Abnormal auditory evoked potentials in early infancy malnutrition

Impact of Early Childhood Malnutrition on Adult Brain Function: An Evoked-Related Potentials Study

More than 200 million children under the age of 5 years are affected by malnutrition worldwide according to the World Health Organization. The Barbados Nutrition Study (BNS) is a 55-year longitudinal study on a Barbadian cohort with histories of moderate to severe protein-energy malnutrition (PEM) limited to the first year of life and a healthy comparison group. Using quantitative electroencephalography (EEG), differences in brain function during childhood (lower alpha1 activity and higher theta, alpha2 and beta activity) have previously been highlighted between participants who suffered from early PEM and controls. In order to determine whether similar differences persisted into adulthood, our current study used recordings obtained during a Go-No-Go task in a subsample of the original BNS cohort [population size (N) = 53] at ages 45-51 years. We found that previously malnourished adults [sample size (n) = 24] had a higher rate of omission errors on the task relative to controls (n = 29). Evoked-Related Potentials (ERP) were significantly different in participants with histories of early PEM, who presented with lower N2 amplitudes. These findings are typically associated with impaired conflict monitoring and/or attention deficits and may therefore be linked to the attentional and executive function deficits that have been previously reported in this cohort in childhood and again in middle adulthood.

Long latency auditory evoked potentials in malnourished children

PURPOSE

To characterize the findings obtained in the long latency auditory evoked potentials in malnourished children, as well as to compare them to the results obtained for children at the same age who present typical development.

METHODS

Sixty-five children aged between 7 and 12 years old, of both genders, were evaluated. The control group consisted of 34 children with normal development and the study group consisted of 31 children diagnosed with malnutrition. All children underwent conventional pure tone audiometry, acoustic impedance measurement, dichotic digit test and long latency auditory evoked potentials.

RESULTS

The study group presented a statistically significant difference for latencies of the components P1, N1 and P300. The latencies of these components were higher than those of the control group. Concerning the types of alterations found in the study group, increased latency for P1 and P300 and the absence of response in N1 were predominant. The control group showed a statistically significant difference in the amplitude of P300 when compared to the right and left ears.

CONCLUSION

Malnourished children present with changes in the long latency auditory evoked potentials, suggesting a deficit in central auditory pathways and alterations in the processing of acoustic information.

Assessment of neurodisability and malnutrition in children in Africa

Neurodevelopmental delay, neurodisability, and malnutrition interact to contribute a significant burden of disease in global settings. Assessments which are well integrated with plans of management or advice are most likely to improve outcomes. Assessment tools used in clinical research and programming to evaluate outcomes include developmental and cognitive tools that vary in complexity, sensitivity, and validity as well as the target age of assessment. Few tools have been used to measure socioemotional outcomes and fewer to assess the disabled child with malnutrition. There is a paucity of tools used clinically which actually provide families and professionals with advice to improve outcomes. Brain imaging, electroencephalography, audiology, and visual assessment can also be used to assess the effect of malnutrition on brain structure and function. The interaction of neurodisability and malnutrition is powerful, and both need to be considered when assessing children. Without an integrated approach to assessment and management, we will not support children and families to reach their best potential outcomes.

Abnormal flash visual evoked potentials in malnourished infants: an evaluation using principal component analysis

OBJECTIVE

To characterize the morphology of flash visual evoked potentials (fVEPs) obtained from infants hospitalized with severe, chronic malnutrition (marasmus).

METHODS

A covariance-based principal component analysis with Promax factor rotation was applied to fVEPs obtained from malnourished infants and age-matched control subjects.

RESULTS

The analysis suggests the presence of a late positive complex in the fVEP, with at least one of its components being significantly diminished in marasmic infants. The N3 component was also diminished in marasmic infants. Following remediation, the marasmic group no longer differed with respect to these components. However, an abnormally large late, positive deflection was evident at discharge.

CONCLUSIONS

The fVEP morphology of infants hospitalized with severe malnutrition was found to be significantly different from age-matched controls. Moreover, although there was evidence of recovery following remediation, fVEPs continued to show abnormality at discharge, suggesting the possibility that nutritional rehabilitation did not fully eliminate the physiological deficit.

SIGNIFICANCE

Malnourishment during early infancy results in altered neurophysiological functioning, possibly in cortical areas responsible for higher order visual processing.

