590 research outputs found
Menarche in Girls and Headache – A Longitudinal Analysis
No full textPuberty is assumed to influence the occurrence of headache, increasing the risk for recurrent episodes, especially in girls. The increase of headache, in particular recurrent headache, in girls from around the age of 12 on, is often ascribed to the occurrence of menarche as the most stringent indicator of completed puberty. We examined the hypothesis that the occurrence of menarche in girls is predictive of recurrent headache in reference to no or rare headache in the past 6 months. Furthermore, the assumption was tested that headache episodes increase after onset of menarche but remain unchanged in girls not having experienced their first menstruation. We also expected a higher probability of migraine type of headache after menarche. In a further analysis girls with and without menarche were compared with boys, and a difference between gender only for girls with menarche was predicted. In an epidemiological study recruiting 8800 families with children 7-14 years in Southern Lower Saxony (Germany), we conducted 3 yearly panels based on postal questionnaires. Headache data are based on self-report of children from 9 years on. Parents were asked for information regarding the onset of menarche. Approximately 1100 girls and about the same number of boys constitute the sample for our analyses. The results of a logistic regression analysis demonstrate that in 11- to 16-year-old girls having experienced menarche in either the year of the assessment of headache or 2 years before that, the risk for recurrent headache is increased when compared with girls without menarche. Intraindividual longitudinal analyses, however, do not support our hypotheses that after the onset of menarche headaches become more frequent. The expected differences in headache between girls with menarche and boys were found. The risk for migraine-like headaches is not significantly higher after onset of menarche than before. Thus, results do not consistently support the hypothesis that puberty is a moderator of headache frequency. Even in cases where the outcome of regression analyses is supportive of our expectations, explained variance is diminutive (maximum 2.2%). Thus, the influence of menarche on headache seems to be only marginal
Tracing sequential waves of rapid visuomotor activation in lateralized readiness potentials
No full textFeedforward activation processes are widely regarded as crucial for the automatic initiation of motor responses, whereas recurrent processes are often regarded as crucial for visual awareness. Here, we used a set of behavioral criteria to evaluate whether rapid processing in the human visuomotor system proceeds as would be expected of a feedforward system that works independent of visual awareness. We measured lateralized readiness potentials (LRPs) for key-press responses to color targets ("masks") preceded by masked color primes mapped onto the same or opposite response, and traced the time-course of motor activation as a function of different prime and mask characteristics. LRP time-courses showed that initial motor activation occurred in prime direction and was time-locked to prime onset. Response activation was then captured on-line by the mask signal, with motor activation now time-locked to the mask and proceeding in mask direction. Crucially, the timecourse of early activation by the prime was independent of all mask characteristics. This invariance in early priming effects contrasted with large differences in visual awareness for the prime produced by different masks. Results suggest that primed responses to color stimuli are controlled by feedforward waves of activation sequentially elicited by prime and mask signals traveling rapidly enough to escape the recurrent processes leading to backward masking. (c) 2006 IBRO. Published by Elsevier Ltd. All rights reserved
The assessment of disability in children and adolescents with headache: Adopting PedMIDAS in an epidemiological study
No full textObjective: The study aimed at the assessment of disability in children with headache (n = 1585, 11-14 yrs) from a randomly drawn population based sample. We explored the suitability of the PedMIDAS in epidemiological research by various indicators of response quality. Furthermore, predictors of disability were examined, as well as its association with measures of health care behaviour. Methods: The PedMIDAS measures functional interference in different domains of life by asking the children for the number of days that their headache partially or totally interfered with their activities. Results: The examination of response behaviour revealed a marked attrition of responses (missing, invalid) in two items. As a consequence, the total score for disability could not be obtained for about 25% of the children. Analysis of homogeneity of the PedMIDAS items revealed low item/total correlations in two items. The grading of disability resulted in 81.2% of all children with headache showing no or low disability. Only 1.4% was "severely" disabled. Disability was predicted by frequency, type and intensity of headache. From all psychological variables only dysfunctional stress coping was significantly associated with disability. Disability itself was significantly associated with medical consultation. Conclusions: Suitability of the PedMIDAS for epidemiological research was supported, however with a caveat and recommendations for item revision. Severe disability due to headache was rare in the studied unselected sample when defined by behavioural interference. It is suggested to explore the construct of disability by a multi-method approach, including further instruments assessing headache related distress, (respectively) quality of life. (C) 2010 European Federation of International Association for the Study of Pain Chapters. Published by Elsevier Ltd. All rights reserved
The burden of multiple pains in children and adolescents - Psychosocial correlates: Findings from an epidemiological study in Germany
No full textRisk Factors for Headache in Children
