Gotowa bibliografia na temat „Late discriminative negativity”

Fragestellung: Defizite im auditiven Kurzzeitgedächtnis werden als Ursache u. a. für Sprachentwicklungs- und Lese-Rechtschreibstörungen diskutiert. Für die ersten Lebensjahre fehlen bislang jedoch aussagefähige Untersuchungen zum Kurzzeitgedächtnis. Ziel der vorliegenden Studie war es, bei jüngeren Kindern die Dauer des auditiven sensorischen Gedächtnisses mit objektiven Methoden zu bestimmen. Methodik: In Gruppen unauffällig entwickelter, zwei- (n = 37) bzw. sechsjähriger (n = 52) Kinder wurden mit einem passiven auditiven Oddball-Paradigma und variablem Interstimulusintervall (ISI: 0.5–5 s, je nach Gruppe) ereigniskorrelierte Potenziale (EKP) abgeleitet. Ergebnisse: Bei kurzem ISI waren eine Mismatch Negativity (MMN) und eine Late Discriminative Negativity (LDN) und bei langem ISI eine P3a zu beobachten. Eine ISI-Abhängigkeit war für die MMN und LDN statistisch zu belegen. Die Änderung der EKP-Komponentenstruktur trat bei den sechsjährigen Kindern bei einem deutlich längeren ISI als bei den zweijährigen ein. Schlussfolgerungen: Die Punkte des Verschwindens von MMN und LDN bei ISI–Verlängerung sprechen dafür, dass die Dauer des auditiven sensorischen Gedächtnisses bei zweijährigen Kindern etwa 1–2 s und bei sechsjährigen 3–5 s beträgt. Allerdings scheinen an der Kurzzeitspeicherung akustischer Signale verschiedene Mechanismen mit unterschiedlicher Dauer der Speicherung beteiligt zu sein, da eine P3a auch nach Verschwinden von MMN und LDN noch ableitbar ist.

People differ in their ability to perceive second language (L2) sounds. In early bilinguals the variability in learning L2 phonemes stems from speech-specific capabilities (Díaz, Baus, Escera, Costa & Sebastián-Gallés, 2008). The present study addresses whether speech-specific capabilities similarly explain variability in late bilinguals. Event-related potentials were recorded (using a design similar to Díaz et al., 2008) in two groups of late Dutch–English bilinguals who were good or poor in overtly discriminating the L2 English vowels /ε-æ/. The mismatch negativity, an index of discrimination sensitivity, was similar between the groups in conditions involving pure tones (of different length, frequency, and presentation order) but was attenuated in poor L2 perceivers for native, unknown, and L2 phonemes. These results suggest that variability in L2 phonemic learning originates from speech-specific capabilities and imply a continuity of L2 phonemic learning mechanisms throughout the lifespan.

