Redes neurales atencionales en enfermedades neurodegenerativas: evidencias anatómico-funcionales empleando el Attention Network Test / Attentional networks in neurodegenerative diseases: anatomical and functional evidence from the Attention Network Test

Introducción: Comprender las alteraciones en la anatomía y función del cerebro en los procesos cognitivos para las enfermedades neurodegenerativas es aún un desafío para la neurociencia actual. Desde la neurociencia experimental algunos test computarizados han sido desarrollados para mejorar nuestro conocimiento de las redes neurales involucradas en la cognición. El Attention Network Test (ANT) permite medir la activad de las 3 redes atencionales (alerta, orientación y función ejecutiva).ObjetivosEl principal objetivo de esta revisión fue describir todas las alteraciones anatómicas y funcionales encontradas en diversas enfermedades neurológicas usando el ANT.Material y métodosUn protocolo de revisión fue aplicado seleccionando estudios desde 2010 en la base de datos PubMed, que involucraban al ATN en diferentes enfermedades neurológicas. Se obtuvieron 32 artículos para esclerosis múltiple, epilepsia o Parkinson entre otras enfermedades.ConclusionesSe confirman algunas de las estructuras anatómicas propuestas para el modelo de 3 grandes redes atencionales. Las estructuras más relevantes para la red de alerta son la corteza prefrontal, las regiones parietales, el tálamo y el cerebelo. El tálamo es también relevante para la red de orientación, junto a regiones parietales posteriores. Respecto a la red ejecutiva no depende exclusivamente de la corteza prefrontal y corteza cingulada anterior, sino también de estructuras subcorticales como los ganglios basales y el cerebelo y sus proyecciones hacia toda la corteza. (AU)

Introduction: Understanding alterations to brain anatomy and cognitive function associated with neurodegenerative diseases remains a challenge for neuroscience today. In experimental neuroscience, several computerised tests have been developed to contribute to our understanding of neural networks involved in cognition. The Attention Network Test (ANT) enables us to measure the activity of 3 attentional networks (alertness, orienting, and executive function).ObjectivesThe main aim of this review is to describe all the anatomical and functional alterations found in diverse neurological diseases using the ANT.Material and methodsWe collected studies published since 2010 in the PubMed database that employed the ANT in different neurological diseases. Thirty-two articles were obtained, addressing multiple sclerosis, epilepsy, and Parkinson's disease, among other disorders.ConclusionsSome of the anatomical structures proposed in the 3 attentional networks model were confirmed. The most relevant structures in the alertness network are the prefrontal cortex, parietal region, thalamus, and cerebellum. The thalamus is also relevant in the orienting network, together with posterior parietal regions. The executive network does not depend exclusively on the prefrontal cortex and anterior cingulate cortex, but also involves such subcortical structures as the basal ganglia and cerebellum and their projections towards the entire cortex. (AU)

Attentional networks in neurodegenerative diseases: anatomical and functional evidence from the Attention Network Test.

INTRODUCTION: Understanding alterations to brain anatomy and cognitive function associated with neurodegenerative diseases remains a challenge for neuroscience today. In experimental neuroscience, several computerised tests have been developed to contribute to our understanding of neural networks involved in cognition. The Attention Network Test (ANT) enables us to measure the activity of 3 attentional networks (alertness, orienting, and executive function). OBJECTIVES: The main aim of this review is to describe all the anatomical and functional alterations found in diverse neurological diseases using the ANT. MATERIAL AND METHODS: We collected studies published since 2010 in the PubMed database that employed the ANT in different neurological diseases. Thirty-two articles were obtained, addressing multiple sclerosis, epilepsy, and Parkinson's disease, among other disorders. CONCLUSIONS: Some of the anatomical structures proposed in the 3 attentional networks model were confirmed. The most relevant structures in the alertness network are the prefrontal cortex, parietal region, thalamus, and cerebellum. The thalamus is also relevant in the orienting network, together with posterior parietal regions. The executive network does not depend exclusively on the prefrontal cortex and anterior cingulate cortex, but also involves such subcortical structures as the basal ganglia and cerebellum and their projections towards the entire cortex.

Attentional networks in neurodegenerative diseases: anatomical and functional evidence from the Attention Network Test. / Redes neurales atencionales en enfermedades neurodegenerativas: evidencias anatómico-funcionales empleando el Attention Network Test.

INTRODUCTION: Understanding alterations to brain anatomy and cognitive function associated with neurodegenerative diseases remains a challenge for neuroscience today. In experimental neuroscience, several computerised tests have been developed to contribute to our understanding of neural networks involved in cognition. The Attention Network Test (ANT) enables us to measure the activity of 3 attentional networks (alertness, orienting, and executive function). OBJECTIVES: The main aim of this review is to describe all the anatomical and functional alterations found in diverse neurological diseases using the ANT. MATERIAL AND METHODS: We collected studies published since 2010 in the PubMed database that employed the ANT in different neurological diseases. Thirty-two articles were obtained, addressing multiple sclerosis, epilepsy, and Parkinson's disease, among other disorders. CONCLUSIONS: Some of the anatomical structures proposed in the 3 attentional networks model were confirmed. The most relevant structures in the alertness network are the prefrontal cortex, parietal region, thalamus, and cerebellum. The thalamus is also relevant in the orienting network, together with posterior parietal regions. The executive network does not depend exclusively on the prefrontal cortex and anterior cingulate cortex, but also involves such subcortical structures as the basal ganglia and cerebellum and their projections towards the entire cortex.

