Executive functions in adults with developmental dyslexia

BackgroundExecutive functioning (EF) deficits are well recognized in developmental dyslexia, yet the majority of studies have concerned children rather than adults, ignored the subjective experience of the individual with dyslexia (with regard to their own EFs), and have not followed current theoretical perspectives on EFs.Aims and MethodsThe current study addressed these shortfalls by administering a self-report measure of EF (BRIEF-A; Roth, Isquith, & Gioia, 2005) and experimental tasks to IQ-matched groups of adults with and without dyslexia. The laboratory-based tasks tested the three factors constituting the framework of EF proposed by Miyake et al. (2000).ResultsIn comparison to the group without dyslexia, the participants with dyslexia self-reported more frequent EF problems in day-to-day life, with these difficulties centering on metacognitive processes (working memory, planning, task monitoring, and organization) rather than on the regulation of emotion and behaviour. The participants with dyslexia showed significant deficits in EF (inhibition, set shifting, and working memory).Conclusions and ImplicationsThe findings indicated that dyslexia-related problems have an impact on the daily experience of adults with the condition. Further, EF difficulties are present in adulthood across a range of laboratory-based measures, and, given the nature of the experimental tasks presented, extend beyond difficulties related solely to phonological processing.     

Differential neuropsychological patterns of frontal variant frontotemporal dementia and Alzheimer's disease in a study of diagnostic concordance

Although the pathological hallmarks of Alzheimer's disease (AD) and frontal variant frontotemporal dementia (fvFTD) predict different cognitive patterns, many comparative neuropsychological studies showed no difference in the expected cognitive domains. Inconsistencies in diagnostic criteria, small cohorts of patients, and neuropsychological assessment may account for such findings. Moreover, discrepancies in memory and executive dysfunctions that are expected to distinguish AD and fvFTD may reflect the basic brain organization. Adhering to a strict concordance of clinical and neuroradiological criteria, we compared many patients with AD and fvFTD using a large neuropsychological battery. One hundred and thirty-nine patients with AD (n = 89) or fvFTD (n = 50) were retrospectively considered in order to verify the diagnostic congruence of clinical and neuroradiological aspects. On this basis, 117 patients with AD (n = 77) or fvFTD (n = 40) with similar duration and severity of dementia were selected. Ninety-one healthy subjects were also controlled. Mean scores in tests for abstract reasoning, planning, set shifting, initiative, verbal fluency, immediate and episodic memory, constructive, ideomotor and orofacial praxis, selective and divided attention, visuomotor coordination, and visual perception were evaluated. Separate analyses of variance and post hoc Bonferroni tests showed that, with respect to controls, both patient groups were significantly impaired in all neuropsychological tests. Compared to fvFTD patients, AD patients were significantly impaired in episodic memory, selective attention, visual perception, visuomotor coordination, and constructive praxis, whereas no differences were found in executive, intellective, and linguistic abilities between the two patient groups. Logistic regression analyses revealed that episodic memory significantly predicted the diagnosis of AD while no executive deficit was able to predict the diagnosis of fvFTD. To conclude, memory, attention, and visuoconstructive deficits may distinguish AD with respect to fvFTD, in accordance with the severe temporo-parietal-occipital degeneration characterizing AD, but no executive impairment is consistently able to identify a relative compromise in fvFTD. Executive functions impairments possibly reflect the altered spatial–temporal integration of the frontal lobes with different brain areas, which prevents a clear-cut cognitive-brain correlation.     