Auditory brainstem potentials in children with protein energy malnutrition

OBJECTIVE

In this study, auditory brainstem potentials (ABPs) were studied in children with protein energy malnutrition (PEM) to determine the effects of PEM on the developing brain in children.

METHODS

A total of 31 children, aged 3-36 months with moderate/severe PEM and 25 healthy children, aged 3-48 months were included in the study. Nutritional status of the children was assessed by the Gomez classification. Recordings of ABPs were performed by using Nihon Kohden Neuropack 2 device.

RESULTS

Of 31 children, 22 (71%) had severe malnutrition, 9 (29%) had moderate malnutrition. Additionally, 8 (26%) and 9 (29%) children had iron deficiency anemia and hypoalbuminemi, respectively. There were significant differences in the mean latencies of the waves I-V on the right and left ears and in the mean interpeak latencies (IPLs) of the waves III-V and I-V on the right ear between the study and control groups (P<0.05). The mean IPLs of I-V on the left side were found to be longer in the moderate PEM group than those of severe PEM group (P<0.05). There was not any difference between the groups of PEM with low serum albumin and PEM with normal serum albumin. While the mean IPLs of I-III on the right side were found longer in the cases of PEM without iron deficiency anemia, the mean latency of wave I on the left side, and the mean IPLs of III-V on the right side were longer in the children with PEM plus iron deficiency anemia (P<0.05).

CONCLUSIONS

Our findings showed that children with moderate/severe PEM had ABPs abnormalities in different degrees, which reflect defects in myelination of auditory brainstem pathways in children with moderate/severe PEM. However, we found contradictory results between abnormalities in ABPs and degree of malnutrition and iron deficiency anemia. We think that more extensive studies should be performed to determine whether or not there was a relationship between these parameters.

Iron deficiency anemia in infancy: long-lasting effects on auditory and visual system functioning

Evoked potentials provide noninvasive measures of nerve transmission and CNS functioning. Auditory brainstem responses (ABR) and visual evoked potentials (VEP) show dramatic changes in infancy, largely as a result of progressive myelination. Because iron is required for normal myelination, pathway transmission in these sensory systems might be affected by early iron deficiency. We previously reported evidence to that effect: infants with iron-deficiency anemia (IDA) had slower transmission through the auditory brainstem pathway, uncorrected by iron therapy. To determine long-term effects, ABR and/or VEP of healthy Chilean children who were treated for IDA or were nonanemic in infancy were compared at approximately 4 y of age. Absolute latencies for all ABR waves and interpeak latencies (except I-III interval) were significantly longer in former IDA children. Longer latency was also observed for the P100 wave on VEP. The magnitude of differences was large-about 1 SD. These findings, with differences in latencies but not amplitudes, further support the hypothesis that IDA in infancy alters myelination and provide evidence that effects on transmission through the auditory and visual systems can be long lasting. Subtle changes in sensory pathway transmission might be an underlying mechanism for the derailment of other developmental aspects in early IDA.

An event-related potential study of older children with an early history of failure to thrive

Elementary and junior high school children (n = 13), who were diagnosed with nonorganic failure to thrive (FTT) as infants and toddlers, were compared with a normal control group (n = 14) on visual event-related potentials (ERPs) elicited during a primed lexical decision task. Positive stimuli were real words that were identical to the priming stimuli; negative stimuli were nonpronounceable letter strings. Although the groups did not differ in word-list reading level, the former FTT group had slower reaction (decision) times and did not show ERP evidence of priming in the N400 epoch. Anterior sites yielded better separation of the real words and letter strings than posterior sites. A late anterior component between 500 msec to 650 msec poststimulus onset showed the largest condition effect for both groups. The control group had a larger negative going late anterior component to words than the FTT group. The combined reaction time and ERP findings point to less automatized word recognition in the FTT group.

An electrophysiological study of school-aged children with a history of failure to thrive during infancy

