Cognitive slowing in cognitive-motordisorder associated to type 1 humanimmunodeficiency virus: tr and P300

Introduction. Reaction time (RT) deficit exhibited by HIV-1 asymptomatic seropositive individuals cannot alwaysbe explained by the effect of a cognitive slowing single factor.Evidence exists that decisional and peripheral componentsof RT may have differential slowing.Objectives. To assess the hypothesis of a cognitive slowing single factor as the main responsible for RT slowingin these subjects. Methodology. Thirty two (32) HIV-1 neurologically asymptomatic seropositive individuals were compared to 29 seronegative controls in two discriminative reaction time tasks (DRT) having increased cognitive difficulty but equal motorresponse demands. P300 component of the event-related potential was recorded simultaneously. RT, PPI, errors, and P300 latency were assessed using ANOVA. Results: Seropositives were slower than controls in RT,made more errors and showed delayed latencies of P300 in both tasks. However, while the increase of RT from the easier to the more difficult task was additive, the increase of P300 latencies was multiplicative. Conclusions. These results reveal differences in patternsof slowing between central and motor information processing mechanisms. Such results suggest that a singlecommon factor is not enough to explain cognitive slowing in HIV-1 seropositive subjects(AU)

Introducción. Los déficit de tiempo de reacción (TR) en los sujetos infectados por el virus de inmunodeficienciahumana tipo 1 (VIH-1) en las etapas iniciales de la infección no parecen siempre comprensibles por la acciónde un factor general de enlentecimiento cognitivo. Existen evidencias que indican que los componentes dela decisión y periféricos del TR pueden lentificarse diferencialmente.Objetivos. Evaluar la acción de un factor general de enlentecimiento cognitivo como causa principal de incrementodel TR en estos sujetos. Métodos. Treinta y dos sujetos seropositivos al VIH-1 neurológicamente asintomáticos fueron comparados con 29 controles seronegativos en dos tareas de tiempo de reacción discriminativo (TRD) de dificultad creciente, perocon iguales demandas de respuesta. Simultáneamente se registró el componente P300 del potencial evocadopor las tareas. El TR, el IPP, los errores y la latencia del componente P300 fueron comparados mediante ANOVA.Resultados. Los seropositivos fueron más lentos, cometieron más errores y exhibieron latencias más prolongadasque los controles, pero mientras que el incremento del TR entre tareas fue aditivo, el de latencia de P300 fuemultiplicativo. Conclusiones. Los resultados revelan una disociaciónen el patrón de enlentecimiento de los mecanismos centrales y los de producción de respuesta. Tales resultadossugieren que un factor general no es suficiente paraexplicar el enlentecimiento cognitivo de estos(AU)

Enlentecimiento cognitivo en el trastorno cognitivo-motor asociado al virus de inmunodeficiencia humana tipo 1: TR y P300 / Cognitive slowing in cognitive-motor disorder associated to type 1 human immunodeficiency virus: TR and P300

Introducción. Los déficit de tiempo de reacción (TR) en los sujetos infectados por el virus de inmunodeficiencia humana tipo 1 (VIH-1) en las etapas iniciales de la infección no parecen siempre comprensibles por la acción de un factor general de enlentecimiento cognitivo. Existen evidencias que indican que los componentes de la decisión y periféricos del TR pueden lentificarse diferencialmente. Objetivos. Evaluar la acción de un factor general de enlentecimiento cognitivo como causa principal de incremento del TR en estos sujetos. Métodos. Treinta y dos sujetos seropositivos al VIH-1 neurológicamente asintomáticos fueron comparados con 29 controles seronegativos en dos tareas de tiempo de reacción discriminativo (TRD) de dificultad creciente, pero con iguales demandas de respuesta. Simultáneamente se registró el componente P300 del potencial evocado por las tareas. El TR, el IPP, los errores y la latencia del componente P300 fueron comparados mediante ANOVA. Resultados. Los seropositivos fueron más lentos, cometieron más errores y exhibieron latencias más prolongadas que los controles, pero mientras que el incremento del TR entre tareas fue aditivo, el de latencia de P300 fue multiplicativo. Conclusiones. Los resultados revelan una disociación en el patrón de enlentecimiento de los mecanismos centrales y los de producción de respuesta. Tales resultados sugieren que un factor general no es suficiente para explicar el enlentecimiento cognitivo de estos sujetos

