1,721,050 research outputs found
Stereotyped episodes of aphasia and immobility: how cataplexy mimics stroke in an elderly patient
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Can smartphone sleep applications reliably assess sleep-wake cycle? Preliminary findings from a PSG study.
No full textObjectives: Smartphone applications are considered as the prime candidate for the purposes of large scale, low cost and long term sleep monitoring. How reliable is smartphone assessment of sleep remains a key issue and more validation studies with both healthy and patient populations are needed. In this study we compared the performance of four smartphone applications (Sleep Cycle-accelerometer; Sleep Cycle-microphone; Smart Alarm; Sense) with polysomnoghraphy (PSG). Our main objective was evaluating whether sleep reports provided by applications offer reliable assessment of standard sleep parameters and establishing which of the application features result more promising for personal home use.
Methods: 20 healthy participants were recorded at home, for two consecutive nights. Four iPhone applications (two per each night) designed for sleep–wake detection were used simultaneously with PSG.
Results: Pearson’s correlation coefficients between PSG parameters (Time in bed, TIB; Total Sleep Time, TST; Wake After Sleep Onset, WASO; Sleep Efficiency, SE; Sleep Latency, SL; NREM Sleep Stages 1-4, N1, N2, N3, N4; Slow Wave Sleep, SWS; Rapid Eye Movement Sleep, REMS) and app reports were calculated. Significant correlations are reported below. Sense: TIB (app) and TIB (PSG): r= .713, p=.003; TST (app) and TST (PSG): r= .777, p=.001; Sleep Score (app) and SE (PSG): r= .482, p=.069; Light Sleep (app) and N1+N2+ REM (PSG): r= .424, p=.062; Sleeping Soundly(app) and N3: r= .596, p=.019; Sleeping Soundly(app) and N4(PSG): r= .520, p=.047. Smart Alarm: TIB (app) and TIB (PSG): r= .944, p< .001; Time Awake (app) and WASO (PSG): r= .473, p=.035; Sleep Quality (app) and SE(PSG): r= .431, p=.057. Sleep Cycle-accelerometer: TIB(app) and TIB (PSG): r= .672, p=.002; Sleep quality (app) and SE (PSG): r= -.480, p=.038. Sleep Cycle-microphone: TIB (app) and TIB (PSG): r= .492, p=.045; Sleep quality (app) and TIB (PSG): r= -.522, p=.032.
Conclusions: Two apps provided partially reliable estimates of SE and showed significant correlations with TST and WASO measured by PSG. Only one app showed significant correlations with SWS parameters. In general, the examined apps do not offer reliable sleep stage data, not discriminating light sleep from deep sleep and especially not providing any estimate of REM
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
(Not so) Smart sleep tracking through the phone: Findings from a polysomnography study testing the reliability of four sleep applications
Full text linkAn increasing number of sleep applications are currently available and are being widely used for in-home sleep tracking. The present study assessed four smartphone applications (Sleep Cycle-Accelerometer, SCa; Sleep Cycle-Microphone, SCm; Sense, Se; Smart Alarm, SA) designed for sleep−wake detection through sound and movement sensors, by comparing their performance with polysomnography. Twenty-one healthy participants (six males, 15 females) used the four sleep applications running on iPhone (provided by the experimenter) simultaneously with portable polysomnography recording at home, while sleeping alone for two consecutive nights. Whereas all apps showed a significant correlation with polysomnography-time in bed, only SA offered significant correlations for sleep efficacy. Furthermore, SA seemed to be quite effective in reliable detection of total sleep time and also light sleep; however, it underestimated wake and partially overestimated deep sleep. None of the apps resulted capable of detecting and scoring rapid eye movement sleep. To sum up, SC (functioning through both accelerometer and microphone) and Se did not result sufficiently reliable in sleep−wake detection compared with polysomnography. SA, the only application offering the possibility of an epoch-by-epoch analysis, showed higher accuracy than the other apps in comparison with polysomnography, but it still shows some limitations, particularly regarding wake and deep sleep detection. Developing scoring algorithms specific for smartphone sleep detection and adding external sensors to record other physiological parameters may overcome the present limits of sleep tracking through smart phone apps
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dream Generation and Recall in Daytime NREM Sleep of Patients With Narcolepsy Type 1
Full text linkThe less rigid architecture of sleep in patients with narcolepsy type 1 (NT1) compared with healthy subjects may provide new insights into some unresolved issues of dream experience (DE), under the assumption that their DE frequencies are comparable. The multiple transition from wakefulness to REM sleep (sleep onset REM period: SOREMP) during the five trials of the Multiple Sleep Latency Test (MSLT) appears of particular interest. In MSLT studies, NT1 patients reported a DE after about 80% of SOREMP naps (as often as after nighttime REM sleep of themselves and healthy subjects), but only after about 30% of NREM naps compared to 60% of daytime and nighttime NREM sleep of healthy subjects. To estimate accurately the “real” DE frequency, we asked participants to report DE (“dream”) after each MSLT nap and, in case of failure, to specify if they were unable to retrieve any content (“white dream”) or DE did not occur (“no-dream”). The proportions of dreams, white dreams, and no dreams and the indicators of structural organization of DEs reported after NREM naps by 17 adult NT1 patients were compared with those reported by 25 subjects with subjective complaints of excessive daytime sleepiness (sc-EDS), who take multiple daytime NREM naps. Findings were consistent with the hypothesis of a failure in recall after awakening rather than in generation during sleep: white dreams were more frequent in NT1 patients than in sc-EDS subjects (42.86 vs 17.64%), while their frequency of dreams plus white dreams were similar (67.86 and 61.78%) and comparable with that of NREM-DEs in healthy subjects. The longer and more complex NREM-DEs of NT1 patients compared with sc-EDS subjects suggest that the difficulty in DE reporting depends on their negative attitude toward recall of contents less vivid and bizarre than those they usually retrieve after daytime SOREMP and nighttime REM sleep. As this attitude may be reversed by some recall training before MSLT, collecting wider amounts of DE reports after NREM naps would cast light on both the across-stage continuity in the functioning of cognitive processes underlying DE and the difference in content and structural organization of SOREM-DEs preceded by N1 or also N2 sleep
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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