Prothrombin Time and Coagulation Factor IX as Hemostatic Risk Markers for Legg- Calvé-Perthes Disease.

BACKGROUND: Legg-Calvé-Perthes disease (LCPD) is a pediatric disorder that occurs due to the avascular necrosis of the femoral head and affects the range of motion of the hip in various degrees. Its etiology is still unknown, although it has been associated with coagulation abnormalities, however, the lack of reproducibility in the results in various studies has created a controversy as to whether hemostasis disorders are related to LCPD. On the other hand, there is little information on laboratory studies that could facilitate the diagnosis and treatment of LCPD. METHODS: Blood and plasma samples were tested from 25 patients with LCPD and 50 healthy controls, matched by sex and age. Cellular markers were evaluated through complete blood count, as well as coagulation times, coagulation factors activity, antithrombotic proteins, and homocysteine concentration. RESULTS: After assessing activity value frequencies in each group, the results showed more significant activity in some of the biological risk markers of thrombophilia, presenting a substantial difference in prothrombin time↘, FV↗, FVIII↗, FIX↗, and Hcy↗. These values imply that there may be hypercoagulable states in patients, which can cause thrombotic events. CONCLUSIONS: Diminished prothrombin time and increase in FV activity, FVIII, FIX, and Hcy concentration support the hypothesis that microthrombi formation in small-caliber vessels could be causing avascularity and femoral necrosis, which are traits of LCPD. In addition, based on our results, we believe that the laboratory studies carried out are very useful in the diagnosis and treatment of LCPD.

Neuropsychological screening with TOWI: Performance in 6- to 12-year-old children.

Videogames represent an exciting development in neuropsychological assessment of cognitive function. Here, we used TOWI, a series of games based on standardized tests, to evaluate the cognitive performance of a large sample of school-age children. We compared the metrics produced by TOWI with the performance metrics reported for the standardized tests that inspired each of these tasks. We found ascending values together with age for scores reflecting correct answers and descending values together with age for scores reflecting completion times, mistakes or missed entries. Sensitivity to developmental changes, similarities with standardized tests of task metrics contribute to the validity of TOWI as a screening tool.

Brain-Computer Interface Coupled to a Robotic Hand Orthosis for Stroke Patients' Neurorehabilitation: A Crossover Feasibility Study.

Brain-Computer Interfaces (BCI) coupled to robotic assistive devices have shown promise for the rehabilitation of stroke patients. However, little has been reported that compares the clinical and physiological effects of a BCI intervention for upper limb stroke rehabilitation with those of conventional therapy. This study assesses the feasibility of an intervention with a BCI based on electroencephalography (EEG) coupled to a robotic hand orthosis for upper limb stroke rehabilitation and compares its outcomes to conventional therapy. Seven subacute and three chronic stroke patients (M = 59.9 ± 12.8) with severe upper limb impairment were recruited in a crossover feasibility study to receive 1 month of BCI therapy and 1 month of conventional therapy in random order. The outcome measures were comprised of: Fugl-Meyer Assessment of the Upper Extremity (FMA-UE), Action Research Arm Test (ARAT), motor evoked potentials elicited by transcranial magnetic stimulation (TMS), hand dynamometry, and EEG. Additionally, BCI performance and user experience were measured. All measurements were acquired before and after each intervention. FMA-UE and ARAT after BCI (23.1 ± 16; 8.4 ± 10) and after conventional therapy (21.9 ± 15; 8.7 ± 11) were significantly higher (p < 0.017) compared to baseline (17.5 ± 15; 4.3 ± 6) but were similar between therapies (p > 0.017). Via TMS, corticospinal tract integrity could be assessed in the affected hemisphere of three patients at baseline, in five after BCI, and four after conventional therapy. While no significant difference (p > 0.05) was found in patients' affected hand strength, it was higher after the BCI therapy. EEG cortical activations were significantly higher over motor and non-motor regions after both therapies (p < 0.017). System performance increased across BCI sessions, from 54 (50, 70%) to 72% (56, 83%). Patients reported moderate mental workloads and excellent usability with the BCI. Outcome measurements implied that a BCI intervention using a robotic hand orthosis as feedback has the potential to elicit neuroplasticity-related mechanisms, similar to those observed during conventional therapy, even in a group of severely impaired stroke patients. Therefore, the proposed BCI system could be a suitable therapy option and will be further assessed in clinical trials.