Sixty-five subjects, ages 8 to 12, participated in a visual electrophysiological study. Twenty-two of the subjects had received a diagnosis of nonorganic failure-to-thrive (FTT) before the age of three. The remaining 43 subjects had no history of FTT and served as Controls. IQs were obtained with the abbreviated WISC-III, and the Controls were split into two groups, LO IQ and HI IQ, to provide a LO IQ Control group with an average IQ equivalent to the FTT group. Event-related brain potentials (ERPs) were recorded from five scalp locations during a cued continuous performance task (CPT). Subjects had to press a button every time they saw the letter "X" following the letter "A" (50 targets out of 400 stimuli). During the CPT, the FTT subjects made marginally more errors of omission to targets than the LO IQ Control group and significantly more errors of omission than the HI IQ Control subjects. The groups did not differ significantly on errors of commission (false alarms) or reaction times to targets. ERP averages revealed a group difference in amplitude in a late slow wave for the 50 non-X stimuli (false targets) that followed the letter A. This difference was greatest over frontal sites, where the FTT group had a more negative going slow wave than each control group. Late frontal negativity to No Go stimuli has been linked with post-decisional processing, notably in young children. Thus, the FTT subjects may have less efficient inhibitory processes, reflected by additional late frontal activation.

Brainstem auditory and visual evoked potentials in children with protein-energy malnutrition

BACKGROUND

To determine the effects of malnutrition on the developing brain with brainstem auditory evoked potentials (BAEP) and flash visual evoked potentials (fVEP).

METHODS

The BAEP and fVEP of 11 kwashiorkor (8 +/- 1.56 months) and 10 marasmus (7.9 +/- 1.27 months) patients and 10 healthy control subjects (7.65 +/- 0.82 months) were recorded and the measurements were compared with each other in relation with plasma total protein and albumin levels.

RESULTS

There were no differences between the mean latencies of the waves I, II, III and IV and mean interpeak latencies (IPL) of the waves I-III of the BAEP and the wave IV (N2) of the fVEP between the three groups. Mean latency of the wave V and mean IPL of the waves I-V and the waves III-V were significantly different between the three groups. The kwashiorkor group had significantly longer mean latency of the wave V than the marasmus group on the right ear and the control group on the both of the ears. The kwashiorkor group had significantly longer mean IPL of the waves I-V than the marasmus group on the right ear and than the control group on the left ear. The kwashiorkor group had also significantly longer mean IPL of the waves III-V than the control group on the left.

CONCLUSIONS

The BAEP and fVEP are non-invasive electrophysiologic methods reflecting the integrity or disruption of the central neurologic pathways. The present results confirm the disruption of the central nervous system with the BAEP in children with protein-energy malnutrition, especially in kwashiorkor patients.

Delta (0.5-1.5 Hz) and sigma (11.5-15.5 Hz) EEG power dynamics throughout quiet sleep in malnourished infants

The present study aimed to quantify, through power spectral analysis, the dynamics (temporal pattern and temporal interrelationship) of the EEG power in the low-delta (delta) and in the sigma-spindle (sigma) frequency band during quiet sleep (QS) in 5 malnourished infants (MI), 5.5 to 13.5 months old, and in 5 age-matched, healthy control infants (CI). Malnutrition results in modification of the temporal pattern of delta and sigma band power during QS. The delta band power increases faster in MI than in CI, leading to higher power levels in MI at the same time segment. However, the overall trend of the delta band power throughout QS is similar in MI and CI. The premature ending of QS phases (uninterrupted QS periods), and the reduced total amount of QS which have been reported in MI could result in an increased slow wave sleep (SWS) "pressure". This SWS pressure could account for both the higher level and the faster increase of the delta band power during the QS phase which are found in MI when compared to CI.

