Is memory impaired in narcolepsy type 1?

Memory deficits in narcolepsy with cataplexy type 1 (NT1) have been poorly studied, and the results are controversial. Patients with NT1 usually report memory deficits, which are not seen in objective memory assessments. This study aimed to assess attention and memory processes in NT1 patients using standardised neuropsychological tests and to compare the results with a control group. Performance in memory and attention tests was studied in 12 NT1 patients (diagnosed according to ICSD-3 criteria) and the results compared with those of 14 control subjects. All participants completed questionnaires on sleepiness and depression symptoms. Significant differences were found in the depression symptoms questionnaire. Regarding neuropsychological assessment, NT1 patients performed worse in attention than the control group in that they processed fewer stimuli and achieved fewer correct stimuli. However, no significant differences were found in the memory test results, and the performance was similar between both groups. After application of the Holm-Bonferroni correction, the only differences that remained significant were those in the ESS and in BDI-II scores. Our results showed that memory processes are preserved in NT1 patients and that memory complaints may not be associated with an objective memory deficit. In addition, the significant difference observed for patients in the depression questionnaire could explain the subjective memory complaints.

Neuropsychological Alterations in Narcolepsy with Cataplexy and the Expression of Cognitive Deficits.

OBJECTIVES: The objective of our study was to assess attention processes and executive function in patients with narcolepsy with cataplexy (NT1). To do so, we compared the results with those of a control group from the general population using an extensive neuropsychological test battery. METHODS: We studied 28 patients with NT1 and 28 healthy control participants matched for age, gender, and educational level. They all completed questionnaires on sleepiness, anxiety, and depression symptoms. In addition, they underwent neuropsychological tests. The ability to maintain attention was assessed using three computer tasks with different levels of complexity. RESULTS: Patients had significantly more daytime sleepiness than controls. A significant negative correlation between depression and disease duration was found in NT1 patients. The results of the anxiety questionnaire correlated with the presence of sleep paralysis. There were significant differences in information processing speed subtasks. Patients made significantly more omissions and generally reacted slower and more variably than controls in computerized tasks. As for executive function, patients performed worse in phonologic fluency tasks than controls. However, when the influence of processing speed on fluency tasks was statistically controlled, part of this significant difference disappeared. CONCLUSIONS: Our results indicate that the negative correlation between depression and disease duration probably reflects progressive adaptation to the functional burden of the disease. Information processing speed plays a fundamental role in the expression of cognitive deficits. We emphasized the need to control the influence of processing speed and sustained attention in the neuropsychological assessment of NT1 patients.

Exploring the clinical features of narcolepsy type 1 versus narcolepsy type 2 from European Narcolepsy Network database with machine learning.

Narcolepsy is a rare life-long disease that exists in two forms, narcolepsy type-1 (NT1) or type-2 (NT2), but only NT1 is accepted as clearly defined entity. Both types of narcolepsies belong to the group of central hypersomnias (CH), a spectrum of poorly defined diseases with excessive daytime sleepiness as a core feature. Due to the considerable overlap of symptoms and the rarity of the diseases, it is difficult to identify distinct phenotypes of CH. Machine learning (ML) can help to identify phenotypes as it learns to recognize clinical features invisible for humans. Here we apply ML to data from the huge European Narcolepsy Network (EU-NN) that contains hundreds of mixed features of narcolepsy making it difficult to analyze with classical statistics. Stochastic gradient boosting, a supervised learning model with built-in feature selection, results in high performances in testing set. While cataplexy features are recognized as the most influential predictors, machine find additional features, e.g. mean rapid-eye-movement sleep latency of multiple sleep latency test contributes to classify NT1 and NT2 as confirmed by classical statistical analysis. Our results suggest ML can identify features of CH on machine scale from complex databases, thus providing 'ideas' and promising candidates for future diagnostic classifications.

Alteraciones neuropsicológicas en la narcolepsia con cataplejía: una revisión / Neuropsychological alterations in narcolepsy with cataplexy: a review