From mesial temporal lobe to temporoperisylvian seizures: A quantified study of temporal lobe seizure networks

Purpose: The determination of epileptogenic structures in partial epilepsy is crucial in the context of epilepsy surgery. In this study we have quantified the “epileptogenicity” of mesial temporal lobe structures (M), lateral neocortical regions (L), and extratemporal perisylvian structures (ET) in patients with temporal lobe epilepsy (TLE), in order to classify the brain networks involved in seizure generation. Methods: Thirty‐four patients having TLE investigated by intracerebral recordings using stereotactic electroencephalography (EEG) (SEEG) were selected. Epileptogenicity of M, L, and ET structures was quantified according to the “epileptogenicity index” (EI), a new way to quantify rapid discharges at seizure onset, ranging from 0 (no epileptogenicity) to 1 (maximal epileptogenicity). Results: Automatic clustering using EI values from M, L, and ET separated patients into four classes: mesial group (max EI in M), lateral group (max EI in L), mesiolateral group (high EI in both M and L) and temporoperisylvian group (TPS) (high values in ET). The median number of highly epileptogenic structures (defined by EI >0.3) was four, a result confirming that most TLE is organized as “epileptogenic networks.” We found that the duration of epilepsy was correlated with the number of epileptogenic structures and that surgical prognosis was also related to the extent of the epileptogenicity in the brain. Conclusions: Several distinct epileptogenic networks are involved in seizure generation in TLE. Findings advocate for a progressive recruitment of epileptogenic structures in human brain with time.     

Executive functions in clinical and preclinical Alzheimer's disease

Executive functions is an umbrella term describing a wide range of higher order processes that allow the flexible modification of thought and behaviour in response to changing cognitive or environmental contexts. Impairment of executive functions is common in neurodegenerative disorders such as Alzheimer's disease. These deficits negatively affect everyday activities and hamper the ability to cope with other cognitive or behavioural disorders. In this paper, we propose a synthesis of the knowledge on executive impairments in clinical and preclinical Alzheimer's disease, mostly leaning on the current studies made in this domain. We made some propositions for neuropsychological assessment of executive functions in preclinical and clinical phases of Alzheimer's disease. We hope that this overview will provide a useful insight into an area that is still insufficiently explored in the field of the neuropsychology of Alzheimer's disease.     

Executive functions,parental punishment,and aggression: Direct and moderated relations

The main focus of the current study was to assess whether executive functions (EFs) moderate the effect of parental punishment on adolescent aggression. The sample were 370 participants (53% girls, 47% boys) enrolled at secondary and higher secondary levels and ranged in age between 13–19 years (M = 15.5, SD = 1.3). Participants were assessed on a self-report measure of aggression and two punishment measures, in addition to a demographic sheet. Then, they were individually assessed on four tests taken from the Delis–Kaplan Executive Functions System (D-KEFS) namely Trial Making Test (TMT), Design Fluency Test (DFT), Color Word Interference Test (CWIT), and Card Sorting Test (CST) to assess cognitive flexibility, nonverbal fluency, inhibition, and problem-solving ability, respectively. Correlation coefficients indicated that all four executive functioning measures and the two punishment measures were significantly correlated with aggression. Moderation analysis indicated that all EFs moderated the relationship between physical punishment and aggression, and only inhibition and problem-solving ability, but not cognitive flexibility and nonverbal fluency, moderated the relations between symbolic punishment and aggression. The findings support the hypothesis that EFs are protective personal factors that promote healthy adolescent adjustment in the presence of challenging environmental factors.     

Executive functions in children with frontal and temporal lobe epilepsy.

Even though frontal lobe epilepsy (FLE) is a relatively common seizure type, no formal psychometric studies of children with FLE have been reported. We compared 12 children with FLE and 15 children with temporal lobe epilepsy (TLE) on neuropsychological tests of attention, memory, executive functioning, and adaptive functioning. The results of these tests indicated that the children with FLE had deficits in planning and executive functions, whereas their verbal and nonverbal memory was intact. The opposite pattern was observed in children with TLE. Measures of executive functioning and impulse control were the best predictors of adaptive functioning. The findings suggest that children with FLE have a pattern of cognitive deficits that differs markedly from the pattern seen in children with TLE. Children with FLE have prominent deficits in executive functioning that appear to be related to poor behavioral adaptation.     

Executive functions and updating of the contents of working memory in unipolar depression

Background: Depression is characterized by cognitive impairments, including executive dysfunctions. These executive deficits could reflect impairments of more basic executive processes, such as updating, set shifting and inhibition. While shifting and inhibition impairments are often reported, studies on depression have been somewhat obscure about specific deficits of the updating process. The main goal of that study was to assess the updating process in young in-patients with depression.

