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171. Is working memory capacity diminished in students with low academic achievement?
Society Proceedings / Clinical Neurophysiology 119 (2008) e99–e164
software to process the electro-oculographic data was obtained to calculate the saccadic peak velocity, amplitude, latency, and deviation. The electro-oculographic data obtained using the same tests and equipment of five healthy subjects and five severe SCA2 patients, was processed using the algorithm developed to identify the set and unset of saccades. The results for healthy and SCA2 patients were compared with other two algorithms and the medical criteria by means of an ANOVA on repeated measurements. The software with the algorithm developed is being used to process the electro-oculographic data in saccadic studies, with more than 150 study cases processed up to date, to determine significant quantitative variables and its statistic behavior, used as quantitative markers in the diagnose and evolution of the disease. The algorithm has a better performance in the identification of set and unset points of saccades, as compared to other methods, specially in the processing of the severe SCA2 patients, with saccades deeply affected by the disease in terms of shape, slope and noise. The software calculates the most significant parameters of the identified saccades, being very useful in electro-oculographic saccadic tests for diagnose and evolution of SCA2 patients. doi:10.1016/j.clinph.2008.04.185
170. Does spatiotemporal synchronization of EEG change prior to absence seizures?—A. Aarabi, F. Wallois, R. Grebe (Francia) We aimed to characterize the synchrony between cortical regions and detect cerebral epileptic states in scalp EEG recordings recorded prior and during typical absence seizures. We applied linear and nonlinear synchronization measures to characterize the synchrony between cortical regions and detect cerebral epileptic states in scalp EEG recordings recorded prior and during typical absence seizures. An overall rapid increase in the synchronization level between different cerebral regions was observed during the ictal state. During the interictal state, the degree of interdependence between EEG channels was significantly less than that observed in the ictal state (p < 0.05). In 63% of the 35 seizures analyzed, a preictal state was identified by a significant decrease in the synchronization level with respect to the interictal state. However, in 31% of the seizures, the synchronization level in the preictal state was higher than that of the interictal state. In the remaining 6% of the seizures, no significant changes were found in the synchronization values in the interictal state prior to the seizures onset. In all the seizures analyzed, the interchannel synchrony persisted in the postictal state with synchronization level significantly higher than that observed in the interictal state. This study supports the hypothesis of having a focal susceptibility of the cerebral cortex prior to absence seizures and further underlines that this susceptibility is reproducible and patient-specific. doi:10.1016/j.clinph.2008.04.186
171. Is working memory capacity diminished in students with low academic achievement?—D.M. Aguirre Pe´rez, G.A. Otero Ojeda, F.B. Pliego Rivero, A.A. Ferreyra Martı´nez, H.H. Manjarrez Dolores (Mexico)
e141
Our objective was to identify biological and behavioural components which could determine differences between students who show a high and low school performance. Taking into account the results obtained in the National Examination to Access Pre-University Stage Education 21 students, 15–17 years-old were divided in two groups (1) Low Academic Attainment Group (LA): 10 subjects with academic scores one standard deviation below the mean and (2) High Academic Attainment (HA) Group: 11 individuals with academic marks one standard deviation above the mean. The qEEG under the 10–20 derivation system was recorded at rest (broad band analysis) and while completing a 3-back working memory (WM) task (narrow band analysis every 0.78 Hz, from 0.78 to 18.78 Hz). A Mann–Whitney U-test was applied to establish mean differences between groups for reaction times and task execution (number of correct answers and errors) and to the qEEG analysis at rest. By a non-parametric, multivariate analysis of permutations applied to the qEEG narrow band differences between groups were assessed. LA students showed more mistakes executing the WM task and more theta and total absolute power at rest. HA showed more energy in frequencies 1.56–4.68 HZ in frontal and parietal regions suggesting more internal concentration capacity: We conclude that a diminished WM capacity is present in LA students. doi:10.1016/j.clinph.2008.04.187
172. Strong evidence of anemia in infants leading to a delay in CNS maturation—F.B. Pliego Rivero, G.A. Otero, R. Ayala, M.R. Porcayo Mercado (Mexico) Iron deficiency anaemia (IDA) knowingly leads to suboptimal psychomotor development and cognitive problems. In order to obtain direct biological evidence of CNS developmental alterations in anaemic infants a qEEG and behavioural study was performed. Twenty 3–15 months-old IDA infants were age/gender matched to another 20 non-IDA infants: all fullterm, single pregnancy products, weight at eutocic birth 2.5– 3.9 kg, and healthy in every other respect. Through a complete blood test and iron kinetics the IDA status was determined. Psychomotor development was assessed through the Sally Rogers test and qEEG performed under the 10–20 International Derivation system (during sleep, stage II). A Pearson’s correlation test was applied between haematological data vs. psychomotor and broad band EEG variables vs psychomotor and haematological values. Psychomotor data and the AP means of each frequency band were compared through ANOVAS. In IDA infants lower scores in cognition, fine motor and social/ emotional areas were found; their qEEG AP mostly showed higher delta/theta power and lower alpha energy; and most correlations between haematology and psychological variables were positive. Delta/theta correlations were negative with self-care/ gross motor items while alpha/beta AP showed positive correlations with psychomotor variables in almost all derivations. A clear association was found between EEG alterations and a low haematological/iron profile leading to a delayed psychomotor development. Essentially, a slow EEG concurs with a worsened psychomotor performance. doi:10.1016/j.clinph.2008.04.188
