Sentence comprehension in young adults with developmental dyslexia

Rules generalization in children with dyslexia

BACKGROUND

Rule learning (RL) is the ability to extract and generalize higher-order repetition-based structures. Children with Developmental Dyslexia (DD) often report difficulties in learning complex regularities in sequential stimuli, which might be due to the complexity of the rule to be learned. Learning high-order repetition-based rules represents a building block for the development of language skills.

AIMS

This study investigates the ability to extract and generalize simple, repetition-based visual rules (e.g., ABA) in 8-11-year-old children without (TD) and with a diagnosis of Development Dyslexia (DD) and its relationship with language and reading skills.

METHOD

Using a forced-choice paradigm, children were first exposed to a visual sequence containing a repetition-based rule (e.g., ABA) and were then asked to recognize familiar and novel rules generated by new visual elements. Standardized language and reading tests were also administered to both groups.

RESULTS

The accuracy in recognizing rules was above chance for both groups, even though DD children were less accurate than TD children, suggesting a less efficient RL mechanism in the DD group. Moreover, visual RL was positively correlated with both language and reading skills.

CONCLUSION

These results further confirm the crucial role of RL in the acquisition of linguistic skills and mastering reading abilities.

Insights from a Web-based survey into the psychosocial experiences of adults with dyslexia: Findings from a final comment question

Not seemingly measuring up to Western societies' educational and occupational expectations for success, adults with dyslexia are at risk for discrimination, humiliation, low self-esteem, low self-efficacy, depression, and anxiety. We analysed 113 responses to the final comment question that was incorporated at the end of a quantitative survey on the socioemotional experiences of adults with dyslexia. The final comment question was not intended for conveying personal experiences, yet the final comment responses were personal, in-depth, and substantive - indicators of quality recommended in survey research. Thematic analysis was used to analyse the data and develop themes. One overarching theme was yearnings for understanding and acceptance. Its associated subthemes included (1) "This stuff is torture", (2) "Thank God I'm not normal, (3) educational experience, (4) coping strategies, (5) family support, and (6) generational dyslexia. This study contributes to the small but growing body of literature on the socioemotional experiences of adults with dyslexia. Among the implications for practice, policy and research, a larger challenge at the broader society level that embraces diversity, equity, and inclusion for individuals with dyslexia is forefront.

Developing inclusive lateral layouts for students with dyslexia - Chinese reading materials as an example

BACKGROUND/AIM

Students with learning disabilities have difficulties in reading abilities; however, their IQ is no less than that of ordinary students of the same age. This study investigated and developed three articles as the author and schoolteachers developed reading materials. Article A is with a standard layout; Article B is with keywords of various font sizes, and Article C is with a related illustration.

METHODS

Data of eye movements and reading tests from thirty students wherein 15 participants have dyslexia were collected. An eye-tracking methodology was employed to assess the dyslexics' students reading patterns and behavior.

RESULTS

ANOVA analysis shows differences in reading test performance among students for Article A with usual layout [F (1, 28) = 133.16, p = 0.000], but no significant differences for the other two articles. Based on the gaze map analysis, Article C (with illustration) can improve the reading completeness of the dyslexic students (eight out of fifteen dyslexic students had completed the reading during our experiment) than Article A and Article B.

CONCLUSION

The results affirm that special layouts and narrative writing styles can improve the reading attention of students with dyslexia. This study's results and conclusions can reference future teaching materials or lesson preparation using lateral layouts for people with dyslexia.

Profiles of Poor Decoders, Poor Comprehenders, and Typically Developing Readers in Adolescents Learning English as a Second Language

This study examined (a) the identification of various reading groups across languages in Chinese (L1) adolescents learning English as a second language (ESL), in terms of their word-reading and reading comprehension skills, (b) overlap in reading group membership across languages, and (c) the performance of the various reading groups on reading-related language comprehension measures in English. The participants were 246 eighth-grade students from an English-immersion program in a middle school in China. Latent profile analysis identified three reading groups in each language: (a) a typically developing reader group with average or above-average word-reading and reading comprehension, (b) a group with poor decoding/word-reading skills and weak reading comprehension, and (c) a group with poor reading comprehension in the absence of poor decoding/word reading. The overlap in profile characteristics across languages for typically developing readers and poor decoders was high (about 68% for typically developing readers and 54% for poor decoders), whereas the overlap for being poor comprehenders in each language was moderate (about 37%). Furthermore, poor decoders in either language performed more poorly than the typically developing and poor comprehender groups on word reading in the other language, while poor comprehenders in either language performed more poorly than the typically developing and poor decoder groups on reading comprehension in the other language. The comparison of the reading groups' performance on English reading-related language comprehension measures showed that poor comprehenders and poor decoders performed worse than typically developing readers. Implications for identification and instruction of ESL children with reading difficulties are discussed.

