Subjective effects of peak clipping and compression limiting in normal and hearing-impaired children and adults

Despite many advances in hearing-aid signal processing, compression limiting and peak clipping are still used. To date, perceptual studies have been conducted only with adults. The current study was designed to investigate the clarity of peak-clipped and compressed speech for both adults and children. Subjects were 30 normal-hearing and 30 hearing-impaired individuals in three age ranges (7-9, 10-12, and 16-50 years). Stimuli were processed at 60, 70, 75, and 80 dB SPL using peak clipping and at 80 dB SPL using compression limiting. Paired-comparison measures were used to assess the clarity of sentences, and a signal-to-distortion ratio (SDR) based on a measure of coherence between input and output was computed for each condition. For the peak-clipping conditions, there was a decrease in perceived clarity as the input increased from 60 to 80 dB SPL. This perceptual continuum was most apparent for the normal-hearing adults. The normal-hearing 10-12 year olds and the hearing-impaired adults showed a similar, but less pronounced, pattern. In contrast, the remaining three subject groups showed minimal differences in perceived clarity across conditions. Surprisingly, only the two oldest normal-hearing groups showed a clear preference for compression limiting over peak clipping at the highest input level, and only their results were consistent with the pattern of coherence across stimuli. Judgments of clarity by the normal-hearing subjects correlated best with the SDR in the 500-2000-Hz range, while clarity judgments of the hearing-impaired subjects correlated best with the SDR below 1000 Hz.     

Doppler studies in normal kidneys of healthy children

Oral malodor (halitosis) is a common concern in Western society. As with other human perceptions, emotional as well as cognitive variables play a major role in one's sensation and complaint. To study factors potentially associated with the complaint of oral malodor, periodontal and psychological evaluations were carried out on 38 subjects (66% female, mean age 43 years) with a complaint of oral malodor. Subjects underwent evaluation of their periodontal status, odor evaluation by an odor judge, and psychopathological symptom survey by means of the SCL-90 questionnaire. The patient's self-rating of oral odor was significantly higher than the evaluation of an objective odor judge and was not associated with their periodontal status. The SCL-90 profile of subjects was relatively higher than that of an age- and gender-matched reference group of dental patients. The results suggest that the complaint of oral malodor may be related to psychopathological symptoms as recorded by the SCL-90 questionnaire.     

Diagnostic studies of optic neuritis in children and adolescents]

Cytolytic processes induced by membrane-associated proteins of human lymphokine-activated killer (LAK) cells with different phenotypes (CD3+, CD16-, CD8+ and CD16+, CD8+, CD3-) were studied using L929 and K562 types of target cells. Independently of the phenotype of effector cells and the type of target cells, total fractions of membrane proteins induced several different cytolytic processes occurring with different rates and involving different mechanisms of genome fragmentation. The membrane fraction induced, irrespective of the phenotype of LAK cells, mostly apoptotic processes in the L929 line. At the same time, cytolytic processes induced in K562 line differed by the mechanisms of DNA fragmentation. An inhibitor of lysosome activation, NH4Cl, and a Ca(2+)-binding reagent, ethylene glycol bis-(beta-aminoethyl ether) N,N,N',N'-tetraacetic acid (EGTA), induced partial inhibition of short-term cytolytic processes (developing within 1-5 h) but did not affect the development of long-term cytolytic processes requiring more than 6-8 h for their development.     

Psychophysical measures of auditory nonlinearities as a function of frequency in individuals with normal hearing

In order to gain a better understanding of how auditory nonlinear phenomena vary as a function of location along the cochlea, several psychophysical measures of nonlinearity were examined as a function of signal frequency. Six normal-hearing individuals completed three experiments, each designed to measure one aspect of nonlinear behavior: (1) the effects of level on frequency selectivity in simultaneous masking, measured using notched-noise maskers at spectrum levels of 30 and 50 dB, (2) two-tone suppression, measured using forward maskers at the signal frequency (fs) and suppressor tones above fs, and (3) growth of masking, measured using forward maskers below fs at a signal/masker frequency ratio of 1.44. Four signal frequencies (375, 750, 1500, and 3000 Hz) were tested to sample the nonlinear behavior at different locations along the basilar membrane, in order to test the hypothesis that the apical (low-frequency) region of the cochlea behaves more linearly than the basal (high-frequency) region. In general, all three measures revealed a progressive increase in nonlinear behavior as signal frequency increased, with little or no nonlinearity at the lowest frequency, consistent with the hypothesis.     

