The interaction between sex and click polarity in brain-stem auditory potentials evoked from control subjects of Oriental and Caucasian origin

Brain-stem auditory evoked potentials (BAEPs) were performed on 30 male and 30 female young normal Oriental subjects, using both condensation and rarefaction stimulation. The effects of sex and click polarity on the BAEP latencies and amplitudes were studied. Females had shorter absolute and interpeak latencies and higher absolute amplitudes than the males. These sex-related BAEP differences were independent of the click polarity. Rarefaction clicks produced shorter wave I latency and longer I–III interpeak latency, but the differences were significant in the female only. The polarity-related BAEP amplitude differences were essentially independent of the sex. BAEPs performed on 60 sex- and age-matched young Caucasian subjects produced similar results. The importance of establishing control BAEP values according to the sex and click polarity is emphasised.     

Clinical correlates of brain-stem auditory evoked potential variables in multiple sclerosis. Relation to click polarity

The correlations between clinical signs and BAEP latency, amplitude and dispersion variables were investigated in 98 multiple sclerosis patients. A new dispersion variable, the wave IV–V “shape ratio” (SR IV–V), correlated most strongly with brain-stem signs (i.e., nystagmus). Severely reduced wave IV–V amplitude was frequently found in patients with vertical nystagmus or internuclear ophthalmoplegia, and interpeak latency (IPL) III–V correlated most strongly with cerebellar dysfunction (i.e., ataxia). The results may reflect different localizing ability among the various BAEP variables.The association between ataxia and increased IPL III–V was significantly stronger for BAEP to C clicks than to R clicks. Patients with abnormal BAEPs to one polarity (C or R) but not to the other, had significantly more clinical dysfunction than patients with normal BAEPs to both C and R clicks. Hence, C vs. R discordance may be interpreted to indicate possible brain-stem dysfunction.     

The effect of click rate on latency and interpeak interval of the brain-stem auditory evoked potentials in children from birth to 6 years

Latency and interpeak interval of the brain-stem auditory evoked potentials at different click rates were measured in 80 healthy children from birth to 6 years, and 21 adults. Clicks were presented at 10, 30, 50, 70 and 90/sec, and 70, 40 and 20 db HL. At high stimulus intensity (70 dB SL), all latencies of waves I, III and V and the I–V, I–III and III–V intervals showed a progressive prolongation with increasing repetition rate. The latency- and the interval-rate functions were similar for all age groups but their slopes were slightly steeper in younger than in older. As click rate increased from 10/sec to 90/sec, the latencies of waves I, III and V at different age groups were prolonged by 4–10%, 9–13% and 12–15% respectively, and the intervals of I–V, I–III and III–V were prolonged by 15–16%, 8–16% and 14–24% respectively. The mean increments of wave V latency and I–V interval in different age groups were 0.404–0.575 and 0.332–0.526 msec respectively with increasing click rate from 10 to 50/sec, and 0.697–1.009 and 0.629–0.776 msec respectively with increasing click rate from 10 to 90/sec. The younger the age the larger the absolute increments for all these BAEP parameters, but the increasing rates for a BAEP measure were similar among different age groups, exhibiting no age-dependent differences. The III–V/I–III interval ration in most age groups was increased by 3–10% with increasing click rate from 10 to 90/sec, suggesting that the III–V interval was affected by stimulus rate slightly more than I–III interval.At moderate (40 dB HL) and low (20 dB SL) intensity, all waves and intervals showed similar latency- and interval-rate functions to those at high intensity. This demonstrates that the shifting latencies and interpeak intervals with increasing click rate appeared to be independent of the stimulus intensities.     

Effect of computer work on the state of physiological functions in children aged 7 to 10 years

We studied the age- and sex-related functional characteristics of the central nervous system (CNS), cardiovascular system (CVS), lability of the visual sensory system, and mental capacity before and after a continuous computer work for 15 min in children aged 7, 8, 9, and 10 years. The results of the research showed that the resistance of the physiological systems of the body to loads associated with computer work increases in primary school children with age. We also observed sex-related differences: many parameters of functional performance during computer work at the age of 8 years were better in girls than in boys, which was due to a higher rate of development; at the age of 10 years, girls had a larger number of adverse changes in the functional state of the body compared with boys, which is possibly due to the onset of puberty.     

