Children's perception of temporally distorted sentential approximations of varying length.

The purpose of this study was to investigate the abilities of second-grade and fourth-grade children to auditorially process three orders of three- and five-word sentential approximations, which had normal interstimulus intervals (ISI) and ISIs of 200 and 400 ms. Results showed that percent correct scores decreased as a function of increasing sentence length and ISI, and decreasing order of sentential approximation and grade level. The results are discussed relative to theoretical notions of short-term memory and auditory perceptual processing as well as potential clinical applications.     

Normal-hearing teenagers' performance on time-compressed sentential stimuli

Teenagers with normal hearing, reading, and learning abilities yielded normative data on time-compressed speech, either the Revised CID sentences or 3rd-order sentential approximations. There were 6 Ss, either all boys or all girls, in each of 12 subgroups combining age (median ages: 13, 15, 17 yrs), gender (M or F), SPL of test (45 or 60 db SPL), type of material ( RCIDs or sentential approximations), and percent time compression (0, 40, or 60%). The expected poorer performance was found with sentential approximations, either increased time compression, and with decreased level. This study provides normative data for teenagers' performance on tests of time-compressed sentential material.     

Auditory Analysis Of Temporally Distorted Sentential Approximations

Previous investigators have emphasized the significant role of time in auditory perceptual processing. Two factors important in this process are word duration and interstimulus interval. This study was designed to investigate the perceptual consequences of independent modification of these two factors, using two orders of sentential approximations. The results show that while both temporal factors operate in perceptual accuracy, word duration plays a more significant role than interstimulus interval. Also, perceptual errors may be offset by increasing the order of sentential approximations. The results are discussed in view of their implications for audiological assessment.     

Children's performance on multidimensionally scored time-compressed sentential stimuli

Normative data were obtained for 96 children with normal auditory and language abilities in grades 2, 4, and 6 when presented monaurally with time-compressed (TC) sentences and 1st- and 2nd-order sentential approximations at 32 db re SRT. Oral responses were taped and multidimensionally scored in order to sensitize the test. Consistent with previous reports of normative data at other age levels, performance became poorer for 0 to either 40 or 60% TC (there was a negligible difference between the latter), was better for normal sentences than for sentential approximations, and improved slightly in the higher grades.     

Older adult performance on an altered version of the SSI test

The Synthetic Sentence Identification (SSI) test has been used extensively in investigations of reduced speech understanding skills in older adults. In this study the SSI test was altered by adding noise to the competing message and by administering practice lists and equivalent test lists, as well as versions of the test that have 4- and 12-s interstimulus intervals (ISIs), along with the standard 8-s ISI. The purpose was to determine the effect of these alterations on performance in a group of older adults with average pure-tone average 2 values less than 33 dB HL. Performance changed as a function of the ISI, with less rollover occurring for the 4-s ISI condition than the other 2 ISIs.     

Effect of interstimulus interval on subjective categorical loudness judgements

The Independent Hearing Aid Fitting Forum uses the visual input/output locator algorithm and the Contour Test of Loudness Perception to achieve the goal of restoring normal loudness perception with amplification. This method presupposes that subjective categorical loudness judgments are valid and reliable when using the procedure outlined by the test developers. There is no indication in the instructions of the Contour Test of a specific duration for interstimulus interval (ISI). The effect of ISI on loudness perception is important to establish because of potential time-error effects. Time-error refers to the extent to which the judged magnitude of a second stimulus varies with the time interval by which it follows the first stimulus. Past research has indicated that judgments of a second stimulus are shifted in the direction of the intensity of the preceding stimulus and that this effect intensifies with shorter ISIs. The current experiment was designed to examine whether a change in ISI produced a change in the loudness rating of the subsequent stimulus for subjective categorical loudness judgment testing. A trend toward lower, median dB values for ratings 2 to 5 at 500 Hz in a group of subjects with normal hearing was noted when 1-sec intervals were used in comparison with longer ISIs. No trends for the effect of ISI were noted at 3000 Hz. The findings provide ISI recommendations for loudness judgment test administration.     

