Cognitive and magnetic resonance volumetric abnormalities in new-onset pediatric epilepsy

Language function in childhood idiopathic epilepsy syndromes

PURPOSE

To examine the impact of diverse syndromes of focal and generalized epilepsy on language function in children with new and recent onset epilepsy. Of special interest was the degree of shared language abnormality across epilepsy syndromes and the unique effects associated with specific epilepsy syndromes.

METHODS

Participants were 136 youth with new or recent-onset (diagnosis within past 12 months) epilepsy and 107 healthy first-degree cousin controls. The participants with epilepsy included 20 with Temporal Lobe Epilepsy (TLE; M age = 12.99  years, SD = 3.11), 41 with Benign Epilepsy with Centrotemporal Spikes (BECTS; M age = 10.32, SD = 1.67), 42 with Juvenile Myoclonic Epilepsy (JME; M age = 14.85, SD = 2.75) and 33 with absence epilepsy (M age = 10.55, SD = 2.76). All children were administered a comprehensive test battery which included multiple measures of language and language-dependent abilities (i.e., verbal intelligence, vocabulary, verbal reasoning, object naming, reception word recognition, word reading, spelling, lexical and semantic fluency, verbal list learning and delayed verbal memory). Test scores were adjusted for age and gender and analyzed via MANCOVA.

RESULTS

Language abnormalities were found in all epilepsy patient groups. The most broadly affected children were those with TLE and absence epilepsy, whose performance differed significantly from controls on 8 of 11 and 9 of 11 tests respectively. Although children with JME and BECTS were less affected, significant differences from controls were found on 4 of 11 tests each. While each group had a unique profile of language deficits, commonalities were apparent across both idiopathic generalized and localization-related diagnostic categories.

DISCUSSION

The localization related and generalized idiopathic childhood epilepsies examined here were associated with impact on diverse language abilities early in the course of the disorder.

The executive profile of children with Benign Epilepsy of Childhood with Centrotemporal Spikes and Temporal Lobe Epilepsy

RATIONALE

Benign Epilepsy of Childhood with Centrotemporal Spikes (BECTS) and temporal lobe epilepsy (TLE) represent two distinct models of focal epilepsy of childhood. In both, there is evidence of executive dysfunction. The purpose of the present study was to identify particular deficits in the executive function that would distinguish children with BECTS from children with TLE.

METHODS

We prospectively evaluated 19 consecutive children and adolescents with TLE with hippocampal sclerosis (HS) (57.9% male; mean 11.74years [SD 2.05]; mean IQ 95.21 [SD 15.09]), 19 with BECTS (36.8% male; mean 10.95years [SD 2.33]; mean IQ 107.40 [SD 16.01]), and 21 age and gender-matched controls (33.3% male; mean 11.86years [SD 2.25]; mean IQ 108.67 [15.05]). All participants underwent a neuropsychological assessment with a comprehensive battery for executive and attentional functions. We used ANOVA and chi-square to evaluate differences on demographic aspects among groups (BECTS, TLE-HS, and control groups). Group comparisons on continuous variables were complemented by MANOVA and Bonferroni posthoc comparisons.

RESULTS

Patients with BECTS had worse performance than controls in: Matching Familiar Figures Test, time (p=0.001); Matching Familiar Figures Test, time×errors index (p<0.001); Verbal Fluency for foods (p=0.038); Trail Making Test, part B time (p=0.030); Trail Making Test, part B number of errors (p=0.030); and WCST, number of categories achieved (p=0.043). Patients with BECTS had worse performance than patients with TLE-HS on Matching Familiar Figures Test, time (p=0.004), and Matching Familiar Figures Test, time×errors index (p<0.001). Patients with TLE-HS had worse performance than controls on the following tests: Verbal Fluency for foods (p=0.004); Wisconsin Card Sorting Test, the number of categories achieved (p<0.001); and Wisconsin Card Sorting Test, the number of perseverative errors (p=0.028). Patients with TLE-HS had worse performance than patients with BECTS on Digit Backward (p=0.002); and the Wisconsin Card Sorting Test, the number of perseverative errors (p<0.001).

CONCLUSIONS

Patients with TLE and BECTS present distinct cognitive profiles. Patients with TLE-HS had worse performance in mental flexibility, concept formation, and working memory compared to BECTS. Patients with BECTS had worse inhibitory control compared to children with TLE-HS. Both TLE-HS and BECTS had a higher number of errors on an inhibitory control test. However, patients with BECTS had a slower mental processing even when compared to patients with TLE-HS. Rehabilitation programs for children with epilepsy must include children with benign epilepsies and must take into account the epileptic syndrome and its particular neurocognitive phenotype.