Abstract Abstract 4333 Adult acute lymphoblastic leukemia (ALL) differs from pediatric ALL by higher frequency of unfavorable biological features including cytogenetics (often t(9;22), rare t(12;21)), slower molecular response (MRD negativity is lower at day near +30 in adults - 47% vs 80%; Bruggemmann, Blood, 2006; Borowitz, Blood, 2010), more toxicity followed by less complience, all this translating in less efficacy. Another very important, early and simple predictor of antileukamia effect in ALL is prednisolone (PRD) sensitivity, that is to say tumor clearance within one week of prephase. It's a well documented fact in childhood ALL, but scarcely characterized in adults. 35% of adults with ALL are considered to be resistant to PRDN compaired to 10% children after evaluation of PB blast count on day +8 (Annino, Blood, 2002; Shrappe, Leukemia 2002), but few data exists about bone marrow blasts clearance. We initiated a prospective multicenter trial for Ph-negative ALL under the age of 55 based on: 1.evaluation of blast clearance in b/m after 7 days of PRD and its substitution by dexamethazone (DEXA) if blast count was 25% and more. 2. “no interruptions” protocol with 8 weeks induction and 5 consolidation phases followed by 2-years maintenance. 3. prolonged L-asparaginase application at 10.000 IU weekly in induction, once in two weeks in consolidations, twice a month in maintenance (total proposed dose 560.000 IU). The study started in April, 2009. 20 participating centers enrolled 77 patients (median age 27y (16-55), 44f, 33m, 61,5%=B-lin, 38,6%=T-lin; 41% with normal karyotype (NK)). 30,7% of patients were in the standrad risk (SR) group (WBC <30 for B-Lin, <100 for T-Lin, EGIL BII-III, T-III; LDH < 2N, No late CR, t(4;11)-), 69,3% - in the high risk (HR) group (WBC >30 for B-Lin, >100 for T-Lin, EGIL BI, T-I-II-IV; LDH > 2N, No late CR, t(4;11)+). The analysis was performed in June, 2010, and comprised 70 pts. The data on the day +8 b/m count was reported in 67 pts: 70% of them had b/m blasts 25% and more, thus were considered as non-responders to PRD (60 mg/m2) and were switched to DEXA (10 mg/m2). It's worth to note that the proportion of non-responders to PRD was almost equal in the SR and HR groups: 12 of 20 (60%) in SR and 35 of 47 (74,5%). CR rate was high in both risk groups (SR=95,5%; HR=89,4%) and immunological subsets (B=91,4%;T=91,6%). For the whole group of analysed patients (n=70) there were 5 induction deaths (7,1%) and 1 resistant leukemia (1,4%). Median of days without treatment during induction period was 8 days (0-56). Death in remission was reported in 2 of 64 CR pts (3,1%). Relapses occurred in 4/64 (4,2%). Within the short period of follow-up (14 mo) the probability of OS for 70 patients constituted 78,8%, DFS – 76,7%, continuous CR – 81,2%. The difference in DFS between PRD responders and non-responders was at borderline: 63,3% vs 93,8% (p=0,1), and statistically proved in pts with NK vs all other abnormalities: 100% vs 72% (p=0,03). Age, WBC, immunophenotype, risk group, time without treatment did not influence survival. We concluded that in adult Ph-negative ALL the proportion of non-responders to PRD is very high (70%), thus providing much poorer results than in children; sensitivity to PRD may still be used as very simple discriminative marker of unfavorable prognosis. Disclosures: No relevant conflicts of interest to declare.

Our brains rapidly respond to human faces and can differentiate between many identities, retrieving rich semantic emotional-knowledge information. Studies provide a mixed picture of how such information affects event-related potentials (ERPs). We systematically examined the effect of feature-based attention on ERP modulations to briefly presented faces of individuals associated with a crime. The tasks required participants ( N = 40 adults) to discriminate the orientation of lines overlaid onto the face, the age of the face, or emotional information associated with the face. Negative faces amplified the N170 ERP component during all tasks, whereas the early posterior negativity (EPN) and late positive potential (LPP) components were increased only when the emotional information was attended to. These findings suggest that during early configural analyses (N170), evaluative information potentiates face processing regardless of feature-based attention. During intermediate, only partially resource-dependent, processing stages (EPN) and late stages of elaborate stimulus processing (LPP), attention to the acquired emotional information is necessary for amplified processing of negatively evaluated faces.

This study examined behavioral and neurophysiological indices of discrimination of an English vowel contrast [ɪ–ɛ] by early and late bilingual Spanish–English speakers, compared to monolingual English speakers. Electrophysiological measures (Mismatched Negativity – MMN) and behavioral measures (AX discrimination and forced-choice identification) were employed to examine perception of a nine-step vowel continuum, re-synthesized from natural tokens. Results revealed that (i) both monolingual and early bilinguals showed similar behavioral perception while late bilinguals performed more poorly on all behavioral tasks; and (ii) monolinguals showed robust evidence of discrimination (MMN) at a pre-attentive level that was significantly larger than found for either early or late bilinguals. These findings suggested that early input of English vowels to bilinguals did not necessarily lead to robust, automatic processing, as measured at a more attention-independent neural level; but earlier experience with a second language allowed for native-like speech perception measured with behavioral tasks.