Brain-computer interface performance analysis of monozygotic twins with discordant hand dominance: A case study.

Brain-computer interfaces (BCI) decode user's intentions to control external devices. However, performance variations across individuals have limited their use to laboratory environments. Handedness could contribute to these variations, especially when motor imagery (MI) tasks are used for BCI control. To further understand how handedness affects BCI control, performance differences between two monozygotic twins were analysed during offline movement and MI tasks, and while twins controlled a BCI using right-hand MI. Quantitative electroencephalography (qEEG), brain structures' volumes, and neuropsychological tests were assessed to evaluate physiological, anatomical and psychological relationships with BCI performance. Results showed that both twins had good motor imagery and attention abilities, similar volumes on most subcortical brain structures, more pronounced event-related desynchronization elicited by the twin performing non-dominant MI, and that this twin also obtained significant higher performances with the BCI. Linear regression analysis implied a strong association between twins' BCI performance, and more pronounced cortical activations in the contralateral hemisphere relative to hand MI. Therefore, it is possible that BCI performance was related with the ability of each twin to elicit cortical activations during hand MI, and less associated with subcortical brain structures' volumes and neuropsychological tests.

Longitudinal Analysis of Stroke Patients' Brain Rhythms during an Intervention with a Brain-Computer Interface.

Stroke is a leading cause of motor disability worldwide. Upper limb rehabilitation is particularly challenging since approximately 35% of patients recover significant hand function after 6 months of the stroke's onset. Therefore, new therapies, especially those based on brain-computer interfaces (BCI) and robotic assistive devices, are currently under research. Electroencephalography (EEG) acquired brain rhythms in alpha and beta bands, during motor tasks, such as motor imagery/intention (MI), could provide insight of motor-related neural plasticity occurring during a BCI intervention. Hence, a longitudinal analysis of subacute stroke patients' brain rhythms during a BCI coupled to robotic device intervention was performed in this study. Data of 9 stroke patients were acquired across 12 sessions of the BCI intervention. Alpha and beta event-related desynchronization/synchronization (ERD/ERS) trends across sessions and their association with time since stroke onset and clinical upper extremity recovery were analyzed, using correlation and linear stepwise regression, respectively. More EEG channels presented significant ERD/ERS trends across sessions related with time since stroke onset, in beta, compared to alpha. Linear models implied a moderate relationship between alpha rhythms in frontal, temporal, and parietal areas with upper limb motor recovery and suggested a strong association between beta activity in frontal, central, and parietal regions with upper limb motor recovery. Higher association of beta with both time since stroke onset and upper limb motor recovery could be explained by beta relation with closed-loop communication between the sensorimotor cortex and the paralyzed upper limb, and alpha being probably more associated with motor learning mechanisms. The association between upper limb motor recovery and beta activations reinforces the hypothesis that broader regions of the cortex activate during movement tasks as a compensatory mechanism in stroke patients with severe motor impairment. Therefore, EEG across BCI interventions could provide valuable information for prognosis and BCI cortical activity targets.