Electrophysiologic changes in preterm neonates: auditory brain stem response and distortion product otoacoustic emissions

The purposes of this investigation were to determine 1) if auditory peripheral maturity is present in the newborn; 2) if not, at what age maturational changes occur in the peripheral auditory system from preterm to full-term; and 3) how results of tests used to identify auditory dysfunction in neonates, such as distortion product otoacoustic emissions (DPEs) and auditory brain stem responses (ABRs), change during this period. Longitudinal DPE amplitude and ABR wave I latency measurements were obtained from a single ear of 18 preterm neonates. The DPEs were evoked at f2s of 2, 3, 4, and 5 kHz. The longitudinal data revealed that in general, DPE amplitude increased and ABR wave I latency decreased as a function of postconceptional age. These findings suggest that 1) the peripheral auditory system has not reached maturity in the preterm neonate; 2) maturational changes continue from preterm to full-term; and 3) these changes are reflected in ABR and DPE measurements.     

Electrophysiologic indices of Stroop and Garner interference reveal linguistic influences on auditory and visual processing

The purpose of this study was to examine linguistic influences on the auditory and visual processing of words both behaviorally and electrophysiologically. Our task yielded measures of the effect of irrelevant semantic content (Stroop interference) and of the effect of irrelevant linguistic variability (Garner interference). The behavioral results allow us to assess whether the linguistic and nonlinguistic dimensions of verbal stimuli are processed dependently or independently. The electrophysiologic results allow us to determine where any processing interactions are arising, particularly regarding perceptual versus postperceptual underpinnings, and to evaluate the similarity and dissimilarity between the two interference effects. Results show pronounced Stroop and Garner interference both behaviorally and electrophysiologically, indicating linguistic influences on auditory and visual processing. Subjects could not ignore the irrelevant linguistic dimension and attend selectively to the physical dimension of either spoken or written words. The results indicate that the physical and linguistic dimensions of words are not processed independently. With regard to the stage of processing underlying the interference effects, our results suggest that both Stroop and Garner interference involve multiple stages of processing. The two interference effects are not duplicate measures, however, and different electrophysiologic signatures were observed. Stroop interference is characterized by perceptual and postperceptual components. Similar electrophysiologic patterns within the auditory and visual modalities suggest that each interference effect is tapping similar processes for spoken and written stimuli.     

Rapid auditory processing in normal and disordered language development

A cell type, preadipocytes, isolated from the stroma of adult human adipose tissue appears capable of differentiating, in culture, into a cell with morphological features similar to that observed in terminally differentiated human adipocytes cultured under similar conditions. During this process of differentiation, preadipocytes develop extensive rough endoplasmic reticulum with prominent cisternae, the chromatin of most nuclei becomes decondensed and lipid bodies accumulate to levels observed in cultured adipocytes. Fibroblasts derived from non-adipose tissue do not undergo the same morphological changes when cultured under similar conditions.     

Hemodynamics, metabolism and function of the perfused pancreas under normal temperature]

The canine pancreas-duodenum has been perfused for 3 h with a membrane oxygenator, a pulsatile pump and a heat exchanger at a temperature of 37 degrees C. Among the criteria used in this study, the insulin output into the venous blood in response to glucose administration, as well as pancreas secretion after secretion stimulation were those found to be the most reliable indicators as to the viability of the pancreas. This is further supported by an average oxygen consumption of 0,77 ml O2/100 g at a constant flow of 80 ml/min and a perfusion pressure of 75 mm Hg. The pressure/flow relationship as for any other perfused organ was a safe indicator as to the viability of the perfused pancreas. The functional viability correlated with our anatomical findings.     

Epidemiological studies on 321 children with congenital diaphragmatic hernia in China]

Perinatal babies delivered in hospitals with gestation of 28 weeks to seven days after birth were monitored by National Birth Defects Monitoring Network from September 1986 to December 1993 to study the prevalence of congenital diaphragmatic hernia in China and the risk factors contributing to their prognosis. Results showed that 321 cases of congenital diaphragmatic hernia in 4,777,220 perinatal babies were detected with an incidence of 0.7 per ten thousand, a case-fatality ratio of 84.1 percent and, fetal death and stillbirth accounting for 28.1 percent of the total perinatal deaths. There was significant difference in birth weight between perinatal deaths and survival perinatal. And, 54.4 percent of the cases complicated with other congenital deformities and severe deformities in heart, lung and central nervous system accounted for the most proportion of them, which were the most important factors contributing to death. A case-fatality ratio of cases with single malformation was 74.7 percent and that of those with multiple malformation 92 percent, with a statistically significant difference. The cases diagnosed antenatally accounted for 11.3 percent of the total, and multiple malformation accounted for a large proportion of them. It indicated that proportion of antenatal diagnosis for congenital diaphragmatic hernia deformity was lower, and their perinatal case-fatality ratio was higher and their prognosis worse.     

