Gap Detection Ability Research Articles

Binaural advantages in sound temporal information processing by neurons in the rat inferior colliculus.

Previous studies on the advantages of binaural hearing have long been focused on sound localization and spatial stream segregation. The binaural advantages have also been observed in speech perception in reverberation. Both human speech and animal vocalizations contain temporal features that are critical for speech perception and animal communication. However, whether there are binaural advantages for sound temporal information processing in the central auditory system has not been elucidated. Gap detection threshold (GDT), the ability to detect the shortest silent interval in a sound, has been widely used to measure the auditory temporal resolution. In the present study, we determined GDTs of rat inferior collicular neurons under both monaural and binaural hearing conditions. We found that the majority of the inferior collicular neurons in adult rats exhibited binaural advantages in gap detection, i.e., better neural gap detection ability in binaural hearing conditions compared to monaural hearing condition. However, this binaural advantage in sound temporal information processing was not significant in the inferior collicular neurons of P14-21 and P22-30 rats. Additionally, we also observed age-related changes in neural temporal acuity in the rat inferior colliculus. These results demonstrate a new advantage of binaural hearing (i.e., binaural advantage in temporal processing) in the central auditory system in addition to sound localization and spatial stream segregation.

Tactile misfit detection ability at the implant-abutment interface of internal connection dental implants: an in-vitro study

Objective The aim of this in-vitro study was to investigate the tactile assessment ability at the implant impression-taking stage. Methods Thirty clinicians (18 novices, 12 experts) were included for a tactile fit assessment by using a used/new probe (tip diameter 100 µm/20 µm). Six implant replicas and related impression copings of two internal connection implant systems were used, each with a perfect fit (0 µm) and defined vertical micro gaps of 8, 24, 55, 110 and 220 µm at the interface. Statistical analysis was performed using descriptive methods and non-parametric tests with a focus on specificity (ability to detect perfect fit), sensitivity (ability to detect misfit), and predictive values. P-values <5% were considered statistically significant. Results The tactile assessment showed a mean total sensitivity for the Straumann and Nobel Biocare systems of 83% and 80% with a used probe, and 91% and 92% with a new probe, respectively. The mean total specificities were 33% and 20% with a used probe and 17% and 3% with a new probe, respectively. No statistical significance was observed between novice and expert clinicians concerning their tactile assessment ability. Conclusions The ability to detect a perfect fit (specificity) with a probe was very poor for both implant systems and impaired with the use of a new probe. The use of a new probe improved the gap detection ability (sensitivity) significantly at the expense of the specificity. A combination of additional chairside techniques with training and calibration could improve clinicians’ ability to correctly assess the fit/misfit at the implant-abutment interface.

Incorporating Auditory Cortex Potentials and Gap Pre-pulse Inhibition of Acoustic Startle: A Probable Way to Objectively Assess Tinnitus

Background and Objectives: Tinnitus is a complex condition that varies in loudness, quality, location, and distress. Different definitions, heterogeneity, and lack of objective measuring have challenged the understanding the mechanisms involved and definitive cure. The integrative model correlates each of these characteristics to separate parallel and overlapping subnetworks that process tinnitus’s perception and emotional reaction. Many of these networks are common with the gap pre-pulse inhibition of acoustic startle (GPIAS) neural circuity. GPIAS, which measures tinnitus in animals, has recently been used for humans with various recording methods. The present study aimed to review the evidence achieved with gap stimuli in patients with tinnitus to support the potential of cortical responses recorded with the GPIAS stimulus and to objectively detect tinnitus in humans. Methods: Studies were identified by searching electronic databases with relevant keywords. Results: The role of the auditory cortex in processing short gaps, the possibility of evaluating the gap detection ability with GPIAS, and the advantage of cortical responses in reflecting both stimulus properties and different aspects of tinnitus emphasize the importance of this issue. The results of most studies have proven the gap detection deficiency in tinnitus. However, the validity of the auditory startle reflex still needs to be verified due to the inherent variability and different methods. Conclusion: Further human studies are recommended because the perception of tinnitus can be controlled. An appealing research line in this area is multi-channel cortical evoked potentials. Defects of GPIAS with cortical recording can indicate tinnitus.