HspE7 treatment of pediatric recurrent respiratory papillomatosis: final results of an open-label trial

OBJECTIVES: We sought to evaluate the effectiveness of HspE7, a recombinant fusion protein of Hsp65 from Mycobacterium bovis BCG and E7 protein from human papillomavirus 16, to improve the clinical course of pediatric patients with recurrent respiratory papillomatosis. METHODS: An open-label, single-arm intervention study was conducted in 8 university-affiliated medical centers. Twenty-seven male and female patients with recurrent respiratory papillomatosis, ages 2 to 18 years, were enrolled and followed up to 60 weeks. Before enrollment, these patients required surgery on average every 55 days. After a baseline debulking surgery, the patients received HspE7 500 microg subcutaneously monthly, for 3 doses over 60 days. The primary end point was the length of the interval from the last surgery during the treatment period until the first debulking surgery in the posttreatment period, compared with the median intersurgical interval (ISI) of the 4 surgeries before the treatment. RESULTS: The mean of the first posttreatment ISI increased 93% (from 55 days to 106 days; p < .02). The median ISI for all surgeries after treatment was similarly prolonged (mean, 107 days; p < .02), indicating a sustained treatment effect, and was associated with a significant decrease in the number of required surgeries (p < .003). Unexpectedly, the treatment effect was most striking in the 13 female patients, who had statistically significant increases in both the first posttreatment ISI (142%; p < .03) and the median ISI (147%; p < .03). The most common adverse events were mild-to-moderate injection site reactions. CONCLUSIONS: Treatment with HspE7 appears to significantly improve the clinical course in pediatric patients with RRP insofar as it reduces the frequency of required surgeries. These results warrant a confirmatory phase III trial.     

Interaction of age and intersignal interval on acoustic reflex amplitude

We studied the effect of intersignal interval (ISI) on the averaged acoustic reflex in nine young and nine elderly subjects. Over the range of ISIs from 1.5 to 9 sec, there was an interaction between ISI and age group, but the effect was unique to reflex mode. Results emphasize the importance of measuring both crossed and uncrossed reflex waveforms, in the study of aging, and of controlling the ISI in order to avoid overestimation of aging effects.     

Chemosensory event-related potentials to trigeminal stimuli change in relation to the interval between repetitive stimulation of the nasal mucosa

Event-related potentials (ERPs) to olfactory and trigeminal stimuli have been used commonly to evaluate chemosensory dysfunction. The aim of the present study was to investigate how ERPs could be modified by repetitive stimulations of the intranasal trigeminal nerve using 52% v/v CO₂ stimuli for 200 ms periods. Nine subjects were exposed to 6 sessions each during which trains of 16 stimuli were applied. The interval between stimuli was constant for each experiment, but varied between experiments (10, 20, 30, 40, 60, and 90 s). Trigeminal ERPs were obtained from three positions on the skull. Both intensity ratings and ERP amplitudes decreased as the interstimulus interval (ISI) shortened. Specifically, ratings and response amplitudes were most strongly reduced by approximately 30–50% at the shortest ISI used (10 s) and were largest at an ISI of 90 s. The decrease of amplitudes was strongest for the P₄₆ amplitude. Our findings suggest that this may be the result of both habituation and stimulus predictability. We hypothesize that the ISI dependence of chemosensory ERPs may also be a function of an interaction between A_delta and C fibers. Received: 17 April 1998 / Accepted: 29 July 1998     

Intrinsic oscillations in spike trains indicate non-renewal statistics due to convergence of inputs in dorsal cochlear nucleus neurons

