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Biomedical subjects

N Marlow

Publications and source records attributed to N Marlow.

At least 19 recordsLinked to original sources

Posterior tibial somatosensory evoked potentials in very preterm infants.

Cortical posterior tibial somatosensory (SSEP) responses were reliably recorded from 67 infants of 33 weeks gestation or less who had normal neurological outcome at 24 months corrected age. Cross-sectional and longitudinal data did not show a change in waveform morphology with advancing gestation or postnatal age. The latency of the first cortical component shortened as maturation increased. This study provides normative data for the peak component waveforms of the response in very preterm infants. The role of the posterior tibial SSEP in the prediction of functional brain injury in this high risk population can now be determined.

Cross-Sectional Studies

Risk factors for developing neonatal septicaemia at a Malaysian hospital.

A case-control study of antecedents of neonatal septicaemia was performed using 50 cases of neonatal septicaemia and 73 comparison infants from a Malaysian hospital nursery. Multivariate analysis indicated the following independent risk factors: maternal primiparity, pre-eclampsia, prolonged rupture of membranes, twin pregnancy, prematurity, assisted ventilation, umbilical catheterization, and formula feeding. Although the spectrum of causative organisms varied between our study and past studies from Western countries, the risk factors for developing neonatal septicaemia were strikingly similar. Therefore, preventative guidelines based on risk factors described in Western countries, should help reduce the incidence of neonatal septicaemia at this Malaysian hospital.

Case-Control Studies

Attention deficit hyperactivity disorders and other psychiatric outcomes in very low birthweight children at 12 years.

One hundred and thirty-seven very low birthweight (VLBW) children were compared at 12 years with a sample of matched peers on a number of psychiatric symptoms including Attention Deficit/Hyperactivity Disorder, depression, anxiety, and antisocial behaviour using the Child and Adolescent Psychiatric Assessment parent interview and various parent and child questionnaires. The main psychiatric risk was Attention Deficit Hyperactivity (ADH) disorders, with 31/136 (23%) VLBW children meeting clinical criteria, compared to 9/148 (6%) of peers. VLBW children were also more likely to have generalised anxiety and more symptoms of depression. More than one quarter of VLBW children (38/136; 28%) showed a psychiatric disorder of some type compared to 9% (14/148) of peers. VLBW children are at increased risk of psychiatric symptoms especially ADHD. This outcome is discussed in relation to neurological, demographic, and cumulative impairment factors.

Anxiety Disorders

Visual impairment in very low birthweight children.

AIMS: To compare the visual function of a cohort of very low birthweight (VLBW) children in early adolescence with that of their normal birthweight peers; to correlate visual impairment in this group with available perinatal data; and to examine the relation between the visual ability of VLBW children and their cognitive and motor skills. METHODS: As part of a long term neurodevelopmental study, 137 VLBW children and 163 normal birthweight controls were visually assessed between the ages of 11 and 13 years. Their eyes were examined for strabismus and movement disorders, and the use of visual correction for refractive errors was noted. Measures were made of visual acuity, stereopsis, and contrast sensitivity. All children had standardised tests of motor ability and cognitive skills. Perinatal data, including cranial ultrasonography results, had been obtained from the children's notes. No data were available however, regarding retinopathy of prematurity as screening was not established when these infants were born. RESULTS: On all measures, the visual function of the VLBW children was poorer than that of the controls. Reduced visual function was present in 63.5% of VLBW children compared with 36% of controls. Poor contrast sensitivity and strabismus were predictive of poor motor skills in the VLBW children. Poor contrast sensitivity and poor visual acuity (at 0.3 metres) were predictive of lower IQ. Low birthweight, intraventricular haemorrhage, intrauterine growth retardation and low 1 minute Apgar scores predicted reduced visual function. CONCLUSIONS: VLBW children have a high incidence of impaired vision. Stereopsis and contrast sensitivity are useful additions to the screening of this high risk group. They identified impaired vision that was not detected by normal screening and were related to impaired neurodevelopmental outcome.

Adolescent

Handedness in very-low-birthweight (VLBW) children at 12 years of age: relation to perinatal and outcome variables.

The authors assessed 137 VLBW children and 162 controls for laterality by observation and questionnaire at 12 years of age. A significantly higher proportion of the VLBW children were either left-handed or mixed-handed. A number of motor cognitive and educational outcome variables were measured. Impaired manual dexterity was found to be significantly more common in VLBW non-right-handers. This group was also found to be more at risk of poor near vision. No cognitive or educational outcomes were associated with handedness. The results seem to support the theory that at least in a proportion of VLBW children, non-right-handedness has a pathological basis, but the relationship to perinatal events remains obscure.

Adolescent

Focal intestinal perforation in preterm infants is an emerging disease.

