dyslexia.

Many studies have highlighted short-term memory (STM) impairment in dyslexic individuals. Several studies showed deficits for both item and serial order aspects of verbal STM in dyslexic individuals. These group-based studies, however, do not inform us about the prevalence of these deficits and, importantly, their potential heterogeneity at the individual level. The present study examined both group-level and individual STM profiles in dyslexic and age-matched non-dyslexic children. While confirming previous group-based results of both item and serial order STM deficits, individual analyses indicated two distinct profiles: one profile was associated with verbal item STM and phonological impairment while another profile showed selective serial STM deficits in both verbal and visual domains. Our results highlight the need for practitioners to consider the heterogeneous nature of STM impairment in dyslexia and to adapt STM and reading treatment strategies accordingly.

Does reading anxiety impact on academic achievement in higher education students?

Poor readers have lower academic achievement and increased anxiety, including reading anxiety, which may perpetuate lower academic achievement. We explored reading anxiety in university students, investigating whether the association between reading ability and academic achievement is mediated by reading anxiety (independent of general anxiety). Participants were students (n = 169, 69% female, age = 20.70) at an Australian university who completed an online reading assessment (decoding skills, phonological awareness, orthographical knowledge and comprehension), and a survey examining reading anxiety, trait anxiety and self-reported reading history. Academic achievement was based on university grades. Two reading anxiety factors (social and non-social) were identified; both factors were distinct from trait anxiety. Reading ability was negatively correlated with reading anxiety and positively correlated with academic achievement. Reading anxiety was not correlated with academic achievement and it did not mediate the relationship between reading ability and academic achievement as expected. As this was the first study to explore reading anxiety in adults, further research is required to determine the impact reading anxiety may have on university students beyond academic achievement.

The cumulative effect of socioeconomic status and dyslexia on linguistic, cognitive and reading skills among Arabic-speaking children.

Research has shown that children with dyslexia and children with a low socioeconomic status (SES) fall behind in terms of literacy acquisition, but a question remains regarding the cumulative effect of dyslexia and SES on linguistic, cognitive and reading skills. To examine the impact of cognition and environment on literacy development, we returned to the data set of 1,441 elementary school children (223 dyslexic readers and 1,241 typical readers) from low and medium-high SES backgrounds within Palestinian society in Israel who had participated in the development study of a comprehensive battery of tests in oral and written Arabic. The findings of this retrospective study reveal that, across grade levels, dyslexic readers from a low SES background showed similar performance to those from a medium-high SES background on most linguistic, cognitive and reading measures. As for typical readers, SES contributed to individual differences in all linguistic, cognitive and reading indices, with the exception of RAN. Finally, a cumulative effect of dyslexia and SES was found in relation to morphology, vocabulary, listening comprehension and text-reading accuracy.

Word-centred neglect dyslexia as an inhibitional deficit: A single case study.

Word-centred neglect dyslexia is most commonly characterised as consequence of visuospatial neglect rather than an independent condition. However, recent research has suggested that this deficit may be dissociable from spatial attentional biases. This study aims to provide preliminary evidence investigating alternative mechanisms which could account for cases of word-centred neglect dyslexia which cannot be explained by visuospatial neglect. Patient EF is a chronic stroke survivor who presented with clear right-lateralised word-centred neglect dyslexia in conjunction with severe left egocentric neglect and left hemianopia following a right PCA stroke. The severity of EF's neglect dyslexia was not found to be affected by factors which modulate the severity of visuospatial neglect. EF demonstrated an intact ability to identify all letters in words, but reliably committed neglect dyslexia errors when subsequently reading the same words as a whole. EF did not exhibit neglect dyslexic impairment in standardised spelling, word-meaning matching, and word-picture matching tasks. Critically, EF exhibited marked cognitive inhibition impairment and committed neglect dyslexia errors which were characterised by misreading less familiar target words as more familiar responses. This behavioural pattern cannot be clearly accounted for by theories which characterize word-centred neglect dyslexia as a consequence of neglect. Instead, this data suggests that this case of word-centred neglect dyslexia may be related to a deficit of cognitive inhibition. Overall, these novel findings call for reevaluation of the dominant model of word-centred neglect dyslexia.

Can We Train Multisensory Integration in Adults? A Systematic Review.

The ability to efficiently combine information from different senses is an important perceptual process that underpins much of our daily activities. This process, known as multisensory integration, varies from individual to individual, and is affected by the ageing process, with impaired processing associated with age-related conditions, including balance difficulties, mild cognitive impairment and cognitive decline. Impaired multisensory perception has also been associated with a range of neurodevelopmental conditions, where novel intervention approaches are actively sought, for example dyslexia and autism. However, it remains unclear to what extent and how multisensory perception can be modified by training. This systematic review aims to evaluate the evidence that we can train multisensory perception in neurotypical adults. In all, 1521 studies were identified following a systematic search of the databases PubMed, Scopus, PsychInfo and Web of Science. Following screening for inclusion and exclusion criteria, 27 studies were chosen for inclusion. Study quality was assessed using the Methodological Index for Non-Randomised Studies (MINORS) tool and the Cochrane Risk of Bias tool 2.0 for Randomised Control Trials. We found considerable evidence that in-task feedback training using psychophysics protocols led to improved task performance. The generalisability of this training to other tasks of multisensory integration was inconclusive, with few studies and mixed findings reported. Promising findings from exercise-based training indicate physical activity protocols warrant further investigation as potential training avenues for improving multisensory integration. Future research directions should include trialling training protocols with clinical populations and other groups who would benefit from targeted training to improve inefficient multisensory integration.

