SUMMARYThere is controversy over the definition of hypoglycaemia in neonates and children and over its significance when 'asymptomatic'. We measured sensory evoked potentials in relation to blood glucose concentration in 17 children: 13 were fasted or given insulin to investigate endocrine or metabolic abnormalities and four had spontaneous episodes of hypoglycaemia. Abnormal evoked potentials were recorded in 10 of

SUMMARY The motor cortex can be excited in adults using electromagnetic stimulation, and the latency to the evoked muscle action potential allows an assessment of the integrity of corticospinal tracts. We applied this technique in children to describe the maturation of corticospinal tracts. The latency from cortical stimulation to the onset of the evoked muscle action potentials and the subject's height were recorded. The subject's height was divided by the latency to the onset of the evoked muscle action potential to provide an index of the conduction velocity within descending motor pathways (VI). It is possible to evoke muscle action potentials after electromagnetic stimulation of the motor cortex in children including preterm babies and there is a stepwise increase in the sensitivity to stimulation between 8 and 11 years of age. In addition there is a progressive increase in VI with age; adult values are attained at about 11 years.The successful application of this technique in children suggests that electromagnetic stimulation of the motor cortex has the potential to allow detection of abnormality in motor pathways in newborn babies and young children.In young children it is difficult to assess the integrity of central motor pathways. Clinical examination is unreliable particularly in the very young child or in the newborn infant.' The recent development of the technique of electromagnetic stimulation of the motor cortex provides, for the first time, the opportunity to assess objectively the integrity of corticospinal tracts in children.2 This method uses a flat circular stimulating coil through which a brief current is passed.2 The pulsed magnetic field so generated induces electrical currents in the brain, which are assumed to excite the superficial layers of the cortex. When the coil is held over the motor cortex, activity is evoked in the corticospinal tracts and results in muscle action potentials, measureable by surface electromyogram electrodes.2 3 The method is simple, painless, and quick and is therefore particularly suitable for use in children. Before this technique can be used to investigate abnormalities in motor pathway function in children, however, the normal developmental changes in the conduction velocity within the motor pathways need to be defined.

SUMMARY Major paediatric textbooks and the views of neonatologists in the United Kingdom were surveyed to establish a definition of neonatal hypoglycaemia. The definition ranged from a glucose concentration of <1 mmol/l to <4 mmol/l. Hypoglycaemia is recognised to cause neurological sequelae and yet there is no accepted definition of the lower limit of normality for circulating blood glucose concentrations.There are few areas in neonatology that are as controversial as the definition of hypoglycaemia. Hypoglycaemia is recognised as a common problem in newborn babies but its incidence is difficult to ascertain due to the controversy over definition. Sexson highlighted the issue in his paper where he showed that the incidence of hypoglycaemia in the 232 babies he studied would be 8-1% if hypoglycaemia was defined as a blood glucose concentration of <1*7 mmol/ or 20-6% if it was defined as <2-2 mmol/l.1The aim of our study was to establish the degree of variation in the definitions of hypoglycaemia among paediatric textbooks and paediatricians in charge of special care nurseries in the United Kingdom. MethodsThe definition of hypoglycaemia, with reference to the glucose concentrations in whole blood in term babies who were born with a weight appropriate for gestational age and in babies who were preterm or small for gestational age, was ascertained (a) in 36 current paediatric textbooks and (b) from consultants in charge of special care nurseries with one or more intensive care cots. The names of the consultants were obtained from the Directory of Emergency and Special Care Units 1986,2 and postal questionnaires were sent to them. ResultsThe definitions of hypoglycaemia obtained from the review of the 36 textbooks of paediatrics are shown in fig 1. There was a very wide variation in the definitions given ranging from a glucose concentration of <1 mmol/ to <2*5 mmol/l with a modal value of <1-7 mmol/l for term babies of appropriate weight, and <1-1 mmol/l for babies who were preterm or small for gestational age.

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The association of pancreatoblastoma and Wiedemann-Beckwith syndrome has not been noted previously. In this report we describe a child with Wiedemann-Beckwith syndrome who had a pancreatoblastoma resected on day 27 of life. He is also the first reported case of Wiedemann-Beckwith syndrome in a black baby.