Search

Objective. Abnormalities in brain structure, cognition, and behavior have been described in children born prematurely. However, no direct in vivo evidence has yet demonstrated abnormal neural processing in these children. Our aim was to compare brain activity associated with phonologic and semantic processing of language between term and preterm children using functional magnetic resonance imaging (fMRI). Methods. fMRI scans were acquired during a passive language comprehension task in 26 preterm children at 8 years of age and in 13 term community control children who were comparable in age, sex, maternal education, and minority status. IQ was assessed using a standard measure of intelligence. Results. The pattern of brain activity identified in a semantic processing task in the preterm children closely resembled the pattern of brain activity identified in a phonologic processing task in term controls. The greater this resemblance in the preterm children, the lower their verbal comprehension IQ scores and the poorer their language comprehension during the scanning task. Conclusions. Preterm children with the poorest language comprehension seemed not to fully engage normal semantic processing pathways in a language comprehension task. These children instead engaged pathways that normal term children used to process meaningless phonologic sounds. Aberrant processing of semantic content in these preterm children may account in part for their lower verbal IQ scores. Pediatrics 2002;110:1153-1162; functional MRI, children, prematurity, cognition, outcome., Children born prematurely are known to be at risk for cognitive and behavioral problems, including lower IQ, learning disorder, thought disturbance, and excessive distractibility and hyperactivity. (1-6) Anatomic abnormalities in [...]

A novel method for detecting determinism in short time series is developed and applied to investigate determinism in stationary electroencephalogram (EEG) recordings. This method is based on the observation that the trajectory of a time series generated from a differentiable dynamical system behaves smoothly in an embedded state space. The angles between two successive tangent vectors in the trajectory reconstructed from the time series is calculated as a function of time. The irregularity of the angle variations obtained from the time series is estimated using second-order difference plots, and compared with that of the corresponding surrogate data. Using this method, we demonstrate that scalp EEG recordings from normal subjects do not exhibit a low-dimensional deterministic structure. This method can be useful for analyzing determinism in short time series, such as those from physiological recordings. Index Terms--Determinism, smoothness, stationary EEG, time series.

A significant majority of children who have Tourette syndrome (TS) have a definite pattern to the convulsive tics which characterize the disorder, increasing in frequency and severity until a certain age and then decreasing. Of 42 children with TS born in the same year, the average was an increase in tics until the worst period at age 10, then a decrease until, by age 18, there were practically no tic episodes for nearly half of the group. Puberty did not seem to have any connection with the pattern., Objective. Prevalence studies indicate a 10-fold higher rate of Tourette syndrome (TS) among children compared with adults. The purpose of this investigation was to examine the course of tic severity during the first 2 decades of life. Method. A birth-year cohort of 42 TS patients followed at the Yale Child Study Center was recontacted an average of 7.3 years after their initial clinical evaluation. Data concerning the onset and course of tic severity until 18 years of age were available on 36 TS patients. A variety of statistical techniques were used to model aspects of the temporal patterning of tic severity. Results. Mean (SD) tic onset at 5.6 (2.3) years of age was followed by a progressive pattern of tic worsening. On average, the most severe period of tic severity occurred at 10.0 (2.4) years of age. In eight cases (22%), the frequency and forcefulness of the tics reached a severe level during the worst-ever period such that functioning in school was impossible or in serious jeopardy. In almost every case this period was followed by a steady decline in tic severity. By 18 years of age nearly half of the cohort was virtually tic-free. The onset of puberty was not associated with either the timing or severity of tics. Conclusions. A majority of TS patients displayed a consistent time course of tic severity. This consistency can be accurately modeled mathematically and may reflect normal neurobiological processes. Determination of the model parameters that describe each patient's course of tic severity may be of prognostic value and assist in the identification of factors that differentially influence the course of tic severity. Pediatrics 1998;102:14-19. Tourette syndrome, natural history, growth curve analysis, puberty. ABBREVIATIONS. TS, Tourette syndrome; YCSC, Yale Child Study Center Tic Disorders Clinic; ADHD, attention deficit-hyperactivity disorder; OCD, obsessive-compulsive disorder; CGI, Clinical Global Impression (scale); SES, socioeconomic status; YGTSS, Yale Global Tic Severity Scale; ARRTS, annual rating of relative tic severity; STOBS-R, Schedule for Tourette and Other Behavioral Syndromes, Adult-on-Child Version, Revised; MSRPF, Modified Schedule for Risk and Protective Factors., Epidemiologic studies have indicated a higher prevalence rate of Tourette syndrome (TS) among children compared with adults. In children, prevalence rates as high as 50 per 10 000 have been [...]

Tourette's syndrome pathogenesis model includes phenomenology, natural history, genetic, epigenetic and environmental factors and neurobiological substrates. The disease has a wide range of motor and phonic tic symptoms including, sudden, repetitive movements, gestures or utterances. Twin and family studies indicate that genetic factors affect the transmission and expression of the syndrome, while epigenetic and environmental factors determine its nature and severity. Evidence suggests the involvement of cortico-striato-thalamo-cortical circuits and certain neurotransmitters.