Catarina A. Guimarães

Specific language impairment: linguistic and neurobiological aspects

Specific language impairment (SLI) occurs when children present language maturation, at least 12 months behind their chronological age in the absence of sensory or intellectual deficits, pervasive developmental disorders, evident cerebral damage, and adequate social and emotional conditions. The aim of this study was to classify a group of children according to the subtypes of SLI and to correlate clinical manifestations with cortical abnormalities. Seventeen children with SLI were evaluated. Language assessment was based on standardized test (Peabody) and a non-standardized protocol, which included phonological, syntactical, semantical, pragmatical and lexical aspects of language. All children, except one, had abnormal MRI. Thirteen children presented perisylvian polymicrogyria. The MRI findings in the remaining three patients were: right frontal polymicrogyria, bilateral fronto-parietal atrophy, and hypogenesis of corpus callosum with Chiari I. The data show that patients with posterior cortical involvement tended to present milder form of SLI (no sign of articulatory or bucofacial praxis disturbance), while diffuse polymicrogyric perisylvian cortex usually was seen in patients who presented severe clinical manifestation, mainly phonological-syntactic deficit. In conclusion, SLI may be associated with perisylvian polymicrogyria and clinical manifestation may vary according to the extent of cortical anomaly.

Temporal Lobe Epilepsy in Childhood: Comprehensive Neuropsychological Assessment

The neuropsychological features of children with temporal lobe epilepsy are not yet well defined. The aim of this study was to identify the neuropsychological deficits in children with temporal lobe epilepsy. We evaluated 25 patients and compared them with 25 normal children. All children underwent a comprehensive neuropsychological assessment. We found a significant difference in favor of the control group in the following measures: IQ; forward digit; Trail Making Test for Children B; Wisconsin Card Sorting Test; block design; Boston naming test, verbal fluency; and Wide Range Assessment of Memory and Learning verbal learning, visual learning, verbal memory, visual memory, delayed recall of verbal learning, delayed recall of stories, and recognition of stories. Our findings show that children with temporal lobe epilepsy present with several neuropsychological deficits, despite normal IQ. These findings point to a dysfunction of cerebral areas other than temporal lobe, particularly the frontal lobes.

Landau–Kleffner syndrome: Long-term follow-up

PURPOSE Landau-Kleffner syndrome (LKS) is a rare entity characterized by epilepsy and aphasia. It occurs in previously normal children, usually between three and seven years of age. The long-term outcome of LKS is not completely clear. The aim of this study is to verify the long-term follow-up of a group of patients with LKS, focusing on clinical and electroencephalographic (EEG) aspects, and quality of life. METHODS This was a transversal study. Between November 2006 and April 2007 seven patients with previous diagnosis of LKS were interviewed. They had had a follow-up of three to 16 years after their disease onset. They were all males between the ages of eight and 27 years old. All patients had normal MRI. Parents and/or patients were interviewed by one of the authors using a structured questionnaire. The Vineland Adaptive Behavior Scales, the Conners Rating Scales-Revised, and Short-Form Health Survey (SF 36) were used. Each patient had a prolonged interictal EEG recording. All patients had normal MRI. RESULTS The present investigation revealed that two patients still have seizures several years after epilepsy onset. One patient had total and three others had partial remission of language disturbance, while three patients still have aphasia and verbal auditory agnosia. With respect to quality of life, only one of our patients has a normal life at present. The remaining six patients with some sort of limitation consider the aphasia/agnosia to be the main difficulty in their lives. Five patients have normal EEGs. CONCLUSIONS The long-term follow-up of patients with LKS shows that epilepsy and EEG abnormalities do not always disappear. Language disturbances tend to persist in most patients. The age of onset of language dysfunction does not seem to correlate with the prognosis for recovery of language function. Patients with LKS have an overall poor quality of life, mostly due to language difficulties.

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.