Objetivo. Describir el estado actual de conocimiento sobre los principales déficits cognitivos que presentan los pacientes con narcolepsia con cataplejía o narcolepsia de tipo 1. Desarrollo. La mayoría de los estudios ha encontrado que las funciones cognitivas más afectadas son la atención (especialmente el mantenimiento de la atención o atención sostenida), la velocidad de procesamiento de la información y las funciones ejecutivas (en particular, la fluidez verbal y la resistencia a la interferencia de estímulos). Estos datos indican una dificultad para utilizar los recursos cognitivos de los que dispone el sujeto. Estas alteraciones son similares a las presentes en otras hipersomnias, aunque difieren en la intensidad. Por otra parte, la mayoría de los estudios destaca una elevada prevalencia de diferentes trastornos depresivos y ansiosos. Se ha sugerido que la predisposición a la ansiedad forma parte del fenotipo característico de estos pacientes. La ansiedad podría actuar como un factor desencadenante de la enfermedad y ser asimismo una consecuencia de la enfermedad. Conclusiones. Los déficits cognitivos en los pacientes con narcolepsia de tipo 1 se manifiestan en tareas de larga duración o monótonas y en tareas con alta demanda cognitiva, principalmente en tareas de atención sostenida. La presencia de sintomatología depresiva en estos pacientes, junto con la excesiva somnolencia diurna, parecen afectar a su rendimiento en las pruebas neuropsicológicas, y estar estrechamente relacionadas con la apreciación subjetiva de dificultades cognitivas (AU)

Aim. To describe the current state of the art about the main cognitive deficits that appear in patients affected with narcolepsy with cataplexy (NT1). Development. The majority of the studies have found that the most impaired cognitive functions are attention (especially maintenance of attention or sustained attention), speed of information processing and executive functions (in particular, verbal fluency and resistance to the stimuli interference). These data indicate the difficulty to use the available cognitive resources of the patient. These alterations are similar to those present in other hypersomnias, although they might differ in intensity. Moreover, most of the studies emphasize a high prevalence of different depressive and anxious disorders. It has been suggested that predisposition to anxiety could be part of the characteristic phenotype of these patients. Anxiety could act either as a trigger for the disease or a consequence of the disease. Conclusions. Cognitive deficits in patients with NT1 appear in long lasting and/or monotonous tasks and in high cognitive demanding tasks. The presence of depressive symptomatology, together with excessive daytime sleepiness in these patients could affect their performance in neuropsychological test, and it might be related to their subjective perception of the cognitive deficits (AU)

[Cognitive and emotional alterations in chronic insomnia]. / Alteraciones cognitivas y emocionales en el insomnio crónico.

INTRODUCTION: Little is known about the cognitive and emotional alterations associated with chronic insomnia. DEVELOPMENT: After reviewing the aetiology and pathophysiology of chronic insomnia, taking into account the patient's vulnerability and its inheritability, this study reports on the knowledge currently held about the cognitive deficits and emotional alterations observed in patients with chronic insomnia. CONCLUSIONS: Most aetiological models include factors that predispose an individual to insomnia, as well as precipitating and maintaining it. Predisposing factors can be of a biological or psychosocial nature. One predisposing factor that plays an important role is the vulnerability to insomnia, which is related to a non-adaptive way of coping with stress (focused on the emotion rather than on the problem) and the internalisation of negative emotions, which favours a state of physiological, cognitive and emotional hyperactivation that disrupts sleep and may lead to insomnia. This vulnerability is largely hereditary. Two phenotypes, based on the objective duration of sleep, have been described, the difference between them being the severity of the disorder. Insomniacs with an objective sleep time below six hours present significant cognitive deficits. These become manifest in tasks that require a large number of cognitive resources, complex attention tasks, changes in the focus of attention, the process of consolidation of memory during sleep, and working memory. These data suggest the existence of a prefrontal dysfunction. Comorbidity between insomnia and anxiety-depression is high. The anxiety-depression triggered by the internalisation of emotions predisposes the individual to insomnia and this, in turn, intensifies the depression.

TITLE: Alteraciones cognitivas y emocionales en el insomnio cronico.Introduccion. Las alteraciones cognitivas y emocionales asociadas al insomnio cronico son poco conocidas. Desarrollo. Tras revisar la etiologia y fisiopatologia del insomnio cronico, considerando la vulnerabilidad a este y su heredabilidad, se describe el estado actual de conocimientos acerca de los deficits cognitivos y las alteraciones emocionales observados en el insomnio cronico. Conclusiones. La mayoria de los modelos etiologicos incluye factores que predisponen al insomnio, que lo precipitan y que lo mantienen. Los factores predisponentes pueden ser de tipo biologico o psicosocial. Un factor predisponente que desempeña un importante papel es la vulnerabilidad al insomnio, que se relaciona con un modo no adaptativo de afrontar el estres (centrado en la emocion en vez de en el problema) y la internalizacion de las emociones negativas, lo cual favorece un estado de hiperactivacion fisiologica, cognitiva y emocional que altera el sueño y puede desembocar en insomnio. Esta vulnerabilidad es en gran parte hereditaria. Se han descrito dos fenotipos, basados en la duracion objetiva del sueño, que difieren en la gravedad del trastorno. Los insomnes con duracion objetiva del sueño menor de seis horas presentan deficits cognitivos significativos. Estos se manifiestan en tareas que requieren gran cantidad de recursos cognitivos, tareas de atencion complejas, cambio de foco de atencion, proceso de consolidacion de la memoria durante el sueño y memoria operativa. Estos datos sugieren la existencia de una disfuncion prefrontal. Se da una alta comorbilidad entre insomnio y ansiedad-depresion. La ansiedad-depresion provocada por la internalizacion de las emociones predispone al insomnio, y este, a su vez, intensifica la depresion.