The occurrence of intrinsic oscillations (IOs) in a unit’s discharge is reflected by a prominent peak in the power spectrum (i.e., Fourier transform of the autocorrelation function) of spike trains obtained from single-unit discharge, at a frequency independent of stimulus spectral characteristics. IOs have been reported by researchers in the dorsal cochlear nucleus (DCN) of both the cat and the Mongolian gerbil. It has been hypothesized that IOs are related to inter-spike interval (ISI) regularity (e.g., [Hear. Res. 58 (1992) 153]). This hypothesis is tested in this paper. Responses to multiple presentations of 50–300 ms duration tone bursts, at and near the unit’s best frequency (BF) at 20–60 dB re threshold were recorded from DCN units of barbiturate-anesthetized (30 units), as well as decerebrate (53 units) Mongolian gerbils. IOs in the recordings were then compared with the IOs in simulations of spiking-neuron models. The models were selected because: (1) their ISI regularity characteristics follow those of experimental data and (2) their IO properties are completely determined by their ISI regularity. Such comparison reveals that Ghoshal’s hypothesis fails for a fraction of the units. These results suggest a re-evaluation of the purported relationship between IOs, ISI regularity, and SAM response. Alternate hypotheses are proposed here using computational models that are based on convergence of multiple neural inputs onto the unit under study. These models produce non-renewal statistics that resemble those of the experimental data, as is evident from IO-based analysis.     

The effects of very slow rates of stimulus presentation on event-related potential estimates of hearing threshold

The present study evaluated the use of slow rates of stimulus presentation on the accuracy of the N1-P2 cortical response in estimating hearing threshold. Long interstimulus intervals (ISI) allow the non-specific component of the N1 response to emerge, believed to reflect widespread cortical arousal that facilitates sensory and motor responses. We examined whether the non-specific N1 would be elicited at intensity levels near threshold. Event-related potentials were recorded to 0.5-, 1.0, and 4.0-kHz tone bursts with a long ISI (8-12 s) while the eleven subjects read a book. The stimulus level varied from -5 to 45 dB nHL. The 1.0-kHz tone burst was also presented with a shorter ISI (1.5-2.5 s), akin to that typically used in the audiological setting. The amplitude of N1-P2 was significantly enhanced in the long compared to short ISI condition, but, importantly, only for the stimuli with a level > or =25 dB nHL. Therefore, the N1-P2 recorded with long ISIs was not more precise in estimating threshold than that recorded with short ISIs, remaining visible to within 10 dB of behavioural threshold.     

Discrimination of time-altered sentential approximations and monosyllables by children with reading problems

This study compared the performance of normal-reading and reading-impaired children using time-compressed three- and five-word sentential approximations to full grammaticality, and the Word Intelligibility by Picture Identification (WIPI) test presented with and without pictures. Results suggested that reading-impaired children could be differentiated from normal readers by scores on these measures and by types of errors made. Theoretical and pragmatic implications are discussed.     

A facial nerve study using transcranial magnetic paired stimulation

OBJECTIVE: The purpose of this study was to evaluate the refractory period of the facial nerve by transcranial magnetic paired stimulation (TMPS) with as short interstimulus interval (ISI) as possible. Also, by applying TMPS, the long latency response obtained at the same time was recorded and its neurophysiological characteristics were studied. METHODS: (Experiment 1) The subjects comprised of 30 normal volunteers and 19 patients with Bell's palsy. The experiments were carried out using two sets of Magstim model 200 and Bistim modules, a large coil measuring 90 mm in diameter with a maximal output of 2.0 tesla (T), and a Neuropack 8 (Nihon Kohden Co., Japan) to control the stimulation and record the electromyographic findings. The amplitude of compound muscle action potentials (CMAP) to the orbicularis oris muscle was studied by TMPS at the parieto-occipital region. The ISI was set at 0.9, 1.1, 1.3, 1.5, 1.7, 1.9 and 2.1 ms in order to measure the refractory periods of the nerve. (Experiment 2) The subjects comprised of ten normal volunteers. The same method as in experiment 1 was carried out. However, this time, the lead electrodes were placed on the orbicularis oculi muscle, similar to that of the blink reflex. The ISI was set at 40, 60, 80, 100, 200, 300, 500, 800 and 1000 ms, and the effects of the facilitation and inhibition were studied. RESULTS: (Experiment 1) In normal subjects, when the ISI was less than 1 ms, a significant decrease in the amplitude was noted. In severe palsy cases with House-Brackmann Grade IV-V TMS yielded no response. In two of the cases of House-Brackmann Grade III, the CMAP was obtained. (Experiment 2) The long latency response with TMPS was most strongly inhibited when ISI was 80 ms. CONCLUSION: We were able to investigate the refractory periods, the reflex pathway of the facial nerve and the trigeminal nerve including the pons and the medulla oblongata by TMPS.     