software to process the electro-oculographic data was obtained to calculate the saccadic peak velocity, amplitude, latency, and deviation. The electro-oculographic data obtained using the same tests and equipment of five healthy subjects and five severe SCA2 patients, was processed using the algorithm developed to identify the set and unset of saccades. The results for healthy and SCA2 patients were compared with other two algorithms and the medical criteria by means of an ANOVA on repeated measurements. The software with the algorithm developed is being used to process the electro-oculographic data in saccadic studies, with more than 150 study cases processed up to date, to determine significant quantitative variables and its statistic behavior, used as quantitative markers in the diagnose and evolution of the disease. The algorithm has a better performance in the identification of set and unset points of saccades, as compared to other methods, specially in the processing of the severe SCA2 patients, with saccades deeply affected by the disease in terms of shape, slope and noise. The software calculates the most significant parameters of the identified saccades, being very useful in electro-oculographic saccadic tests for diagnose and evolution of SCA2 patients. doi:10.1016/j.clinph.2008.04.185
170. Does spatiotemporal synchronization of EEG change prior to absence seizures?—A. Aarabi, F. Wallois, R. Grebe (Francia) We aimed to characterize the synchrony between cortical regions and detect cerebral epileptic states in scalp EEG recordings recorded prior and during typical absence seizures. We applied linear and nonlinear synchronization measures to characterize the synchrony between cortical regions and detect cerebral epileptic states in scalp EEG recordings recorded prior and during typical absence seizures. An overall rapid increase in the synchronization level between different cerebral regions was observed during the ictal state. During the interictal state, the degree of interdependence between EEG channels was significantly less than that observed in the ictal state (p < 0.05). In 63% of the 35 seizures analyzed, a preictal state was identified by a significant decrease in the synchronization level with respect to the interictal state. However, in 31% of the seizures, the synchronization level in the preictal state was higher than that of the interictal state. In the remaining 6% of the seizures, no significant changes were found in the synchronization values in the interictal state prior to the seizures onset. In all the seizures analyzed, the interchannel synchrony persisted in the postictal state with synchronization level significantly higher than that observed in the interictal state. This study supports the hypothesis of having a focal susceptibility of the cerebral cortex prior to absence seizures and further underlines that this susceptibility is reproducible and patient-specific. doi:10.1016/j.clinph.2008.04.186
171. Is working memory capacity diminished in students with low academic achievement?—D.M. Aguirre Pe´rez, G.A. Otero Ojeda, F.B. Pliego Rivero, A.A. Ferreyra Martı´nez, H.H. Manjarrez Dolores (Mexico)
e141
Our objective was to identify biological and behavioural components which could determine differences between students who show a high and low school performance. Taking into account the results obtained in the National Examination to Access Pre-University Stage Education 21 students, 15–17 years-old were divided in two groups (1) Low Academic Attainment Group (LA): 10 subjects with academic scores one standard deviation below the mean and (2) High Academic Attainment (HA) Group: 11 individuals with academic marks one standard deviation above the mean. The qEEG under the 10–20 derivation system was recorded at rest (broad band analysis) and while completing a 3-back working memory (WM) task (narrow band analysis every 0.78 Hz, from 0.78 to 18.78 Hz). A Mann–Whitney U-test was applied to establish mean differences between groups for reaction times and task execution (number of correct answers and errors) and to the qEEG analysis at rest. By a non-parametric, multivariate analysis of permutations applied to the qEEG narrow band differences between groups were assessed. LA students showed more mistakes executing the WM task and more theta and total absolute power at rest. HA showed more energy in frequencies 1.56–4.68 HZ in frontal and parietal regions suggesting more internal concentration capacity: We conclude that a diminished WM capacity is present in LA students. doi:10.1016/j.clinph.2008.04.187
172. Strong evidence of anemia in infants leading to a delay in CNS maturation—F.B. Pliego Rivero, G.A. Otero, R. Ayala, M.R. Porcayo Mercado (Mexico) Iron deficiency anaemia (IDA) knowingly leads to suboptimal psychomotor development and cognitive problems. In order to obtain direct biological evidence of CNS developmental alterations in anaemic infants a qEEG and behavioural study was performed. Twenty 3–15 months-old IDA infants were age/gender matched to another 20 non-IDA infants: all fullterm, single pregnancy products, weight at eutocic birth 2.5– 3.9 kg, and healthy in every other respect. Through a complete blood test and iron kinetics the IDA status was determined. Psychomotor development was assessed through the Sally Rogers test and qEEG performed under the 10–20 International Derivation system (during sleep, stage II). A Pearson’s correlation test was applied between haematological data vs. psychomotor and broad band EEG variables vs psychomotor and haematological values. Psychomotor data and the AP means of each frequency band were compared through ANOVAS. In IDA infants lower scores in cognition, fine motor and social/ emotional areas were found; their qEEG AP mostly showed higher delta/theta power and lower alpha energy; and most correlations between haematology and psychological variables were positive. Delta/theta correlations were negative with self-care/ gross motor items while alpha/beta AP showed positive correlations with psychomotor variables in almost all derivations. A clear association was found between EEG alterations and a low haematological/iron profile leading to a delayed psychomotor development. Essentially, a slow EEG concurs with a worsened psychomotor performance. doi:10.1016/j.clinph.2008.04.188