Reading, listening and memory-related brain activity in children with early-stage temporal lobe epilepsy of unknown cause-an fMRI study

BACKGROUND AND AIMS

The changes in functional brain organization associated with paediatric epilepsy are largely unknown. Since children with epilepsy are at risk of developing learning difficulties even before or shortly after the onset of epilepsy, we assessed the functional organization of memory and language in paediatric patients with temporal lobe epilepsy (TLE) at an early stage in epilepsy.

METHODS

Functional magnetic resonance imaging was used to measure the blood oxygenation level-dependent (BOLD) response to four cognitive tasks measuring reading, story listening, memory encoding and retrieval in a population-based group of children with TLE of unknown cause (n = 21) and of normal intelligence and a healthy age and gender-matched control group (n = 21).

RESULTS

Significant BOLD response differences were found only in one of the four tasks. In the story listening task, significant differences were found in the right hemispheric temporal structures, thalamus and basal ganglia. Both activation and deactivation differed significantly between the groups, activation being increased and deactivation decreased in the TLE group. Furthermore, the patients with abnormal electroencephalograms (EEGs) showed significantly increased activation bilaterally in the temporal structures, basal ganglia and thalamus relative to those with normal EEGs. The patients with normal interictal EEGs had a significantly stronger deactivation than those with abnormal EEGs or the controls, the differences being located outside the temporal structures.

CONCLUSIONS

Our results suggest that TLE entails a widespread disruption of brain networks. This needs to be taken into consideration when evaluating learning abilities in patients with TLE. The thalamus seems to play an active role in TLE. The changes in deactivation may reflect neuronal inhibition.

Investigating inhibitory control in children with epilepsy: an fMRI study

OBJECTIVE

Deficits in executive function are noted increasingly in children with epilepsy and have been associated with poor academic and psychosocial outcomes. Impaired inhibitory control contributes to executive dysfunction in children with epilepsy; however, its neuroanatomic basis has not yet been investigated. We used functional magnetic resonance imaging (fMRI) to probe the integrity of activation in brain regions underlying inhibitory control in children with epilepsy.

METHODS

This cross-sectional study consisted of 34 children aged 8-17 years: 17 with well-controlled epilepsy and 17 age- and sex-matched controls. Participants performed the antisaccade (AS) task, representative of inhibitory control, during fMRI scanning. We compared AS performance during neutral and reward task conditions and evaluated task-related blood oxygen level-dependent (BOLD) activation.

RESULTS

Children with epilepsy demonstrated impaired AS performance compared to controls during both neutral (nonreward) and reward trials, but exhibited significant task improvement during reward trials. Post hoc analysis revealed that younger patients made more errors than older patients and all controls. fMRI results showed preserved activation in task-relevant regions in patients and controls, with the exception of increased activation in the left posterior cingulate gyrus in patients specifically with generalized epilepsy across neutral and reward trials.

SIGNIFICANCE

Despite impaired inhibitory control, children with epilepsy accessed typical neural pathways as did their peers without epilepsy. Children with epilepsy showed improved behavioral performance in response to the reward condition, suggesting potential benefits of the use of incentives in cognitive remediation.

ADHD in idiopathic epilepsy

Our aim was to clarify the correlation of attention deficit hyperactivity disorder (ADHD) with epilepsy and behavior problems. This was a cross-sectional study. Sixty children with idiopathic epilepsy were interviewed using the MTA-SNAP IV Teacher and Parent Rating Scale, Vineland Adaptive Behavior Scales and Conners' Rating Scales. We used the chi-square test to analyze the correlation of epilepsy variables in patients with and without ADHD with a significance level of 0.05. Eight patients had ADHD symptoms (13%), seven had the inattentive ADHD subtype and only three had behavioral problems. When epileptic patients with and without ADHD symptoms were compared we found no significant difference in regard to epilepsy variables. All patients were controlled and 43% were either without AED or undergoing withdrawal. Our study revealed a low comorbidity of ADHD symptoms and epilepsy due to low interference of seizures and drug treatment on the comorbid condition.

Regional brain volumes and cognition in childhood epilepsy: does size really matter?

PURPOSE

Recent studies have correlated neurocognitive function and regional brain volumes in children with epilepsy. We tested whether brain volume differences between children with and without epilepsy explained differences in neurocognitive function.

