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Investigation of Performance in Selected Auditory Tasks by Blind and Visually Impaired Children and Teenagers

100%
Bogusz E., Koprowska H., Skrodzka E.
Acta Physica Polonica A
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2012
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vol. 121
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issue 1A
A-13-A-18
EN
The present work discusses results concerning sound perception obtained in selected auditory tasks, such as pitch discrimination and pitch-timbre categorization for blind and visually impaired subjects (children and teenagers). Listeners were divided into two age groups: 7-13 year olds and 14-18 year olds. The study tested 20 individuals (8 congenitally blind and 12 visually impaired) and 20 sighted persons comprising reference groups. The timing of the experiments was as short as possible due to the fact that our listeners were children. To date, no study has described results of such experiments for blind/visually handicapped children and teenagers. It was shown that the performance of blind/visually impaired participants was not as good as that of blind adults in pitch discrimination and pitch-timbre categorization tasks. These results may have implications for the development of auditory training in orientation and mobility of young visually handicapped people.
2
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Frequency Discrimination for Amplitude Modulated Sinusoidal Signals at High Carrier Frequencies

63%
Sęk A., Kordus M.
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vol. 125
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issue 4A
A-149-A-154
EN
The current study is a continuation of experiments presented by Sęk and Bukała (Acta Physica Polonica A 123, 1106 (2013)). The purpose of the present study was to investigate frequency discrimination of amplitude modulated high frequency carriers. Using 2AFC procedure, the subjects were presented with two observation intervals of which the first interval contained four pulses of the same high frequency signal (called SSSS), while in the second interval (called SHSH) the second and fourth pulses had higher frequencies values (i.e. shifted upwards by Δ f). The carrier frequency (in S pulses) was fixed and equal to 10 kHz. Modulation rates were equal to 100, 200, 337, 500, 600, 733, and 800 Hz. The value of the modulation rate was limited to keep all components of the sinusoidal modulation within one auditory filter (17% of the center frequency) centered at the carrier frequency. Two different types of modulation were used: a simple sinusoidal modulation with the modulation depth m set to 100%, and a logarithmic modulation with the modulation depth m set to 50 dB. Results indicate a strong relationship between frequency discrimination threshold and modulation type. The thresholds are significantly higher for logarithmic modulation in comparison to sinusoidal modulation. Amplitude modulation as well as logarithmic modulation applied to the high frequency carrier cause significant increase in the frequency discrimination threshold. For high frequency sinusoidal signal carriers (i.e. close to 10 kHz), frequency discrimination thresholds do not depend on amplitude modulation rates up to about 800 Hz. In general, the excitation pattern mechanism was a primary cue enabling frequency discrimination of modulated and unmodulated signals to compare with the mechanism based on the temporal fine structure. However, the excitation pattern was not the only mechanism responsible for the frequency discrimination.
3
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The Use of the Phase Locking Information in the Human Auditory System for Frequencies Above 5 kHz

63%
Sęk A., Bukała M.
Acta Physica Polonica A
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2013
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vol. 123
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issue 6
1106-1113
EN
Accurate allocation of neural impulses to the same phase (i.e. phase locking) in the auditory system, ceases for frequencies above 5 kHz. However, some recent works suggest that it may have a much higher value. A discrimination of harmonic complex and inharmonic complex sound, formed using sound harmonic complex, in which all components were shifted towards higher frequency by the same number in hertzs, was analyzed. Fundamental frequency was F_0=1 kHz and signals were bandpass filtered by a fixed filter center frequency of which was 11F_0 and bandwidth 5F_0. Discrimination threshold was Δ F=0.089F_0 for 10 normal-hearing subjects. However, replacing the sinusoidal components with the noise bands brought about a significant increase in thresholds. The largest increase was observed for 700 Hz bandwidth. The replacement of sinusoidal components with noisebands reduces information conveyed by phase locking. The differences in excitation pattern for harmonic complex and inharmonic complex signals, for the average threshold, did not exceed 0.7 dB. Therefore they could not be a useful cue for harmonic complex and inharmonic complex discrimination. A simplified model of phase locking showed that the substitution of sinusoids with bands of noise significantly reduced number of intervals between successive neural spikes corresponding to the virtual pitch of harmonic complex and inharmonic complex sounds. This degradation of discrimination suggests that the main source of information about the pitch of harmonic complex and inharmonic complex, especially for sinusoidal components, was the phase locking.
4
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Comparison of Effects of Auditory and Music Training of Blind or Visually Impaired Young People on Performance in Selected Auditory Tasks

51%
Skrodzka E., Furmann A., Bogusz-Witczak E., Hojan E.
Acta Physica Polonica A
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2015
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vol. 128
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issue 1A
A-29-A-35
EN
Performance of blind/visually impaired children and teenagers before and after the auditory training and the music training in some auditory tasks (pitch discrimination, pitch-timbre categorization, pitch memory, lateralization of a stationary sound of a drum, lateralization of one or two moving motor vehicles) is compared. In the auditory training, the subjects were actively involved, i.e. they had to answer questions related to presented sound material. The music training was based on passive listening to sounds presented according to the Tomatis method. The training (auditory or music) effectiveness was measured as a difference between results of a pre- and post-training verification test in which the subjects were asked to perform the auditory tasks mentioned at the beginning. The persons who took part in the study were divided into two age groups: 7-12 year olds and 13-19 year olds. According to the results, the auditory training was beneficial for blind or visually impaired teenagers, especially in respect of lateralization tasks. For small children the auditory training was not as effective as for adolescents. However, it has been shown that the music training was generally beneficial for them, although none of the verification tasks was privileged.
5
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Results of Auditory Training for Blind and Visually Handicapped Children and Adolescents

51%
Bogusz-Witczak E., Skrodzka E., Furmann A., Hojan E., Przybek K.
Acta Physica Polonica A
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2015
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vol. 127
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issue 1
117-119
EN
Results of an auditory training for blind/visually impaired children and teenagers are presented. A measure of the training effectiveness is the difference between the results of a pre- and post-training verification test. Two age groups of visually handicapped young persons were tested: 7-12 years old and 14-19 years old. It was shown that the training may be beneficiary for blind or visually impaired children and teenagers, especially in tasks related to localization of moving sound sources. No differences in training results were found between age groups. The results of trained groups were compared to those obtained for not trained control groups of young blind individuals.
6
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The Concept of the Auditory Training for Blind and Visually Impaired Children and Teenagers

51%
Skrodzka E., Maciągowski M., Furmann A.
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vol. 125
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issue 4A
A-31-A-37
EN
The paper was inspired by the hitherto published results concerning provision of efficient assistance to visually impaired persons by means of acoustic and vibratory signals. The aim of the auditory training is to shorten the time necessary for execution of auditory information processing, sensibilize blind persons to differences in sounds and teach them to focus auditory attention on small differences in parameters of acoustic waves, in order to achieve independent and correct interpretation of environment by hearing and listening. The basic concept of the auditory training addressed to blind or visually impaired children and teenagers is presented in detail. Preliminary verification of the effectiveness of training of young adults without vision impairments has not shown statistically significant differences in performance before and after the training. Possible reasons for such an effect are pointed out and solutions are suggested.
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