Methods: We used a verbal n-back task to assess updating process. Load and mental manipulation within working memory (WM) were incremented by using three different levels of complexity (1,2,3-back). Neuropsychological tests and an attentional task (0-back) were also administered to subjects. Twenty-two individuals meeting DSM-IV criteria for Major Unipolar Depression and 22 healthy control subjects, matched on age, verbal IQ and education, were included in the study.

Results: Subjects with depression showed significant deficits at the n-back task compared to control subjects. They were normal in tasks assessing the short-term maintenance in WM and attention. This suggests that depressed patients exhibit impairment in the updating process. Depressed patients also showed set shifting and inhibition deficits. Only the n-back task was correlated with the number of hospitalizations and the longitudinal course of the illness.

Conclusions: Our results suggest that young depressed in-patients have widespread executive dysfunctions, including updating, shifting and inhibition processes. We also found a correlation between a longitudinal measure of depression severity and an updating task performance. We suggest that using multiple executive tasks gives the opportunity to distinguish the specific influence of various executive processes on clinical dimensions in depression.     

额叶癫(癎)执行功能损害及磁共振弥散张量成像研究

目的用磁共振弥散张量成像技术研究额叶癫患者执行功能损害的相关脑区及病理改变,探讨其可能的发生机制。方法对32例成人额叶癫患者和75例正常健康对照者进行神经心理检查,并对18例常规影像无病灶的额叶癫患者和20例正常健康对照者进行弥散张量成像扫描及统计分析。结果额叶癫患者组语义流畅性明显差于对照组,数字广度测验得分和90min正确填写数字符号个数明显低于对照组。与对照组比较,额叶癫患者右侧额叶MD值明显高于对照组;右侧外囊、尾状核和双侧丘脑的FA值明显低于对照组,差异具有显著性意义。相关分析显示双侧内囊前肢、左侧外囊、左枕叶皮质下白质FA值与语义流畅性呈正相关。左侧内囊膝部、内囊后肢和丘脑MD值与MMSE呈负相关;双侧内囊前肢、左侧外囊、额叶、枕叶相应白质内FA值与MMSE呈正相关。结论DTI显示额叶癫患者右侧额叶MD值明显增高、右侧外囊、尾状核和双侧丘脑的FA值明显减低,提示额叶癫患者在上述区域可能存在细微病理改变,执行功能可能超出前额叶的范围。     

Qualitative features of semantic fluency performance in mesial and lateral frontal patients

Semantic verbal fluency is widely used in clinical and experimental studies. This task is highly sensitive to the presence of brain pathology and is frequently impaired after frontal lesions. Besides the total number of words generated, a qualitative analysis of their sequence can add valuable information about the impaired cognitive components. Thirty-four frontal patients and a group of matched controls were examined. Besides the number of words and subcategories retrieved by each group, we analysed two distinct aspects of the word sequence: the search strategy through a semantically organised store and the ability to switch from one subcategory to another. We checked whether the pattern of impairment changed according to the lesion site within the frontal lobe. Overall, patients produced fewer words than controls. However, only lateral frontal patients presented a reduced semantic relatedness between contiguously produced words and a specifically increased proportion of switches to different subcategories. The performance of lateral frontal patients was in line with the hypothesis of a search strategy impairment and cannot be attributed to a switching deficit. The performance of mesial frontal patients could be ascribed to a general deficit of activation.     

Reliability and validity of the Executive Function and Occupational Routines Scale (EFORTS)

Sustainable daily routines during childhood are important both for children and their parents. Although their affective completion requires well developed executive functions (EF), this issue has not been studied until now. The current study examined the reliability and validity of the Executive Functions and Occupational Routines Scale – EFORTS (developed in Hebrew) which measures children's executive control in their daily routines. Internal consistency and construct and convergent validity were examined by applying the EFORTS and the Behavior Rating Inventory of Executive Functions/preschool version (BRIEF/P) to 261 children (129 boys, 132 girls) between the ages 3 and 10 (mean = 6.1, SD = 1.43). The findings indicate that the EFORTS is a reliable and valid tool for examining children's executive control in three occupational daily routines, focusing specifically on metacognitive manifestations of EF. These findings suggest that the EFORTS can be a useful tool to assess children with EF deficits, and may serve targeting intervention programs toward the accomplishment of daily occupational goals.     

