Somatosensory Evoked Potentials in Very Preterm Infants in Relation to <scp>l</scp>-Thyroxine Supplementation

Smit, Bert; Kok, Joke H.; Vries, Linda S. de; Wassenaer, Aleid G. van; Dekker, Friedo W.; Visser, B.W. Ongerboer de

doi:10.1542/peds.101.5.865

Cited by 13 publications

(4 citation statements)

References 36 publications

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“…In younger preterm infants the responses are delayed and prolonged in duration, probably due to a slower conduction velocity due to immature myelination (Klimach and Cooke, 1988a;Taylor et al, 1996;Smit et al, 2000). The latencies decrease rapidly towards term (Hrbek et al, 1973;Karniski et al, 1992;Smit et al, 1998), but delayed maturation of sensory pathways has been suggested on the basis of longer latencies of the N1 at term in preterm infants compared with fullterm infants (Smit et al, 2000). However, this finding was not corroborated in another study (Klimach and Cooke, 1988a).…”

Section: Introductionmentioning

confidence: 91%

“…The sensitivity of abnormal median-nerve SEPs to predict CP has ranged from 13 to 100%, with a specificity of 87-100% (Klimach and Cooke, 1988b;Willis et al, 1989;Majnemer et al, 1990;De Vries et al, 1992;Pierrat et al, 1997), whereas respective values for abnormal tibial nerve SEPs have been 63-96% for sensitivity and 50-99% for specificity (White and Cooke, 1994;Pierrat et al, 1997;Pike and Marlow, 2000). Many SEP studies have experienced technical difficulties in reliably recording the responses, particularly in the youngest preterm infants (Klimach and Cooke, 1988a;Smit et al, 1998Smit et al, , 2000. These difficulties probably explain part of the variability in the specificity and sensitivity.…”

Section: Introductionmentioning

confidence: 99%

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Does very premature birth affect the functioning of the somatosensory cortex? — A magnetoencephalography study

Nevalainen

Pihko

Metsäranta

et al. 2008

International Journal of Psychophysiology

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Section: Introductionmentioning

confidence: 91%

Section: Introductionmentioning

confidence: 99%

Does very premature birth affect the functioning of the somatosensory cortex? — A magnetoencephalography study

Nevalainen

Pihko

Metsäranta

et al. 2008

International Journal of Psychophysiology

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“…These children were evaluated at 6 months to 5.5 years of age (78). Although the treated group showed significantly higher levels of serum T 4 , neurophysiological functioning (71,72) or cognitive abilities were not improved (71,73,74). However, when children were stratified by gestation age, a marked benefit of TH therapy was observed for early neuromotor skills and later cognitive abilities in children born before 27 weeks (72) whereas children born at 28 or 29 weeks showed the opposite effect, performing worse than controls.…”

Section: Maternal Hypothyroidismmentioning

confidence: 99%

Timing of Thyroid Hormone Action in the Developing Brain: Clinical Observations and Experimental Findings

