Adaptive data-driven selection of sequences of biological and cognitive markers in pre-clinical diagnosis of dementia.

Effective clinical decision procedures must balance multiple competing objectives such as time-to-decision, acquisition costs, and accuracy. We describe and evaluate POSEIDON, a data-driven method for PrOspective SEquentIal DiagnOsis with Neutral zones to individualize clinical classifications. We evaluated the framework with an application in which the algorithm sequentially proposes to include cognitive, imaging, or molecular markers if a sufficiently more accurate prognosis of clinical decline to manifest Alzheimer's disease is expected. Over a wide range of cost parameter data-driven tuning lead to quantitatively lower total cost compared to ad hoc fixed sets of measurements. The classification accuracy based on all longitudinal data from participants that was acquired over 4.8 years on average was 0.89. The sequential algorithm selected 14 percent of available measurements and concluded after an average follow-up time of 0.74 years at the expense of 0.05 lower accuracy. Sequential classifiers were competitive from a multi-objective perspective since they could dominate fixed sets of measurements by making fewer errors using less resources. Nevertheless, the trade-off of competing objectives depends on inherently subjective prescribed cost parameters. Thus, despite the effectiveness of the method, the implementation into consequential clinical applications will remain controversial and evolve around the choice of cost parameters

Acoustic stimulation during sleep predicts long-lasting increases in memory performance and beneficial amyloid response in older adults

BACKGROUND: Sleep and neurodegeneration are assumed to be locked in a bi-directional vicious cycle. Improving sleep could break this cycle and help to prevent neurodegeneration. We tested multi-night phase-locked acoustic stimulation (PLAS) during slow wave sleep (SWS) as a non-invasive method to improve SWS, memory performance and plasma amyloid levels. METHODS: 32 healthy older adults (agemean: 68.9) completed a between-subject sham-controlled three-night intervention, preceded by a sham-PLAS baseline night. RESULTS: PLAS induced increases in sleep-associated spectral-power bands as well as a 24% increase in slow wave-coupled spindles, known to support memory consolidation. There was no significant group-difference in memory performance or amyloid-beta between the intervention and control group. However, the magnitude of PLAS-induced physiological responses were associated with memory performance up to 3 months post intervention and beneficial changes in plasma amyloid. Results were exclusive to the intervention group. DISCUSSION: Multi-night PLAS is associated with long-lasting benefits in memory and metabolite clearance in older adults, rendering PLAS a promising tool to build upon and develop long-term protocols for the prevention of cognitive decline

Acoustic stimulation during sleep predicts long-lasting increases in memory performance and beneficial amyloid response in older adults.

BACKGROUND Sleep and neurodegeneration are assumed to be locked in a bi-directional vicious cycle. Improving sleep could break this cycle and help to prevent neurodegeneration. We tested multi-night phase-locked acoustic stimulation (PLAS) during slow wave sleep (SWS) as a non-invasive method to improve SWS, memory performance and plasma amyloid levels. METHODS 32 healthy older adults (agemean: 68.9) completed a between-subject sham-controlled three-night intervention, preceded by a sham-PLAS baseline night. RESULTS PLAS induced increases in sleep-associated spectral-power bands as well as a 24% increase in slow wave-coupled spindles, known to support memory consolidation. There was no significant group-difference in memory performance or amyloid-beta between the intervention and control group. However, the magnitude of PLAS-induced physiological responses were associated with memory performance up to 3 months post intervention and beneficial changes in plasma amyloid. Results were exclusive to the intervention group. DISCUSSION Multi-night PLAS is associated with long-lasting benefits in memory and metabolite clearance in older adults, rendering PLAS a promising tool to build upon and develop long-term protocols for the prevention of cognitive decline