Executive functions recover earlier than episodic memory after microsurgical transsphenoidal resection of pituitary tumors in adult patients – a longitudinal study

Pituitary tumors may lead to cognitive dysfunction, and the most prevalent deficits are impaired memory and attention. To investigate whether memory and executive functions improve after surgical treatment we performed a prospective longitudinal study comprising 106 patients with pituitary tumors. Psychometric evaluation was performed with the d2-Letter Cancellation test, the Trail Making test, the Digit Span test and the Intelligence Structure test–Verbal Memory test at three timepoints: preoperatively, and at 3 months and 12 months after surgery. The preoperative and postoperative maximum suprasellar tumor extension and hormone status was assessed in all participants. The main finding was that concentration, working memory, and attentional speed improved significantly within the first 3 months after surgery (p < 0.05), while improvement of episodic memory was not observed until 12 months after surgery (p < 0.001). In the patients harbouring non-functioning adenomas, prolactinomas or other sellar lesions, the most important factor promoting improvement of neurocognitive function was the removal of the suprasellar tumor extension.     

Advanced clinical interpretation of the Delis-Kaplan Executive Function System: multivariate base rates of low scores

Objective: Multivariate base rates allow for the simultaneous statistical interpretation of multiple test scores, quantifying the normal frequency of low scores on a test battery. This study provides multivariate base rates for the Delis-Kaplan Executive Function System (D-KEFS). Method: The D-KEFS consists of 9 tests with 16 Total Achievement scores (i.e. primary indicators of executive function ability). Stratified by education and intelligence, multivariate base rates were derived for the full D-KEFS and an abbreviated four-test battery (i.e. Trail Making, Color-Word Interference, Verbal Fluency, and Tower Test) using the adult portion of the normative sample (ages 16–89). Results: Multivariate base rates are provided for the full and four-test D-KEFS batteries, calculated using five low score cutoffs (i.e. ≤25th, 16th, 9th, 5th, and 2nd percentiles). Low scores occurred commonly among the D-KEFS normative sample, with 82.6 and 71.8% of participants obtaining at least one score ≤16th percentile for the full and four-test batteries, respectively. Intelligence and education were inversely related to low score frequency. Conclusions: The base rates provided herein allow clinicians to interpret multiple D-KEFS scores simultaneously for the full D-KEFS and an abbreviated battery of commonly administered tests. The use of these base rates will support clinicians when differentiating between normal variations in cognitive performance and true executive function deficits.     

Prospective memory and mesial temporal epilepsy associated with hippocampal sclerosis

Episodic memory impairment is commonly observed in patients with epilepsy associated with mesial temporal sclerosis (MTS). Prospective memory (PM) is a set cognitive abilities that allow future performance of a present intention, in response to time- or event-based evocation cues, that trigger the intended action at the appropriate time. PM has not been evaluated in mesial temporal sclerosis. We evaluated the role of right and left hippocampal lesions on performance in both the retrospective and prospective PM components in patients with epilepsy secondary to mesial temporal sclerosis and correlated with performance in traditional neuropsychological tests, as well as with self-perception of memory impairment. We tested the hypotheses that a hippocampal lesion impacts on the prospective components of PM, and that a left-sided lesion had a greater impact on performance in the prospective component of PM than a right-sided lesion. We evaluated PM in 26 patients with right MTS, 22 left MTS patients, and 26 age-gender and education matched controls. The prospective component of PM was impaired in both patient groups, with both a lesion (patients performed significantly worse in the PM battery) and laterality effect (left MTS patients performed significantly worse than right MTS patients in the PM battery). Performance in the prospective component of the PM battery correlated with long-term delay performance in episodic verbal memory and self-perception of memory impairment in the left MTS group. The retrospective component was impaired in left MTS patients. Impaired performance was not accounted for solely by depression, anxiety or an antiepileptic drug effect. We conclude that mesial temporal lobe structures, including the hippocampus, play an important role in both the prospective and retrospective components of PM processes in tasks involving long delay intervals.     