Brainstem auditory evoked potentials in the fetal sheep, in utero

We studied brainstem auditory evoked potentials (BAEPs) in 8 fetal sheep in utero, ranging in gestational age from 105 to 142 days gestation (normal term 147 days). We could not elicit BAEPs prior to 117 days of gestation. After this age rapid maturation was seen, with three discernible peaks observed prior to 120 days and five peaks after 120 days. A significant (P less than 0.05) gestational age related fall in peak latencies and interpeak latencies was observed. The rate of stimulus presentation that could be tolerated without significant changes in wavepeak latency or amplitude also increased with advancing gestational age. In older fetuses (greater than 125 days), where a differentiated electrocorticogram (ECOG) was observed, differences were seen in latency and amplitude of several of the BAEP wavepeaks dependent upon the state. In high voltage ECOG states the amplitudes of wave IV and V were significantly (P less than 0.05) greater than in the low voltage ECOG state and the latencies of wave I, II and V were significantly (P less than 0.05) longer in low as compared to high voltage ECOG state. The BAEP, being obtainable over very short periods of time, appears to provide a useful indice of neural maturation for the sheep fetus in utero.     

Functional changes in brainstem auditory structures in humans suffering from the Chernobyl’ catastrophe

We analyzed the temporal characteristics of short-latency auditory evoked potentials (SL AEP) in people involved in the cleanup work after the Chemobyl’ catastrophe (hereafter, cleanup workers), who now are living within the “clean” territories or remain within the radionuclide-contaminated area (groups 2 and 3, respectively), and in persons who were not involved in the cleanup works but are permanently living within the contaminated zone (group 4). The latencies of the SL AEP were peaks (peak latencies, PL) in all these groups regularly exceeded corresponding values in the control group 1. The increments were mild (several percent) but significant for the waves II–V. The most substantial PL increments were characteristic for group 3. Analysis of the interpeak intervals showed that an increase in the I–III interval provided the greatest contribution to modification of the SL AEP, temporal parameters. The mechanisms of influence of the Chernobyl’ catastrophe-related factors on the brainstem auditory structures are discussed. The data allow us to conclude that functional modifications in the above structures contribute to the hearing change for the worse observed in the people suffering from the Chernobyl’ catastrophe; a prolonged stay within the contaminated territories represents a considerable factor aggravating these changes.     

BAEP subcomponents and wave form — relation to click phase and stimulus rate

The latency distributions of normal brain-stem auditory evoked potential (BAEP) components elicited by condensation (C) and rarefaction (R) clicks at 10 and 50 Hz were found to be double- or multi-peaked for II (10 and 50 Hz), III (50 Hz), IV (10 and 50 Hz) and V (10 Hz). A bifid component III was found in 3.5% (10 Hz) and 7.4% (50 Hz) of BAEPs. A bifid II and triple IV/V configuration were occasionally noted. The prevalences of the different IV/V complex configurations were significantly dependent upon click phase and rate. These results suggest that several subcomponent might participate in the generation of the single BAEP components and that a single generator may contribute to different BAEP components in different subjects.Early subcomponents between I and II (Ib) were found in 13% of 10 Hz BAEPs and 27% of 50 Hz BAEPs (P = 0.002) and the latency distribution of Ib seemed to be bimodal. Ib/I relative amplitude frequently increased with 50 Hz stimulation.We suggest that the generator of Ib is partially cochlear (CM) and partially neural (equivalent to N2 of the ECochG-AP) in origin.The existence of subcomponents must be recognized in clinical use of BAEPs both to avoid misinterpretation and to decrease the normal variability in monophasic click evoked BAEP studies.     

Brain-stem auditory evoked potentials in the common marmoset (Callithrix jacchus)

Brain-stem auditory evoked potentials (BAEPs) were recorded in 10 common marmosets (Callithrix jacchus) to investigate the effects of recording electrode configurations, stimulus rate, and stimulus frequency on BAEP wave forms and peak latencies. Tone burst stimulations were used to evaluate the effects of pure tone on BAEP wave forms. Five positive peaks superimposed on positive and negative slow potentials were identified in the BAEP recorded at the linkage between the vertex and the dorsal base of the ear ipsilateral to a monaural stimulus. When the reference electrode was placed at the ipsilateral mastoid or the neck, the amplitudes of positive and negative slow potentials and the incidence of wave I increased. There were no significant changes in peak latencies of BAEP waves with changes in stimulus rate from 5 to 20/s. It was possible to record the BAEPs in response to tone burst stimulations at frequencies extending from 0.5 to 99 kHz. Wave I appeared apparently at high stimulus frequencies; while waves III to V, at low frequencies. Wave II was recorded at frequencies ranging from 0.5 to 99 kHz and comprised a superposition of 2 or 3 potentials.     