Deficits in auditory temporal and spectral resolution in language-impaired children

Between 3 and 6 per cent of children who are otherwise unimpaired have extreme difficulties producing and understanding spoken language. This disorder is typically labelled specific language impairment. Children diagnosed with specific language impairment often have accompanying reading difficulties (dyslexia), but not all children with reading difficulties have specific language impairment. Some researchers claim that language impairment arises from failures specific to language or cognitive processing. Others hold that language impairment results from a more elemental problem that makes affected children unable to hear the acoustic distinctions among successive brief sounds in speech. Here we report the results of psychophysical tests employing simple tones and noises showing that children with specific language impairment have severe auditory perceptual deficits for brief but not long tones in particular sound contexts. Our data support the view that language difficulties result from problems in auditory perception, and provide further information about the nature of these perceptual problems that should contribute to improving the diagnosis and treatment of language impairment and related disorders.     

Do children with repaired low anorectal malformations have normal bowel function?

To determine the association of Epstein-Barr virus (EBV) with primary cutaneous amyloidosis (PCA), a retrospective study was conducted on skin tissue from 27 Chinese patients with lichen amyloidosus and macular amyloidosis. In situ hybridization with oligonucleotide probes was used to detect the expression of EBV-encoded RNAs (EBERs). Eleven of 27 cases (40.7%) were found to contain the EBV genome. No EBV genome was detected in the skin of the control groups, including three cases of secondary cutaneous amyloidosis, two cases of primary systemic amyloidosis, and four cases of lichen simplex chronicus. Our study showed no correlation between the presence of EBV in PCA patients and the patients' age, sex, clinical type or severity of the skin lesions. Although our results suggest that EBV may be associated with some cases of PCA, the true aetiological role of EBV in PCA remains unknown.     

Minimal criteria of epidemiologic studies of dental health of school children]

OBJECTIVE: To understand the developmental psychopathology of eating disorders, it is crucial to explain the large gender discrepancy in the rates of these disorders, especially anorexia nervosa and bulimia nervosa. In this paper, meta-analysis was used to examine the relationship between gender role adherence and the existence of eating problems. METHOD: Of the 69 studies examined, 22 contained data deemed valid for the analyses. Measures of difference (d) and homogeneity were calculated. These studies used the Personal Attributes Questionnaire (PAQ) or the Bem Sex Role Inventory (BSRI) to measure gender role adherence. RESULTS: Findings indicated a small, heterogeneous positive relationship between femininity and eating problems and a small, heterogeneous negative relationship between masculinity and eating problems. Studies that used a clinical sample showed a larger discrepancy in masculinity scores between the eating-disordered and the control groups than did studies using surveys to identify eating problems. Six studies measured gender role traditionalism. The eating-disordered groups did not differ significantly on these measures compared to the control groups. DISCUSSION: Despite construct validity problems with the use of the PAQ and the BSRI in this area of study, data suggest that gender role is related to eating problems. Crucial aspects of femininity likely to be related to eating problems need to be operationalized and their link to eating disorders examined.     

Tables of normal values of average and long latency auditory potentials

INTRODUCTION AND OBJECTIVE: In view of the disparity of data and methodology concerning medium (MAEP) and long latency (LAEP) acoustic evoked potentials, we have obtained tables of normal values using a reliable method and statistical study of these potentials in 30 healthy persons, in order to serve as a basis for clinical reference and for possible further studies. MATERIAL AND METHODS: In the MAEP we used the two types of stimuli most commonly employed, first a click and then a rising-plateau-falling tone (2-6-2). We observed that this did not affect the latency or amplitude of the different waves, although the best defined waves are obtained with tones. In the LAEP we always used a tone with rise-plateau-fall of 10-50-10, as recommended by the American Electroneurophysiological Society. In all cases the intensity was of 70 db, with rarefaction and masking of the contralateral ear with an intensity of 50 db. Self-adhesive electrodes were used for captation; the active one was placed on the ipsilateral ear lobe and the reference electrode in Cz for the LAEP. For the LAEP the lower filter was of 1 Hz and the higher of 70 Hz. In view of the variety of filters recommended, 10 Hz at the lower level and 500, 1000 and 2000 at the higher level were used successively for the MAEP. We observed that these did not affect the latency or amplitude of the waves, so these three values may all be used equally well. RESULTS AND CONCLUSIONS: In the inter-sexual study, no differences were seen between men and women. Nor were there significant differences between the acoustic evoked potentials on the right and left sides of the same person.     