Use of Parsing Heuristics in the Comprehension of Passive Sentences: Evidence from Dyslexia and Individual Differences

This study examined the comprehension of passive sentences in order to investigate whether individuals with dyslexia rely on parsing heuristics in language comprehension to a greater extent than non-dyslexic readers. One hundred adults (50 dyslexics and 50 controls) read active and passive sentences, and we also manipulated semantic plausibility. Eye movements were monitored, while participants read each sentence, and afterwards, participants answered a comprehension question. We also assessed verbal intelligence and working memory in all participants. Results showed dyslexia status interacted with sentence structure and plausibility, such that participants with dyslexia showed significantly more comprehension errors with passive and implausible sentence. With respect to verbal intelligence and working memory, we found that individuals with lower verbal intelligence were overall more likely to make comprehension errors, and individuals with lower working memory showed particular difficulties with passive and implausible sentences. For reading times, we found that individuals with dyslexia were overall slower readers. These findings suggest that (1) individuals with dyslexia do rely on heuristics to a greater extent than do non-dyslexic individuals, and (2) individual differences variables (e.g., verbal intelligence and working memory) are also related to the use of parsing heuristics. For the latter, lower ability individuals tended to be more consistent with heuristic processing (i.e., good-enough representations).

Comprehension and Eye Movements in the Processing of Subject- and Object-Relative Clauses: Evidence from Dyslexia and Individual Differences

In this study, we examined eye movements and comprehension in sentences containing a relative clause. To date, few studies have focused on syntactic processing in dyslexia and so one goal of the study is to contribute to this gap in the experimental literature. A second goal is to contribute to theoretical psycholinguistic debate concerning the cause and the location of the processing difficulty associated with object-relative clauses. We compared dyslexic readers (n = 50) to a group of non-dyslexic controls (n = 50). We also assessed two key individual differences variables (working memory and verbal intelligence), which have been theorised to impact reading times and comprehension of subject- and object-relative clauses. The results showed that dyslexics and controls had similar comprehension accuracy. However, reading times showed participants with dyslexia spent significantly longer reading the sentences compared to controls (i.e., a main effect of dyslexia). In general, sentence type did not interact with dyslexia status. With respect to individual differences and the theoretical debate, we found that processing difficulty between the subject and object relatives was no longer significant when individual differences in working memory were controlled. Thus, our findings support theories, which assume that working memory demands are responsible for the processing difficulty incurred by (1) individuals with dyslexia and (2) object-relative clauses as compared to subject relative clauses.

The influence of the multimedia and modality principles on the learning outcomes, satisfaction, and mental effort of college students with and without dyslexia

The purpose of this study was to examine the application of the multimedia and modality principles on cued-recall, recognition, and mental effort of college students with and without dyslexia. The study used a Multimedia (Image Present vs. Image Absent) × Modality (Narration vs. Onscreen Text) × Dyslexia (Dyslexia vs. Non-Dyslexia) 3-way factorial design with each independent variable serving as a between-subject condition. A total of N = 148 participants (73 with dyslexia and 75 without dyslexia) were recruited from five different institutions of higher education in the Southeastern United States and systematically assigned to one of four multimedia learning conditions. After assessing our data for statistical assumptions, we employed factorial Analysis of Variance (ANOVA) models on each dependent measure. Our findings show a reverse modality effect for students with dyslexia who performed better than their peers without dyslexia in Onscreen Text conditions. Although performance was better across groups and conditions when images were present, there were no significant interactions related to the multimedia condition. Similarly, there were no significant interactions related to mental effort even though learners with dyslexia exhibited high instructional efficiency in the Onscreen Text-Image Present condition while learners without dyslexia exhibited low task involvement in the Onscreen Text-Image Absent condition. Our results provide theoretical implications and important avenues for future research and practice as related to how multimedia learning influences students with dyslexia. We also suggest studies that could inform the eventual design of adaptive and personalized multimedia learning solutions for learners with dyslexia.