Zoeller

Rovet

2004

J Neuroendocrinology

543

369

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The original concept of the critical period of thyroid hormone (TH) action on brain development was proposed to identify the postnatal period during which TH supplement must be provided to a child with congenital hypothyroidism to prevent mental retardation. As neuropsychological tools have become more sensitive, it has become apparent that even mild TH insufficiency in humans can produce measurable deficits in very specific neuropsychological functions, and that the specific consequences of TH deficiency depends on the precise developmental timing of the deficiency. Models of maternal hypothyroidism, hypothyroxinaemia and congential hyperthyroidism have provided these insights. If the TH deficiency occurs early in pregnancy, the offspring display problems in visual attention, visual processing (i.e. acuity and strabismus) and gross motor skills. If it occurs later in pregnancy, children are at additional risk of subnormal visual (i.e. contrast sensitivity) and visuospatial skills, as well as slower response speeds and fine motor deficits. Finally, if TH insufficiency occurs after birth, language and memory skills are most predominantly affected. Although the experimental literature lags behind clinical studies in providing a mechanistic explanation for each of these observations, recent studies confirm that the specific action of TH on brain development depends upon developmental timing, and studies informing us about molecular mechanisms of TH action are generating hypotheses concerning possible mechanisms to account for these pleiotropic actions.Clinical and experimental studies demonstrate thyroid hormone (TH) is essential for normal brain development. This was documented initially in children with congenital hypothyroidism (1-5), followed by animal studies focused on cerebellar development, which occurs largely postnatally (6-9). However, recent observations in humans (10-13) provide important new evidence that TH is also important in early (foetal) brain development, and that the timing and severity of TH insufficiency predicts the type and severity of the neurological deficits. Because these deficits presumably reflect the impact of a loss of TH on different aspects of brain development, this clinical research provides clues as to when and where TH exerts its actions in developing brain.Animal models of developmental TH insufficiency are beginning to provide mechanistic explanations for these observations in humans. The use of genetic models of TH insufficiency, of TH receptor deletion and mutation, and of cofactor deletion (14-17), are showing us how different brain regions may exhibit different sensitivity to TH during development. Moreover, these studies show that TH exerts different effects in different brain areas at different times during development. However, despite advances in our understanding of TH action, the specific developmental events affected by TH remain poorly understood. Several recent comprehensive reviews on TH actions in brain development have appeared (6,7,14). Thus, our go...

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“…The infants were tested without sedation, while awake. MNCV and SEP recordings took about an hour to complete, were stored on disk and reassessed later as described earlier (13,14). During follow-up, neurologic development and performance on the Bayley Scales of Infant Development were assessed by a developmental paediatrician and developmental psychologist at 6, 12 and 24 mo of corrected age.…”

mentioning

confidence: 99%

The Neurologic Development of the Newborn and Young Child in Relation to Maternal Thyroid Function

et al. 1999

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Neurologic development of the newborn and young child in relation to maternal thyroid function. Acta Paediatr 2000; 89: 291-5. Stockholm. ISSN 0803-5253A prospective observational study was performed in pregnant women with known thyroid disease. We studied the effect of maternal thyroid function in the first half of pregnancy on the neurologic development of the infant in the first 2 y of life. Clinical and thyroid function data were collected from 20 pregnant women with known thyroid disease and their newborn children. Infants were divided into three groups according to their maternal thyroid function within the first half of pregnancy: Group A (n = 7): maternal subclinical hypothyroidism, Group B (n = 6): maternal euthyroidism, and Group C (n = 7): maternal hyperthyroidism or subclinical hyperthyroidism. Neurophysiologic, i.e. motor nerve conduction velocity and somatosensory evoked potentials and neurologic and developmental (Bayley scales) assessments were done. One infant, born to a mother with Graves' disease, developed transient hyperthyroidism. At the age of 6 and 12 mo, the mean mental developmental index (MDI) score was 16 points lower for infants in Group A than for those in Group B (p = 0.03 and 0.02, respectively). At the age of 24 mo, the mean MDI score was 6 points lower, which was not statistically significant. Neurophysiologic and neurologic assessments and the mean Psychomotor Developmental scores did not differ among the three groups.In concl was a lower

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Somatosensory Evoked Potentials in Very Preterm Infants in Relation to l-Thyroxine Supplementation

Abstract: L-Thyroxine supplementation during the first 6 weeks of life did not decrease cortical N1 peak latency in infants of <30 weeks' gestational age.

Cited by 13 publications

References 36 publications

Does very premature birth affect the functioning of the somatosensory cortex? — A magnetoencephalography study

Does very premature birth affect the functioning of the somatosensory cortex? — A magnetoencephalography study

Timing of Thyroid Hormone Action in the Developing Brain: Clinical Observations and Experimental Findings

The Neurologic Development of the Newborn and Young Child in Relation to Maternal Thyroid Function

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