Cognitive and spectral coherence of EEG alterations in resting state in children with chronic TBI / Alteraciones cognitivas y en la coherencia espectral del EEG en estado de reposo en niños con TCE crónico

Abstract Introduction TBI is associated with alterations in cortico-subcortical connectivity. However, little attention has been paid to its clinical characteristics and functional connectivity in pediatric patients with chronic TBI. Objective To evaluate the cognitive performance and spectral coherence of a group of children with TBI in non-acute phase. Method Cross-sectional study of 15 children with chronic TBI and 17 healthy children. The Neuropsychological Assessment of Children (Evaluación Neuropsicológica Infantil, ENI) was used and the resting activity of the EEG with eyes-closed was recorded. Offline, two-second epochs of the EEG of each participant were chosen and the spectral coherence was estimated in a range of 1.6 to 30 Hz. The cognitive performance between groups was compared with T-test/Mann-Whitney U Test and MANOVA for the coherence values. Results The TBI group showed a lower performance (p ≤ 0.05) in metalinguistic, visuospatial skills, attention, memory, non-verbal flexibility, planning, and organization. Differences (p ≤ 0.000) were found both inter and intrahemispherically in the spectral coherence between the groups, particularly on F1-F3 (95% CI: 0.543 - 0.557) over the whole frequency range and F3-C3 (95% CI: 0.503 - 0.515) in delta, theta, alpha2, and beta frequencies. Discussion and conclusión Our findings suggest alterations of hypo and hyper functional connectivity, particularly on the frontal and parietal lobes of both hemispheres, even after several years of a TBI. It is possible that a subtle difference in the degree of connectivity is crucial in the genesis or successful development of attentional, mnesic, executive, and visuospatial processes.

Resumen Introducción El TCE se asocia con alteraciones en la conectividad cortico-subcortical. Sin embargo, se ha prestado poca atención a las características clínicas y de conectividad funcional en pacientes pediátricos con TCE crónico. Objetivo Evaluar el desempeño cognitivo y la coherencia espectral de un grupo de niños con TCE en fase no aguda. Método Estudio transversal de 15 niños con TCE y 17 niños controles. Se empleó la Evaluación Neuropsicológica Infantil (ENI) y se registró la actividad en reposo del EEG con ojos cerrados. Fuera de línea, se eligieron épocas de 2 s del trazo de cada participante y se estimó la coherencia espectral en un rango de 1.6 a 30 Hz. Se comparó el rendimiento cognitivo entre los grupos con la prueba T/U-Mann de Whitney y MANOVA para los valores de coherencia. Resultados El grupo con TCE mostró un menor rendimiento (p ≤ 0.05) en habilidades metalingüísticas, visuoespaciales, atención, memoria, flexibilidad no verbal, planeación y organización. Se encontraron diferencias (p ≤ 0.000) en la coherencia espectral tanto inter como intrahemisférica entre los grupos. Particularmente, en F1-F3 (95%IC: 0.543 - 0.557) en todo el rango de frecuencias y F3-C3 (95%IC: 0.503 - 0.515) en delta, theta, alfa2 y beta. Discusión y conclusión Los resultados sugieren que distintas redes en estado de reposo muestran alteraciones de hipo e hiperconectividad funcional aun después de varios años de un TCE. Es probable que una sutil diferencia en el grado de conectividad sea determinante en la génesis o desarrollo exitoso de procesos atencionales, mnésicos, ejecutivos y visoespaciales.

Correlación del funcionamiento ejecutivo y la potencia absoluta del EEG en niños / Correlation of excutive functioning and the absolute power of the EEG in children