Short- and middle-latency auditory evoked potentials in abstinent chronic alcoholics: preliminary findings

Short- and middle-latency auditory evoked potentials (BAEPs and MAEPs) were studied in 15 chronic alcoholic patients after 1 month's abstinence and compared with those of 15 healthy controls, matching the patients pairwise for sex and age. Most of the parameters studied varied more within the alcoholic group than within the control group. The BAEP results agree with previous reports; in the alcoholic group, BAEP peak V was significantly delayed and the inter-peak intervals, III–V and I–V, were lengthened. The latencies of the MAEP components Na and Pa, on the other hand, were significantly shortened. These findings suggest that chronic abusive consumption of alcohol may bring about structural and/or neurochemical alterations at various levels in the auditory pathway.     

Serum IGF-I and IGFBP-3 levels of Turkish children during childhood and adolescence: establishment of reference ranges with emphasis on puberty

AIMS/METHODS: We established age- and sex-related reference ranges for serum insulin-like growth factor-I (IGF-I) and insulin-like growth factor binding protein-3 (IGFBP-3) levels in 807 healthy Turkish children (428 boys, 379 girls), and constructed a model for calculation of standard deviation scores of IGF-I and IGFBP-3 according to age, sex and pubertal stage. RESULTS: Serum IGF-I and IGFBP-3 concentrations tended to be higher in girls compared to boys of the same ages, but the differences were statistically significant only in pubertal ages (9-14 years) for IGF-I and only in prepubertal ages for IGFBP-3 (6-8 years) (p < 0.05). Peak IGF-I concentrations were observed earlier in girls than boys (14 vs. 15 years, Tanner stage IV vs. V) starting to decline thereafter. IGFBP-3 levels peaked at age 13 and at Tanner stage IV in both sexes with a subsequent fall. Serum levels of IGF-I and IGFBP-3 increased steadily with age in the prepubertal stage followed by a rapid increase in IGF-I in the early pubertal stages. A relatively steeper increase in IGF-I but not in IGFBP-3 levels was observed at age 10-11 years in girls and at 12-13 years in boys which preceded the reported age of pubertal growth spurt. At late pubertal stages, both IGF-I and IGFBP-3 either did not change or decreased by increasing age. Interrelationships between growth factors and anthropometric measurements have been described, and the physiologic consequences of these have been discussed in detail. CONCLUSIONS: Differences in the pattern of IGF-I and IGFBP-3 in the present paper and those reported in other studies emphasize the importance of locally established reference ranges. Establishment of this reference data and a standard deviation score prediction model based on age, sex and puberty will enhance the diagnostic power and utility of IGF-I and IGFBP-3 in evaluating growth disorders in our population.     

The prognostic significance of the adaptation potential of the cardiovascular system in 10- and 11-year-old children

Experimental physiological studies were made in 10–11-year-old boys and girls, students of a gymnasium and an education-upbringing complex. The functional parameters recorded in children momentarily included: the heart rate, systolic and diastolic arterial pressure, Roufier index, and the adaptation potential (AP) of the cardiovascular system as an integral index of the adaptivity level of human organism on the whole, measured according to special formulas, and the index of the risk of disease development. Apart from it, the height, body mass, vital lung capacity, and strength of hand grip were measured, the puberty stage and deviations in the functioning of organs and systems were revealed. The AP levels used to evaluate adults’ adaptation did not agree with 10–11-year-old children’s physical development degree, puberty stages, and health condition (belonging to different health groups). No agreement was found between the levels of these parameters and the degrees of AP of the cardiovascular system in 10–11-year-old children based on their individual values and sigmal deviations of this index. Therefore, a conclusion on the adaptation capacities of a child’s organism and the risk of disease development in it based on the AP values may be erroneous. The authors suggest an age scale of the AP levels for 10–11-year-old children.     