No full textBackground: 10% to 30% of all children worldwide suffer from headaches at least once a week, potentially constituting a serious health problem that may lead to impairment in multiple areas. Therefore, one aim of the epidemiological longitudinal study "Children, Adolescents, and Headache" (KiJuKo) is the study of potential risk factors for the development of recurrent headaches. Methods: In the first survey (2003), questionnaires were sent to 8800 households with a child between 7 and 14 years of age. Three further surveys followed, one each year from 2004 to 2006. A number of predictors having to do with family characteristics and leisure activities were identified on the basis of the first survey and were then studied in the second survey (n = 2952) with respect to their influence on the new occurrence of headaches. Results: The risk of developing recurrent headaches between the first and the second survey was elevated by a factor of approximately 1.8 for boys who experienced quarrels in the family more than once per week, and by a factor of 2.1 for boys who only "sometimes" had free time for themselves. The risk of developing recurrent headaches was 25% higher in girls whose parents' behavior towards the child positively or negatively reinforced the occurrence of headaches. Conclusions: These findings are in accordance with those of other studies showing that, for boys, the frequency of quarreling in the family and the extent of leisure time are major factors in the development of recurrent headaches. For girls, the manner in which the parents respond to the child's headache seems to be important.German Federal Ministry of Education and Research (BMBF) [01EM0521
Fitting of one ARMA model to multiple trials increases the time resolution of instantaneous coherence
No full textThis study presents a least mean squares (LMS) algorithm for the ensemble modeling of a multivariate ARMA process. Generally, an LMS algorithm makes possible the tracking of parameters for nonstationary time series. Our estimation incorporates multiple process observations that improve the accuracy of the parameter estimation. As a consequence, the estimation sequences come close to the true model parameters with a fast adaptation speed. This advantage also holds true of spectral quantities (e.g., the momentary coherence), which are derived from the model parameters. Thus the extension of the ARMA fitting from one to multiple trajectories allows the investigation of nonstationary biological signals with an increased time resolution. The applicability of the algorithm is demonstrated for event-related EEG coherence analysis of the Sternberg task. The changing interaction between posterior association cortex and anterior brain area was shown for verbal and nonverbal stimuli by means of the time-variant theta coherence
Multiple Pains in Children and Adolescents: A Risk Factor Analysis in a Longitudinal Study
No full textObjective: The aim of the study was to ascertain the prevalence of multiple pains (MPs) and detect psychosocial risk factors assessed 1 year previously. Method: MPs were defined by the number of sites where pain was reported to occur at least "sometimes" in a general population sample of 2,219 German youths. Results: Two or more sites of recurrent pain were reported by 54% of the participants, whereas 27% reported no pains. Girls were much more prone to MPs than boys. Stability of MP was high in the two waves. Regression analysis revealed that prior MP, age, sex, internalizing/externalizing symptoms, and time spent with visual media explained 25% of the variance: the contribution of the psychosocial factors to the model was small. Separate analyses for boys and girls displayed different risk-factor profiles and a higher degree of predictability in girls. Conclusion: A supposedly biological disposition, namely pain vulnerability, being particularly high in girls, is assumed to build the basis of pains felt in various sites of the body. Further research is needed to corroborate and specify these assumptions
Phase-coupling of theta-gamma EEG rhythms during short-term memory processing
No full textBecause of the importance of oscillations as a general phenomenon of neuronal activity the use of EEG spectral analysis is among the most important approaches for studying human information processing. Usually, oscillations at different frequencies occur simultaneously during information processing. Thus, the question for synchronisation of different frequencies by phase coupling and its possible functional significance is of primary importance. An answer may be given by bispectral analysis. Estimation of the (cross-) bispectrum allows to identify synchronised frequencies and possibly, the existence of non-linear phase coupling of different oscillators. Previous studies have demonstrated the simultaneous occurrence of slow (4-7 Hz) and fast (20-30 Hz) oscillations at frontal and prefrontal electrode positions during memory processing. However, interrelations between these rhythms have not been investigated up to now. In order to test short-term memory, the Sternberg task with random figures and number words was carried out on 10 female subjects. During the task EEG was recorded. Power and bispectral analyses from frontal, prefrontal and frontopolar regions were performed off-line. Increased power was found in both the theta and the gamma bands. Strong phase-coupling between theta at Fz and gamma at F3 and at Fp1, respectively, was shown for memorising number words by means of cross-bicoherence. A possible reason for this is an amplitude modulation of gamma frequencies by slow oscillations. The correspondent coherence analysis between the envelope of gamma frequencies at Fp1 and the raw EEG at Fz supports this presumption. This finding is interpreted as an EEG aspect of the functional linking between the prefrontal areas and the G.cinguli (as part of the limbic system), which are both extremely important for memory functions. (C) 2002 Elsevier Science B.V. All rights reserved
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