scholarly journals Forward-masking patterns produced by symmetric and asymmetric pulse shapes in electric hearing

2010 ◽  
Vol 127 (1) ◽  
pp. 326-338 ◽  
Author(s):  
Olivier Macherey ◽  
Astrid van Wieringen ◽  
Robert P. Carlyon ◽  
Ingeborg Dhooge ◽  
Jan Wouters
Keyword(s):  
Forward Masking ◽  
Electric Hearing ◽  
Asymmetric Pulse

scholarly journals The Spatial Selective Auditory Attention of Cochlear Implant Users in Different Conversational Sound Levels

2021 ◽  
Vol 10 (14) ◽  
pp. 3078
Author(s):  
Sara Akbarzadeh ◽  
Sungmin Lee ◽  
Chin-Tuan Tan
Keyword(s):  
Cochlear Implant ◽  
Sound Level ◽  
Auditory Attention ◽  
Impaired Hearing ◽  
Speech Stimuli ◽  
Electric Hearing ◽  
Sound Levels ◽  
Acoustic Hearing ◽  
Speech Envelope ◽  
Different Levels

In multi-speaker environments, cochlear implant (CI) users may attend to a target sound source in a different manner from normal hearing (NH) individuals during a conversation. This study attempted to investigate the effect of conversational sound levels on the mechanisms adopted by CI and NH listeners in selective auditory attention and how it affects their daily conversation. Nine CI users (five bilateral, three unilateral, and one bimodal) and eight NH listeners participated in this study. The behavioral speech recognition scores were collected using a matrix sentences test, and neural tracking to speech envelope was recorded using electroencephalography (EEG). Speech stimuli were presented at three different levels (75, 65, and 55 dB SPL) in the presence of two maskers from three spatially separated speakers. Different combinations of assisted/impaired hearing modes were evaluated for CI users, and the outcomes were analyzed in three categories: electric hearing only, acoustic hearing only, and electric + acoustic hearing. Our results showed that increasing the conversational sound level degraded the selective auditory attention in electrical hearing. On the other hand, increasing the sound level improved the selective auditory attention for the acoustic hearing group. In the NH listeners, however, increasing the sound level did not cause a significant change in the auditory attention. Our result implies that the effect of the sound level on selective auditory attention varies depending on the hearing modes, and the loudness control is necessary for the ease of attending to the conversation by CI users.

Masker interaction in pure‐tone forward masking

1980 ◽  
Vol 68 (2) ◽  
pp. 475-479 ◽  
Author(s):  
Gregory P. Widin ◽  
Neal F. Viemeister
Keyword(s):  
Pure Tone ◽  
Forward Masking

Monaural inhibition in cat auditory cortex

1995 ◽  
Vol 73 (5) ◽  
pp. 1876-1891 ◽  
Author(s):  
M. B. Calford ◽  
M. N. Semple
Keyword(s):  
Auditory Cortex ◽  
Lateral Inhibition ◽  
Cortical Neurons ◽  
Frequency Tuning ◽  
Inhibitory Response ◽  
Forward Masking ◽  
Excitatory Response ◽  
Rate Level ◽  
Wide Range ◽  
Response Area

1. Several studies of auditory cortex have examined the competitive inhibition that can occur when appropriate sounds are presented to each ear. However, most cortical neurons also show both excitation and inhibition in response to presentation of stimuli at one ear alone. The extent of such inhibition has not been described. Forward masking, in which a variable masking stimulus was followed by a fixed probe stimulus (within the excitatory response area), was used to examine the extent of monaural inhibition for neurons in primary auditory cortex of anesthetized cats (barbiturate or barbiturate-ketamine). Both the masking and probe stimuli were 50-ms tone pips presented to the contralateral ear. Most cortical neurons showed significant forward masking at delays beyond which masking effects in the auditory nerve are relatively small compared with those seen in cortical neurons. Analysis was primarily concerned with such components. Standard rate-level functions were also obtained and were examined for nonmonotonicity, an indication of level-dependent monaural inhibition. 2. Consistent with previous reports, a wide range of frequency tuning properties (excitatory response area shapes) was found in cortical neurons. This was matched by a wide range of forward-masking-derived inhibitory response areas. At the most basic level of analysis, these were classified according to the presence of lateral inhibition, i.e., where a probe tone at a neuron's characteristic frequency was masked by tones outside the limits of the excitatory response area. Lateral inhibition was a property of 38% of the sampled neurons. Such neurons represented 77% of those with nonmonotonic rate-level functions, indicating a strong correlation between the two indexes of monaural inhibition; however, the shapes of forward masking inhibitory response areas did not usually correspond with those required to account for the "tuning" of a neuron. In addition, it was found that level-dependent inhibition was not added to by forward masking inhibition. 3. Analysis of the discharges to individual stimulus pair presentations, under conditions of partial masking, revealed that discharges to the probe occurred independently of discharges to the preceding masker. This indicates that even when the masker is within a neuron's excitatory response area, forward masking is not a postdischarge habituation phenomenon. However, for most neurons the degree of masking summed over multiple stimulus presentations appears determined by the same stimulus parameters that determine the probability of response to the masker.(ABSTRACT TRUNCATED AT 400 WORDS)

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