Introduction. Reaction time (RT) deficit exhibited by HIV-1 asymptomatic seropositive individuals cannot always be explained by the effect of a cognitive slowing single factor. Evidence exists that decisional and peripheral components of RT may have differential slowing. Objectives. To assess the hypothesis of a cognitive slowing single factor as the main responsible for RT slowing in these subjects. Methodology. Thirty two (32) HIV-1 neurologically asymptomatic seropositive individuals were compared to 29 seronegative controls in two discriminative reaction time tasks (DRT) having increased cognitive difficulty but equal motor response demands. P300 component of the event-related potential was recorded simultaneously. RT, PPI, errors, and P300 latency were assessed using ANOVA. Results. Seropositives were slower than controls in RT, made more errors and showed delayed latencies of P300 in both tasks. However, while the increase of RT from the easier to the more difficult task was additive, the increase of P300 latencies was multiplicative. Conclusions. These results reveal differences in patterns of slowing between central and motor information processing mechanisms. Such results suggest that a single common factor is not enough to explain cognitive slowing in HIV-1 seropositive subjects

Cognitive slowing in cognitive-motor disorder associated to type 1 human immunodeficiency virus: TR and P300.

INTRODUCTION: Reaction time (RT) deficit exhibited by HIV-1 asymptomatic seropositive individuals cannot always be explained by the effect of a cognitive slowing single factor. Evidence exists that decisional and peripheral components of RT may have differential slowing. OBJECTIVES: To assess the hypothesis of a cognitive slowing single factor as the main responsible for RT slowing in these subjects. METHODOLOGY: Thirty two (32) HIV-1 neurologically asymptomatic seropositive individuals were compared to 29 seronegative controls in two discriminative reaction time tasks (DRT) having increased cognitive difficulty but equal motor response demands. P300 component of the event-related potential was recorded simultaneously. RT, PPI, errors, and P300 latency were assessed using ANOVA. RESULTS: Seropositives were slower than controls in RT, made more errors and showed delayed latencies of P300 in both tasks. However, while the increase of RT from the easier to the more difficult task was additive, the increase of P300 latencies was multiplicative. CONCLUSIONS: These results reveal differences in patterns of slowing between central and motor information processing mechanisms. Such results suggest that a single common factor is not enough to explain cognitive slowing in HIV-1 seropositive subjects.

[Cognitive slowing in asymptomatic individuals who are seropositive for human immunodeficiency virus type 1]. / Enlentecimiento cognitivo en sujetos seropositivos asintomáticos al virus de inmunodeficiencia humana tipo 1.

INTRODUCTION: Reaction time (RT) is thought to be the most suitable measure to detect cognitive deficits in neurologically asymptomatic human immunodeficiency virus type I (HIV-1) infected individual since cognitive slowing is the earliest signal of cognitive-motor disorder related to HIV-1 infection. There is evidence suggesting that the greater the degree of central processing demands required by a task, the more likely that it will be sensitive to the effect of HIV-1 infection. Such statement suggests that the RT deficits exhibited by HIV-1 infected individuals at initial stages could be caused by the slowing of central information processing mechanisms. AIM: To assess the relationships between demands of central information processing and RT in HIV-1 seropositive individuals. SUBJECTS AND METHODS: 50 neurologically asymptomatic HIV-1 individuals were compared with 34 seronegative controls on four discriminative RT tasks of different levels of central processing demands except by the motor response requirements. RESULTS: Seropositive group was slower in RT and performed worse on the higher demanding task. On the lesser demanding tasks no differences in RT nor in accuracy were observed. For the task demanding sensory coding efforts seropositive individual were slower but achieved the same level of accuracy. CONCLUSIONS: Even when these results point to that RT slowing in HIV-1 asymptomatic individuals emerged with the increase in cognitive demands, the fact that RT slowing without accuracy declining can also appear in some tasks demanding sensory processing, preclude ruling out a peripheral deficit as the locus of the RT slowing in these subjects.

Enlentecimiento cognitivo en sujetos seropositivos asintomàticos al virus de inmunodeficiencia humana tipo 1 / Cognitive slowing in asymptomatic individuals who are seropositive for human immunodeficiency virus type 1