Profile of language abilities in a sample of adults with developmental disorders

This study investigated the profile of language abilities in a sample of high-achieving English speaking adults with developmental disorders. Ninety-seven adult participants were recruited: 49 with a dyslexia diagnosis (dyslexic group), 16 with a diagnosis of a different developmental disorder including dyspraxia, autism and SpLD (non-dyslexic developmental disorder group) and 32 with no diagnosis (non-disordered group). Dyslexic and non-dyslexic developmental disorder groups demonstrated similar impairments across measures of word reading, working memory, processing speed and oral language. Dyslexic participants showed the usual pattern of impaired phonological skills but spared non-verbal intelligence and vocabulary. There were also some suggestions of impaired structural oral language skills in this group. A data-driven clustering analysis found that diagnosis was not a reliable predictor of similarity between cases, with diagnostic categories split between data-driven clusters. Overall, the findings indicate that high-achieving adults with developmental disorders do demonstrate impairments that are likely to affect success in higher education, but that support needs should be assessed on a case-by-case basis, rather than according to diagnostic label.

Developmental Dyslexia: Where Do We Go from Here?

This editorial follows an influential review paper published in Brain Sciences in 2018 (What is Developmental Dyslexia? by John Stein). In this editorial, I present a critical look at the arguments in Stein's review, with a particular view towards "looking ahead". In looking ahead, I will focus on why dyslexia has been largely neglected by psycholinguistics and, in particular, shortfalls in knowledge about sentence processing. I will highlight some things that I think psycholinguistic methodologies can contribute to the understanding of developmental dyslexia. The editorial will then turn to address the larger research context of dyslexia. In short, investigations of dyslexia tend to be conducted across a wide range of disciplines, and by individuals with varied backgrounds, divergent views, and different goals. One argument I advance is that dyslexia has reached a point where "interdisciplinary" collaboration is essential, and in the event that that is not successful, the field would at least benefit from "adversarial collaborations". Finally, I briefly address the issue of interventions (raised by Stein) for older children and adolescents by returning to the contributions that psycholinguistics can provide to dyslexia. The crux of my argument here is that there exists a missing link in interventions, and that missing link is sentence-level language comprehension.

Syntactic ambiguity resolution in dyslexia: An examination of cognitive factors underlying eye movement differences and comprehension failures

This study examined eye movements and comprehension of temporary syntactic ambiguities in individuals with dyslexia, as few studies have focused on sentence-level comprehension in dyslexia. We tested 50 participants with dyslexia and 50 typically developing controls, in order to investigate (a) whether dyslexics have difficulty revising temporary syntactic misinterpretations and (b) underlying cognitive factors (i.e., working memory and processing speed) associated with eye movement differences and comprehension failures. In the sentence comprehension task, participants read subordinate-main structures that were either ambiguous or unambiguous, and we also manipulated the type of verb contained in the subordinate clause (i.e., reflexive or optionally transitive). Results showed a main effect of group on comprehension, in which individuals with dyslexia showed poorer comprehension than typically developing readers. In addition, participants with dyslexia showed longer total reading times on the disambiguating region of syntactically ambiguous sentences. With respect to cognitive factors, working memory was more associated with group differences than was processing speed. Conclusions focus on sentence-level syntactic processing issues in dyslexia (a previously under-researched area) and the relationship between online and offline measures of syntactic ambiguity resolution.

Independence of syntactic and phonological deficits in dyslexia: A study using the attraction error paradigm

This paper addresses the question of whether dyslexic children suffer from syntactic deficits that are independent of limitations with phonological processing. We looked at subject-verb agreement errors after sentence subjects containing a second noun (the attractor) known to be able to attract incorrect agreement (e.g., "the owner(s) of the house(s) is/are away"). In the general population, attraction errors are not straightforwardly dependent on the presence or absence of morphophonological plural markers but on their syntactic configuration. The same would be expected for dyslexic children if their syntactic problems are not phonological in nature. We also looked at the possible effect of system overload on syntactic processing by comparing auditory and written presentation of stimuli and stimuli with high and low frequency attractors. Dyslexic children produced more agreement errors than age-matched controls, but their errors were distributed in the expected manner and did not align with the presence of morphophonological number markers in the subject overall. Furthermore, there was no effect of either presentation mode or attractor frequency on the number of agreement errors. Our results confirm the existence of syntactic difficulties in dyslexia and suggest that they are not due to a phonological deficit or to verbal working memory limitations.