Growth, development and differentiation: a functional food science approach

Few other aspects of food supply and metabolism are of greater biological importance than the feeding of mothers during pregnancy and lactation, and of their infants and young children. Nutritional factors during early development not only have short-term effects on growth, body composition and body functions but also exert long-term effects on health, disease and mortality risks in adulthood, as well as development of neural functions and behaviour, a phenomenon called 'metabolic programming'. The interaction of nutrients and gene expression may form the basis of many of these programming effects and needs to be investigated in more detail. The relation between availability of food ingredients and cell and tissue differentiation and its possible uses for promoting health and development requires further exploration. The course of pregnancy, childbirth and lactation as well as human milk composition and the short- and long-term outcome of the child are influenced by the intake of foods and particularly micronutrients, e.g. polyunsaturated fatty acids, Fe, Zn and I. Folic acid supplementation from before conception through the first weeks of pregnancy can markedly reduce the occurrence of severe embryonic malformations; other potential benefits of modulating nutrient supply on maternal and child health should be further evaluated. The evaluation of dietary effects on child growth requires epidemiological and field studies as well as evaluation of specific cell and tissue growth. Novel substrates, growth factors and conditionally essential nutrients (e.g. growth factors, amino acids, polyunsaturated fatty acids) may be potentially useful as ingredients in functional foods and need to be assessed carefully. Intestinal growth, maturation, and adaptation as well as long-term function may be influenced by food ingredients such as oligosaccharides, gangliosides, high-molecular-mass glycoproteins, bile salt-activated lipase, pre- and probiotics. There are indications for some beneficial effects of functional foods on the developing immune response, for example induced by antioxidant vitamins, trace elements, fatty acids, arginine, nucleotides, and altered antigen contents in infant foods. Peak bone mass at the end of adolescence can be increased by dietary means, which is expected to be of long-term importance for the prevention of osteoporosis at older ages. Future studies should be directed to the combined effects of Ca and other constituents of growing bone, such as P, Mg and Zn, as well as vitamins D and K, and the trace elements F and B. Pregnancy and the first postnatal months are critical time periods for the growth and development of the human nervous system, processes for which adequate substrate supplies are essential. Early diet seems to have long-term effects on sensory and cognitive abilities as well as behaviour. The potential beneficial effects of a balanced supply of nutrients such as I, Fe, Zn and polyunsaturated fatty acids should be further evaluated. Possible long-term effects of early exposure to tastes and flavours on later food choice preferences may have a major impact on public health and need to be further elucidated. The use of biotechnology and recombinant techniques may offer the opportunity to include various bioactive substances in special dietary products, such as human milk proteins, peptides, growth factors, which may have beneficial physiological effects, particularly in infancy and early childhood.

Early malnutrition followed by nutritional restoration lowers the conduction velocity and excitability of the corticospinal tract

The physiological sequelae of undernutrition were investigated in rats that were undernourished from day 1-21 and subsequently free-fed to 75 days of age. Population responses were recorded in the corticospinal tract following surface stimulation of the motor cortex, which activates corticospinal cells directly, and also indirectly via cortical synapses. The conduction velocity of the fastest corticospinal fibers in 15 malnourished rats was 16.9 m/s, significantly slower (P < 0.001) than the 20.0 m/s observed in 26 controls. In addition, the excitability of corticospinal neurons to direct stimulation was reduced as much as 67% in malnourished rats, while no effect on synaptic activation was observed. Our findings suggest that early malnutrition reduces the number of large fibers in the adult corticospinal tract. These results are discussed with respect to known morphological and behavioral effects of malnutrition in rats and their relevance to humans.

Computerized cry analysis in infants affected by severe protein energy malnutrition

A new method of computerized cry analysis has been utilized to evaluate the cries of infants affected by severe protein energy malnutrition. We studied 17 Kenian babies affected by severe malnutrition for more than four months (9 cases of marasmus and 8 of kwashiorkor) and a control group of 17 well-nourished babies. The cries of the malnourished children showed lower inter-utterance variability, formants' frequencies and cry score, assigned by the Infant Cry Modulation Assessment Scale. The melodic pattern was more often flat, rising or falling-rising, when compared to the cries of the well-nourished babies. We hypothesize that these differences reflect the state of brain damage associated with protein energy malnutrition. No differences were found between the cries of infants affected by marasmus and those affected by kwashiorkor, between the cries recorded before and after nutritional therapy and between the first cries of malnourished children who subsequently died during hospitalization and those of infants who survived.

Early child health in Lahore, Pakistan: XII. Milestones

Psychomotor development was assessed in 1476 infants from four different levels of urbanization in and around Lahore, Pakistan. Development was assessed monthly at birth to 24 months of age by using a set of 10 milestones selected from the Denver Developmental Screening Test and the Developmental Screening Inventory. The psychomotor development of children in the upper middle (Um) class was consistent with reference population groups in Europe and North America, hence this group was used as control. There was significant delay in the psychomotor development of infants belonging to the poorer areas compared to the Um class. There was no sex difference in the development of the milestones in any study area, except for girls in the Um class who were earlier for about one month than boys in talking. Infants in the poorer areas were, on average about 3 months, delayed in their walking and fine motor activity (building a tower of 3 cubes) in comparison with the Um class. Observed disturbance in psychomotor development at an early age may affect the abilities and achievements in later life.

Infant malnutrition affects cortical auditory evoked potentials

Auditory evoked potentials (AEPs) to click and name stimuli were recorded for 23 malnourished infants on admission to and 17 on discharge from hospital, together with those from age-matched controls. The number of peaks on the AEPs and the amplitude were examined. The malnourished infants' AEPs to click stimuli differed from the controls' on admission but not on discharge. The malnourished infants had smaller AEP amplitudes to name than to click stimuli on discharge while the controls did not. The data show that cortical AEPs in infants are affected by malnutrition.

