Biomedical subjects

Daphne Ari-Even Roth

Publications and source records attributed to Daphne Ari-Even Roth.

7 recordsLinked to original sources

PubMed2005

The effect of number of perceptual categories on identification functions of non-speech stimuli and the relationship to categorization of Hebrew voicing.

Category boundary (CB) of Hebrew voicing on voice-onset time (VOT) continuum was found to be different from non-speech stimuli on tone-onset time (TOT) continuum. This is in contrast to data in English, thus suggesting that CB for speech stimuli may be determined not only by general auditory sensitivities but by additional factors that may be speech specific. The data in Hebrew voicing, however, can also be explained by the fact that in Hebrew voicing, two categories were available to the listener, whereas for the TOT stimuli there were three: leading, simultaneous and lagging temporal events. The purpose of the present study was to investigate the effect of number of perceptual categories on CB of non-speech analogs of voicing in Hebrew-speaking subjects and compare them to those obtained on a VOT continuum. Twenty-four Hebrew-speaking adults participated in this study. Stimuli consisted of (a) a two-tone complex continuum that varied in the relative onset time of the lower frequency tone, and (b) a /ba-pa/ continuum which varied in VOT values similar to (a). The same TOT continuum was tested twice. In one, subjects identified TOT stimuli as belonging to one of three categories (TOT3): leading, simultaneous, or lagging; and in the other to two categories of TOT (TOT2): leading or lagging. VOT stimuli were labeled as /ba/ or /pa/. Results show that (1) when listeners were offered only two perceptual categories of temporal events, the pattern of identification functions matched one of the two functions shown for TOT3, and (2) the category boundary of VOT stimuli was similar for all subjects regarding the value calculated for TOT2. The present study supports the hypotheses that (1) CB of non-speech stimuli is not influenced by the number of perceptual categories available to the listener, and (2) different mechanisms may underlie the categorical perception of speech versus non-speech stimuli.

Acoustic Stimulation↗

PubMed2004

Frequency discrimination training: is there ear symmetry?

While it is well documented that significant improvements in a frequency discrimination task occur following training of normal-hearing adult subjects, less is known about the symmetry between the ears. The objectives of the present study were (1) to compare the first obtained DLF thresholds between left and right ears, (2) to determine whether single-session training would result in similar improvements in those subjects trained in the right ear versus those trained in the left ear, and (3) to evaluate the generalization of learning to the untrained ear and compare its extent between the left and right ears. Two groups of 10 normal-hearing subjects participated in a single-session training. One group of 10 subjects was trained in the left ear and the second group of 10 additional subjects was trained in the right ear. Single-session training consisted of 10 difference limen frequency (DLF) thresholds for 1 kHz using a two-interval, two-alternative forced choice paradigm. Generalization to the untrained ear was tested 24 hours post-training. Our results show that: (1) No significant differences were found in the first obtained DLF thresholds between left and right ears; (2) Similar improvement in DLF thresholds occurred in both ears for single-session training; and (3) Twenty-four hours post-training, learning generalized to the untrained ear with similar generalization to both ears. Future studies are required in order to establish whether this symmetry is maintained with verbal stimuli and/or after multi-session training.

Acoustic Stimulation↗

PubMed2004

Frequency discrimination thresholds: the effect of increment versus decrement detection of frequency.

Difference limen for frequency (DLF) is traditionally tested using a frequency increment detection paradigm in which listeners are requested to distinguish between a reference tone and a series of comparison tones of higher frequency. Sporadic findings indicated that an increment paradigm is not necessarily comparable to a decrement paradigm, in which the comparison tones are lower than the reference tone. The purpose of the present study was to test whether the ability to detect frequency increments is different from that of frequency decrements. DLFs of 16 young women were measured at 200 Hz and 1,000 Hz, using detection of both frequency increment and decrement paradigms. Results indicated that: (1) the frequency increment detection paradigm was significantly smaller (i.e., superior) to the decrement paradigm for the DLF task at 200 Hz, (2) for both frequencies, the number of participants who exhibited better DLF using the frequency increment detection paradigm was significantly larger than the number of those who had better DLFs using the frequency decrement paradigm, and (3) for both frequencies, strong correlations were found between DLFs obtained in the increment versus the decrement paradigms. These results have implications: (1) to studies whose subjects may have reduced sensitivities at frequencies higher than the reference tone (such as the hearing impaired), and (2) to models related to the role of auditory feedback on voice accuracy and to the underlying processes of frequency discrimination.

Acoustic Stimulation↗

PubMed2003

The effect of training on frequency discrimination: generalization to untrained frequencies and to the untrained ear.