达斡尔族学生皮下脂肪发育的研究

作者内蒙古莫力达瓦达斡尔族自治旗１７５９例中小学生项项皮褶厚度及体脂发育情况进行了调查研究。结果表明：（１）达斡尔族学生进入青春期后,随着年龄的增长,男性躯干部皮变厚,四肢部皮褶变薄,女性躯干、四肢部皮褶均增厚。（２）１２岁后,女性皮褶厚度显著大于男性。（３）青春发育早期,男性体脂逐渐有下降,女性于１２－１４岁体脂迅速增加。（４）总体说来,达斡尔族学生并不偏于肥胖。     

Evoked potential findings in Behçet's disease. Brain-stem auditory,visual, and somatosensory evoked potentials in 44 patients

We studied 54 patients with Behçet's disease, 41 males and 13 females, mean age 28 years. Forty-four patients had auditory brain-stem evoked potential (BAEP) recordings, 39 had pattern reversal visual evoked potentials (VEP), 27 had median nerve somatosensory evoked potential (SEP) recordings, and 25 tibial nerve SEPs. BAEPs were abnormal in 16 patients (52%) with neurological manifestations and in 4 (31%) without, because of decreased amplitude of wave V, prolonged I–III or III–V interpeak latencies, or uncertain/absent waves III and/or V. Eleven patients (40%) with neurological symptoms and 3 patients (25%) without, had abnormal VEPs. Absent potentials, decreased amplitude, with or without prolonged P100 latency, were found in 75% of the cases, the rest had prolonged P100 latency only. Median SEPs were abnormal in 8 patients (38%) with neurological manifestations. Four patients (21%) had abnormal tibial SEPs. Decreased amplitude with or without mild slowing in central conduction was the predominant SEP abnormality. SEPs were normal in all patients without neurological symptoms. In total, 84% of patients with, and 38% of patients without, neurological symptoms had abnormalities of one or more EP modality.When used cautiously, EP studies in Behçet's disease might be helpful to separate neuro-Behçet from other disorders with similar symptomatology, to disclose subclinical CNS involvement, to evaluate and monitor CNS disease activity, and to provide objective measures of treatment response.     

Brain-stem auditory evoked potentials (BAEPs): maturation of interpeak latency I–V (IPL I–V) in the first years of life

BAEPs were recorded from 89 healthy children aged 0.1–52.1 months. The maturation kinetics of interpeak latency I–V can be well approximated by an exponential model with a horizontal asymptote. Adult values are reached by about 3 years of life. Differences between males and females become significant when maturation is completed. A non-fragmented reference range for interpeak latency I–V in the first years of life is provided.     

Chronic effects of phenytoin on brain-stem auditory evoked potentials in man

The effects of phenytoin (PHT) on brain-stem auditory evoked potentials (BAEPs) were studied in 65 epileptic patients who received long-term PHT monotherapy at therapeutic and supra-therapeutic levels with no clinical evidence of brain-stem toxicity. Abnormal BAEPs were found in 7.5% and 33.3% of patients with therapeutic and supra-therapeutic PHT levels respectively. Serum PHT levels had a trend towards a positive relationship with the I–V interpeak latency (IPL), and a significant negative relationship with the amplitudes of waves I and V. at supra-therapeutic levels, both I–V and I–III IPLs were significantly prolonged while at therapeutic evels onl I–III IPLs were prolonged. The absolute latency of wave I was prolonged in both the therapeutic and the supra-therapeutic groups. These results suggest that PHT acts both peripherally on either the auditory nerve or the cochlea, and centrally on brain-stem conduction.     

Longitudinal analysis of adolescent growth of ladino and Mayan school children in Guatemala: effects of environment and sex.