Attention and executive functions profile in childhood absence epilepsy

Childhood absence epilepsy (CAE) has been associated with executive functions and attention deficits. To clarify the issue of neurocognitive impairments in CAE, we investigated whether specific executive functions and attention deficit patterns were present in a well-defined group of children with CAE who were taking valproic acid. Participants included 15 children with CAE and 15 healthy controls aged 8–15 years and matched for sex, age and IQ. We compared the performances of the two groups in the following neuropsychological domains: planning and problem solving (TOL), verbal fluency (FAS and CAT), verbal short-term memory (DSF), verbal working memory (DSB), visuospatial memory (Corsi Block Tapping Test) and sustained and divided attention (TMT-A and TMT-B). No differences were found between the two groups on measures of intellectual functioning, verbal short-term memory and visuospatial memory. By contrast, significant differences were found in total time of planning task, phonological and category fluency and sustained and divided attention. Future studies that systematically examine different aspects of attention and executive functions are needed to outline a clear and specific neuropsychological profile in CAE.     

Commentary: Executive functions and rehabilitation of the integrated self: a commentary on Ylvisaker and Feeney

This commentary is a response to Ylvisaker and Feeney's paper 'Executive functions, self-regulation and learned optimism in paediatric rehabilitation: a review and suggestions for intervention'. Drawing on a diverse literature, the authors provide a broad empirical basis for a pragmatic approach to rehabilitation for children. Their contribution is critically reviewed in terms of the validity of their central thesis and the likely impact of their proposals. Although theoretically ambiguous in places and lacking the benefit of a truly developmental framework for intervention, their proposals, nevertheless, represent a coherent heuristic framework for teachers, clinicians and parents that has corollary implications for how paediatric rehabilitation is funded.     

Executive functions and speed of mental processing in elderly patients with frontal or nonfrontal ischemic stroke

Impairments in executive functions have been related to aging and frontal lobe lesions. Aging also causes slowing of mental processing. We examined whether ischemic stroke in the frontal brain area results in dysexecutive syndrome, or whether the frontal stroke causes increased slowing of mental processing. Neurological, radiological and neuropsychological examinations were carried out 3 months post-stroke on 250 ischemic stroke patients (55-85 years) and on 39 healthy control subjects. Of the patients, 62 had frontal and 188 had nonfrontal lesions. The neuropsychological examination comprised several cognitive domains, including tests considered to measure executive functions. The frontal group was slower than the nonfrontal group in tasks measuring speed of mental processing which were time-limited (Trail Making A, Stroop dots and fluency). They were also inferior in the Digit Span backwards task. There were no differences between the groups in other cognitive domains, nor in some tests which are considered to be measures of executive functions (e.g. WCST). Impairments in executive functions were evident in both the frontal and the nonfrontal groups compared with the controls, but no dysexecutive syndrome specifically related to frontal lesions was found. Frontal stroke related mainly to the slowing of mental processing.     

Hyperactivity in boys with attention-deficit/hyperactivity disorder (ADHD): The role of executive and non-executive functions

Motor activity of boys (age 8–12 years) with (n = 19) and without (n = 18) ADHD was objectively measured with actigraphy across experimental conditions that varied with regard to demands on executive functions. Activity exhibited during two n-back (1-back, 2-back) working memory tasks was compared to activity during a choice-reaction time (CRT) task that placed relatively fewer demands on executive processes and during a simple reaction time (SRT) task that required mostly automatic processing with minimal executive demands. Results indicated that children in the ADHD group exhibited greater activity compared to children in the non-ADHD group. Further, both groups exhibited the greatest activity during conditions with high working memory demands, followed by the reaction time and control task conditions, respectively. The findings indicate that large-magnitude increases in motor activity are predominantly associated with increased demands on working memory, though demands on non-executive processes are sufficient to elicit small to moderate increases in motor activity as well.