Gap detection responses modelled using the Hill equation in adults with well-controlled HIV

Objective This study’s objective was determining whether gap detection deficits are present in a longstanding cohort of people living with HIV (PLWH) compared to those living without HIV (PLWOH) using a new gap detection modelling technique (i.e. fitting gap responses using the Hill equation and analysing the individual gap detection resulting curves with non-linear statistics). This approach provides a measure of both gap threshold and the steepness of the gap length/correct detection relationship. Design The relationship between the correct identification rate at each gap length was modelled using the Hill equation. Results were analysed using a nonlinear mixed-effect regression model. Study sample 45 PLWH (age range 41–78) and 39 PLWOH (age range 38–79) were enrolled and completed gap detection testing. Results The likelihood ratio statistic comparing the full regression model with the HIV effects to the null model, assuming one population curve for both groups, was highly significant (p < 0.001), suggesting a less precise relationship between gap length and correct detection in PLWH. Conclusions PLWH showed degraded gap detection ability compared to PLWOH, likely due to central nervous system effects of HIV infection or treatment. The Hill equation provided a new approach for modelling gap detection ability.

Effect of Musical Training on Temporal Resolution and Temporal Fine Structure Processing

Background and Aim: Many aspects and features of auditory system can be improved by musical training. This study aimed to investigate the effects of a stringed musical instrument playing course on temporal resolution and temporal fine structure (TFS) processing. Methods: This analytical cross-sectional study was conducted on 44 normal-hearing adults aged 20–40 years divided to two groups. The first group included 22 stringed musical instruments players (13 males) with at least three years of experience, and the second group were 22 non- players (13 males). The random gap detection test (RGDT) was used to measure temporal resolution aspect of hearing. For TFS processing, latest version of temporal fine structure-adaptive frequency (TFS-AF) test was used. Results: The TFS-AF results showed no statistically significant difference between groups in different interaural phase differences (IPDs). The RGDT results showed significant differences between groups at 500, 1000 and 2000 Hz, but not at 4000 Hz. Spearman correlation test results showed no statistically significant correlation between the results of TFS-AF and RGDT. Conclusion: Musical training has no effect on TFS processing but considerably enhances gap detection ability. Their underlying mechanisms for TFS processing and gap detection are different.

Investigating the Role of Auditory Processing Abilities in Long-Term Self-Reported Hearing Aid Outcomes among Adults Age 60+ Years.

Self-reported hearing aid outcomes among older adults are variable and important to improve. The extent of the role of auditory processing in long-term hearing aid outcomes is not well understood. To determine how auditory processing abilities are related to self-reported hearing aid satisfaction and benefit along with either aided audibility alone or exploratory factors suggested by previous literature. Descriptive analyses and multiple regression analyses of cross-sectional self-reported outcomes. Adult participants, >60 years (n = 78), fitted with bilateral hearing aids to treat symmetric, mild to moderate sensorineural hearing loss. Participants were recruited from a single audiology clinic to complete a series of questionnaires, behavioral assessments, and obtain data from their hearing aids, including real ear measures and data logging of hearing aid use. Multiple linear regressions were used to determine the amount of variance explained by predictive factors in self-reported hearing aid satisfaction and benefit. The primary predictive factors included gap detection threshold, spatial advantage score, dichotic difference score, and aided audibility. Exploratory factors included personality, self-efficacy, self-report of disability, and hearing aid use. All interpretations of statistical significance used p < 0.05. Effect sizes were determined using Cohen's f 2 with a medium effect suggesting clinical relevance. Gap detection threshold was a statistically significant predictor in both primary regression models with a medium effect size for satisfaction and a small effect size for benefit. When additional exploratory factors were included in the regression models with auditory processing abilities, gap detection and self-efficacy were both significant predictors of hearing aid satisfaction with medium effect sizes, explaining 10 and 17% of the variance, respectively. There were no medium effect sizes found for other predictor variables in either the primary or exploratory hearing aid benefit models. Additional factors were statistically significant in the models, explaining a small amount of variance, but did not meet the medium effect size criterion. This study provides initial evidence supporting the incorporation of measures of gap detection ability and hearing aid self-efficacy into clinical practice for the interpretation of postfitting long-term hearing aid satisfaction.