Temporal processing deficits in Hebrew speaking children with reading disabilities.

The purpose of this study was to assess to what extent specific reading disabilities and poor phonologic processing in children who read Hebrew, a primarily consonant orthography, are related to central auditory temporal processing deficits (TPDs).Twenty-four Hebrew-speaking children (ages 10-13) with and without reading disabilities were asked to discriminate auditorily pairs of syllables (/ba/ vs. /pa/) that differ by voice onset time (VOT) only. Two paradigms were used, 1 with a short interstimulus interval (ISI) (50 ms) and 1 with a long ISI (500 ms). Event-related potentials (ERPs) were measured in response to the two syllables in an auditory oddball task. Results showed significantly lowered accuracy, longer reaction times, and prolonged P3 latency among the group with reading disabilities compared with the control group. No significant differences were found between the short ISI task and the long ISI task. However, significant correlations were found between the phonologic processing tasks and the short ISI task.These findings in the Hebrew language are consistent with findings from other languages and add support to the central TPD hypothesis of reading disabilities. The discussion highlights how investigating different orthographic systems can deepen our understanding of the role TPD plays in reading.     

Speech evoked cortical potentials: effects of age and stimulus presentation rate

We examined the effects of stimulus complexity and stimulus presentation rate in ten younger and ten older normal-hearing adults. A 1 kHz tone burst as well as a speech syllable were used to elicit the N1 -P2 complex. Three different interstimulus intervals (ISI) were used (510, 910, and 1510 msec). When stimuli were presented at the medium presentation rate (910 msec ISI), N1 and P2 latencies were prolonged for older listeners in response to the speech stimulus but not the tone stimulus. These age effects were absent when stimuli were presented at a slower rate (1510 msec ISI). Results from this study suggest that rapidly occurring stimulus onsets, either within a stimulus or between stimuli, result in prolonged N1 and P2 responses in older adults. This is especially true when processing complex stimuli such as speech. One potential explanation for this age effect might be age-related refractory differences in younger and older auditory systems. Refractory issues might in turn affect synchronized neural activity underlying the perception of critical time-varying speech cues and may partially explain some of the difficulties older people experience understanding speech.     

Auditory Evoked Brain Potentials as a Function of Interstimulus Interval in Adults with Down's Syndrome

Auditory-evoked potentials (AEP) to repeated binaural tone pips of several interstimulus intervals (ISIs) ≥1 s were recorded from the vertex of young adults with Down's syndrome (DS; trisomy 21) and normal young adults. The following results were obtained: (1) AEP amplitudes, as well as one latency measure, of both experimental groups increased with the lengthening of ISI. (2) AEP peak latencies of the DS group were longer than AEP peak latencies of the normal group for all the ISIs employed. (3) AEP amplitudes of the DS group tended to be larger than AEP amplitudes of the normal group. These findings are discussed in relationship to issues of attention.

Nous avons comparé les potentiels auditifs tardifs en fonction de trois valeurs de ISI (1, 4 et 8 s) chez de jeunes adultes normaux et de jeunes adultes atteints de syndrome de Down (SD). Nous avons observé: 1) que l'amplitude ainsi que la mesure de la latence des potentiels augmentaient avec la valeur de ISI chez les deux groupes de sujets; 2) que ces augmentations étaient plus fortes chez les sujets atteints de SD. Nous pensons qu'il s'agit d'un trouble de l'inhibition et de l'attention.     

Auditory temporal pattern discrimination and reading ability.

The relation between reading ability and performance on an auditory temporal pattern discrimination task was investigated in children who were either good or delayed readers. The stimuli in the primary task consisted of sequences of tones, alternating between high and low frequencies. The threshold interstimulus interval (ISI) for discrimination of differences in the temporal properties of the sequences was measured. An ISI threshold was also measured in a control task that was identical to the primary task, except all tones in a control sequence had the same frequency. Delayed readers and good readers were equally able to discriminate the timing of the sequences at short ISIs, for both the primary and control tasks. Furthermore, the ISI thresholds were not correlated with the ability to read either irregular words or nonwords. These results suggest that reading ability is not related to the ability to track large and rapid frequency changes in auditory temporal patterns.     

