Development of a fast method for determining sensitivity to temporal fine structure

Department of Experimental Psychology, University of Cambridge, Downing Street, Cambridge, UK.
International journal of audiology (Impact Factor: 1.84). 01/2009; 48(4):161-71. DOI: 10.1080/14992020802475235
Source: PubMed


Recent evidence suggests that sensitivity to the temporal fine structure (TFS) of sounds is adversely affected by cochlear hearing loss. This may partly explain the difficulties experienced by people with cochlear hearing loss in understanding speech when background sounds, especially fluctuating backgrounds, are present. We describe a test for assessing sensitivity to TFS. The test can be run using any PC with a sound card. The test involves discrimination of a harmonic complex tone (H), with a fundamental frequency F0, from a tone in which all harmonics are shifted upwards by the same amount in Hertz, resulting in an inharmonic tone (I). The phases of the components are selected randomly for every stimulus. Both tones have an envelope repetition rate equal to F0, but the tones differ in their TFS. To prevent discrimination based on spectral cues, all tones are passed through a fixed bandpass filter, usually centred at 11F0. A background noise is used to mask combination tones. The results show that, for normal-hearing subjects, learning effects are small, and the effect of the level of testing is also small. The test provides a simple, quick, and robust way to measure sensitivity to TFS.

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    • "Thus, clinical needs for accurately assessing ability to use TFS cue have been increased. Moore and Sek33) developed a simple and quick test for assessing sensitivity to TFS that can be used in clinical setting. The test is designed to discriminating a harmonic complex tone (H), with a fundamental frequency F0, from a similar tone in which all harmonics were shifted up by the same amount in hertz, which becomes an inharmonic tone (I). "
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    ABSTRACT: Complex sound like speech can be characterized as the sum of number of amplitude-modulated signals representing the outputs of an array of narrow frequency bands. Temporal information at the output of each band can be separated into temporal fine structure (TFS), the rapid oscillations close to the center frequency and temporal envelope (ENV), slower amplitude modulations superimposed on the TFS. TFS information can be carried in the pattern of phase locking to the stimulus waveform, while ENV by the changes in firing rate over time. The relative importance of temporal ENV and TFS information in understanding speech has been studied using various sound-processing techniques. A number of studies demonstrated that ENV cues are associated with speech recognition in quiet, while TFS cues are possibly linked to melody/pitch perception and listening to speech in a competing background. However, there are evidences that recovered ENV from TFS as well as TFS itself may be partially responsible for speech recognition. Current technologies used in cochlear implants (CI) are not efficient in delivering the TFS cues, and new attempts have been made to deliver TFS information into sound-processing strategy in CI. We herein discuss the current updated findings of TFS with a literature review.
    Korean Journal of Audiology 04/2014; 18(1):1-7. DOI:10.7874/kja.2014.18.1.1
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    • "For the low-frequency stimulus, the listeners were required to detect a common upward frequency shift (Δf Hz) imposed on the individual components of the SSMC with the spectral envelope remaining unchanged. The stimulus parameters and measurement methods for a detection threshold for the frequency shift was in accordance with the “TFS1” test developed by Moore and Sek (2009). It has been reported that such a shift in component frequencies is accompanied with shift in pitch (De Boer, 1956; Schouten et al., 1962; Moore and Moore, 2003). "
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    ABSTRACT: This study explored the source of inter-listener variability in the performance of lateralization tasks based on interaural time or level differences (ITDs or ILDs) by examining correlation of performance between pairs of multiple psychoacoustical tasks. The ITD, ILD, Time, and Level tasks were intended to measure sensitivities to ITD; ILD; temporal fine structure or envelope of the stimulus encoded by the neural phase locking; and stimulus level, respectively. Stimuli in low- and high-frequency regions were tested. The low-frequency stimulus was a harmonic complex (F 0 = 100 Hz) that was spectrally shaped for the frequency region around the 11th harmonic. The high frequency stimulus was a "transposed stimulus," which was a 4-kHz tone amplitude-modulated with a half-wave rectified 125-Hz sinusoid. The task procedures were essentially the same between the low- and high-frequency stimuli. Generally, the thresholds for pairs of ITD and ILD tasks, across cues or frequencies, exhibited significant positive correlations, suggesting a common mechanism across cues and frequencies underlying the lateralization tasks. For the high frequency stimulus, there was a significant positive correlation of performance between the ITD and Time tasks. A significant positive correlation was found also in the pair of ILD and Level tasks for the low- frequency stimulus. These results indicate that the inter-listener variability of ITD and ILD sensitivities could be accounted for partially by the variability of monaural efficiency of neural phase locking and intensity coding, respectively, depending of frequency.
    Frontiers in Neuroscience 02/2014; 8(8):27. DOI:10.3389/fnins.2014.00027 · 3.66 Impact Factor
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    • "Scatter plot of scores for the TFS-LF test (log scale) at 500 Hz against age. the auditory system has diffi culty in measuring very long inter-spike intervals (de Cheveign é & Pressnitzer, 2006; Moore & Sek, 2009; Moore et al, 2009; Moore & Glasberg, 2010 "
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    ABSTRACT: Objective: To extend the study of Hopkins and Moore (2011) by examining the effect of age in the medium age range on sensitivity to temporal fi ne structure (TFS), which is assumed to be represented in the patterns of phase locking in the auditory nerve. Design: Monaural TFS sensitivity was assessed using the TFS1 test (Moore & Sek, 2009) at centre frequencies of 850 and 2000 Hz, and binaural TFS sensitivity was assessed using the TFS-LF test (Hopkins & Moore, 2010a) at centre frequencies of 500 and 850 Hz, using a sensation level of 30 dB. Study sample: Thirty-fi ve newly recruited normal-hearing subjects (thresholds better than 20 dB HL from 250 to 6000 Hz) were tested. Their ages ranged from 22 to 61 years. Results: There was a signifi cant correlation between age and TFS sensitivity at all frequencies for both TFS tests. For the single centre frequency (850 Hz) that was used for both tests, scores for the two tests were modestly but signifi cantly correlated. Conclusions: Sensitivity to TFS decreases with increasing age. The monaural and binaural TFS tests appear to reflect at least somewhat distinct auditory processes.
    International journal of audiology 10/2012; 51(10). DOI:10.3109/14992027.2012.690079 · 1.84 Impact Factor
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