[The impact of ADHD on reading]. / El impacto del TDAH sobre la lectura.

Beyond the frequent coexistence of attention deficit hyperactivity disorder (ADHD) and reading disorder (dyslexia), the present review aims to examine the available empirical evidence on how ADHD negatively impacts on learning to read. Existing data suggest that the presence of the disorder (especially inattention symptoms), may affect i) the correct acquisition of reading, either directly or through its influence on the precursors to reading; ii) decoding skills themselves (reading accuracy and fluency), both directly and indirectly through its influence on cognitive processes such as distractibility or executive functions; and iii) reading comprehension, probably indirectly through the executive and verbal memory difficulties characteristic of ADHD. These findings have important implications for better characterizing and intervening on reading difficulties in ADHD, whether clinical or subclinical.

Más allá de la frecuente coexistencia del trastorno por déficit de atención con hiperactividad (TDAH) y el trastorno específico del aprendizaje de la lectura, la presente revisión pretende examinar la evidencia empírica disponible sobre cómo el TDAH impacta negativamente sobre el aprendizaje de la lectura. Los datos existentes apuntan a que la presencia del trastorno (especialmente los síntomas de falta de atención), puede afectar a i) la correcta adquisición de lectura, ya sea de manera directa o a través de su influencia sobre los precursores de la lectura; ii) las propias habilidades de decodificación (precisión y fluidez lectora), tanto de manera directa como indirecta a través de su influencia sobre procesos cognitivos como la distracción o las funciones ejecutivas; y ii) la comprensión lectora, probablemente de manera indirecta por las dificultades ejecutivas y en la memoria de trabajo verbal características del TDAH. Estas conclusiones presentan importantes implicaciones para caracterizar e intervenir mejor sobre las dificultades lectoras en el TDAH, ya sean clínicas o subclínicas.

Speech therapy and hyperbaric oxygen for aphasia after carbon monoxide intoxication.

Acute carbon monoxide (CO) intoxication may result in delayed neurological sequelae, which can include amnesia, ataxia, aphasia, emotional lability, disorientation, dysphagia, and other manifestations. A 27-year-old man reported symptoms of aphasia with agraphia and alexia in a review after CO intoxication. The patient received outpatient speech therapy, as well as repeated sessions of hyperbaric oxygen for 15 days, interspersing speech therapy with hyperbaric oxygen therapy for two months. After this period of combined treatment the aphasic symptomatology remitted, and oral and written language was normal. The complete disappearance of aphasia with agraphia and alexia confirms the efficacy of the combined intervention. More data from large clinical studies are needed to assess the outcomes of hyperbaric oxygen treatment in patients with delayed neurological sequelae after CO intoxication, but this case suggests it may be a good therapeutic option in combination with specific speech therapy.

Diagnostic survey of dyslexia and accompanying behavioral indicators in primary school students in Saudi Arabia.

BACKGROUND: Although dyslexia is the most common learning disorder in children, it has not received adequate attention in Saudi Arabia. AIMS: This study aimed at determining the prevalence of dyslexia among Saudi students in Grades 3-6, exploring associations between severity of dyslexia, its behavioral indicators, gender and grade, and the moderating role of grade in the relationship between severity and behavioral indicators. METHODS AND PROCEDURES: The sample consisted of 2848 female students and 2647 male students in Zulfi governorate, Saudi Arabia. A survey-based mixed-methods design was chosen including a structured interview with teachers and three assessments using the Diagnostic Assessment Scale for Dyslexia, the Arabic Reading Test, and the Dyslexia Behavioral Indicators Scale. OUTCOMES AND RESULTS: Dyslexia was assessed in 5.86 % of the total sample. It was twice as prevalent among male students as among female students (6.54 % and 3.83 %, respectively). The mean score for behavioral indicators of dyslexia was also significantly higher for male than for female students. The correlation between dyslexia severity and behavioral indicators score was high and significant, with grade level as a significant moderator. CONCLUSIONS AND IMPLICATIONS: We found that, for children with dyslexia in Saudi Arabia, dyslexia was twice as prevalent among male students as among female students. Early dyslexia diagnosis and intervention services are suggested to reduce the risk for reading problems.

Differences Between Semantic and Phonemic Verbal Fluency in Adolescents With Reading Disorders.

OBJECTIVES: This study aimed to examine which verbal fluency task is most useful in assessing adolescents with reading disorders (RD). METHOD: Eighty-three Hebrew-speaking adolescents (ages 12-15), 42 of them with RD, completed semantic and phonemic fluency tasks, and their scores were converted to standardized scores according to population norms. RESULTS: Scores on the semantic task were similar in the RD and the control group, unlike scores on the phonemic task, which were significantly lower in the RD group. The RD group demonstrated higher semantic than phonemic scores, unlike the control group whose standardized scores on both tasks were similar. Phonemic but not semantic fluency scores predicted spelling scores within the RD group. CONCLUSIONS: Adolescents with RD have no difficulty on a semantic fluency task, but perform below expected age-matched levels on the phonemic fluency task. To document this task-difference, practitioners must administer both fluency tasks when assessing RD.

A case of aneurysmal subarchnoid haemorrhage and superficial siderosis complicated by prospagnosia, simultagnosia and alexia without agraphia.

A 42-year-old lady presented with acute aneurysmal subarachnoid haemorrhage and developed difficulty recognising faces (prosopagnosia), inability to process visual information in busy environments (simultagnosia) and difficulty to read (alexia). She was subsequently found to have superficial siderosis on MRI.