167 resultados para developmental disorder


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Heart rate (HR) has been widely studied as a measure of an individual's response to painful stimuli. It remains unclear whether changes in mean HR or the variability of HR are specifically related to the noxious stimulus (i.e. pain). Neither is it well understood how such changes reflect underlying neurologic control mechanisms that produce these responses, or how these mechanisms change during the first year of life. To study the changes in cardiac autonomic modulation that occur with acute pain and with age during early infancy, the relationship between respiratory activity and short-term variations of HR (i.e. respiratory sinus arrhythmia) was quantified in a longitudinal study of term born healthy infants who underwent a finger lance blood collection at 4 months of age (n = 24) and again at 8 months of age (n = 20). Quantitative respiratory activity and HR were obtained during baseline, lance, and recovery periods. Time and frequency domain analyses from 2.2-min epochs of data yielded mean values, spectral measures of low (0.04-0.15 Hz) and high (0.15-0.80 Hz) frequency power (LF and HF), and the LF/HF ratio. To determine sympathetic and parasympathetic cardiac activity, the transfer relation between respiration and HR was used. At both 4 and 8 months, mean HR increased significantly with the noxious event (p > 0.01). There were age-related differences in the pattern of LF, HF, and LF/HF ratio changes. Although these parameters all decreased (p > 0.01) at 4 months, LF and LF/HF increased at 8 months and at 8 months HF remained stable in response to the noxious stimulus. Transfer gain changes with the lance demonstrated a change from predominant vagal baseline to a sympathetic condition at both ages. The primary finding of this study is that a response to an acute noxious stimulus appears to produce an increase in respiratory-related sympathetic HR control and a significant decrease in respiratory-related parasympathetic control at both 4 and 8 months. Furthermore, with increasing age, the sympathetic and parasympathetic changes appear to be less intense, but more sustained.

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Caretakers intuitively use various sources of evidence when judging infant pain, but the relative importance of salient cues has received little attention. This investigation examined the predictive significance for judgements of painful discomfort in preterm and full-term neonates of behavioural (facial activity and body movement), contextual (invasiveness of the procedure), and developmental (gestational age) information. Judges viewed videotapes showing infants varying in the foregoing characteristics undergoing heel incisions for routine blood sampling purposes. Findings indicated all but the contextual information contributed uniquely to judgements of pain, with facial activity accounting for the most unique variance (35%), followed by bodily activity and gestational age, each accounting for 3% and 1% of the judgmental variance, respectively. Generally, 71% of the variance in ratings of pain could be predicted using facial activity alone, compared to 30% of the variance using bodily activity alone, 19% by relying on context alone, and 8% by referring to gestational age alone. Noteworthy was the tendency to judge early preterm infants to be experiencing less pain even though they were subjected to the same invasive procedure as the older infants. This finding also runs counter to evidence from developmental neurobiology which indicates that preterm newborns may be hypersensitive to invasive procedures.

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Age-related changes in the facial expression of pain during the first 18 months of life have important implications for our understanding of pain and pain assessment. We examined facial reactions video recorded during routine immunization injections in 75 infants stratified into 2-, 4-, 6-, 12-, and 18-month age groups. Two facial coding systems differing in the amount of detail extracted were applied to the records. In addition, parents completed a brief questionnaire that assessed child temperament and provided background information. Parents' efforts to soothe the children also were described. While there were consistencies in facial displays over the age groups, there also were differences on both measures of facial activity, indicating systematic variation in the nature and severity of distress. The least pain was expressed by the 4-month age group. Temperament was not related to the degree of pain expressed. Systematic variations in parental soothing behaviour indicated accommodation to the age of the child. Reasons for the differing patterns of facial activity are examined, with attention paid to the development of inhibitory mechanisms and the role of negative emotions such as anger and anxiety.

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The purpose of this study was to examine the behavioural responses of infants to pain stimuli across different developmental ages. Eighty infants were included in this cross-sectional design. Four subsamples of 20 infants each included: (1) premature infants between 32 and 34 weeks gestational age undergoing heel-stick procedure; (2) full-term infants receiving intramuscular vitamin K injection; (3) 2-month-old infants receiving subcutaneous injection for immunisation against DPT; and (4) 4-month-old infants receiving subcutaneous injection for immunisation against DPT. Audio and video recordings were made for 15 sec from stimulus. Cry analysis was conducted on the first full expiratory cry by FFT with time and frequency measures. Facial action was coded using the Neonatal Facial Action Coding System (NFCS). Results from multivariate analysis showed that premature infants were different from older infants, that full-term newborns were different from others, but that 2- and 4-month-olds were similar. The specific variables contributing to the significance were higher pitched cries and more horizontal mouth stretch in the premature group and more taut tongue in the full-term newborns. The results imply that the premature infant has the basis for communicating pain via facial actions but that these are not well developed. The full-term newborn is better equipped to interact with his caretakers and express his distress through specific facial actions. The cries of the premature infant, however, have more of the characteristics that are arousing to the listener which serve to alert the caregiver of the state of distress from pain.