Acoustically Enriched Environment during the Critical Period of Postnatal Development Positively Modulates Gap Detection and Frequency Discrimination Abilities in Adult Rats

Throughout life, sensory systems adapt to the sensory environment to provide optimal responses to relevant tasks. In the case of a developing system, sensory inputs induce changes that are permanent and detectable up to adulthood. Previously, we have shown that rearing rat pups in a complex acoustic environment (spectrally and temporally modulated sound) from postnatal day 14 (P14) to P28 permanently improves the response characteristics of neurons in the inferior colliculus and auditory cortex, influencing tonotopical arrangement, response thresholds and strength, and frequency selectivity, along with stochasticity and the reproducibility of neuronal spiking patterns. In this study, we used a set of behavioral tests based on a recording of the acoustic startle response (ASR) and its prepulse inhibition (PPI), with the aim to extend the evidence of the persistent beneficial effects of the developmental acoustical enrichment. The enriched animals were generally not more sensitive to startling sounds, and also, their PPI of ASR, induced by noise or pure tone pulses, was comparable to the controls. They did, however, exhibit a more pronounced PPI when the prepulse stimulus was represented either by a change in the frequency of a background tone or by a silent gap in background noise. The differences in the PPI of ASR between the enriched and control animals were significant at lower (55 dB SPL), but not at higher (65-75 dB SPL), intensities of background sound. Thus, rearing pups in the acoustically enriched environment led to an improvement of the frequency resolution and gap detection ability under more difficult testing conditions, i.e., with a worsened stimulus clarity. We confirmed, using behavioral tests, that an acoustically enriched environment during the critical period of development influences the frequency and temporal processing in the auditory system, and these changes persist until adulthood.

Age-Related Decline of Sensorimotor Integration Influences Resting-State Functional Brain Connectivity

Age-related decline in sensorimotor integration involves both peripheral and central components related to proprioception and kinesthesia. To explore the role of cortical motor networks, we investigated the association between resting-state functional connectivity and a gap-detection angle measured during an arm-reaching task. Four region pairs, namely the left primary sensory area with the left primary motor area (S1left–M1left), the left supplementary motor area with M1left (SMAleft–M1left), the left pre-supplementary motor area with SMAleft (preSMAleft–SMAleft), and the right pre-supplementary motor area with the right premotor area (preSMAright–PMdright), showed significant age-by-gap detection ability interactions in connectivity in the form of opposite-sign correlations with gap detection ability between younger and older participants. Morphometry and tractography analyses did not reveal corresponding structural effects. These results suggest that the impact of aging on sensorimotor integration at the cortical level may be tracked by resting-state brain activity and is primarily functional, rather than structural. From the observation of opposite-sign correlations, we hypothesize that in aging, a “low-level” motor system may hyper-engage unsuccessfully, its dysfunction possibly being compensated by a “high-level” motor system, wherein stronger connectivity predicts higher gap-detection performance. This hypothesis should be tested in future neuroimaging and clinical studies.

Gap Detection Deficits in Chinchillas with Selective Carboplatin-Induced Inner Hair Cell Loss.

Temporal resolution is essential for processing complex auditory information such as speech. In hearing impaired persons, temporal resolution, often assessed by detection of brief gaps in continuous sound stimuli, is typically poorer than in individuals with normal hearing. At low stimulus presentation levels, hearing impaired individuals perform poorly but the deficits are greatly reduced when the sensation level of the stimuli are adjusted to match their normal hearing peers. In the present study, we evaluated the effect of selective inner hair cell loss on gap detection in chinchillas treated with carboplatin, an anticancer drug that selectively damages inner hair cells and afferents in this species. Treatment with carboplatin-induced inner hair cell loss of ~ 70% but had little effect on audiometric thresholds in quiet and produced no evidence of outer hair cell loss. In contrast, selective inner hair cell loss had a significant effect on gap detection ability across a wide range of presentation levels. These results suggest that gap detection tasks are more sensitive to inner hair cell pathology than audiometric thresholds.