Brainstem conduction time abnormalities in small for gestational age infants

Brainstem auditory evoked responses (BAER) were recorded in 89 neonates born between 32 and 40 weeks, in order to analyze the consequences of intrauterine growth retardation on brainstem conduction time. The I-V interval was measured in 28 appropriate for gestational age (AGA) infants (control group), in 24 small for gestational age (SGA) infants with maternal hypertensive disease (MHD) and in 37 SGA infants without MHD. At any gestational age, SGA infants with MHD always presented an acceleration of their brainstem conduction time as compared to the other SGA infants. For the SGA full-term twins without MHD, the brainstem conduction time was delayed. These results reflect the specific consequences on brainstem development of the various factors responsible for intrauterine growth retardation (IURG).

Disturbances of brain maturation and neurodevelopment during chronic renal failure in infancy

Fifteen infants with moderate to severe congenital renal disease were prospectively studied by serial renal, neurodevelopmental, neurophysiologic, and anthropometric assessments. The observation period ranged from 3 to 25 months (mean = 10.9). Eight patients maintained a Mental Development Index (MDI) above the 16th percentile (greater than -1 SD) and comprised group 1. Of the remaining seven patients (group 2), three had an MDI less than 16th percentile when first studied and four had serial decreases of the MDI to less than 16th percentile. Although motor development was more delayed in group 2 at study entry, there were no significant changes of motor performance levels for either group during the study period. Group 2 patients had smaller length (p less than 0.05) and head circumference (p less than 0.05) standard deviation scores in comparison with group 1, and they had higher serum creatinine values (mean = 3.8 vs 1.3 mg/dl, respectively; p less than 0.01). By spectral electroencephalography, the expected progressive increase of the frequency of cerebral cortical background activity with age was demonstrated in group 1 but was not seen in group 2 (multivariate analysis of variance p less than 0.03). This increase of faster-frequency activity was primarily manifested in the left cerebral hemisphere of group 1 patients (p less than 0.01), a finding that was also absent in group 2. The frequent occurrence of neurodevelopmental abnormalities in infants with renal failure is possibly a consequence of impaired dominant hemispheric maturation in the first several years of life, which is clinically manifested as deterioration of cognitive function.

Functional development of the visual system in normal and protein-deprived rats. VI. Evoked responses in adult rats, protein deprived in early life and nutritionally rehabilitated from weaning

Previous studies have shown an increase in latency of the visual evoked response (VER) recorded from the cortical surface of adult rats subjected to protein deprivation (PD) during pre- and postnatal development. This alteration has been shown to originate mainly from the cortex itself. In the present study the possibility of normalizing such VER alterations by nutritional rehabilitation after early protein deprivation (R-PD) was investigated. Male rats were subjected to pre- and early postnatal protein deprivation through their mothers. Nutritional rehabilitation was started from weaning. The rats gained weight rapidly compared with rats subjected to protein deprivation throughout postnatal development but never reached the weight of controls (C) of the same age. Food consumption in relation to body weight was similar to that of controls. Rehabilitation continued until adult age when neurophysiological experiments were performed. The VER recordings from the dorsal lateral geniculate nucleus (dLGN) showed latencies similar to those reported previously for adult C and PD rats. The latencies of onset and first peaks of the cortical response recorded from the surface were increased by 5-6 ms in R-PD compared with C rats and hence similar to the latencies of adult PD rats. Intracortical responses to electrical stimulation in the dLGN were also similar to those of adult PD rats showing an normal onset latency but an increased latency of the peaks of the monosynaptic and late responses compared with C rats. The present results imply that the increased VER latencies noted in adult PD and R-PD rats are due to changes installed by protein deprivation during early development since they can not be reversed by nutritional rehabilitation starting at weaning.