A method for removing cochlear implant artifact

When cortical auditory evoked potentials (CAEPs) are recorded in individuals with a cochlear implant (CI), electrical artifact can make the CAEP difficult or impossible to measure. Since increasing the interstimulus interval (ISI) increases the amplitude of physiological responses without changing the artifact, subtracting CAEPs recorded with a short ISI from those recorded with a longer ISI should show the physiological response without any artifact. In the first experiment, N1–P2 responses were recorded using a speech syllable and tone, paired with ISIs that changed randomly between 0.5 and 4 s. In the second experiment, the same stimuli, at ISIs of either 500 or 3000 ms, were presented in blocks that were homogeneous or random with respect to the ISI or stimulus. In the third experiment, N1–P2 responses were recorded using pulse trains with 500 and 3000 ms ISIs in 4 CI listeners. The results demonstrated: (1) N1–P2 response amplitudes generally increased with increasing ISI. (2) Difference waveforms were largest for the homogeneous and random-stimulus blocks than for the random-ISI block. (3) The subtraction technique almost completely eliminated the electrical artifact in individuals with cochlear implants. Therefore, the subtraction technique is a feasible method of removing from the N1–P2 response the electrical artifact generated by the cochlear implant.     

短期持续正压通气治疗对阻塞性睡眠呼吸暂停低通气综合征伴2型糖尿病患者胰岛素敏感性的影响

目的:探讨阻塞性睡眠呼吸暂停低通气综合征(OSAHS)伴2型糖尿病患者行UPPP前,应用短期(7 d)持续正压通气(CPAP)治疗对其胰岛素敏感性的影响.方法:选择由PSG确诊的中、重度OSAHS伴2型糖尿病并需要行UPPP的患者30例,记录其AHI及夜间最低血氧饱和度(LSaO2),采用稳态模式评估(HOMA)指数评估胰岛素的敏感性,行7 d CPAP治疗后,复查PSG和计算HOMA指数,并与治疗前做比较.结果:经过7 dCPAP治疗后,AHI及LSaO2明显改善(P<0.05),胰岛素敏感性升高(P<0.05);AHI与空腹胰岛素水平呈正相关(r=0.636 5,P<0.05),与胰岛素敏感性呈负相关(r=-0.622 9,P<0.05);夜间LSaO2与空腹胰岛素水平呈负相关(r=0.8889,P<0.05),与胰岛素敏感性呈正相关(r=0.952 6,P<0.05).结论:短期CPAP治疗能改善OSAHS伴2型糖尿病患者夜间低血氧的情况,增加其胰岛素的敏感性,降低UPPP的危险性.     

Interactions among variables in the P300 response to a continuous performance task in normal and ADHD adults

This study investigated the effect of variable interstimulus intervals (ISIs) in a group of normal and ADHD (attention deficit hyperactivity disorder) adults on behavioral reaction time and the auditory P300 event-related potential. This study involved 20 adult subjects with no history of ADHD and 11 adult subjects diagnosed with ADHD. The subjects were instructed to respond to the common stimuli and ignore the rare stimulus. Significant differences in the latency of the P300a, P300b, the amplitude of the P300b, and in the number of false alarms and correct rejections between ISIs were observed in the normal group. The group with ADHD failed to show any significant differences between ISIs. Psychophysical measures of hits showed significant differences for the number of hits for ISI 2 (2 sec) between the two groups. False alarms and correct rejections for all ISIs showed significant differences between groups. Significant group differences were seen for latency of the P300a and P300b at each of the three ISIs, for amplitude of the P300a and P300b for ISI 1 and ISI 3, and for the amplitude of the P300b for ISI 2. There was a greater separation in the group with ADHD between the P300a and P300b suggesting a processing lag in that group.