Distribution of regional gray matter abnormalities in a pediatric population with temporal lobe epilepsy and correlation with neuropsychological performance

OBJECTIVE The goals of the work described here were to determine if hippocampal and extrahippocampal atrophy in children with temporal lobe epilepsy (TLE) follows a pattern similar to that in adult patients, and to assess the clinical and neuropsychological relevance of regional brain atrophy in pediatric TLE. METHODS Children with symptomatic TLE (n=14: 9 with mesial TLE due to hippocampal atrophy and 5 with TLE due to neocortical lesions), healthy children (n=14), and 9 adults with mesial temporal lobe epilepsy (MTLE) were compared using voxel-based morphometry (VBM) of brain magnetic resonance imaging (MRI). The children underwent a comprehensive neuropsychological battery. RESULTS Children with MTLE with unilateral hippocampal atrophy (n=9) exhibited a significant reduction in gray matter in the hippocampus ipsilateral to the seizure origin and significant atrophy in the ipsilateral cingulate gyrus and contralateral middle frontal lobe. Children with TLE (n=14) exhibited a significant reduction in the gray matter of the ipsilateral hippocampus and parahippocampal gyrus. There was a correlation between gray matter volume in children with TLE and scores on several neuropsychological tests. Atrophy in pediatric patients with MTLE was less extensive than that in adults, and involved the hippocampi and the frontal cortex. CONCLUSIONS Similar to adult MTLE, pediatric MTLE is associated with hippocampal and extrahippocampal cell loss. However, children display less intense quantifiable gray matter atrophy, which affects predominantly frontal lobe areas. There was a significant association between volume of gray matter in medial temporal and frontal regions and scores on neuropsychological tests. In childhood, TLE and the concomitant cognitive/behavior disturbances are the result of a damaged neural network.

A new candidate locus for bilateral perisylvian polymicrogyria mapped on chromosome Xq27

Polymicrogyria (PMG) is characterized by an excessive number of small and prominent brain gyri, separated by shallow sulci. Bilateral perisylvian polymicrogyria (BPP) is the most common form of PMG. Clinical signs include pseudobulbar paresis, mental retardation, and epilepsy. Familial forms of BPP have been described and a candidate locus was previously mapped to chromosome Xq28, distal do marker DXS8103. The objective of this study was to perform linkage analysis in one family segregating BPP. A total of 15 individuals, including 8 affected patients with BPP were evaluated. Family members were examined by a neurologist and subjected to magnetic resonance imaging scans. Individuals were genotyped for 18 microsatellite markers, flanking a 42.3 cM interval on ch Xq27‐q28. Two‐point and multipoint linkage analysis was performed using the LINKAGE package and haplotype reconstruction was performed by GENEHUNTER software. Our results showed a wide spectrum of clinical manifestations in affected individuals with BPP, ranging from normal to mild neurological abnormalities. Two‐point linkage analysis yield a Zmax = 2.06 at θ = 0.00 for markers DXS1205 and DXS1227. Multipoint lod‐scores indicate a candidate interval of 13 cM between markers DSXS1205 and DXS8043, on ch Xq27.2‐Xq27.3. These results point to a new locus for BPP in a more centromeric location than previously reported.

Neuropsychological assessment of children with rolandic epilepsy: Executive functions

Rolandic epilepsy (RE) is the most common type of childhood focal epilepsy. Although there is no intellectual deficit, children with RE may have specific cognitive impairments. The aims of this study were to identify changes in executive functions in children with RE and to verify the influence of epilepsy and seizure variables. We evaluated 25 children with RE and 28 healthy controls. A comprehensive neuropsychological battery was utilized. The results showed that the RE children had worse performance than the control group in some categories of the Wisconsin Card Sorting Test, the Trail Making Test part B, and the Verbal Fluency Test (FAS). Children with earlier onset of epilepsy had worse performance when compared with children with later onset of epilepsy. We conclude that children with RE may show a deficit in executive function despite their normal IQ. The set of tests was more extensive than what was previously used in other studies. Our study suggests that early seizures can interfere with brain development. Regarding cognition, the term benign should be used cautiously in RE.