RESUMEN: Introducción: La potencia espectral en reposo a menudo se considera como un marcador robusto de la función cerebral; sin embargo, pocos estudios la han asociado con una función específica. Objetivo: Analizar la relación entre la potencia absoluta (PA) del EEG con el desempeño en las tareas de funcionamiento ejecutivo en niños. Método: Investigación transversal correlacional en 30 niños (8.6 ± 1 años). Se realizó el EEG con ojos cerrados y análisis de derivaciones bipolares. Con la transformada de Fourier se calculó la PA en el espectro de 1.6-30 Hz. Se aplicó la batería NEUROPSI Atención y Memoria y se calculó el Indice de Atención y Funciones Ejecutivas (IAFE). En función de éste, se comparó la PA con Kruskal-Wallis y valor Z, coeficiente de Spearman para la correlación con las subpruebas. Resultados: Los niños con alteraciones severas ( x - = 63 ± 8 IC 95% [57.2, 68.5]) tuvieron mayor PA delta en F1F7, P301 y P402, así como valores Z cercanos a 2 DE en F7T3, F3C3 y F8T4 en frecuencias lentas. Las correlaciones fueron significativas (rho, p ≤ .05) entre el IAFE con la PA delta en P301 (-.57), P402 (-.43) y T5O1 (-.37); con PA alfa principalmente en zonas fronto-temporo-parieto-occipitales izquierdas. La puntuación en Detección Visual y Fluidez Semántica se relacionó con la PA alfa. Discusión y conclusión: El rendimiento en actividades de FE es diferente en relación con la PA delta frontal y parietal. Existe una relación inversa entre la PA delta y alfa en reposo con la atención y fluidez (245/250).

ABSTRACT: Introduction: The resting EEG power is considered as a robust marker of brain function; however, a few studies have associated it to a specific function. Objective: To analyze the relationship between EEG absolute power (AP) with performance on tasks of executive functioning in children. Method: Correlational cross-sectional study of 30 children (8.6 ± 1 year). EEG was performed with eyes closed and bipolar leads. With the Fourier transform AP was calculated in the spectrum of 1.6, 30 Hz. NEUROPSI Attention and Memory was applied and the Index of Attention and Executive functions (IAFE) was calculated. Based on this, the AP was compared with Kruskal-Wallis and the Z value, Spearman coefficient for correlation with the subtests. Results: Children with severe impairment ( x - = 63 ± 8 CI 95% [57.2, 68.5]) had higher delta AP (α ≤ .05) in F1F7, P301 and P402, and Z values near 2 SD in F7T3, F3C3 and F8T4 at slow frequencies. Correlations were significant between the IAFE and delta AP P301 (-.57), P402 (-.43) and T5O1 (-.37); with AP alpha mainly on left fronto- temporo - parietal- occipital areas. The score in Visual Detection and Semantic Fluency inversely related to AP alpha frequency. Discussion and conclusion: Performance on tasks of executive functioning is different in relation to the frontal and parietal AP delta. There is an inverse relationship between AP delta and alpha at rest with attention and verbal fluency.

Evolución de la potencia absoluta, relativa e índices de ritmos electroencefalográficos en estudiantes de primaria, licenciatura y maestría / Evolution of absolute and relative power and indices of electroencephalographic rhythms in elementary, college, and graduate students

Resumen: ANTECEDENTES: La función cerebral resulta de la actividad eléctrica en redes glío-neuronales, integradas de forma activa por interacciones sensoriales, motoras y reguladores. Redes que oscilan desde la infancia y se modulan por diversos factores de maduración, incluyendo procesos educativos. OBJETIVO: Identificar el espectro de potencia separado en delta (δ), theta (θ), alfa 1 (α1), alfa 2 (α2), beta 1 (β1) y beta 2 (β2) y su topografía en los hemisferios cerebrales de niños, jóvenes y adultos para establecer indicadores EEGc. MÉTODO: Se estudiaron tres grupos de 16 participantes: niños en primaria (GN), estudiantes de licenciatura (GL) y de maestría (GM). Los padres y los participantes otorgaron su consentimiento. En el aparato Nicolet se registró el EEG utilizando el sistema 10/20. Se analizaron muestras bipolares, con T Fourier se obtuvo la potencia absoluta (PA), se calculó su promedio (PPA), la potencia relativa (PR) y los índices de frecuencias lentas/rápidas. Las diferencias se evaluaron con Kruskal Wallis y la comparación de Dunnet para sub-grupos. RESULTADOS: El PPA de seis frecuencias fue mayor en GN que en GL y GM. En éstos fue similar con excepciones, relacionadas con la distribución topográfica. El índice δ/α fue mayor en GN con particular distribución topográfica y θ/α fue más variable. La PR de α fue mayor en GL y GM comparados con GN, la de θ y de δ en algunas derivaciones, fueron mayores en el GN. DISCUSIÓN Y CONCLUSIÓN: En la maduración cerebral disminuye la PA debido a la integración de más ensambles glío-neuronales, que presentan mayor asimetría en determinada frecuencia. Estos perfiles establecen indicadores para compararlos con futuros registros EEG.