Effects of Gap Position on Perceptual Gap Detection Across Late Childhood and Adolescence.

The ability to detect a silent gap within a sound is critical for accurate speech perception, and gap detection has been shown to have an extended developmental trajectory. In certain conditions, the detectability of the gap decreases as the gap is placed closer to the beginning of the signal. Early in development, the detection of gaps shortly after signal onset may be especially difficult due to immaturities in the encoding and perception of rapidly changing sounds. The present study explored the development of gap detection from age 8 to 19years, specifically when the temporal placement of the gap varied. Performance improved with age for all temporal placements of the gap, demonstrating a gradual maturation of gap detection abilities throughout adolescence. Younger adolescents did not benefit from increasing gap onset times, while older adolescents' thresholds gradually improved as gap onset time lengthened. Regardless of age, listeners learned between the two testing days but did not improve within days. Younger adolescents had poorer thresholds for the last block of testing on the second day, returning to baseline performance despite learning between days. These data support earlier studies showing that gaps are harder to detect near stimulus onset and confirm that gap detection abilities continue to mature into adolescence. The data also suggest that younger adolescents do not receive the same benefit of increasing gap onset time and respond differently to repeated testing than older adolescents and young adults.

Evidence for independent peripheral and central age-related hearing impairment.

Deleterious age-related changes in the central auditory nervous system have been referred to as central age-related hearing impairment (ARHI) or central presbycusis. Central ARHI is often assumed to be the consequence of peripheral ARHI. However, it is possible that certain aspects of central ARHI are independent from peripheral ARHI. A confirmation of this possibility could lead to significant improvements in current rehabilitation practices. The major difficulty in addressing this issue arises from confounding factors, such as other age-related changes in both the cochlea and central non-auditory brain structures. Because gap detection is a common measure of central auditory temporal processing, and gap detection thresholds are less influenced by changes in other brain functions such as learning and memory, we investigated the potential relationship between age-related peripheral hearing loss (i.e., audiograms) and age-related changes in gap detection. Consistent with previous studies, a significant difference was found for gap detection thresholds between young and older adults. However, among older adults, no significant associations were observed between gap detection ability and several other independent variables including the pure tone audiogram average, the Wechsler Adult Intelligence Scale-Vocabulary score, gender, and age. Statistical analyses showed little or no contributions from these independent variables to gap detection thresholds. Thus, our data indicate that age-related decline in central temporal processing is largely independent of peripheral ARHI.

Relationship between temporal processing and phonological awareness in children with speech sound disorders

ABSTRACTTemporal processing ability contributes to the identification of small phonetic elements that is important for speech perception. Difficulty in these interferes with normal speech perception and phoneme recognition. The present study aimed to assess the temporal and phonological processing abilities in children with speech sound disorders (SSD). Temporal processing and phonological skills were evaluated in 32 participants in the age range of 6–10 years, equally divided into two groups. Group I included typically developing children, and Group II included children with SSD. Gap detection test and duration pattern test were used to assess temporal processing abilities, and phonological sensitivity training kit in Kannada (PhoST-K) assessed phonological processing abilities. The results showed that there was a significant difference in temporal and phonological processing between the two groups of children. A significant correlation between gap detection ability and deletion tasks and between duration pattern ability and oddity tasks was obtained. Based on the results, it is recommended to assess the temporal process pertinent to central auditory processing in children with SSD, as a close relationship between temporal processing abilities and phonological awareness exists.