In order to elicit the pathogenesis of focal intestinal perforation in preterm infants we contrasted 8 infants who developed this disease with 16 gestation-matched controls. The cases were found to have lower birthweights for gestation (median standard deviation score of -1.02 in cases versus -0.08 in controls), and more frequently had pre-existing patent ductus arteriosus and intraventricular haemorrhage (88 and 63% in cases versus 25 and 6% in controls, respectively). There were similar rates of other perinatal variables in the two groups, including indomethacin and umbilical arterial catheter use. Conditions associated with fetal or neonatal hypoxia are important antecedents for this emerging distinct clinical entity.

Case-Control Studies

Phase I study of intraventricular recombinant tissue plasminogen activator for treatment of posthaemorrhagic hydrocephalus.

AIM: Phase I study to evaluate intraventricular fibrinolytic treatment with recombinant tissue plasminogen activator (tPA) as a method of clearing blood from the cerebrospinal fluid, and thus preventing permanent hydrocephalus. METHODS: Twenty two preterm infants, aged 7 to 26 days, with progressive posthaemorrhagic ventricular dilatation (ventricular width > 4 mm over 97th centile) received one to five intraventricular bolus injections of 1.0 mg or 0.5 mg tPA at intervals of one to seven days. RESULTS: The mean cerebrospinal fluid concentration of tPA 24 hours after 1 mg was 1860 micrograms/ml. The half life of tPA in cerebrospinal fluid was about 24 hours. Twenty one (95%) infants survived, 12 (55%) without shunt surgery. One infant had secondary intraventricular haemorrhage. CONCLUSION: Intraventricular tPA resulted in survival without a shunt for most of the infants, but with some risk. Failure may have been due to plasminogen deficiency, an inhibitor, or late intervention.

Cerebral Hemorrhage

Growth impairment in very low birthweight children at 12 years: correlation with perinatal and outcome variables.

AIM: To compare the growth of very low birthweight (VLBW) children in early adolescence with that of their normal birthweight peers; to examine the role of factors contributing to growth-parental height, perinatal variables, bone maturity and sexual maturation; to examine the correlation between head growth and cognitive and educational outcome. METHODS: Standing and sitting heights, weight, occipito-frontal circumference (OFC), skinfold thicknesses and pubertal staging were assessed in 137 VLBW children and 160 controls at 11-13.5 years of age. Ninety six (70%) of the VLBW children had their bone age assessed using the TW2 method. Reported parental heights were obtained by questionnaire. All children had standardised tests of cognitive and educational ability. Perinatal data had been collected prospectively as part of a longitudinal study. RESULTS: VLBW children had lower heights, weight, and OFC. Skinfold thicknesses were no different. The children's short stature was not accounted for by difference in parental height, degree of pubertal development, or by retarded bone age. Indeed, the TW2 RUS score was significantly advanced in the VLBW children. Using the bone ages to predict final adult height, 17% have a predicted height below the third centile and 33% below the tenth. Weight was appropriate for height, but there was a residual deficiency in OFC measurements after taking height into account. In the VLBW group smaller head size was associated with lower IQ and mathematics and reading scores. CONCLUSIONS: Growth problems persist in VLBW children and final heights may be even more abnormal than present heights suggest. VLBW children have smaller OFCs than expected from their short stature alone and this may be associated with poorer educational and cognitive outcomes.

Adolescent

Motor impairment in children 12 to 13 years old with a birthweight of less than 1250 g.

AIM: To determine whether poor motor skills, previously identified in a cohort of very low birthweight (< 1250 g) children, born in 1980-1, have persisted or improved. Previous assessments had shown significant improvement between the ages of 6 and 8 years. METHODS: The original cohort were traced and were assessed using the Movement Assessment Battery for Children, an update of the Test Of Motor Impairment, used at 6 and 8 years. Where possible the classroom-matched controls from the original studies were assessed, otherwise new controls were selected. Teachers were also asked to identify those children whom they considered clumsy. Forty seven of the original cohort of 53 children, all but one still attending mainstream school, and 40 original and 20 new classroom-matched controls were studied. RESULTS: Fifty one per cent of the cohort showed clinically important or borderline impairment. More of these children had significant impairment (16/47, 34%) than the controls (3/60, 5%). The improvement seen by 8 years of age was maintained but there was no further improvement. Girls had significantly higher overall impairment scores (median 16; interquartile range 10-21.5) than the boys (5.5 (1.5-12.5)), and on a wider variety of subtests (5/8) than the boys (3/8). CONCLUSIONS: Many very low birthweight children have impaired motor skills. Despite early improvement it persists into adolescence and the deficit remains. Interventional studies may help to see if these problems can be alleviated.

Adolescent

Women's views of ultrasonography. A comparison of women's experiences of antenatal ultrasound screening with cerebral ultrasound of their newborn infant.

