J. Ardura-Fernández

Decline and loss of birth seasonality in Spain: analysis of 33 421 731 births over 60 years

Background and aim: Several seasonal variations have been found in birth rates in different countries at different periods. The characteristics of the rhythmic patterns vary according to geographical location and chronological changes. This study presents data on spanish birth seasonality over six decades. Methods: A time series composed of 33 421 731 births in Spain in the period 1941–2000 was analysed. The series comes from the National Institute of Statistics and was processed according to the following norms: (1) normalisation of the duration of months and years; (2) clinical analysis of temporal series (isolation of seasonal component); (3) Fourier’s spectral analysis; and (4) cosinor analysis (adjustment to the cosine curve of two harmonics). Results: Significant seasonal rhythm was found in the set of births, both for a 12-month period and a 6-month period. The rhythm shows bimodal morphology, with a pronounced birth peak in April and a smaller one in September. These peaks correspond to July and December conceptions, respectively. The major birth peak shifted to March–May between the 1940s and the 1980s. Birth rhythm changed after the 1960s, with a decrease in amplitude and later loss of seasonality in the 1990s. Conclusions: In Spain, seasonal birth rhythm shows a decline from 1970, and, finally, lack of birth seasonality in 1991–2000. This trend is similar to other European countries, although Spain shows a more intense loss of seasonality.

Nonlinear analysis of actigraphic signals for the assessment of the attention-deficit/hyperactivity disorder (ADHD)

Attention-deficit/hyperactivity disorder (ADHD) is the most common neurobehavioral disorder in children and adolescents; however, its etiology is still unknown, which hinders the existence of reliable, fast and inexpensive standard diagnostic methods. In this paper, we propose a novel methodology for automatic diagnosis of the combined type of ADHD based on nonlinear signal processing of 24h-long actigraphic registries. Since it relies on actigraphy measurements, it constitutes an inexpensive and non-invasive objective diagnostic method. Our results on real data reach 96.77% sensitivity and 84.38% specificity by means of multidimensional classifiers driven by combined features from different time intervals. Our analysis also reveals that, if features from a single time interval are used, the whole 24-h interval is the only one that yields classification figures with practical diagnostic capabilities. Overall, our figures overcome those obtained by actigraphy-based methods reported and are comparable with others based on more expensive (and not so convenient) adquisition methods.

Melatonin rhythm in children with enuresis

To study the circadian rhythm of melatonin in children with enuresis.

Beta blocker therapy modifies circadian rhythm acute myocardial infarction

Some studies about the onset time of AMI revealed that the peak incidence of pain onset signaling the occurrence of AMI ranged from 08:00 to 11:00 h in presumably diurnally active persons [1,2]. A recent study published by our group showed a morning incidence peak as well [3]. Otherwise the use of beta blockers could be caused by an attenuation or complete removal of the peaks of incidence of myocardial ischemia andAMI [4,5].When cardio selective beta blocker agents were used, no peaks of incidence were found [6]. The objective of this study is to evaluate, by means of a new method of analysis [7], the presence of circadian variation in the time of onset of AMI in subgroups of patients receiving beta-adrenergic blockade agents. Patients with diagnosis of AMI at ICU discharge in 119 Spanish hospitals, according to WHO criteria, were collected from the ARIAM database. Among the whole group of 14,952 AMI, we selected a subgroup of 2055 patients who were taking beta-blocker agents. The selected study variable was the time of onset of symptoms. In order to carry out the rhythmometric analysis, we record and round AMI onset time to the nearest integer hour for every patient. With the purpose of verifying the presence of circadian rhythm, we used themultiple-sinusoid cosinor analysis.We identify the periods of these new sinusoids by means of nonlinear optimization techniques but it is also common to infer them using their clinical meaning. Following the latter approach, three sinusoids with periods of 24, 12 and 8 h were used [7]. We obtained the parameters of the model (MESOR and two additional parameters per sinusoid, namely, a function of the amplitude and the acrophase), as previously stated, by linear least squares fitting. A simple inspection of the cosinor fit and the original data showed that the fit was acceptable, and we did not consider further goodness-of-fit tests worth taking. The characteristics of the study population were: The mean age was 66.5±11.3 years old (64.8±11 for males and 71.3±9.2 for females). 46% were older than 70 years. Male/Female ratio was 72.9%/27.1%. 60.9% of AMI was Q-wave AMI. AMI location was anterior in 39.8%. 90.3% of AMI were alive at ICU discharge. In addition, previous cardiovascular risk factors were hypertension

Characterization of activity epochs in actimetric registries for infantile colic diagnosis: Identification and feature extraction based on wavelets and symbolic dynamics

The diagnosis and therapy planning of high prevalence pathologies such as infantile colic can be substantially improved by statistical signal processing of activity/rest registries. Assuming that colic episodes are associated to activity episodes, diagnosis aid systems should be based on preprocessing techniques able to separate real activity from rest epochs, and feature extraction methods to identify meaningful indices with diagnostic capabilities. In this paper, we propose a two step diagnosis aid methodology for infantile colic in children below 3 months old. Identification of activity periods is performed by means of a wavelet based activity filter which does not depend on the acquisition device (as so far proposed methods do). In addition, symbolic dynamic analysis is used for extraction of discriminative indices from the activity time series. Results on real data yielded 100% sensitivity and 80% specificity in a study group composed of 46 cases and 10 control subjects.

Diferencias en el ritmo circadiano del infarto de miocardio según su extensión electrocardiográfica

Fundamento y objetivo: Determinar la existencia de ritmo circadiano en la hora de inicio del infarto de miocardio (IM) segun su extension electrocardiografica Q/no Q. Pacientes y metodo: Estudio retrospectivo de una cohorte de pacientes del proyecto ARIAM que incluyo 54.249 IM. Se analizan variables generales del infarto (edad, sexo, cardiopatia isquemica previa, extension del infarto, localizacion, supervivencia al alta de la unidad de cuidados intensivos), factores de riesgo cardiovascular y tratamientos farmacologicos previos al episodio estudiado. Para verificar la presencia de ritmo circadiano se ha desarrollado un test simple de igualdad de series basado en el analisis cosinor de multiples sinusoides, utilizando 3 sinusoides de periodos de 24, 12 y 8 h. Resultados: La hora de inicio de los sintomas del infarto mostro ritmo circadiano (p < 0,0000) tanto en el IM Q como en el IM no Q. Los IM Q presentan un patron con un unico maximo de incidencia matinal y los no Q, un patron bimodal con doble pico de incidencia. La comparacion entre dichos patrones muestra diferencias significativas en su ajuste (p < 0,0000). Conclusiones: La hora de inicio del IM sigue un patron circadiano, que tambien se observa en los subgrupos analizados. Las diferencias entre los ritmos circadianos segun el tipo de IM (Q frente a no Q) podrian explicarse por el distinto mecanismo fisiopatologico de ambos subtipos de infarto. El modelo de analisis de cosinor ajustado con 3 componentes (periodos de 24, 12 y 8 h) muestra buena sensibilidad para la deteccion de ritmo circadiano.