Behavioral evaluation of auditory function abnormalities in adult rats with normal hearing thresholds that were exposed to noise during early development

Noise-exposed rat pups provide a model of early deprivation of sensory input to the central auditory system, allowing the study of developmental neuroplasticity. Our previous results have demonstrated that a brief exposure of rats to broadband noise (125 dB SPL 8 min, 14th postnatal day) at the onset of hearing resulted in an altered intensity perception and frequency discrimination in adulthood despite normal hearing thresholds. In this study, we assessed the gap-detection ability and possible presence of tinnitus- and hyperacusis-like behavior in adult rats after the same neonatal acoustic trauma, using measurements of the acoustic startle response (ASR) in quiet and noisy environments and its prepulse inhibition by gaps in noise (gap-PPI). A significant deficit in the ability to detect gap was observed in the exposed rats when 55 dB SPL broadband noise was used as background. An increase of noise intensity to 65–75 dB SPL led to strengthening of the gap-PPI in exposed animals, which approached the gap-PPI values of control animals at these levels. Behavioral signs of tinnitus (gap detection deficits in 10 kHz narrow band noise) were found in 25% of exposed rats. An increased sensitivity to continuous noise was manifested in all exposed rats by suppression of the ASR at significantly lower background noise levels than in the controls. This effect was particularly pronounced in rats with tinnitus-like behavior. Our results indicate that neonatal acoustic trauma, producing only a transient threshold shift, may produce permanent abnormalities in suprathreshold auditory functions and the development of tinnitus and hyperacusis-like behavior.

A New Statistical Approach for the Evaluation of Gap-prepulse Inhibition of the Acoustic Startle Reflex (GPIAS) for Tinnitus Assessment.

Background: An increasingly used behavioral paradigm for the objective assessment of a possible tinnitus percept in animal models has been proposed by Turner and coworkers in 2006. It is based on gap-prepulse inhibition (PPI) of the acoustic startle reflex (ASR) and usually referred to as GPIAS. As it does not require conditioning it became the method of choice to study neuroplastic phenomena associated with the development of tinnitus.Objective: It is still controversial if GPIAS is really appropriate for tinnitus screening, as the hypothesis that a tinnitus percept impairs the gap detection ability (“filling-in interpretation” is still questioned. Furthermore, a wide range of criteria for positive tinnitus detection in GPIAS have been used across different laboratories and there still is no consensus on a best practice for statistical evaluation of GPIAS results. Current approaches are often based on simple averaging of measured PPI values and comparisons on a population level without the possibility to perform valid statistics on the level of the single animal.Methods: A total number of 32 animals were measured using the standard GPIAS paradigm with varying number of measurement repetitions. Based on this data further statistical considerations were performed.Results: We here present a new statistical approach to overcome the methodological limitations of GPIAS. In a first step we show that ASR amplitudes are not normally distributed. Next we estimate the distribution of the measured PPI values by exploiting the full combinatorial power of all measured ASR amplitudes. We demonstrate that the amplitude ratios (1-PPI) are approximately lognormally distributed, allowing for parametrical testing of the logarithmized values and present a new statistical approach allowing for a valid and reliable statistical assessment of PPI changes in GPIAS.Conclusion: Based on our statistical approach we recommend using a constant criterion, which does not systematically depend on the number of measurement repetitions, in order to divide animals into a tinnitus and a non-tinnitus group. In particular, we recommend using a constant threshold based on the effect size as criterion, as the effect size, in contrast to the p-value, does not systematically depend on the number of measurement repetitions.

Individual gap detection ability can be enhanced with transcranial alternating current stimulation

Individual gap detection ability can be enhanced with transcranial alternating current stimulation

Untangling the effects of tinnitus and hypersensitivity to sound (hyperacusis) in the gap detection test

In recent years, there has been increasing use of the gap detection reflex test to demonstrate induction of tinnitus in animals. Animals with tinnitus show weakened gap detection ability for background noise that matches the pitch of the tinnitus. The usual explanation is that the tinnitus ‘fills in the gap’. It has recently been shown, however, that tinnitus is commonly associated with hyperacusis-like enhancements of the acoustic startle response, a change which might potentially alter responses in the gap detection test. We hypothesized that such enhancements could lead to an apparent reduction of gap suppression, resembling that caused by tinnitus, by altering responses to the startle stimulus or the background noise. To test this hypothesis, we compared gap detection abilities in 3 subsets of noise-exposed animals with those in unexposed controls. The results showed that exposed animals demonstrated altered gap detection abilities, but these alterations were sometimes explained as consequences of hyper-responsiveness to either the startle stimulus or to the background noise. Two of the three subsets of animals studied, however, displayed weakened gap detection abilities that could not be explained by enhanced responses to these stimuli or by reduced sound sensitivity or a reduction of temporal processing speed, consistent with the induction of tinnitus. These results demonstrate that not only hearing loss but also changes in sensitivity to background noise or to startle stimuli are potential confounds that, when present, can underlie changes in gap detection irrespective of tinnitus. We discuss how such confounds can be recognized and how they can be avoided.

