21 research outputs found

    The acute mania of King George III: A computational linguistic analysis.

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    We used a computational linguistic approach, exploiting machine learning techniques, to examine the letters written by King George III during mentally healthy and apparently mentally ill periods of his life. The aims of the study were: first, to establish the existence of alterations in the King's written language at the onset of his first manic episode; and secondly to identify salient sources of variation contributing to the changes. Effects on language were sought in two control conditions (politically stressful vs. politically tranquil periods and seasonal variation). We found clear differences in the letter corpus, across a range of different features, in association with the onset of mental derangement, which were driven by a combination of linguistic and information theory features that appeared to be specific to the contrast between acute mania and mental stability. The paucity of existing data relevant to changes in written language in the presence of acute mania suggests that lexical, syntactic and stylometric descriptions of written discourse produced by a cohort of patients with a diagnosis of acute mania will be necessary to support the diagnosis independently and to look for other periods of mental illness of the course of the King's life, and in other historically significant figures with similarly large archives of handwritten documents

    Effect of Modafinil on Impairments in Neurobehavioral Performance and Learning Associated with Extended Wakefulness and Circadian Misalignment

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    Although worldwide millions of people work prolonged hours, at adverse circadian phases, evidence suggests that cognitive function is impaired under these conditions with important societal consequences. In a double-blind placebo-controlled laboratory-based study, we investigated the effect of the wakefulness-promoting drug modafinil as a countermeasure against such neurobehavioral impairments induced by both prolonged wakefulness and circadian misalignment. Neurobehavioral performance, alertness, and sleep were studied in young healthy participants (N=18) who underwent a 25-day forced desynchrony protocol in which the period of the sleep-wakefulness cycle was scheduled to be 42.85 h (duration of each wakefulness episode: 28.57 h; sleep/rest episode: 14.28 h). Each waking day, participants were treated with either 400 mg modafinil, divided into three doses, or placebo, according to a randomized, parallel-group design. Treatment with modafinil significantly attenuated the performance decrements seen for several parameters including cognitive-psychomotor speed, visual attention and reaction times both with progressive hours awake and when working at adverse circadian phases. Subjective alertness and sleep parameters were similar between treatment groups, but modafinil-treated participants had fewer bouts of inadvertent sleep during scheduled waking. Modafinil reduced the neurobehavioral impairment associated with work, both during prolonged wakefulness and at adverse circadian phases, without adversely affecting subjective alertness or subsequent sleep. These features suggest that modafinil might be a particularly relevant countermeasure against the deleterious effects of prolonged work hours, shift work, and transmeridian travel

    Writing proficiency level and writing development of low-achieving adolescents: the roles of linguistic knowledge, fluency, and metacognitive knowledge

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    In a longitudinal design, 51 low-achieving adolescents' development in writing proficiency from Grades 7 to 9 was measured. There were 25 native-Dutch and 26 language-minority students. In addition, the roles of (i) linguistic knowledge, (ii) metacognitive knowledge, and (iii) linguistic fluency in predicting both the level and development of writing proficiency were assessed. Low-achieving students improved in writing proficiency, the language-minority students more so than the native-Dutch students. Regarding the level of writing proficiency, individual differences between low-achieving adolescents could be accounted for by receptive vocabulary, grammatical knowledge, and speed of sentence verification, suggesting that these are important components in low-achieving adolescents' writing. Regarding development in writing proficiency, grammatical knowledge predicted variation between lowachieving students. Explanations and educational implications of these findings are discussed

    Modulation of the acoustic startle response by the level of arousal: comparison of clonidine and modafinil in healthy volunteers

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    A sudden loud sound evokes an electromyographic (EMG) response from the orbicularis oculi muscle in humans together with an auditory evoked potential (AEP) and an increase in skin conductance (SC). Startle responses are inhibited by weak prepulses (prepulse inhibition, (PPI)) and may also be modified by the level of alertness. We compared the sedative drug clonidine and the alerting drug modafinil on sound-evoked EMG, AEP, and SC responses, on the PPI of these responses and on level of arousal and autonomic functions. Sixteen healthy male volunteers participated in four weekly sessions (clonidine 0.2 mg, modafinil 400 mg, their combination, placebo) in a double-blind, cross-over, balanced design. Responses were evoked by sound pulses of 115 and 85 dB (PPI) for 40 ms and recorded conventionally. Level of alertness, autonomic functions (pupil diameter, blood pressure, heart rate, salivation, temperature) and the plasma levels of the hormones prolactin, thyroid-stimulating hormone and growth hormone were also measured. Data were analyzed with analysis of variance with multiple comparisons. Both prepulses and clonidine attenuated all three startle responses and modafinil antagonized clonidine's effects on the EMG and AEP responses. None of the drugs affected PPI. Clonidine showed sedative and sympatholytic effects, and modafinil showed alerting and sympathomimetic effects. In conclusion, startle responses were susceptible not only to PPI but also to the level of arousal

    The antibody aducanumab reduces Aβ plaques in Alzheimer's disease

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    Alzheimer's disease (AD) is characterized by deposition of amyloid-β (Aβ) plaques and neurofibrillary tangles in the brain, accompanied by synaptic dysfunction and neurodegeneration. Antibody-based immunotherapy against Aβ to trigger its clearance or mitigate its neurotoxicity has so far been unsuccessful. Here we report the generation of aducanumab, a human monoclonal antibody that selectively targets aggregated Aβ. In a transgenic mouse model of AD, aducanumab is shown to enter the brain, bind parenchymal Aβ, and reduce soluble and insoluble Aβ in a dose-dependent manner. In patients with prodromal or mild AD, one year of monthly intravenous infusions of aducanumab reduces brain Aβ in a dose- and time-dependent manner. This is accompanied by a slowing of clinical decline measured by Clinical Dementia Rating-Sum of Boxes and Mini Mental State Examination scores. The main safety and tolerability findings are amyloid-related imaging abnormalities. These results justify further development of aducanumab for the treatment of AD. Should the slowing of clinical decline be confirmed in ongoing phase 3 clinical trials, it would provide compelling support for the amyloid hypothesis

    Pathophysiology of levodopa-induced dyskinesia: Potential for new therapies

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