Development of lumbar spinal cord and cortical evoked potentials after tibial nerve stimulation in the pre-term newborns: effects of gestational age and other factors

Pre-term neonates are at increased risk for neurological dysfunction. Several investigators have found scalp recorded somatosensory evoked potential studies (SSEPs) after median nerve stimulation useful in the evaluation of newborn infants with asphyxiation and the effects of other adverse prenatal and perinatal factors. In order to evaluate the entire developing neuraxis, we undertook SSEPs after tibial nerve stimulation (PTN-SSEP) in pre-term neonates. Using bilateral simultaneous stimulation, potentials were recorded from the following sites: PF-spT6 (N5), spL1-spT6 (N16), spC7-Fpz (N27), Cz' (1 cm behind the vertex)-Fpz (P55). In all newborns studied, the N5 and N16 were reliably recorded. The N5 appeared relatively independent of the length of the newborns. The N16 correlated inversely with length. The N27 and P55 were recorded in 52% and 65% of the newborns, respectively. N27 inversely correlated modestly with length. The P55 was independent of most factors and probably reflects variable rates of cerebral myelination, neuronogenesis, varying states of alertness, and possibly subclinical encephalopathies. These results demonstrate the feasibility of obtaining such data in pre-term newborns.

The central auditory conduction at term date and three months after birth. IV. Auditory cortical responses

Auditory cortical responses (ACRs) were recorded in 25 healthy mature newborns with a follow-up at 3 months. The waveform, latencies and amplitudes for the ACRs for this time period are studied. Topographic differences between the central and central-temporal derivations and changes between term and 3 months are found with respect to latencies and amplitudes for different peaks and troughs. The ACRs, obtained as a part of a protocol covering the entire auditory afference, offer consistent parameters, which can be used to study developmental neurophysiological properties of audition and which are potential diagnostic tools for the detection of deviant sensory or mental development.

Maturation of the brain-stem auditory evoked potential in premature infants

Patterns of development and extent of variability of the brain-stem auditory evoked potential (BAEP) are described in 52 healthy premature infants and 50 normal term newborns with reliable conceptional ages. Binaural and monaural stimulation are compared. Serial studies of individual prematures are emphasized and demonstrate that the most consistent and least variable measures are the monaurally derived interpeak intervals. All the BAEP parameters studied mature including wave form, relative amplitude, peak and interpeak intervals, but there is far more variability in preterms than in term infants or adults, even when infants are carefully matched for conceptional age. As term is approached, BAEP variability decreases substantially, suggesting that near term the BAEP becomes a more reliable indicator of neurologic function. The variability of the BAEP in the normal preterm limits its usefulness in determining neurologic dysfunction in individual high risk infants. Nevertheless, the BAEP may still prove useful for defining group differences among infants and could provide an objective measure of those factors influencing neurologic development. Serial change in the BAEP is a specific parameter which we believe merits further study in premature infants as an index of neurologic maturation.

Developmental trend of quiet sleep is altered by early human malnutrition and recovered by nutritional rehabilitation

Thirteen infants malnourished from birth have been recorded with polygraphic techniques continuously for 24 h. The developmental trend of Quiet Sleep was found to be altered; infants older than 4 months had a diminution of Quiet Sleep with shorter phases. Ambiguous Sleep was increased. These findings reflect the effects of malnutrition on central nervous system development and could have implications for growth and for anabolic processes. Nutritional rehabilitation performed through an intracave catheter led to an increase of Quiet Sleep and to a decrease of Ambiguous Sleep.

Effects of undernutrition on development of far-field auditory brain stem responses in rat pups

Timed-pregnancy Sprague-Dawley rats were placed on special diets on day 15 of their pregnancy. One group received a normal, 24% protein diet, and the second a deficient, 8% protein diet. After birth the litters within each group were cross-fostered, thinned to 8 pups each, and maintained on their respective diets. Beginning with postnatal day 16 the ABR (auditory brain stem response) was repeatedly recorded from the pups until day 43. Undernourished rat pup body weights were less than one-third of those of the well-nourished litters at the conclusion of testing. ABRs taken from the undernourished group were significantly delayed in early development compared with the controls, but the differences decreased with age despite continuation of a deficient diet. A second experiment was run to rule out body temperature differences between the two groups and showed that the ABR effect was not solely due to this variable. These results indicate that undernourishment is one of the factors that can affect the rate of maturation of the ABR.

The effect of postnatal undernourishment on epileptiform kindling of dorsal hippocampus

Rats were undernourished postnatally from birth through 20 days of age. They were subsequently tested for susceptibility to motor seizures kindled in hippocampus in adulthood. Compared to littermate control animals the postnatally undernourished rats were more susceptible to the kindling treatment. We conclude that early postnatal undernourishment has a permanent effect on susceptibility of the hippocampus to electrically-induced seizures.