Electrophysiological gap detection thresholds: effects of age and comparison with a behavioral measure.

Temporal processing ability has been linked to speech understanding ability and older adults often complain of difficulty understanding speech in difficult listening situations. Temporal processing can be evaluated using gap detection procedures. There is some research showing that gap detection can be evaluated using an electrophysiological procedure. However, there is currently no research establishing gap detection threshold using the N1-P2 response. The purposes of the current study were to 1) determine gap detection thresholds in younger and older normal-hearing adults using an electrophysiological measure, 2) compare the electrophysiological gap detection threshold and behavioral gap detection threshold within each group, and 3) investigate the effect of age on each gap detection measure. This study utilized an older adult group and younger adult group to compare performance on an electrophysiological and behavioral gap detection procedure. The subjects in this study were 11 younger, normal-hearing adults (mean = 22 yrs) and 11 older, normal-hearing adults (mean = 64.36 yrs). All subjects completed an adaptive behavioral gap detection procedure in order to determine their behavioral gap detection threshold (BGDT). Subjects also completed an electrophysiologic gap detection procedure to determine their electrophysiologic gap detection threshold (EGDT). Older adults demonstrated significantly larger gap detection thresholds than the younger adults. However, EGDT and BGDT were not significantly different in either group. The mean difference between EGDT and BGDT for all subjects was 0.43 msec. Older adults show poorer gap detection ability when compared to younger adults. However, this study shows that gap detection thresholds can be measured using evoked potential recordings and yield results similar to a behavioral measure.

Changes in the Response Properties of Inferior Colliculus Neurons Relating to Tinnitus

Tinnitus is often identified in animal models by using the gap prepulse inhibition of acoustic startle. Impaired gap detection following acoustic over-exposure (AOE) is thought to be caused by tinnitus “filling in” the gap, thus, reducing its salience. This presumably involves altered perception, and could conceivably be caused by changes at the level of the neocortex, i.e., cortical reorganization. Alternatively, reduced gap detection ability might reflect poorer temporal processing in the brainstem, caused by AOE; in which case, impaired gap detection would not be a reliable indicator of tinnitus. We tested the latter hypothesis by examining gap detection in inferior colliculus (IC) neurons following AOE. Seven of nine unilaterally noise-exposed guinea pigs exhibited behavioral evidence of tinnitus. In these tinnitus animals, neural gap detection thresholds (GDTs) in the IC significantly increased in response to broadband noise stimuli, but not to pure tones or narrow-band noise. In addition, when IC neurons were sub-divided according to temporal response profile (onset vs. sustained firing patterns), we found a significant increase in the proportion of onset-type responses after AOE. Importantly, however, GDTs were still considerably shorter than gap durations commonly used in objective behavioral tests for tinnitus. These data indicate that the neural changes observed in the IC are insufficient to explain deficits in behavioral gap detection that are commonly attributed to tinnitus. The subtle changes in IC neuron response profiles following AOE warrant further investigation.

The gap-startle paradigm for tinnitus screening in animal models: Limitations and optimization