Ultrasound screening is now a routine procedure which forms part of antenatal care provision. Within this routine context ultrasound technology has been found to be generally acceptable and indeed is positively demanded by many women. This paper raises the question whether the routine presentation of ultrasound implicitly conveys the message that its use in antenatal care is both valuable and safe. It examines women's views of ultrasound technology beyond a routine context. In study designed to examine women's reactions to cerebral ultrasound on their normal term infants mothers were asked their views and knowledge of ultrasound and a comparison with their antenatal experience of ultrasound was elicited. A generalized concern about ultrasound techniques was found to underlie many of the women's comments. This raised questions concerning the current practice in the presentation of ultrasound to women attending for antenatal care.

Attitude to Health

Outcome at 8 years for children with birth weights of 1250 g or less.

The educational, motor, and behavioural performance of a hospital based cohort of 51 children aged 8 years with birth weights of 1250 g or less is reported, as part of a longitudinal study. Compared with age, race and sex matched classmates, who were examined at school at the same visit, the very low birthweight (VLBW) group performed less well on the basic mathematics test A, the Schonell spelling test, and the test of motor impairment. Reading performance was also poorer in this group. Twenty three (45%) VLBW children were having difficulty with one or more school subjects compared with 11 (19%) controls, and 15 (26%) had difficulties in two or more areas, compared with three (5%) controls. Parents of VLBW children reported a similar frequency of behavioural problems to controls but teachers identified characteristics typical of emotional disorders and overactivity more frequently among the VLBW group. Motor testing at 6 years of age was the best predictor of school problems at 8 years, correctly identifying 15/16 children with multiple problems with a low (33%) positive predictive value but a high (98%) negative predictive value. Children with birth weights of 1250 g or less and no major impairment have a high frequency of learning difficulties that become more apparent with advancing age. Such problems may be predicted at an earlier age by detailed motor testing.

Child

Skin disinfection in preterm infants.

Greater care and a more thorough approach to intravenous catheter site disinfection may be important for the prevention of catheter related sepsis, especially with coagulase negative staphylocci in preterm infants. The efficacy of skin disinfection was evaluated in preterm infants using a skin swabbing technique after disinfectant exposure. In the first part of the study, 25 peripheral intravascular catheter sites were quantitatively sampled immediately after routine cannula insertion. Bacterial counts greater than 100 colony forming units/cm2 were observed from 10 (40%) sites. In the second part, sampling for bacterial colony counts was done after skin cleansing with various durations of exposure of chlorhexidine/alcohol swabs or povidone iodine. The overall mean reduction in bacterial colony counts after skin cleansing ranged from 90-99%. Skin sterilisation was achieved in 33-92% of cases. The use of two consecutive 10 second exposures resulted in a significantly improved reduction in colony counts compared with a single 10 second wipe. A longer 30 second exposure also resulted in a greater reduction of bacterial numbers compared with a shorter duration of 5 or 10 seconds. Repopulation of disinfected sites occurred within 48 hours. This effect was delayed by occluding the cleansed site with a semipermeable dressing. There were no significant differences between povidone iodine and the chlorhexidine swabs in reducing bacterial numbers. This study has demonstrated that a brief exposure with a premoistened disinfectant swab is not sufficient for complete elimination of resident skin flora of newborn infants. The use of two consecutive cleanings, or a longer duration of cleansing is recommended for more effective skin sterilisation.

Catheterization

Oculo-auriculo-vertebral spectrum with vascular ring and other unusual anomalies.

An infant with the oculo-auriculo-vertebral (OAV) spectrum is described with the previously unreported association of rectal agenesis with recto-urethral fistula. The patient died at the age of 14 weeks from respiratory obstruction. Autopsy revealed the cause of death to be tracheal compression from a pulmonary artery sling. Previous reports of vascular rings within the OAV spectrum are reviewed, and it is concluded that these malformations are an uncommon, but clinically important, complication of the disorder.

Abnormalities, Multiple

Rehabilitation and outcome after severe head injury.

After severe head injury, many children continue to experience major cognitive and behavioural problems and consequent educational difficulties, even after good physical recovery. Forty three children referred to the regional multidisciplinary head injury rehabilitation team are described. The clinical outcome at a median interval of 13 months after injury showed that 18 (42%) had persistent neurological impairment and 15 (35%) had an identified need for special educational support. Thirty seven children were further assessed for psychiatric morbidity, cognitive impairment, and classroom performance. Rutter behavioural questionnaires were sent to parents and teachers of head injured index cases and classmate controls matched for age and sex. Index parents scored their children significantly worse in both 'health' and 'habits' and more cases than controls had scores suggesting a psychiatric disorder. Teachers scored index cases significantly worse for five of the traits questioned, but discriminated cases from controls less decisively than parents. Index cases were significantly disadvantaged on teachers' assessments of classroom skills and performance. A need for improved support and training of staff who teach head injured children was identified.

Adolescent