Identifying dyslexia risk for sport-related concussion management: Sensitivity and specificity of self-report and rapid naming

BACKGROUND

Dyslexia is the most common type of learning disability and studies have shown that student-athletes with learning disabilities sustain more concussions than their non-affected peers. However, current methods of dyslexia identification in college students are potentially invalid because they rely on students to self-report formal dyslexia diagnoses.

METHODS

To test the accuracy of self-report against two alternative methods of dyslexia screening, 94 college students completed three dyslexia symptom inventories, two rapid naming (RAN) tasks, and a standard word reading measure.

RESULTS

Reliability was acceptable for screening purposes on the inventories (α =.70, -.72), and excellent for RAN (α = .91, -.94). Specificity was acceptable (82.5%), but sensitivity was low (14.3%) when students self-reported suspected diagnoses of reading impairment. Sensitivity and specificity were higher for the digit RAN task (71 and 98%, respectively) compared to the letter RAN task (57 and 90%). Sensitivity (92.7%) and specificity (92.5%) were optimal when a cut-score of ≥27 seconds was used. A binary logistic regression showed digit RAN alone significantly predicted whether students were classified as typical or inefficient readers, p< .001, whereas the most reliable dyslexia inventory alone did not, p=.284. Including inventories along with RAN provided no additional predictive value.

CONCLUSION

Self-report inventories missed many cases of inefficient word reading. The digit RAN task classified 93.6% of the cases correctly compared to 72.3% for self-report inventory. Thus, we recommend that neuropsychologists working with college concussion management programs add to their baseline screening protocols the digit RAN task, which can be completed in less than one minute.

Prevalence of Developmental Dyslexia in Spanish University Students

A recent concern in the field of dyslexia studies is the lack of awareness and attention to university students suffering from this condition. If this problem is serious in countries where the relative opacity of the writing system allows for an early detection and, therefore, effective interventions, it is most critical in countries where transparent spelling makes such detection difficult, except in the most severe cases. In Spain, the diagnosis of dyslexia is rare among university-level adults. The present study pursues three aims: (a) to put forward a screening instrument for the detection of university students at risk of dyslexia, (b) to determine the ratio of university students that could be at risk of dyslexia by means of two different procedures, and (c) to create awareness for a disorder that causes hitherto unrecognized difficulties for an important subgroup of the college population. Six hundred and eighty-six university students in four different fields of study within the general area of Social Sciences from a public University in Madrid completed a Spanish-adapted version of a protocol including stress assignment, spelling words and nonwords, and timed phonological working memory of reading and writing task. Results showed that between 1.6% and 6.4% of this population could be at risk of suffering dyslexia. Such risk is not evenly distributed across the four fields of study. As for gender, the first criterion used yields 1.8 males at risk for every female, but the second criterion has as many males as females at risk. Women were significantly better than men in word spelling. Spelling was best predicted by the timed phonological working memory task of reading and writing.

Spoken sentence production in college students with dyslexia: working memory and vocabulary effects

BACKGROUND

Individuals with dyslexia demonstrate syntactic difficulties on tasks of language comprehension, yet little is known about spoken language production in this population.

AIMS

To investigate whether spoken sentence production in college students with dyslexia is less proficient than in typical readers, and to determine whether group differences can be attributable to cognitive differences between groups.

METHODS & PROCEDURES

Fifty-one college students with and without dyslexia were asked to produce sentences from stimuli comprising a verb and two nouns. Verb types varied in argument structure and morphological form and nouns varied in animacy. Outcome measures were precision (measured by fluency, grammaticality and completeness) and efficiency (measured by response times). Vocabulary and working memory tests were also administered and used as predictors of sentence production performance.

OUTCOMES & RESULTS

Relative to non-dyslexic peers, students with dyslexia responded significantly slower and produced sentences that were significantly less precise in terms of fluency, grammaticality and completeness. The primary predictors of precision and efficiency were working memory, which differed between groups, and vocabulary, which did not.