While there is growing evidence that frequency discrimination improves with practice, there are, however, limited and inclusive reports regarding the generalization of learning to untrained conditions. The goals of the present study were therefore (1) to measure the effect of multi-session training on difference limen frequency (DLF) thresholds and evaluate the relative contribution of procedural and stimulus learning by comparison to a control (untrained) group; (2) to evaluate the extent of generalization of the trained frequency to two untrained frequencies known to be temporally coded; and (3) to estimate the generalization of the trained frequency to the untrained ear, for both trained and untrained frequencies. Two groups of subjects were included: a trained group (n = 5) and a control group (n = 5). For the trained group, DLF thresholds for 1 kHz (trained frequency) and 1.1 and 2.0 kHz (untrained frequencies) were obtained using a two-interval, two-alternative forced choice paradigm before and after an eight-session training. The control group was tested using the same stimuli only twice, with a 3-week interval between testing. Results showed that (1) multi-session training improves frequency discrimination in normal hearing young adults; (2) adding a control group to the study allowed estimation of the effect of limited exposure to the stimuli and task in naïve listeners and evaluation of the magnitude of procedural learning; (3) learning was generalized across frequencies that are coded by similar mechanisms; (4) generalization of learning occurred in the untrained ear for trained and untrained frequencies. These results have important clinical and theoretical implications regarding the processes underlying perceptual learning and the effectiveness of auditory habilitation strategies.

Acoustic Stimulation↗

PubMed2002

Auditory backward masking in normal hearing children.

Backward masking (BM) is an auditory phenomenon in which the threshold of an auditory signal is elevated due to the presence of another signal (masker) that follows it. Models related to central auditory temporal processes, such as the 'temporal window' model, have been suggested to explain this phenomenon. If this assumption is correct then BM thresholds are expected to improve as a function of age. Electrophysiological data suggest that the central auditory system undergoes maturation in the first two decades of life. Empirical data on the development of BM with age are limited. Therefore, the goals of the present study were to study the effect of age on the performance of backward masking in normal developing children and to determine the age at which children reach adult-like performance. Subjects were 30 normal developing children divided into three groups according to age: 7, 9 and 11 years old. Stimuli consisted of a 1000 Hz pure tone and a bandpass masker (600-1400 Hz). Three BM threshold estimates were obtained for each subject using a three-alternative forced-choice adaptive procedure. The data show a trend for improvement in backward-masking thresholds with increasing age. Specifically, 7 and 9 year-old children performed significantly poorer than those reported for adults, whereas 11 year-old children reached adult-like performance. These data contribute to the small body of literature on backward masking in normal developing children. They are in keeping with what is known regarding the age of physiological maturation of the auditory system and have important clinical implications in the assessment of children with suspected temporal processing deficits.

Acoustic Stimulation↗

PubMedDate not supplied

A latent consolidation phase in auditory identification learning: time in the awake state is sufficient.

Large gains in performance, evolving hours after practice has terminated, were reported in a number of visual and some motor learning tasks, as well as recently in an auditory nonverbal discrimination task. It was proposed that these gains reflect a latent phase of experience-triggered memory consolidation in human skill learning. It is not clear, however, whether and when delayed gains in performance evolve following training in an auditory verbal identification task. Here we show that normal-hearing young adults trained to identify consonant-vowel stimuli in increasing levels of background noise showed significant, robust, delayed gains in performance that became effective not earlier than 4 h post-training, with most participants improving at more than 6 h post-training. These gains were retained for over 6 mo. Moreover, although it has been recently argued that time including sleep, rather than time per se, is necessary for the evolution of delayed gains in human perceptual learning, our results show that 12 h post-training in the waking state were as effective as 12 h, including no less than 6 h night's sleep. Altogether, the results indicate, for the first time, the existence of a latent, hours-long, consolidation phase in a human auditory verbal learning task, which occurs even during the awake state.

Adult↗

PubMedDate not supplied

Reduced medial olivocochlear bundle system function in children with auditory processing disorders.

A common complaint of children with auditory processing disorders (APD) is difficulty in understanding speech in the presence of background noise. Evidence from animal and human studies has suggested that the medial olivocochlear bundle (MOCB) may play a role in hearing in noise. The MOCB function can be evaluated by the suppression effect of the transient evoked otoacoustic emissions (TEOAE) in response to contralateral acoustic stimulation (CAS). The present study was conducted to investigate the suppression effect of TEOAE in APD children. The study groups comprised 15 APD children aged 8-13 years associated with learning disabilities and 15 controls matched for gender and age. The suppression effect of TEOAE was evaluated by comparing the TEOAE levels with and without CAS. A significantly reduced suppression effect of TEOAE was demonstrated in the APD group, when compared to the controls. In addition, higher TEOAE levels were found in the APD group, suggesting inherent reduced MOCB activity on the outer hair cells in APD children. These results imply that some APD children present low activity of the MOCB system, which may indicate a reduced auditory inhibitory function and affect their ability to hear in the presence of background noise.

Adolescent↗