Bitcoin and Its Position on Financial Markets

Import 22/07/2015Cílem této bakalářské práce je empiricky ověřit vliv finančních a makroekonomických ukazatelů na vývoj ceny Bitcoinu. Naplnění tohoto cíle je dosaženo pomocí vědeckých metod syntézy a deskriptivní a korelační analýzy. Důvodem pro ověřování byla skutečnost, že většina autorů prováděla svoji analýzu před téměř dvěma roky, což v případě Bitcoinu představuje dávnou minulost. Vliv konkrétních finančních a makroekonomických indikátorů na cenu Bitcoinu byl nejprve ověřen v dlouhém období, které vzniklo prodloužením původního období použitého v jiné předchozí práci. V tomto období byl potvrzen vztah mezi cenou Bitcoinu a hodnotou Dow Jones indexu. Nepotvrdila se předchozí koncepce závislosti mezi cenou Bitcoinu a hodnotou směnného kurzu USD/EUR, resp. cenou ropy. V tomto období byla rovněž objevena nepřímá závislost mezi cenou Bitcoinu a cenou zlata. V samostatné podkapitole byl pak ověřen vliv všech těchto veličin na cenu Bitcoinu v krátkém období.The aim of this bachelor thesis is to empirically check the influence of financial and macroeconomic indicators on Bitcoin price. This is achieved by using synthesis and descriptive and correlation analysis as the main scientific methods. The reason for the research was that the majority of authors have done their analysis almost two years ago, which in case of Bitcoin means a very long time. First, the influence of specific financial and macroeconomic indicators on Bitcoin price has been checked in the long run (a period that was created by prolonging the period used in previous literature). In this period the relationship between Bitcoin price and Dow Jones Index value has been confirmed. The previous concept of Bitcoin price and its dependence on USD/EUR exchange rate value and oil price respectively has not been confirmed. A negative correlation between Bitcoin price and gold price has been discovered. After that the influence of all these indicators on Bitcoin price has been checked for the short run as well.156 - Katedra národohospodářskávelmi dobř

Transcranial Electric Current Stimulation During Associative Memory Encoding: Comparing tACS and tDCS Effects in Healthy Aging

Associative memory is one of the first cognitive functions negatively affected by healthy and pathological aging processes. Non-invasive brain stimulation (NIBS) techniques are easily administrable tools to support memory. However, the optimal stimulation parameters inducing a reliable positive effect on older adult’s memory performance remain mostly unclear. In our randomized, double-blind, cross-over study, 28 healthy older adults (16 females; 71.18 + 6.42 years of age) received anodal transcranial direct (tDCS), alternating current in the theta range (tACS), and sham stimulation over the left ventrolateral prefrontal cortex (VLPFC) each once during encoding. We tested associative memory performance with cued recall and recognition tasks after a retention period and again on the following day. Overall, neither tDCS nor tACS showed effects on associative memory performance. Further analysis revealed a significant difference for performance on the cued recall task under tACS compared to sham when accounting for age. Our results suggest that tACS might be more effective to improve associative memory performance than tDCS in higher aged samples

Effects of tDCS and tACS on Associative Memory Performance in Healthy Elderly

Sustaining memory performance up to high ages supports independent functioning in activities of daily living and preserves quality of life. However, especially associative memory, the ability to form lasting item-context or item-item associations, is one of the first cognitive functions negatively affected by healthy and pathological aging processes. Non-invasive brain stimulation techniques are a promising tool to support associative memory function in the elderly

PUZZLING THE MIND: EVALUATING THE DIFFICULTY OF GENERATED PUZZLE GAME LEVELS FOR A PUZZLE GAME INTERVENTION — PRELIMINARY RESULTS

Background: Engagement in cognitively stimulating leisure activities plays an important role in mediating cognitive decline. Recentstudies suggest that computerized puzzle games are an activityliked by older adults that offers cognitive benefits. For use as acognitive intervention, however, it is crucial that the puzzle gamedifficulty is constantly adapted to match the player’s level of skill.To this end, we generated large sets of difficulty levels for twotablet-based puzzle games. Methods: We conducted a play-teststudy in 16 healthy younger adults (18 to 40 years) that playedand rated the difficulty of sets of levels for two board-based puzzlegames: A Match-3 puzzle game (40 levels) that is played by swapping two objects to make a row of three identical objects, and aNumberlink puzzle game (55 levels) where paths to connect pairsof objects on the board must be found. For both puzzle games,sets of difficulty levels were generated using Python scripts byvarying puzzle variables, that is the size of the puzzle board (allcombinations of width and height from 4 to 8) and the number ofgame objects (from 4 to 8). For each level played, a subjective difficulty rating (from 1 to 10) and puzzle solving time were recorded.Furthermore, participants completed neurocognitive tests that measure cognitive domains engaged by the puzzle games and generalcognitive ability. Results: Mixed model analyses showed significanteffects of both puzzle board size and number of game objects onpuzzle solving time for both puzzle games. For puzzle difficulty ratings, however, there was only a significant effect of puzzle boardsize. Conclusions: Our results indicate that puzzle difficulty can bemanipulated by varying puzzle variables. In a next step, we willtest more participants, including healthy older adults (above 65years), to further examine whether age and cognitive ability areassociated with performance on the two puzzle games. Lastly,this study will allow us to develop an algorithm for dynamic puzzledifficulty adjustment in a clinical trial using the two puzzle gamesas a cognitive intervention