CONCLUSIONS & IMPLICATIONS

College students with dyslexia were significantly less facile and flexible on this spoken sentence-production task than typical readers, which is consistent with previous studies of school-age children with dyslexia. Group differences in performance were traced primarily to limited working memory, and were somewhat mitigated by strong vocabulary.

Interrelations between cognitive dysfunction and motor symptoms of Parkinson's disease: behavioral and neural studies

Parkinson's disease (PD) is characterized by a range of motor symptoms. Besides the cardinal symptoms (tremor, bradykinesia/akinesia, and rigidity), PD patients also show other motor deficits, including gait disturbance, speech deficits, and impaired handwriting. However, along with these key motor symptoms, PD patients also experience cognitive deficits in attention, executive function, working memory, and learning. Recent evidence suggests that these motor and cognitive deficits of PD are not completely dissociable, as aspects of cognitive dysfunction can impact motor performance in PD. In this article, we provide a review of behavioral and neural studies on the associations between motor symptoms and cognitive deficits in PD, specifically akinesia/bradykinesia, tremor, gait, handwriting, precision grip, and speech production. This review paves the way for providing a framework for understanding how treatment of cognitive dysfunction, for example cognitive rehabilitation programs, may in turn influence the motor symptoms of PD.

Identifying Dyslexia Risk in Student-Athletes: A Preliminary Protocol for Concussion Management

Learning disability (LD) has been identified as a potential risk factor for a sport-related concussion, yet students with LD are rarely included in concussion research. Here, we draw special attention to dyslexia, a common but often underdiagnosed LD. Reading and learning problems commonly associated with dyslexia are often masked by protective factors, such as high verbal ability or general intelligence. Hence, high-achieving individuals with dyslexia may not be identified as being in a high-risk category. To ensure that students with dyslexia are included in LD concussion research and identified as LD in baseline testing, we provide athletic trainers with an overview of dyslexia and a preliminary screening protocol that is sensitive to dyslexia, even among academically high-achieving students in secondary school and college.

A Review about Functional Illiteracy: Definition, Cognitive, Linguistic, and Numerical Aspects

Formally, availability of education for children has increased around the world over the last decades. However, despite having a successful formal education career, adults can become functional illiterates. Functional illiteracy means that a person cannot use reading, writing, and calculation skills for his/her own and the community's development. Functional illiteracy has considerable negative effects not only on personal development, but also in economic and social terms. Although functional illiteracy has been highly publicized in mass media in the recent years, there is limited scientific knowledge about the people termed functional illiterates; definition, assessment, and differential diagnoses with respect to related numerical and linguistic impairments are rarely studied and controversial. The first goal of our review is to give a comprehensive overview of the research on functional illiteracy by describing gaps in knowledge within the field and to outline and address the basic questions concerning who can be considered as functional illiterates: (1) Do they possess basic skills? (2) In which abilities do they have the largest deficits? (3) Are numerical and linguistic deficits related? (4) What is the fundamental reason for their difficulties? (5) Are there main differences between functional illiterates, illiterates, and dyslexics? We will see that despite partial evidence, there is still much research needed to answer these questions. Secondly, we emphasize the timeliness for a new and more precise definition that results in uniform sampling, better diagnosis, conclusion, and intervention. We propose the following working definition as the result of the review: functional illiteracy is the incapability to understand complex texts despite adequate schooling, age, language skills, elementary reading skills, and IQ. These inabilities must also not be fully explained by sensory, domain-general cognitive, neurological or mental disorders. In sum, we suggest that functional illiteracy must be more thoroughly understood and assessed from a theoretical, empirical, and diagnostic perspective.

Executive Function and Ambiguous Sentence Comprehension

PURPOSE

Sentence comprehension is a critical skill in today's literate society. Recent evidence suggests that processing and comprehending language taps cognitive as well as linguistic abilities, a finding that has critical import for clinicians who have clients with language disorders. To promote awareness of the impact of cognition, especially executive function (EF) and working memory (WM), this opinion article presents current views of how sentences are processed and links the various steps of the process to specific EF and WM subcomponents.

METHOD

The article focuses on ambiguous sentences, pointing out the similar types of processing needed when resolving an ambiguity and performing EF tasks.

RESULTS

We discuss the potential overlap between the neurobiology of sentence processing and EF and the evidence supporting a link between EF and sentence processes.