Alteraciones cognitivas y emocionales en el insomnio crónico / Cognitive and emotional alterations in chronic insomnia

Introducción. Las alteraciones cognitivas y emocionales asociadas al insomnio crónico son poco conocidas. Desarrollo. Tras revisar la etiología y fisiopatología del insomnio crónico, considerando la vulnerabilidad a éste y su heredabilidad, se describe el estado actual de conocimientos acerca de los déficits cognitivos y las alteraciones emocionales observados en el insomnio crónico. Conclusiones. La mayoría de los modelos etiológicos incluye factores que predisponen al insomnio, que lo precipitan y que lo mantienen. Los factores predisponentes pueden ser de tipo biológico o psicosocial. Un factor predisponente que desempeña un importante papel es la vulnerabilidad al insomnio, que se relaciona con un modo no adaptativo de afrontar el estrés (centrado en la emoción en vez de en el problema) y la internalización de las emociones negativas, lo cual favorece un estado de hiperactivación fisiológica, cognitiva y emocional que altera el sueño y puede desembocar en insomnio. Esta vulnerabilidad es en gran parte hereditaria. Se han descrito dos fenotipos, basados en la duración objetiva del sueño, que difieren en la gravedad del trastorno. Los insomnes con duración objetiva del sueño menor de seis horas presentan déficits cognitivos significativos. Éstos se manifiestan en tareas que requieren gran cantidad de recursos cognitivos, tareas de atención complejas, cambio de foco de atención, proceso de consolidación de la memoria durante el sueño y memoria operativa. Estos datos sugieren la existencia de una disfunción prefrontal. Se da una alta comorbilidad entre insomnio y ansiedad-depresión. La ansiedad-depresión provocada por la internalización de las emociones predispone al insomnio, y éste, a su vez, intensifica la depresión (AU)

Introduction. Little is known about the cognitive and emotional alterations associated with chronic insomnia. Development. After reviewing the aetiology and pathophysiology of chronic insomnia, taking into account the patient’s vulnerability and its inheritability, this study reports on the knowledge currently held about the cognitive deficits and emotional alterations observed in patients with chronic insomnia. Conclusions. Most aetiological models include factors that predispose an individual to insomnia, as well as precipitating and maintaining it. Predisposing factors can be of a biological or psychosocial nature. One predisposing factor that plays an important role is the vulnerability to insomnia, which is related to a non-adaptive way of coping with stress (focused on the emotion rather than on the problem) and the internalisation of negative emotions, which favours a state of physiological, cognitive and emotional hyperactivation that disrupts sleep and may lead to insomnia. This vulnerability is largely hereditary. Two phenotypes, based on the objective duration of sleep, have been described, the difference between them being the severity of the disorder. Insomniacs with an objective sleep time below six hours present significant cognitive deficits. These become manifest in tasks that require a large number of cognitive resources, complex attention tasks, changes in the focus of attention, the process of consolidation of memory during sleep, and working memory. These data suggest the existence of a prefrontal dysfunction. Comorbidity between insomnia and anxiety-depression is high. The anxiety-depression triggered by the internalisation of emotions predisposes the individual to insomnia and this, in turn, intensifies the depression (AU)

[Generation and functions of dreams]. / Generación y funciones de los ensueños.

INTRODUCTION: Over the last decade an ever-increasing number of articles have been published on dreams, which reflects the interest that several fields of neuroscience have in the topic. In this work we review the main scientific theories that have contributed to the body of knowledge on how they are produced and what function they serve. DEVELOPMENT: The article discusses the evolution of their scientific study, following a neurophysiological and neurocognitive approach. The first of these two methods seeks to determine the neurobiological mechanisms that generate them and the brain structures involved, while the second considers dreams to be a kind of cognition interacting with that of wake-fulness. Several different hypotheses about the function of dreams are examined, and more particularly those in which they are attributed with a role in the consolidation of memory and the regulation of emotional states. CONCLUSIONS: Although the exact mechanism underlying the generation of dreams has not been determined, neurobiological data highlight the importance of the pontine nuclei of the brainstem, several memory systems, the limbic system and the brain reward system and a number of neocortical areas. Neurocognitive data underline the relation between the cognitive and emotional processing that occurs during wakefulness and during sleep, as well as the influence of the surroundings on the content of dreams. With regard to their function, one point to be stressed is their adaptive value, since they contribute to the reprocessing of the information acquired in wakefulness and the control of the emotions. This suggests that dreams participate in the development of the cognitive capabilities.