METHODS

The study sample included 108 individuals with uncomplicated non-syndromic epilepsy (NSE) and 36 healthy age- and gender-matched controls. Participants received a standardized cognitive battery. Whole brain T1-weighted MRI was obtained and volumes analyzed with FreeSurfer (TM).

KEY FINDINGS

Total brain volume (TBV) was significantly smaller in cases. After adjustment for TBV, cases had significantly larger regional grey matter volumes for total, frontal, parietal, and precentral cortex. Cases had poorer performance on neurocognitive indices of intelligence and variability of sustained attention. In cases, TBV showed small associations with intellectual indices of verbal and perceptual ability, working memory, and overall IQ. In controls, TBV showed medium associations with working memory and variability of sustained attention. In both groups, small associations were seen between some TBV-adjusted regional brain volumes and neurocognitive indices, but not in a consistent pattern. Brain volume differences did not account for cognitive differences between the groups.

SIGNIFICANCE

Patients with uncomplicated NSE have smaller brains than controls but areas of relative grey matter enlargement. That this relative regional enlargement occurs in the context of poorer overall neurocognitive functioning suggests that it is not adaptive. However, the lack of consistent associations between case-control differences in brain volumes and cognitive functioning suggests that brain volumes have limited explanatory value for cognitive functioning in childhood epilepsy.

Neuropsychological performance in children with temporal lobe epilepsy having normal MRI findings

BACKGROUND AND AIMS

Most information on the neuropsychological performance of pediatric patients with temporal lobe epilepsy (TLE) is derived from selected surgical series. Non-lesional pediatric TLE patients were studied here at the population level in order to investigate the extent to which neuropsychological deficits predisposing to learning difficulties exist in this more common group.

METHODS

Language, memory and executive functions were measured in children aged 8-15 years with non-lesional TLE and of normal intelligence (n = 21), and their performance was compared with that of healthy age and gender-matched children (n = 21). The effects of clinical epilepsy variables on performance were examined.

RESULTS

Although neuropsychological performance did not differ between the TLE patients and the healthy controls, female gender, early onset, longer duration and abnormal interictal EEG had a negative effect on neuropsychological performance.

CONCLUSIONS

Children with early-onset epilepsy should be assessed carefully for neuropsychological impairment using sufficiently broad batteries of tests in order to detect even slight deficits. Our sample size was small and these findings should be interpreted as preliminary results and need to be confirmed in larger studies.

Clinical and neuropsychological correlation in patients with rolandic epilepsy

OBJECTIVES

To evaluate the presence of neurological soft signs (NSS) and to correlate them with the Wechsler Intelligence Scale for Children (WISC III) in patients with rolandic epilepsy (RE).

METHODS

Forty children and adolescents aged between 9 and 15 years were studied. They were divided into two groups: G1 - patients with RE (n=20) - and G2 - healthy controls without epilepsy (n=20). They were assessed with the Quick Neurological Screening Test (QNST II) - clinical trial to search for NSS -, and the WISC III - neuropsychological test.

RESULTS

No statistical difference between groups was found in WISC III and QNST II. However, children with poorer motor skills had worse performance in the QNST II and also in the execution intelligence quotient - IQ (p=0.001) and in total IQ (p=0.004), thus showing a positive correlation between them.

CONCLUSIONS

The QNST II is a good screening tool for the neurologist to detect abnormalities in fine motor skills.

Future directions in the neuropsychology of epilepsy

Two important themes for future clinical research in the neuropsychology of epilepsy are proposed: (1) the neurobiological abnormalities that underlie neuropsychological impairment in people with epilepsy, and (2) neuropsychological status of persons with new-onset epilepsy.

Efficacy and safety of methylphenidate in treating ADHD symptoms in children and adolescents with uncontrolled seizures: a Brazilian sample study and literature review

OBJECTIVE

Attention-deficit/hyperactivity disorder (ADHD) is observed in 30% of children and adolescents with epilepsy. Recent studies have demonstrated the safety of methylphenidate (MPH) in patients with controlled epilepsy. There are few studies of patients with uncontrolled epilepsy. The goal was to study the efficacy and safety of MPH use in children and adolescents diagnosed with ADHD and uncontrolled epilepsy.

METHODS

We evaluated 24 patients ranging from 7 to 16 years of age who took MPH for 6 months. Inclusion criteria were at least two epileptic seizures in the previous 6 months and a diagnosis of ADHD based on DSM-IV criteria.