CONCLUSION

Awareness of the potential role of EF and WM in sentence comprehension will help clinicians be more aware of potential cognitive-linguistic deficits in their clients. Future research will help to clarify the link between EF and sentence comprehension.

Vocabulary skills are well developed in university students with dyslexia: Evidence from multiple case studies

Most studies in adults with developmental dyslexia have focused on identifying the deficits responsible for their persistent reading difficulties, but little is known on how these readers manage the intensive exposure to written language required to obtain a university degree. The main objective of this study was to identify certain skills, and specifically vocabulary skills, that French university students with dyslexia have developed and that may contribute to their literacy skills. We tested 20 university students with dyslexia and 20 normal readers (matched on chronological age, gender, nonverbal IQ, and level of education) in reading, phonological, vocabulary breadth (number of known words), and vocabulary depth (accuracy and precision) tasks. In comparing vocabulary measures, we used both Rasch model and single case study methodologies. Results on reading and phonological tasks confirmed the persistence of deficits in written word recognition and phonological skills. However, using the Rasch model we found that the two groups performed at the same level in the vocabulary breadth task, whereas dyslexics systematically outperformed their chronological age controls in the vocabulary depth task. These results are supplemented by multiple case studies. The vocabulary skills of French university students with dyslexia are well developed. Possible interpretations of these results are discussed.

Investigating graph comprehension in students with dyslexia: an eye tracking study

The purpose of this study was to examine graph comprehension in college students with developmental dyslexia. We investigated how graph types (line, vertical bar, and horizontal bar graphs), graphic patterns (single and double graphic patterns), and question types (point locating and comparison questions) differentially affect graph comprehension of students with and without dyslexia. Groups were compared for (1) reaction times for answering comprehension questions based on graphed data and (2) eye gaze times for specific graph subregions (x-axis, y-axis, pattern, legend, question, and answer). Dyslexic readers were significantly slower in their graph comprehension than their peers with group differences becoming more robust with the increasing complexity of graphs and tasks. In addition, dyslexic readers' initial eye gaze viewing times for linguistic subregions (question and answer) and total viewing times for both linguistic (question and answer) and nonlinguistic (pattern) subregions were significantly longer than their control peers' times. In spite of using elementary-level paragraphs for comprehension and simple graph forms, young adults with dyslexia needed more time to process linguistic and nonlinguistic stimuli. These findings are discussed relative to theories proposed to address fundamental processing deficits in individuals with dyslexia.

A comparison of the language skills of ELLs and monolinguals who are poor decoders, poor comprehenders, or normal readers

The overall objective of this article is to examine how oral language abilities relate to reading profiles in English language learners (ELLs) and English as a first language (EL1) learners, and the extent of similarities and differences between ELLs and EL1s in three reading subgroups: normal readers, poor decoders, and poor comprehenders. The study included 100 ELLs and 50 EL1s in Grade 5. The effect of language group (ELL/EL1) and reading group on cognitive and linguistic skills was examined. Except for vocabulary, there was no language group effect on any measure. However, within ELL and EL1 alike, significant differences were found between reading groups: Normal readers outperformed the two other groups on all the oral language measures. Distinct cognitive and linguistic profiles were associated with poor decoders and poor comprehenders, regardless of language group. The ELL and EL1 poor decoders outperformed the poor comprehenders on listening comprehension and inferencing. The poor decoders displayed phonological-based weaknesses, whereas the poor comprehenders displayed a more generalized language processing weakness that is nonphonological in nature. Regardless of language status, students with poor decoding or comprehension problems display difficulties with various aspects of language.

High-level language production in Parkinson's disease: a review

This paper discusses impairments of high-level, complex language production in Parkinson's disease (PD), defined as sentence and discourse production, and situates these impairments within the framework of current psycholinguistic theories of language production. The paper comprises three major sections, an overview of the effects of PD on the brain and cognition, a review of the literature on language production in PD, and a discussion of the stages of the language production process that are impaired in PD. Overall, the literature converges on a few common characteristics of language production in PD: reduced information content, impaired grammaticality, disrupted fluency, and reduced syntactic complexity. Many studies also document the strong impact of differences in cognitive ability on language production. Based on the data, PD affects all stages of language production including conceptualization and functional and positional processing. Furthermore, impairments at all stages appear to be exacerbated by impairments in cognitive abilities.