Abstract: ANTECEDENTS: Cerebral function results from the electrical activity in glial-neuronal networks, integrated proactively through sensory, motor, and regulating interactions. These networks oscillate since early life and are modulated by diverse maturation factors, including educational processes. OBJECTIVE: To identify the power spectrum separated in delta (δ), theta (θ), alfa 1 (α1), alfa 2 (α2), beta 1 (β1) y beta 2 (β2), and their topography in cerebral hemispheres of children, youngsters, and adults to establish qEEG indicators. METHOD: We studied three groups of 16 participants each: elementary school children (CG), undergraduate students (UG), and graduate students (GG). Parents and participants granted their consent. The EEG was recorded (Nicolet) following the 10/20 system. Bipolar samples were analyzed. Absolute power (AP) was obtained with Fourier transform; its average (AAP) relative power (RP), and slow/fast frequencies and indices were calculated. Differences were assessed with Kruskal Wallis and Dunnet's comparison for subgroups. RESULTS: The AAP of six frequencies was higher in CG than in UG and GG. Frequencies were similar with exceptions correlating with topographic distribution. The δ/α index was higher in CG with a particular topographic distribution, θ/α varied more. RP of α was higher in UG and GG than in CG; that of θ and δ were higher in some leads of CG. DISCUSSION AND CONCLUSION: During cerebral maturation, AP diminishes due to integration of more glial-neuronal ensembles, presenting greater asymmetry in a giving frequency. These profiles establish indicators for comparison with future EEG recordings.

Valoración de la semántica en la comprensión de palabras orales / Assessment of the semantics in the oral understanding of words

Para reconocer y comprender palabras habladas, se debe combinar información acústico-fonética con conocimiento almacenado sobre los patrones de los sonidos de las palabras y su respectivo significante. En particular, los investigadores a lo largo de muchos años han tratado de determinar cómo el oyente es capaz de asignar significado a una señal acústica en continua variación, conjugando al mismo tiempo una colección de representaciones que genera la memoria con tal velocidad y precisión. Al respecto, dentro de la literatura neurocognitiva y neuropsicológica existen diversos modelos y posturas que intentan dar cuenta de la complejidad de dichos procesos. No obstante, la gran mayoría de los esquemas de exploración clínica comúnmente empleados reducen la comprensión de una palabra al reconocimiento automatizado de ésta. Esta revisión pretende enfatizar la relevancia en la exploración cotidiana del componente semántico como función primaria en la comprensión de palabras orales. Asimismo, se exponen tareas de evaluación del procesamiento léxico-semántico alternas a las de denominación.

To recognize and understand spoken words we should combine acoustic-phonetic information stored knowledge about the patterns of the sounds of words and their respective significant. In particular, researchers over many years have tried to determine how the listener is able to assign meaning to an acoustic signal in continuous variation, combining both a collection of memory representations generated with such speed and precision. In this regard, within the neurocognitive and neuropsychological literature there are many models and positions that attempt to account for the complexity of these processes. However, the vast majority of clinical examination schemes commonly employed reduce the understanding of a word to the automated recognition of it. This paper aims to emphasize the importance in the daily examination of the semantic component as a primary role in understanding spoken words. It also sets assessment tasks lexical-semantic processing alternative to naming.