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Objectives. In a bipolar disorder (BD) sample, the present study investigated: (i) the prevalence of trauma; (ii) the specificity of autobiographical memory (AM); (iii) the influence of childhood trauma on AM specificity, current inter-episode depressive mood, and BD severity; (iv) if AM specificity moderates the influence of childhood trauma on current inter-episode depressive mood and BD severity.

Methods. Fifty-two participants were recruited from a geographically well-defined mental health service in Northern Ireland. The AM test, self-report measures of lifetime experience of trauma, childhood trauma, and depression were administered. Severity of BD was estimated utilizing a systematic tool for reviewing all available clinical data of participants.

Results. A high prevalence of trauma was found. A total of 94.2% (49/52) of participants reported experiencing a traumatic event in either childhood or adulthood. AM specificity was significantly lower than previous reports of such in major depression. However, whilst childhood trauma predicted current inter-episode depressive mood, childhood trauma was not predictive of BD severity or AM specificity. Moreover, the association between childhood trauma and depressed mood was not moderated by AM specificity.

Conclusions. The findings of this study suggest a relationship between early psychosocial adversity and current inter-episode depressive mood in BD. In addition, levels of overgeneral AM are similar to that reported for depression, but are unrelated to childhood trauma, current inter-episode depressive mood, or BD severity. Clinical implications include the importance of routine assessment of trauma in BD and the need for adjunctive evidenced-based psychological therapies.

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Objectives: This study examined: (i) the prevalence of lifetime trauma, childhood trauma and trauma related to civil unrest in a Bipolar Disorder sample, and (ii) the agreement between rates of disclosure of trauma in case notes and self-report questionnaires.

Methods: The case notes of sixty participants, recruited from a geographically well-defined mental health service in Northern Ireland, were examined for reports of experiences of lifetime, childhood and traumatic events related to civil conflict. The participants also completed self-report measures of trauma.

Results: Considerable differences were found between the prevalence of trauma as measured by self-report questionnaires and case notes reports. The prevalence of lifetime trauma as measured by the Trauma History Questionnaire was 61.7% (compared to case notes prevalence of 33.3%). The prevalence of moderate and severe levels of childhood trauma as measured by the Childhood Trauma Questionnaire was 65% (case notes 21.7%). Rates of trauma related to civil unrest were 35% (case notes 3.3%). Poor levels of agreement were found between all self-report trauma measures and case notes reports. Agreement on two categories of trauma (childhood emotional neglect and childhood physical neglect) reached statistical significance but kappa scores suggest this agreement was poor (kappa = .14. p<.05; kappa = .127, p<.05). © 2011 Elsevier B.V. All rights reserved.

Conclusions: It is probable that the increased rate of trauma disclosed in the self-report questionnaire arises because clinicians during initial assessment and subsequent treatment do not consistently enquire about trauma. The need for staff training is discussed. (C) 2011 Elsevier B.V. All rights reserved.

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Macromolecules are a minority but important component of the minerals formed by living organisms, or biominerals. The role these macromolecules play at the early stages of biomineral formation, as well as their long-term and long-range effects on the mature biomineral, is poorly understood. A 42-amino acid peptide, asp2, was derived from the Asprich family of proteins. In this study we present X-ray absorption near-edge structure spectroscopy and X-ray photoelectron emission microscopy data from the asp2 peptide, the calcite (CaCO3) crystals, and the peptide + crystal composites. The results clearly show that asp2 is occluded in fully formed biomineral crystals and slightly but permanently disorders the crystal structure at short- and long-range distances.

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The effect of temperature on the structure of the ice Ih (0001) surface is considered through a series of molecular dynamics simulations on an ice slab. At relatively low temperatures (200K) a small fraction of surface self-interstitials (i.e. admolecules) appear that are formed exclusively from molecules leaving the outermost bilayer. At higher temperatures (ca. 250 K), vacancies start to appear in the inner part of the outermost bilayer exposing the underlying bilayer and providing sites with a high concentration of the dangling hydrogen bonds. Around 250-260 K aggregates of molecules formed on top of the outermost bilayer from self-interstitials become more mobile and have diffusivities approaching that of liquid water. At similar to 270-280 K the inner bilayer of one surface noticeably destructures and it appears that at above 285 K both surfaces are melting. The observed disparity in the onset of melting between the two sides of the slab is rationalised by considering the relationship between surface energy and the spatial distribution of protons at the surface; thermodynamic stability is conferred on the surface by maximising separations between dangling protons at the crystal exterior. Local hotspots associated with a high dangling proton density are suggested to be susceptible to pre-melting and may be more efficient at trapping species at the external surface than regions with low concentrations of protons thus potentially helping ice particles to catalyse reactions. A preliminary conclusion of this work is that only about 10-20 K below the melting temperature of the particular water potential employed is major disruption of the crystalline lattice noted which could be interpreted as being "liquid", the thickness of this film being about a nanometre.