In 2006, Turner and colleagues (Behav. Neurosci., 120:188–195) introduced the gap-startle paradigm as a high-throughput method for tinnitus screening in rats. Under this paradigm, gap detection ability was assessed by determining the level of inhibition of the acoustic startle reflex produced by a short silent gap inserted in an otherwise continuous background sound prior to a loud startling stimulus. Animals with tinnitus were expected to show impaired gap detection ability (i.e., lack of inhibition of the acoustic startle reflex) if the background sound containing the gap was qualitatively similar to the tinnitus pitch. Thus, for the gap-startle paradigm to be a valid tool to screen for tinnitus, a robust startle response from which to inhibit must be present. Because recent studies have demonstrated that the acoustic startle reflex could be dramatically reduced following noise exposure, we endeavored to 1) modify the gap-startle paradigm to be more resilient in the presence of hearing loss, and 2) evaluate whether a reduction in startle reactivity could confound the interpretation of gap prepulse inhibition and lead to errors in screening for tinnitus. In the first experiment, the traditional broadband noise (BBN) startle stimulus was replaced by a bandpass noise in which the sound energy was concentrated in the lower frequencies (5–10 kHz) in order to maintain audibility of the startle stimulus after unilateral high-frequency noise exposure (16 kHz). However, rats still showed a 57% reduction in startle amplitude to the bandpass noise post-noise exposure. A follow-up experiment on a separate group of rats with transiently-induced conductive hearing loss revealed that startle reactivity was better preserved when the BBN startle stimulus was replaced by a rapid airpuff to the back of the rat’s neck. Furthermore, it was found that transient unilateral conductive hearing loss, which was not likely to induce tinnitus, caused an impairment in gap prepulse inhibition as assessed with the traditional BBN gap-startle paradigm, resulting in a false-positive screening for tinnitus. Thus, the present study identifies significant caveats of the traditional gap-startle paradigm, and describes experimental parameters using an airpuff startle stimulus which may help to limit the negative consequences of reduced startle reactivity following noise exposure, thereby allowing researchers to better screen for tinnitus in animals with hearing loss.

An adaptive clinical test of temporal resolution: Age effects

Objective: Children with auditory processing disorder, as well as older adults with and without hearing loss, often report difficulty understanding speech in the presence of noise. There is evidence that deficient temporal resolution contributes to this difficulty. The purpose of this study was to establish within-channel (WC) and across-channel (AC) gap detection thresholds (GDTs) for participants ages 7 to 84 years. Design: GDTs were measured using narrow-band noise markers for two conditions of the Adaptive Tests of Temporal Resolution (ATTR): WC and AC. Study Sample: Participants were 29 children (ages 7-12 years) with normal hearing, 30 younger adults (ages 22-41 years) with normal hearing, and 60 older adults (ages 50 to 84 years) with varying hearing sensitivity. Results: GDTs are smallest and least variable for younger adults with normal hearing and are largest and most variable for the youngest children (ages 7-8 years). The GDTs of the other groups fell between those of the younger adults and youngest children. Group differences were more apparent for AC than WC conditions. Conclusions: WC and AC gap detection ability changes across the lifespan. The ATTR is an efficient tool for the assessment of temporal resolution at both ends of the lifespan.SumarioObjetivo: Los niños con trastornos en el procesamiento auditivo, así como los adultos con o sin hipoacusia, frecuentemente reportan dificultades para entender el lenguaje en presencia de ruido. Existe evidencia que las deficiencias en la resolución temporal contribuyen a esta dificultad. El propósito de este estudio fue establecer los umbrales de detección de brechas (GDT) dentro de los canales (WC) y a través de los canales (AC) para los participantes con edades entre 7 y 84 años. Diseño: Los GDT se midieron usando marcadores de ruido de banda estrecha para dos condiciones con la Prueba Adaptativa de Resolución Temporal (ATTR): WC y AC. Muestra: Los participantes fueron 29 niños (edades de 7 a 12 años) con audición normal, 30 adultos jóvenes (edades 22 a 41 años) con audición normal y 60 adultos mayores (edades de 50 a 84 años) con diferentes niveles de audición. Resultados: Los GDT son más pequeños y menos variables en los adultos jóvenes con audición normal, y más grandes y variables para en los niños pequeños (edades 7 a 8 años). Los GDT de los otros grupos se ubicaron entre los de los adultos jóvenes y los niños. Las diferencias grupales fueron más aparentes en la condición AC que en la WC. Conclusiones: La habilidad en la detección de brecha WC y AC cambia durante la vida. El ATTR es una herramienta eficiente para la evaluación de la resolución temporal en ambos extremos de la vida.