Electrophysiologic effects of propranolol on sinus node function in patients with sinus node dysfunction

The electrophysiologic effects of intravenously administered propranolol (0.1 mg/kg) on three parameters of sinus node function were examined in ten symptomatic patients with sinus node dysfunction. The patients ranged in age from 26 to 79 years. Symptoms ranged from fatigue to frank syncope. Sinoatrial (SA) block and sinus pauses were observed in one patient; sinus pauses alone were observed in three patients. Five (5/10) patients had intraatrial block; three (3/10) patients had atrioventricular block; four (4/10) patients had an intraventricular conduction disturbance. At the time of electrophysiologic study, two patients had a control spontaneous sinus cycle length that exceeded 1000 msec. Following propranolol, the mean spontaneous cycle length increased by 17.4% (924 to 1085 msec, P less than 0.005) and spontaneous second degree SA block reappeared in the one patient. The maximum escape cycle ranged from 116% to 229% of the prepacing spontaneous cycle length and was considered to be prolonged in two of ten patients. Propranolol had no significant effect on the maximum escape cycle/prepacing cycle length X 100 (%). The estimated sinoatrial conduction time (SACT) was determined in seven patients and ranged in value from 120 to 238 mes. Propranolol increased the mean value of the estimated SACT from 179 to 213 msec, P less than 0.025. Propranolol may cause marked bradyarrhythmias in some patients with sinus node dysfunction, and should be used with caution in these patients.     

Evaluation of auditory discrimination in children with ADD and without ADD

BACKGROUND: Through antibody engineering, immunoglobulins can be tailored for their particular application. In this respect, small recognition units are desired for the targeting of antigens in obstructed locations like solid tumors. OBJECTIVES: To design efficient, minimum size recognition units, heavy chain variable regions (VH) had previously been modified for the use as antigen specific, single domain antibody fragments. To develop a rational approach to improve affinity, antigen binding is investigated here by analysing the effect of randomisations of CDR1 and 2 residues in VH domains specific for hapten and protein ligands. STUDY DESIGN: Randomised repertoires were displayed on phage and affinity selected to improve and analyse antigen binding. Affinities of newly selected VH domains were determined in their soluble format to assess the role of modified residues in binding. RESULTS: In four of five randomisation experiments, a new VH with an improved antigen affinity compared to the primary VH was selected. Dissociation constants decreased from 160 nM to 25 nM or 47 nM (CDR1 or CDR2 randomisation of an anti-Ox VH), from 300 nM to 31 nM (CDR2 randomisation of an anti-NIP VH) and from 3.1 microM to 1.6 microM (CDR2 randomisation of an anti-lysozyme VH). CONCLUSIONS: Thus the affinity of VH domains can be improved after site specific, secondary randomisations in CDR1 and CDR2, phage display and antigen selection. As differences in the CDR3 sequences had formed the only difference between the primary VH domains used in this study, the effect of CDR1 and CDR2 mutations of affinity is consistent with a participation of all three CDRs in antigen binding by single VH domains.     

Conversational repair in schizophrenic and normal children

OBJECTIVE: Children acquire the skills to monitor the adequacy of their spoken message and to self-initiate repair strategies that modify the message during early, middle, and late childhood. To characterize further the communication deficits of childhood-onset schizophrenia, this study compared self-initiated repair strategies in schizophrenic and normal children and their relationship with formal thought disorder, discourse deficits, and distractibility. METHOD: Measures of self-initiated repair, formal thought disorder, and cohesion were coded in 32 schizophrenic and 47 normal children, aged 5.6 to 12.4 years, from speech samples elicited with the Story Game. RESULTS: The schizophrenic children used some repair strategies (false starts, fillers, referential revision) more infrequently than the normal children. Within the schizophrenic group, the children who were receiving neuroleptic medication underutilized repair and had more discourse deficits than the unmedicated patients. Loose associations and distractibility were associated with increased use of false starts but not fillers. CONCLUSIONS: In addition to formal thought disorder and discourse deficits, schizophrenic children underutilize self-initiated repair when presenting their thoughts to the listener, particularly if they are being treated with neuroleptics, a potential sign of increased clinical morbidity. Impoverished communication skills might reflect negative signs in childhood-onset schizophrenia.