CONCLUSION

Patients were classified according to ADHD subtype as follows: 41.7% inattentive type, 37.5% combined, and 20.8% hyperactive/impulsive type; 58.3% had partial epilepsy and 41.7% generalized epilepsy. There was an overall improvement in ADHD symptoms in 70.8% of patients, and there was no increase in frequency of epileptic seizures in 22 patients (91.6%).

Attention deficit and hyperactivity disorder in people with epilepsy: diagnosis and implications to the treatment

The association between attention deficit and hyperactivity disorder (ADHD) and epilepsy can cause significant impact on the social life of affected individuals and their families. Clinical studies suggest that 30-40% of people with epilepsy also have ADHD. There are no studies which demonstrate that short or long-term treatment with methylphenidate increases the risk of seizures. Some studies attempt to relate drug interactions between methylphenidate and antiepileptic drugs, but adverse effects of methylphenidate have not been shown clearly. This review presents some neurobiological and physiopathogenic aspects, common to ADHD and epilepsy, from recent research studies, related to pharmacology, neuroimaging and electroencephalography. Possible risk of occurrence of seizures associated with the use of methylphenidate are also discussed.

Is it time to re-prioritize neuroimaging databases and digital repositories?

The development of in vivo brain imaging has lead to the collection of large quantities of digital information. In any individual research article, several tens of gigabytes-worth of data may be represented-collected across normal and patient samples. With the ease of collecting such data, there is increased desire for brain imaging datasets to be openly shared through sophisticated databases. However, very often the raw and pre-processed versions of these data are not available to researchers outside of the team that collected them. A range of neuroimaging databasing approaches has streamlined the transmission, storage, and dissemination of data from such brain imaging studies. Though early sociological and technical concerns have been addressed, they have not been ameliorated altogether for many in the field. In this article, we review the progress made in neuroimaging databases, their role in data sharing, data management, potential for the construction of brain atlases, recording data provenance, and value for re-analysis, new publication, and training. We feature the LONI IDA as an example of an archive being used as a source for brain atlas workflow construction, list several instances of other successful uses of image databases, and comment on archive sustainability. Finally, we suggest that, given these developments, now is the time for the neuroimaging community to re-prioritize large-scale databases as a valuable component of brain imaging science.

Localization of cortical dysfunction based on auditory and visual naming performance

Naming is generally considered a left-hemisphere function without precise localization. However, recent cortical stimulation studies demonstrate a modality-related anatomical dissociation, in that anterior temporal stimulation disrupts auditory description naming ("auditory naming") but not visual object naming ("visual naming"), whereas posterior temporal stimulation disrupts naming on both tasks. We hypothesized that patients with anterior temporal abnormalities would exhibit impaired auditory naming, yet normal range visual naming, whereas patients with posterior temporal abnormalities would exhibit impaired performance on both tasks. Thirty-four patients with documented anterior temporal abnormalities and 14 patients with documented posterior temporal abnormalities received both naming tests. As hypothesized, patients with anterior temporal abnormalities demonstrated impaired auditory naming, yet normal range visual naming performance. Patients with posterior temporal abnormalities were impaired in visual naming; however, auditory naming scores were intact. Although these group patterns were statistically significant, on an individual basis, auditory-visual naming asymmetries better predicted whether individual patients had anterior or posterior temporal abnormalities. These behavioral findings are generally consistent with stimulation results, suggesting that modality specificity is inherent in the organization of language, with predictable neuroanatomical correlates. Results also carry clinical implications regarding localizing dysfunction, identifying and characterizing naming deficits, and potentially, in treating neurologically based language disorders.

Executive dysfunction in children and adolescents with temporal lobe epilepsy: is the Wisconsin Card Sorting Test enough?

The Wisconsin Card Sorting Test (WCST) is the gold standard in the evaluation of executive dysfunction (ED) in patients with temporal lobe epilepsy (TLE). We evaluated 35 children with TLE and 25 healthy controls with the WCST and with a more comprehensive battery. Among the children with TLE, 77.14% showed impairment on the WCST. On other tests (Wechsler Intelligence Scale for Children-Digit Forward, Matching Familiar Figures Test, Trail Making Test, Word Fluency, Finger Windows, and Number-Letter Memory), impairment was demonstrated in 94.29%. The authors concluded that the WCST is a good paradigm to measure executive impairment in children with TLE; however, it may be not enough. Evaluation performed only with the WCST not only underestimated the number of patients with ED, but also missed relevant information regarding the type of ED.