Las medidas de tiempo de reacción (TR) se consideran como las más sensibles para identificar déficit cognitivos en las etapas iniciales de la infección por el virus de inmunodeficiencia humana (VIH-1), debido a que el enlentecimiento cognitivo parece ser el signo más temprano del trastorno cognitivomotor asociado. Las evidencias indican, en general, que a mayores demandas de procesamiento de la tarea, mayor es la probabilidad de que ésta sea sensible a los efectos de la infección por VIH-1. Objetivo. Evaluar la relación entre TR y demandas cognitivas de la tarea en individuos seropositivos al VIH-1. Sujetos y métodos. 50 seropositivos neurológicamente asintomáticos se compararon con 34 controles seronegativos en cuatro tareas de TR discriminativo, con diferente nivel de demandas de procesamiento central y con iguales demandas de respuesta motora. Resultados. En la tarea de mayor demanda de procesamiento los seropositivos fueron más lentos y cometieron más errores. En las de menores demandas no se observaron diferencias de TR ni de calidad de ejecución. En la tarea con un nivel significativo de demandas de codificación sensorial se observaron diferencias de TR, pero no de calidad de la ejecución...(AU)

Reaction time (RT) is thought to be the most suitable measure to detect cognitive deficits in neurologically asymptomatic human immunodeficiency virus type I (HIV-1) infected individual since cognitive slowing is the earliest signal of cognitive-motor disorder related to HIV-1 infection. There is evidence suggesting that the greater the degree of central processing demands required by a task, the more likely that it will be sensitive to the effect of HIV-1 infection. Such statement suggests that the RT deficits exhibited by HIV-1 infected individuals at initial stages could be caused by the slowing of central information processing mechanisms. AIM: To assess the relationships between demands of central information processing and RT in HIV-1 seropositive individuals. 50 neurologically asymptomatic HIV-1 individuals were compared with 34 seronegative controls on four discriminative RT tasks of different levels of central processing demands except by the motor response requirements. Seropositive group was slower in RT and performed worse on the higher demanding task. On the lesser demanding tasks no differences in RT nor in accuracy were observed. For the task demanding sensory coding efforts seropositive individual were slower but achieved the same level of accuracy...(AU)

Enlentecimiento cognitivo en sujetos seropositivos asintomáticos al virus de inmunodeficiencia humana tipo 1 / Cognitive slowing in asymptomatic individuals who are seropositive for human immunodeficiency virus type 1

Introducción. Las medidas de tiempo de reacción (TR) se consideran como las más sensibles para identificar déficit cognitivos en las etapas iniciales de la infección por el virus de inmunodeficiencia humana (VIH-1), debido a que el enlentecimiento cognitivo parece ser el signo más temprano del trastorno cognitivo-motor asociado. Las evidencias indican, en general, que a mayores demandas de procesamiento de la tarea, mayor es la probabilidad de que ésta sea sensible a los efectos de la infección por VIH-1. Objetivo. Evaluar la relación entre TR y demandas cognitivas de la tarea en individuos seropositivos al VIH-1. Sujetos y métodos. 50 seropositivos neurológicamente asintomáticos se compararon con 34 controles seronegativos en cuatro tareas de TR discriminativo, con diferente nivel de demandas de procesamiento central y con iguales demandas de respuesta motora. Resultados. En la tarea de mayor demanda de procesamiento los seropositivos fueron más lentos y cometieron más errores. En las de menores demandas no se observaron diferencias de TR ni de calidad de ejecución. En la tarea con un nivel significativo de demandas de codificación sensorial se observaron diferencias de TR, pero no de calidad de la ejecución. Conclusiones. Aunque se observa una relación positiva entre nivel de demandas de procesamiento central y enlentecimiento del TR, la presencia de diferencias de TR en ausencia de una disminución dela calidad de la ejecución en una tarea con demandas significativas de codificación sensorial, no permite excluir un déficit en los mecanismos periféricos de procesamiento como locus del déficit de TR en las etapas iniciales de la infección por VIH-1 (AU)

Introduction. Reaction time (RT) is thought to be the most suitable measure to detect cognitive deficits in neurologically asymptomatic human immunodeficiency virus type I (HIV-1) infected individual since cognitive slowing is the earliest signal of cognitive-motor disorder related to HIV-1 infection. There is evidence suggesting that the greater the degree of central processing demands required by a task, the more likely that it will be sensitive to the effect of HIV-1 infection. Such statement suggests that the RT deficits exhibited by HIV-1 infected individuals at initial stages could be caused by the slowing of central information processing mechanisms. Aim. To assess the relationships between demands of central information processing and RT in HIV-1 seropositive individuals. Subjects and methods. 50 neurologically asymptomatic HIV-1 individuals were compared with 34 seronegative controls on four discriminative RT tasks of different levels of central processing demands except by the motor response requirements. Results. Seropositive group was slower in RT and performed worse on the higher demanding task. On the lesser demanding tasks no differences in RT nor in accuracy were observed. For the task demanding sensory coding efforts seropositive individual were slower but achieved the same level of accuracy. Conclusions. Even when these results point to that RT slowing in HIV-1 asymptomatic individuals emerged with the increase in cognitive demands, the fact that RT slowing without accuracy declining can also appear in some tasks demanding sensory processing, preclude ruling outa peripheral deficit as the locus of the RT slowing in these subjects (AU)

[Selective attention disorders associated with a history of occupational exposure to organic solvents]. / Alteraciones de la atención selectiva asociadas a la historia de exposición ocupacional a solventes orgánicos.

