The effect of pre- and postnatal maternal dietary fatty acid composition on neurodevelopment in rat pups was studied. Timed pregnant dams were fed, beginning on d 2 of gestation and throughout ...lactation, either nonpurified diet (reference) or a purified diet whose fat source (22% of energy) was either corn oil or menhaden fish oil. On postnatal d 3, pups were randomly cross-fostered among dams of the same diet group and culled to 10 pups per dam. Milk was removed from stomachs of culled pups for fatty acid analyses. From postnatal d 4 to 30, pups were assessed daily for the appearance of neurodevelopmental reflexes. Auditory brainstem conduction times were measured on postnatal d 23 and 29. Pups were killed on postnatal d 30, and cerebrums were removed for fatty acid analyses. The fatty acid composition of maternal milk and pup cerebrums reflected maternal diet with higher levels of (n-3) and (n-6) fatty acids in the fish oil and corn oil groups, respectively. The time of appearance of auditory startle was significantly delayed (P = 0.004), and auditory brainstem conduction times on postnatal d 23 and 29 were significantly longer in pups of the fish oil- than corn oil-fed dams (P less than or equal to 0.05). A delay in the appearance of the auditory startle reflex and longer auditory brainstem conduction times in pups of dams fed fish oil-supplemented diet may be due to negative effects on myelination of the auditory brainstem pathway
Previous studies of the effects of dietary docosahexanoic acid (DHA), 22:6n3, on neurodevelopment have focused mainly on visual-evoked potentials and indices of visual activity, measures that may be ...confounded by effects on the retina rather than on neural pathways. We investigated the effect of pre- and postnatal maternal dietary DHA content on auditory brainstem conduction times (ABCTs), the appearance of the auditory startle reflex (ASR), and 2′,3′-cyclic nucleotide 3′-phosphodiesterase (CNPase) activity in brainstem homogenates. Timed pregnant dams were fed, beginning on day 2 of gestation and throughout lactation, a purified diet containing one of three levels of DHA (0, 1, or 3% of total fatty acids, or 0, 0.4 or 1.2% of total energy). On postnatal day (PND) 3, pups were randomly crossfostered within diet groups to minimize litter effects and culled to 10 per litter. Cerebrums and milk from culled pups stomachs were collected for lipid analysis. The timing of appearance of the ASR was determined between PND 10 through 14 and ABCTs were measured in pups on PND 24 and 31. Pups were sacrificed on PND 31 and cerebrums were removed. In each of two replicated studies, pups in the 1% DHA group weighed significantly less on PND 3 and they gained significantly less weight from PND 3 to 31 compared with pups in the 0 or 3% groups (
p<0.01). The auditory studies were not conducted on the 1% DHA group since measures of auditory function are in part a function of somatic growth. The tissue fatty acid data for the 1% DHA group did not show unexpected findings. Higher dietary DHA was reflected in milk and pup cerebrums, and levels of arachidonic acid were inversely related to levels of DHA. In the pups of dams fed diets containing 3% versus 0% DHA, the ASR appeared significantly later (
p<0.001) and the ABCTs were longer (
p<0.05) on PND 31. CNPase activity levels were not different between the 0 and 3% DHA groups. This study demonstrated that the auditory brainstem response is sensitive for identifying effects of diet on neurodevelopment, and that diets supplemented with high levels of DHA may exert a negative influence on central nervous system development, potentially through effects on myelin. This study suggests the need for further studies of pre- and postnatal long chain polyunsaturated fatty acid dietary supplementation.
This comprehensive atlas presents the clinical practice of neonatal electroencephalography through text, references, and more than 250 detailed figures demonstrating normal and abnormal features of ...the neonatal EEG from the most premature infant to one month post-term. Each chapter contains dozens of full-page EEG images, along with detailed legends that place them in context, to emphasize specific components of the neonatal EEG as a benchmark for recognizing signature characteristics and interpreting clinical data. For the new Fourth Edition, Eli Mizrahi and Richard Hrachovy, established authorities in neonatal neurophysiology, have distilled the advances of the last ten years and provided the latest and best references for each chapter, updating their indispensable atlas to reflect current research and practice throughout. Designed to appeal to practicing neurologists, neurophysiologists, epileptologists, and electroneurodiagnostic technologists, this book is a must-have for anyone involved in recording and interpreting neonatal EEG readouts.
Previous studies of dietary docosahexaenoic acid (DHA; 22:6n-3) effects on neurodevelopment have focused mainly on effects on the visual system; these studies may be confounded by effects on the ...retina rather than on neural pathways. Auditory brainstem conduction times (ABCTs) provide an alternate measure of central neural development. We conducted a dose-response study in which ABCTs were measured in pups whose dams were fed diets containing one of three levels of DHA (2, 4 or 6% of total fatty acids) from a single cell oil. Diets were fed during pregnancy and lactation, and pups were randomly cross-fostered on postnatal day 3 to minimize litter effects. ABCTs showed a dose-response effect, with higher levels of dietary DHA being associated with longer conduction times on postnatal day 31 (p < 0.05). Higher dietary DHA was reflected in pup cerebrums collected on postnatal days 3 and 31, and levels of arachidonic acid (AA, 20:4n-6) were inversely related to levels of DHA. This study demonstrated that the auditory brainstem response is sensitive for identifying effects of diet on neurodevelopment, and that supplementing the maternal diet with high levels of DHA may negatively impact development of the central auditory system of offspring.
This chapter provides an overview of (1) developmental timetables relevant to hearing, and (2) current pediatric audiological techniques and practices. Structural and functional development of the ...auditory pathway and the development of primary auditory processing are summarized. These developmental sequences appear to follow similar paths in humans and animals. Speech and music perception involve more complex processing and are strongly influenced by experience. Hearing disorders affect the perception of complex sounds in a variety of ways, depending on the sites of lesions. Early-onset hearing impairment, including conductive loss from chronic otitis media, can seriously impede language development. Language cannot develop normally without adequate speech stimulation, and deafness is more prevalent than any other handicapping condition for which mandated neonatal screening programs exist. Sensitive and inexpensive techniques are available for performing neonatal hearing screening, and early intervention has a documented positive effect on development of language skills in hearing-impaired children. Thus, the National Institutes of Health has recommended nationwide universal neonatal hearing screening. The rationale for and the methodology of universal screening programs are summarized. Advances in the genetics of hearing impairment are reviewed. Data from these studies have influenced testing and rehabilitative protocols and have implications for future prevention and treatment of hearing impairment.
Thoroughly revised and updated by internationally recognized experts, the Third Edition of this popular and widely used atlas reflects twelve years of vital advances in electrodiagnosis of neurologic ...function in neonates. The authors have distilled the vast, complex literature on neonatal EEG to provide a practical, contemporary, superbly illustrated guide to performing EEG in neonates and interpreting both common and unusual patterns. This edition includes digital as well as analog EEG and features over 200 brand-new, full-sized reproductions of EEG tracings. The authors demonstrate state-of-the-art improvements in recording technique and highlight recent advances in the understanding of normal and abnormal brain development.
Auditory Brain Stem Response Variability in Infants Stockard, Janet E; Stockard, James J; Coen, Ronald W
Ear and hearing,
1983-January/February, 1983 Jan-Feb, 1983-01-00, 19830101, Letnik:
4, Številka:
1
Journal Article
Recenzirano
Variations in auditory brain stem response latency, threshold, and amplitude ratio were related to stimulus, recording, subject, and pathologic factors in normal and high-risk infants.
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