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Growing evidence suggests that significant motor problems are associated with a diagnosis of Autism Spectrum Disorders (ASD), particularly in catching tasks. Catching is a complex, dynamic skill that involves the ability to synchronise one's own movement to that of a moving target. To successfully complete the task, the participant must pick up and use perceptual information about the moving target to arrive at the catching place at the right time. This study looks at catching ability in children diagnosed with ASD (mean age 10.16 ± 0.9 years) and age-matched non-verbal (9.72 ± 0.79 years) and receptive language (9.51 ± 0.46) control groups. Participants were asked to "catch" a ball as it rolled down a fixed ramp. Two ramp heights provided two levels of task difficulty, whilst the sensory information (audio and visual) specifying ball arrival time was varied. Results showed children with ASD performed significantly worse than both the receptive language (p =.02) and non-verbal (p =.02) control groups in terms of total number of balls caught. A detailed analysis of the movement kinematics showed that difficulties with picking up and using the sensory information to guide the action may be the source of the problem. © 2013 Elsevier Ltd.

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Reasoning about problems with empirically false content can be hard, as the inferences that people draw are heavily influenced by their background knowledge. However, presenting empirically false premises in a fantasy context helps children and adolescents to disregard their beliefs, and to reason on the basis of the premises. The aim of the present experiments was to see if high-functioning adolescents with autism are able to utilize fantasy context to the same extent as typically developing adolescents when they reason about empirically false premises. The results indicate that problems with engaging in pretence in autism persist into adolescence, and this hinders the ability of autistic individuals to disregard their beliefs when empirical knowledge is irrelevant.

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Cell and tissue patterning in plant embryo development is well documented. Moreover, it has recently been shown that successful embryogenesis is reliant on programmed cell death (PCD). The cytoskeleton governs cell morphogenesis. However, surprisingly little is known about the role of the cytoskeleton in plant embryogenesis and associated PCD. We have used the gymnosperm, Picea abies , somatic embryogenesis model system to address this question. Formation of the apical-basal embryonic pattern in P. abies proceeds through the establishment of three major cell types: the meristematic cells of the embryonal mass on one pole and the terminally differentiated suspensor cells on the other, separated by the embryonal tube cells. The organisation of microtubules and F-actin changes successively from the embryonal mass towards the distal end of the embryo suspensor. The microtubule arrays appear normal in the embryonal mass cells, but the microtubule network is partially disorganised in the embryonal tube cells and the microtubules disrupted in the suspensor cells. In the same embryos, the microtubule-associated protein, MAP-65, is bound only to organised microtubules. In contrast, in a developmentally arrested cell line, which is incapable of normal embryonic pattern formation, MAP-65 does not bind the cortical microtubules and we suggest that this is a criterion for proembryogenic masses (PEMs) to passage into early embryogeny. In embryos, the organisation of F-actin gradually changes from a fine network in the embryonal mass cells to thick cables in the suspensor cells in which the microtubule network is completely degraded. F-actin de-polymerisation drugs abolish normal embryonic pattern formation and associated PCD in the suspensor, strongly suggesting that the actin network is vital in this PCD pathway.

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Despite being largely characterised as a social and cognitive disorder, strong evidence indicates the presence of significant sensory-motor problems in Autism Spectrum Disorder (ASD). This paper outlines our progression from initial, broad assessment using the Movement Assessment Battery for Children (M-ABC) to subsequent targeted kinematic assessment. In particular, pronounced ASD impairment seen in the broad categories of manual dexterity and ball skills was found to be routed in specific difficulties on isolated tasks, which were translated into focused experimental assessment. Kinematic results from both subsequent studies highlight impaired use of perception-action coupling to guide, adapt and tailor movement to task demands, resulting in inflexible and rigid motor profiles. In particular difficulties with the use of temporal adaption are shown, with "hyperdexterity" witnessed in ballistic movement profiles, often at the cost of spatial accuracy and task performance. By linearly progressing from the use of a standardised assessment tool to targeted kinematic assessment, clear and defined links are drawn between measureable difficulties and underlying sensory-motor assessment. Results are specifically viewed in-light of perception-action coupling and its role in early infant development suggesting that rather than being 'secondary' level impairment, sensory-motor problems may be fundamental in the progression of ASD. This logical and systematic process thus allows a further understanding into the potential route of observable motor problems in ASD; a vital step if underlying motor problems are to be considered a fundamental aspect of autism and allow a route of non-invasive preliminary diagnosis.