Episodic and semantic memory in children with mesial temporal sclerosis

The aim of this study was to analyze semantic and episodic memory deficits in children with mesial temporal sclerosis (MTS) and their correlation with clinical epilepsy variables. For this purpose, 19 consecutive children and adolescents with MTS (8 to 16 years old) were evaluated and their performance on five episodic memory tests (short- and long-term memory and learning) and four semantic memory tests was compared with that of 28 healthy volunteers. Patients performed worse on tests of immediate and delayed verbal episodic memory, visual episodic memory, verbal and visual learning, mental scanning for semantic clues, object naming, word definition, and repetition of sentences. Clinical variables such as early age at seizure onset, severity of epilepsy, and polytherapy impaired distinct types of memory. These data confirm that children with MTS have episodic memory deficits and add new information on semantic memory. The data also demonstrate that clinical variables contribute differently to episodic and semantic memory performance.

Memory in children with temporal lobe epilepsy is at least partially explained by executive dysfunction

An association between memory and executive dysfunction (ED) has been demonstrated in patients with mixed neurological disorders. We aimed to investigate the impact of ED in memory tasks of children with temporal lobe epilepsy (TLE). We evaluated 36 children with TLE and 28 controls with tests for memory, learning, attention, mental flexibility, and mental tracking. Data analysis was composed of comparison between patients and controls in memory and executive function; correlation between memory and executive function tests; and comparison between patients with mild and severe ED in memory tests. Children with TLE had worse performance in focused attention, immediate and delayed recall, phonological memory, mental tracking, planning, and abstraction. Planning, abstraction, and mental tracking were correlated with visual and verbal memory. Children with severe ED had worse performance in verbal and visual memory and learning tests. This study showed that ED was related to memory performance in children with TLE.

Processamento temporal auditivo: relação com dislexia do desenvolvimento e malformação cortical

TEMA: processamento temporal auditivo e dislexia do desenvolvimento. OBJETIVO: caracterizar o processamento temporal auditivo em escolares com dislexia do desenvolvimento e correlacionar com malformacao cortical. METODO: foram avaliados 20 escolares, com idade entre 8 e 14 anos, divididos em grupo experimental (GE) composto por 11 escolares (oito do genero masculino) com o diagnostico de dislexia do desenvolvimento e grupo controle (GC) composto por nove escolares (seis do genero masculino) sem alteracoes neuropsicolinguisticas. Apos avaliacoes neurologica, neuropsicologica e fonoaudiologica (avaliacao de linguagem e leitura e escrita) para obtencao do diagnostico, os escolares foram submetidos a avaliacao audiologica periferica e posteriormente aplicou-se o teste Random Gap Detection Test e/ou Random Gap Detection Test Expanded. RESULTADOS: observou-se diferenca estatisticamente significante entre os escolares do GE e GC, com pior desempenho para o GE. A maioria dos escolares do GE apresentou polimicrogiria perisylviana. CONCLUSAO: escolares com dislexia do desenvolvimento podem apresentar alteracoes no processamento temporal auditivo com prejuizo no processamento fonologico. Malformacao do desenvolvimento cortical pode ser o substrato anatomico dos disturbios.BACKGROUND Temporal auditory processing and developmental dyslexia. AIM To characterize the temporal auditory processing in children with developmental dyslexia and to correlate findings with cortical malformations. METHOD Twenty school-aged children, ranging in age from 8 to 14 years were evaluated. These children were divided into two groups: the experimental group (EG) was composed by 11 children (eight were male) with developmental dyslexia and the control group (CG) was composed by nine normal children (six were male). After neurological assessment and verification of the intellectual level, language, reading and writing skills in order to determine the diagnosis, children underwent a peripheral audiological evaluation and Random Gap Detection Test and/or Random Gap Detection Test Expanded. RESULTS A statistically significant difference between children in the EG and CG were observed, with children in the EG presenting worst performances. Most of the children in the EG presented perisylvian polymicrogyria. CONCLUSION Children with developmental dyslexia may present temporal auditory processing disorders with deficits in phonological processing. Cortical malformations may be the anatomical substrate of these disorders.