INTRODUCTION: The cognitive effects of long-term exposure to organic solvents could be similar to those triggered by certain neurodegenerative diseases. AIMS: The purpose of this study was to evaluate the effects exerted by accumulated exposure on the cognitive functions. PATIENTS AND METHODS: 105 subjects with an average history of exposure of 19.3 years were evaluated using seven computerised cognitive tasks (CPT, digit-symbol substitution, Stroop, memory span, word learning and recognition, and TRD) and results were later compared with the performance of a non-exposure group and with a normative reference. A study was made of the association between the length of exposure and performance in the variables in which the exposed subjects displayed significantly lower values than control subjects. In order to evaluate the effect exerted by age, regression functions between performance and age were calculated for each group. RESULTS: Only the indicators from the Stroop and digit-symbol tasks correlated with the length of exposure. The regression functions between performance and age for each group showed that the former decreased significantly faster among exposed subjects than among controls. CONCLUSIONS: Findings suggest that, while recent exposure seems to have an effect on a wide range of functions, chronic exposure exerts a selective influence on a smaller group. In this case, only selective attention appears to deteriorate. Similar deficits have been observed in the early stages of patients with Alzheimer's and Parkinson's.

Alteraciones de la atención selectiva asociadas a la historia de exposición ocupacional a solventes orgánicos / Selective attention disorders associated with a history of occupational exposure to organic solvents

Introducción. Los efectos cognitivos de la exposición a largo plazo a solventes orgánicos podrían ser similares a los provocados por ciertas enfermedades neurodegenerativas. Objetivo. Evaluar los efectos de la exposición acumulada en las funciones cognitivas. Pacientes y métodos. Se evaluaron 105 sujetos con historia de exposición, con un promedio de 19,3 años, mediante siete tareas cognitivas computarizadas (CPT, dígito-símbolo, Stroop, amplitud de memoria, aprendizaje y reconocimiento de palabras, y TRD) y se comparó su desempeño con el de un grupo no expuesto y con una referencia normativa. Se evaluó la asociación entre la duración de la exposición y el desempeño en aquellas variables en las que los expuestos mostraron valores significativamente inferiores a los controles. Para evaluar el efecto de la edad, se calcularon funciones de regresión entre el desempeño y la edad en cada grupo. Resultados. Sólo los indicadores de las tareas de Stroop y de dígito-símbolo mostraron correlación con la duración de la exposición. Las funciones de regresión entre la edad y el desempeño para cada grupo mostraron que éste declinó significativamente más rápido entre los expuestos que entre los controles. Conclusiones. Los resultados sugieren que, mientras que la exposición reciente parece influir sobre un amplio conjunto de funciones, la exposición crónica ejerce una influencia selectiva sobre un grupo más reducido. En este caso, sólo parece deteriorarse la atención selectiva. Déficit similares se han observado en los estadios tempranos de enfermos de Alzheimer y Parkinson (AU)

Introduction. The cognitive effects of long-term exposure to organic solvents could be similar to those triggered by certain neurodegenerative diseases. Aims. The purpose of this study was to evaluate the effects exerted by accumulated exposure on the cognitive functions. Patients and methods. 105 subjects with an average history of exposure of 19.3 years were evaluated using seven computerized cognitive tasks (CPT, digit-symbol substitution, Stroop, memory span, word learning and recognition, and TRD) and results were later compared with the performance of a non-exposure group and with a normative reference. A study was made of the association between the length of exposure and performance in the variables in which the exposed subjects displayed significantly lower values than control subjects. In order to evaluate the effect exerted by age, regression functions between performance and age were calculated for each group. Results. Only the indicators from the Stroop and digit-symbol tasks correlated with the length of exposure. The regression functions between performance and age for each group showed that the former decreased significantly faster among exposed subjects than among controls. Conclusions. Findings suggest that, while recent exposure seems to have an effect on a wide range of functions, chronic exposure exerts a selective influence on a smaller group. In this case, only selective attention appears to deteriorate. Similar deficits have been observed in the early stages of patients with Alzheimer and Parkinson (AU)