We examine whether early acquisition of a second language (L2) leads to native-like neural processing of phonemic contrasts that are absent in the L1. Four groups (adult and child monolingual speakers of English; adult and child early bilingual speakers of English and Spanish, exposed to both languages before 5 years of age) participated in a study comparing the English /ɪ/ - /ε/ contrast. Neural measures of automatic change detection (Mismatch Negativity, MMN) and attention (Processing Negativity, PN and Late Negativity, LN) were measured by varying whether participants tracked the stimulus stream or not. We observed no effect of bilingualism on the MMN, but adult bilinguals differed significantly from adult monolinguals on neural indices of attention. The child bilinguals were indistinguishable from their monolingual peers. This suggest that learning a L2 before five years of age leads to native-like phoneme discrimination, but bilinguals develop increased attentional sensitivity to speech sounds.

Abstract In this study, we examine the association between perceived age discrimination at the workplace and job stress, with depressive symptoms among currently working late-middle-aged adults. In particular, we investigate whether the association between these work-related factors and depression varies by the strength of their social networks. We use data from the Panel on Ageing and Transitions in Health Survey (PATHS) a national study of 1654 Singaporean citizens and permanent residents aged 50 to 59 years, conducted in 2016-2017. We account for age and other sociodemographic characteristics, measures of economic status, occupation, early retirement intentions, personality traits, as well as multiple physical health measures. Our findings indicate that age discrimination at work and job stress are both positively associated with higher depressive symptom scores. The relationship between age discrimination and depressive symptoms however varies by social networks, with age discrimination negatively associated with depressive symptom scores among those with larger friends-based social networks. Our findings indicate that while psychological wellbeing of late middle-aged workers is adversely affected by age discrimination and job stress, these workers benefit from wider and deeper social connections with friends. Our results provide empirical support to previous research that suggests that friends-based social networks yield distinct benefits in terms of subjective well-being and increased self-worth.

[Truncated abstract] Some children with Specific Language Impairment (SLI) show poor performance on behavioural tasks designed to measure rapid auditory processing, such as the Repetition Test developed by Tallal and colleagues. Stemming from concerns about whether this task reflects higher-order, cognitive variables, this thesis sought to determine whether the performance deficits SLI children show were evident at the neurophysiological level, with minimal cognitive influences, such as attention, using paradigms designed to elicit the mismatch negativity (MMN) and late discriminative negativity (LDN). In the first two studies, a MMN paradigm, equivalent to the Repetition Test, was trialled with a group of 8 adults. In this paired paradigm, the second tone of a pair of pure tones ascending in frequency ('low'-'high') was occasionally replaced with a 'low' tone. The aim was to determine a 'long' and 'short' intra-pair interval (IPI) with which MMN was generated utilizing this paradigm and that were congruent with the Repetition Test findings (i.e., a long IPI at which SLI were able to perform the task, and a short IPI at which SLI children's performance was selectively impaired). In Study One, MMN to a within-pair frequency change was generated with the 30 ms IPI, but not the 700 ms IPI. The grouping parameters of the temporal window of integration (TWI) and temporal distinctiveness were considered less than optimal for the grouping of the pairs presented at 700 ms IPI for the pre-attentive system to register the within-pair frequency change. ... The frequency difference limens (DLs) of the SLI group were significantly higher than a group of 18 normally developing age- and intelligence-matched peers, but there was no significant difference between the groups in their performance on a control intensity discrimination task. The iii SLI group also showed poorer reading skills, yet frequency discrimination was related to oral language ability only. In the final study, MMN was measured to examine the pre-attentive neurophysiological basis of the SLI group's frequency discrimination deficit. Two frequency deviants that were just above each group's 75% DL on the frequency discrimination task were employed in a simple frequency change paradigm: 40 Hz difference for the control group, and 80 Hz difference for the SLI group. MMN and LDN were elicited in the group of 15 normally developing children to their 40 Hz suprathreshold frequency difference and to the 80 Hz difference. A significant MMN was not observed in the group of 13 SLI children to the 40 Hz difference, which was below their threshold level. However, despite discrimination at the behavioural level, MMN did not reach significance in the SLI group to their 80 Hz suprathreshold frequency difference, yet LDN was observed. MMN was larger in both groups for the 80 Hz difference. Furthermore, MMN and LDN amplitude to the suprathreshold deviants were predictive of both frequency and intensity DLs. These results suggested that SLI children have a pre-attentive neurophysiologically mediated insensitivity to small frequency differences, and that MMN (and LDN) to suprathreshold frequency deviants is a sensitive indicator of group discrimination differences and brain-behaviour relationships in children with and without SLI.