Maturation of the corticospinal (CS) tract and hand motor function provide paradigms for central nervous system development. In this study, involving 112 participants (aged from 0.2 to 30 years), we evaluated central motor conduction times (CMCT) obtained with transcranial magnetic stimulation (TMS) during preinnervation conditions of facilitation and relaxation. Auditory reaction time, velocity of a ballistic movement of the arm, finger tapping, diadochokinesis, and fine motor visuomanual tracking were also examined. The maturation profiles for every parameter were calculated. CMCTs for the different preinnervation conditions reached adult values at different times and this could be explained by maturation of excitability at the cortical and spinal level. A stable phase for CMCTs and reaction time was reached during childhood. Parameters which measured motor speed and skill indicated that the development of these continued into adulthood. The maturation of the fast CS tract seems to be completed before the acquisition of the related motor performance has been accomplished. In conclusion, we could demonstrate that data from several neurophysiological methods can be combined and used to study the maturation of the function of the nervous system. This approach could allow appraisal of pathological conditions that show parallels with omissions or lack of developmental progress.

Between 1987 and 1998, 470 patients visited the national clinic for obstetrical brachial plexus palsies at the Karolinska Hospital, Stockholm, Sweden. This study reports on 247 children examined at 5 years of age using a special protocol for testing the sensory and motor function of the hand. The children were distributed in various groups depending on the number of injured nerves, whether they had some muscle activity in their biceps or deltoid muscles at 3 months of age, and whether any operations with nerve reconstruction had been performed. The shoulder range of movement in C5–6 palsies was significantly better in the group which had been operated on (operated group), but otherwise there were no differences between children who had been operated on (non-operated group) and those who had not. A decrease in grip strength and bimanual function in level C5–6 palsies was found, though these roots should not innervate the distal hand. Outcome was not influenced by the number of avulsions in upper-plexus palsies or whether the operation took place before or after the age of 6 months. The group with extensive lesions (C5–Th1) had the most root avulsions, showing a correlation between increased avulsions and decreased hand function. This study does not support operating on children with no activity of the biceps and deltoid muscles at 3 months of age, as other authors have concluded. Rather, it favours waiting for a late recovery.

Children with cerebral palsy (CP) experience a change in motor function with age and development. It is important to consider this expected change in offering a prognosis, or in assessing differences in motor function after an intervention. The Gross Motor Function Classification System for CP (GMFCS) has been developed for these purposes. This study was based on a retrospective chart review of 85 children with CP followed from [les ]2 to [ges ]12 years of age. The GMFCS was applied to clinical notes by two blinded raters four times throughout the study. Interrater reliability was high (G=0.93). Test–retest reliability was high (G=0.79). The positive predictive value of the GMFCS at 1 to 2 years of age to predict walking by age 12 years was 0.74. The negative predictive value was 0.90. The GMFCS can validly predict motor function for children with CP. The results are discussed in terms of their implications for clinical practice and future research.

The aetiology of mental retardation (MR) was studied in a population-based series of Norwegian children derived from 30037 children born between 1980 and 1985. The study included 178 children, 79 with severe MR (SMR) (IQ<50) and 99 with mild MR (MMR) (IQ 50 to 70). Aetiology was divided into two main groups: biopathological and unspecified. The biopathological group comprised 96% of SMR and 68% of MMR, and was subdivided into prenatal (70% and 51%), perinatal (4% and 5%), and postnatal damage (5% and 1%), and a group of undetermined timing of the damaging event (18% and 11%). Single-gene disorders accounted for 15 of the 63 children with genetic disorders, including X-linked recessive in six. During the course of the study, at least 27 (15%) children had their aetiological diagnosis revised. Gestational age <32 weeks, birthweight <1500 g, and Apgar scores 0 to 2 at 1 and 5 minutes implied a significantly increased risk of MR, but contributed to only 4% of the children in the study. Decreased birthweight (1500 to 2499 g) and Apgar scores 3 to 6 at 1 and 5 minutes showed increased probability of MR. Despite extensive investigations, 4% of SMR and 32% of MMR were not identified with any biological markers and were considered as unspecified MR, several most probably representing the lower end of the normal IQ distribution in the population.

To determine the effect of intravenous porcine secretin on autistic behaviours in children aged 2 to 7 years, the effects of secretin on (1) performance on a standardized language measure, and (2) autistic behaviours, as rated by parents and child development professionals was examined. Employing a randomized, double-blind, placebo-controlled design, 95 participants were assigned to one of two groups and administered a single dose of either secretin or placebo. A follow-up assessment was conducted 3 weeks after the injection. No significant differences in language or autistic behaviour measures were observed at the 3-week follow-up between the groups. Also, there was no significant difference in the proportion of individuals who improved by [ges ] 6 points on the language measure at follow-up. This study showed no significant effects of secretin on children with autism. Our results are consistent with a systematic review of randomized controlled trials evaluating the effect of secretin in children with autism.

Injury to the developing cortical plate can result in a variety of neuronal migration disorders. The results are reported of experimental research aimed at determining whether these different types of neocortical malformations are the consequence of comparable injury of varying intensity. Freezing probes were placed on the skulls of 44 newborn rats (age equivalent to 4 to 5 months of gestation in humans) and induced either one or two freezing injuries of durations ranging from 2 to 20 seconds. A variety of cortical malformations including minor laminar dysplasias, molecular layer ectopias, microgyria, and porencephalic cysts were seen in the brains of these animals when they were examined on postnatal day (P)2, P21, and P60. The severity of the malformation was directly related to the strength (number of hits and duration) of the freezing injury. These results suggest that a single etiologic event of varying severity during neuronal migration to the neocortex can induce widely disparate malformations of the cortex.

Sixty-nine very-low-birthweight infants out of a population of 923 had cerebral palsy (CP) at an 18-month follow-up. Thirty-nine of these had cranial ultrasound abnormalities in the neonatal period and 30 had normal cranial ultrasounds. The distribution of subtypes of CP differed markedly between the two groups, with hemiplegia predominating in those with abnormal cranial ultrasounds and diplegia in those with normal cranial ultrasounds. Regardless of ultrasound appearance, the relative risk of CP increased approximately fourfold with a neonatal history of sepsis.

The aim of this study was to examine whether boys who had been previously diagnosed between the ages of 5 and 8 years with deficits in attention, motor control and perception (DAMP) still have problems with motor control, which influence their spare-time and everyday activities, at 11 to 12 years. The study comprised a well defined cohort of 10 boys with DAMP and a control group of 20 boys without DAMP matched for age, height, and weight. The Movement Assessment Battery for Children was used to assess motor control in ability to perform everyday activities, and the spare-time activities in which the boys participated were recorded. Individually, the boys previously diagnosed with DAMP had a markedly higher total score (poor performance) than the boys without DAMP (P<0.001). The everyday activities of boys with DAMP were significantly affected, and they chose to participate in different sports from the control boys, i.e. none participated in team sports. The present study does not support the concept of improvements in motor control with age in children with DAMP.