The rate of growth in height and the timing of adolescent growth events are analyzed for two samples of Guatemalan children. One sample includes Mayan school children, 33 boys and 12 girls between the ages of 5.00 to 17.99 years, living under poor conditions for growth and development. The second sample includes ladino children, 78 boys and 85 girls of the same age range, living under favorable conditions for growth. The Preece-Baines model I function is used to estimate mean values for rates and timing of childhood and adolescent growth events for the two groups. Significant statistical contrasts (t-tests) of these means show Mayan boys reach the age of "take-off" (TO; the onset of the adolescent growth spurt) 1.45 years later, achieve peak height velocity (PHV) 1.68 years later, and continue growing for about 2.0 years longer than do the ladino boys. Despite the Mayan boys' increased duration for growth they grow significantly more slowly than the ladinos. Mayan boys are 6.60 cm shorter than ladinos at the age of TO and are estimated to be 7.71 cm shorter than the ladinos at adulthood. Mayan girls reach the age of TO 0.93 years later than do the ladina girls, but the two groups do not differ in the age at PHV or the age at adulthood. The mean height of Mayan girls is significantly less than that of ladinas at the age of TO (6.5 cm), and this difference increases to an estimated 11.14 cm at adulthood. Possible causes of these ethnic and sex-related differences in amounts and rates of growth are discussed in relation to hypotheses about the genetic and environmental determinants of human development.     

Effects of zinc deficiency and pinealectomy on cellular immunity in rats infected with Toxoplasma gondii

The effects of zinc and/or melatonin deficiencies on cellular immunity were investigated in rats infected with Toxoplasma gondii. A total of 50 adult male Sprague-Dawley rats were divided into 5 groups of 10 rats each. In group I, the rats were infected with T. gondii and fed a zinc-deficient diet; in group II, the rats were infected and their pineal gland was surgically removed. Group III included rats that were infected, pinealectomized, and fed a zinc-deficient diet. Group IV consisted of T. gondii-infested rats that received no treatment of any kind, and group V were normal controls. After 3 wk of treatment, all rats were sacrificed and the percentages of CD3, CD4, and CD8 lymphocytes, zinc, and melatonin levels in plasma and the percentage of lymphocyte in blood smears were analyzed. The CD3 ratios of groups I–III were significantly lower than those of groups IV and V (p<0.01). The CD4 lymphocytes were significantly higher in group IV than that in all other groups (p<0.05). In group IV, the CD8 lymphocytes were higher than in groups I–III (p<0.01) and those in group V were higher than for groups I and III (p<0.01). Lymphocyte incidence in group IV was higher than in the other four groups (p<0.01). The plasma zinc and plasma melatonin levels in groups I–III were significantly lower than those in the controls (p<0.01, both cases). These results suggest that zinc and/or melatonin deficiency have a negative influence on cellular immunity in rats with toxoplasmosis.     

Intellectual development of 15- to 16-year-old boys and girls: Psychophysiological structure

The structure of intelligence in senior adolescents has been studied. The analysis of intelligence in adolescents of both sexes has shown that there are no distinct differences in the structure of intellectual development between boys and girls aged 15–16 years. Significantly better results have been obtained only for the memory development of girls. This suggests that the pattern of cognitive development does not depend on the sex at the last stages of puberty. Significant variation of individual intellectual characteristics confirms a high variability of the psychophysiological structure of intelligence in adolescents at this ontogenetic stage.     

Practice Variation in the Management of Girls and Boys with Delayed Puberty

Objective: Delayed puberty is a common condition, and typical management includes “watchful waiting” and/or sex-steroid therapy. We sought to characterize treatment practices and to assess provider comfort with the management of delayed puberty in girls and boys.Methods: A national survey of pediatric endocrine providers assessed definitions of delayed puberty, practices around sex-steroid therapy, reasons for treatment, and comfort in managing delayed puberty in girls and boys.Results: Of 184 respondents (12% participation rate), 64% and 71% used the traditional age cutoffs for defining delayed puberty of 13 years for girls and 14 years for boys, respectively. Nearly half (45%) of providers would treat boys relatively earlier than girls, compared to 18% who would treat girls relatively earlier (P<.0001). Providers were more likely to cite bone density as a reason to treat girls and alleviating patient and parental distress, accelerating growth, and “jump starting” puberty as reasons to treat boys. Greater experience in endocrine practice was associated with greater comfort managing delayed puberty in both boys and girls. Approximately 80% of providers agreed that clinical guidelines are needed for the management of delayed puberty.Conclusion: There is a high degree of variability in the clinical management of delayed puberty, and our results suggest that providers are more hesitant to treat girls compared to boys and have different reasons for treating each. It remains to be determined if these discrepancies in treatment are justified by biologic differences between girls and boys or represent nonevidence-based disparities in care.Abbreviation: U.S. = United States