Demencia Por Cuerpos De Lewy, Un Reto Diagnóstico / Dementia With Lewy Bodies, A Diagnostic Challenge

Resumen La Demencia por cuerpos de Lewy es una enfermedad neurodegenerativa de etiología desconocida, corresponde a la segunda causa de demencia a partir de la sexta década de vida; su diagnóstico es un reto, debido a que ciertos de los signos y síntomas que presenta son típicos de la Enfermedad de Parkinson y la Enfermedad de Alzheimer. El siguiente reporte de caso es de los primeros en documentar un paciente con Demencia por cuerpos de Lewy en el Ecuador. Se expone un caso con Demencia por cuerpos de Lewy con el fin de plasmar la dificultad diagnóstica que genera esta patología y describir las características principales que la diferencian de otros síndromes demenciales, destacadas en los criterios recientemente actualizados por el Consorcio de Demencia por Cuerpos de Lewy. Un meticuloso examen neurológico y valoración neuropsicológica fueron ejes en el estudio y pronóstico del paciente que presentamos. La Demencia por cuerpos de Lewy requiere un diagnóstico minucioso, debido al desafío que origina su reconocimiento precoz; los criterios descritos aceleraron su reconocimiento gracias a la actualización de las recomendaciones sobre el diagnóstico clínico de Demencia por cuerpos de Lewy.

Abstract Dementia with Lewy bodies is a neurodegenerative disease of unknown etiology, it is the second cause of dementia of the sixth decade of life; Its diagnosis is a challenge, because certain signs and symptoms that it presents are typical of Parkinson's Disease and Alzheimer's Disease. The following case report is one of the few documented patients with Dementia with Lewy bodies in Ecuador. We report this in order to state the diagnostic difficulty that this pathology generates and describe the main characteristics that differentiate it from other dementia syndromes, highlighted in the recently updated criteria by the Consortium of Dementia with Lewy bodies. A meticulous neurological examination and neuropsychological assessment were essential in the study and prognosis of the patient. Dementia with Lewy bodies requires a thorough diagnosis, due to the challenge that originates its early recognition; the criteria described accelerated their recognition due the update of the recommendations on the clinical diagnosis of Dementia with Lewy bodies.

Perfil clínico y neuropsicológico: enfermedad de Parkinson/enfermedad por cuerpos de Lewy / Neuropsychological profile: Parkinson’s Disease/Lewy Body Dementia

La demencia por cuerpos de Lewy y la enfermedad de Parkinson son dos síndromes comunes con signos y síntomas similares que hacen difícil establecer un diagnóstico exacto, especialmente en las etapas intermedias y tardías de cada cuadro clínico en particular. La enfermedad de Parkinson es una entidad lenta y progresiva que se caracteriza por temblor de reposo, rigidez, bradiscinesias e inestabilidad postural. En ella, los síntomas neurocognitivos y conductuales como la depresión, la disfunción ejecutiva y atencional, la baja fluidez verbal y las fallas de memoria inmediata pueden aparecer desde las etapas iniciales de la enfermedad e ir empeorando y progresando, cuando aparece un cuadro demencial secundario a la enfermedad. Por su parte, la enfermedad por cuerpos de Lewy se considera un cuadro neurodegenerativo que se ha asociado a la presencia de cuerpos de Lewy a nivel cortical y subcortical y se caracteriza por signos extrapiramidales, fluctuaciones cognitivas y alucinaciones visuales. En ella los síntomas neurocognitivos y conductuales son "fluctuantes" en lo relacionado con el nivel de consciencia, las funciones ejecutivas y atencionales, la memoria episódica y la presencia/ausencia de alucinaciones visuales. Las diferencias sutiles de ambas enfermedades exigen una revisión exhaustiva en la evolución de los síntomas. La evaluación neuropsicológica como herramienta diagnóstica se limita en tanto que no reemplaza, los estudios de imagen y otros hallazgos neuropatológicos para el diagnóstico definitivo, pero permite objetivar el perfil neuropsicológico más propio de cada enfermedad, en particular para un diagnóstico más preciso.

Lewy body dementia and Parkinson´s disease are two frequent syndromes that share similar signs and symptoms, especially during intermediate and chronic phases of each particular clinical picture, making an accurate diagnosis very difficult to establish. Parkinson’s disease is a slow and progressive disorder characterized by tremor at rest, stiffness, bradykinesia and postural imbalance. Many neurocognitive and behavioral symptoms such as depression, executive and attentional dysfunction, lower verbal fluency and immediate memory failures can appear in early stages of the disease, increasing and progressing as a secondary dementia develops. Lewy body dementia is considered a neurodegenerative disorder associated to Lewy bodies in both cortical and subcortical regions. It is characterized by the presence of extrapyramidal features, cognitive fluctuation and visual hallucinations. Neurocognitive and behavioral symptoms fluctuate concerning level of consciousness, executive and attentional function, episodic memory and the presence/absence of visual hallucinations. Subtle differences in both disorders demand an exhaustive review of symptom´s evolution. Neuropsychological evaluation as a diagnostic tool is limited. It cannot replace neuroimaging studies and other neuropathological findings for a definite diagnosis, but determines each neuropsychological profile in particular for a more accurate diagnosis.