TITLE: Generacion y funciones de los ensueños.Introduccion. En la ultima decada han aumentado considerablemente las publicaciones sobre los ensueños, lo que refleja el interes de varios campos de la neurociencia por el tema. En este trabajo se revisan las principales teorias cientificas que han contribuido al conocimiento de como se producen y cual es su funcion. Desarrollo. Se expone la evolucion de su estudio cientifico, siguiendo el enfoque neurofisiologico y el neurocognitivo. El primero busca determinar los mecanismos neurobiologicos que los generan y las estructuras cerebrales implicadas; el segundo considera los ensueños un tipo de cognicion en interaccion con el de vigilia. Se examinan diversas hipotesis sobre la funcion de los ensueños, en particular las que les atribuyen un papel en la consolidacion de la memoria y la regulacion del estado emocional. Conclusiones. Aunque no se ha determinado con exactitud como se generan los ensueños, los datos neurobiologicos resaltan la importancia de los nucleos pontinos del tronco cerebral, diversos sistemas de memoria, el sistema limbico y el sistema de recompensa cerebral y diversas areas neocorticales. Los datos neurocognitivos subrayan la relacion entre el procesamiento cognitivo y emocional que ocurre durante la vigilia y durante el sueño, asi como la influencia del entorno en el contenido de los ensueños. Respecto a su funcion, cabe destacar su valor adaptativo, al contribuir al reprocesamiento de la informacion adquirida en vigilia y al control de las emociones. Esto sugiere que los ensueños participan en el desarrollo de las capacidades cognitivas.

Generación y funciones de los ensueños / Generation and functions of dreams

Introducción. En la última década han aumentado considerablemente las publicaciones sobre los ensueños, lo que refleja el interés de varios campos de la neurociencia por el tema. En este trabajo se revisan las principales teorías científicas que han contribuido al conocimiento de cómo se producen y cuál es su función. Desarrollo. Se expone la evolución de su estudio científico, siguiendo el enfoque neurofisiológico y el neurocognitivo. El primero busca determinar los mecanismos neurobiológicos que los generan y las estructuras cerebrales implicadas; el segundo considera los ensueños un tipo de cognición en interacción con el de vigilia. Se examinan diversas hipótesis sobre la función de los ensueños, en particular las que les atribuyen un papel en la consolidación de la memoria y la regulación del estado emocional. Conclusiones. Aunque no se ha determinado con exactitud cómo se generan los ensueños, los datos neurobiológicos resaltan la importancia de los núcleos pontinos del tronco cerebral, diversos sistemas de memoria, el sistema límbico y el sistema de recompensa cerebral y diversas áreas neocorticales. Los datos neurocognitivos subrayan la relación entre el procesamiento cognitivo y emocional que ocurre durante la vigilia y durante el sueño, así como la influencia del entorno en el contenido de los ensueños. Respecto a su función, cabe destacar su valor adaptativo, al contribuir al reprocesamiento de la información adquirida en vigilia y al control de las emociones. Esto sugiere que los ensueños participan en el desarrollo de las capacidades cognitivas (AU)

Introduction. Over the last decade an ever-increasing number of articles have been published on dreams, which reflects the interest that several fields of neuroscience have in the topic. In this work we review the main scientific theories that have contributed to the body of knowledge on how they are produced and what function they serve. Development. The article discusses the evolution of their scientific study, following a neurophysiological and neurocognitive approach. The first of these two methods seeks to determine the neurobiological mechanisms that generate them and the brain structures involved, while the second considers dreams to be a kind of cognition interacting with that of wakefulness. Several different hypotheses about the function of dreams are examined, and more particularly those in which they are attributed with a role in the consolidation of memory and the regulation of emotional states. Conclusions. Although the exact mechanism underlying the generation of dreams has not been determined, neurobiological data highlight the importance of the pontine nuclei of the brainstem, several memory systems, the limbic system and the brain reward system and a number of neocortical areas. Neurocognitive data underline the relation between the cognitive and emotional processing that occurs during wakefulness and during sleep, as well as the influence of the surroundings on the content of dreams. With regard to their function, one point to be stressed is their adaptive value, since they contribute to the reprocessing of the information acquired in wakefulness and the control of the emotions. This suggests that dreams participate in the development of the cognitive capabilities (AU)