1 / 21

Effects of Broadband Noise on Frequency-Following Response to Voice Pitch

Effects of Broadband Noise on Frequency-Following Response to Voice Pitch. Ximing Li . Specific aim. the study aims to examine the effects of broadband noise on frequency-following response (FFR) , in aspects of signal-to-noise ratio (SNR) and signal intensity level. . Background .

robert
Download Presentation

Effects of Broadband Noise on Frequency-Following Response to Voice Pitch

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Effects of Broadband Noise on Frequency-Following Response to Voice Pitch Ximing Li

  2. Specific aim • the study aims to examine the effects of broadband noise on frequency-following response (FFR) , in aspects of signal-to-noise ratio (SNR) and signal intensity level.

  3. Background • FFR is scalp recorded response; reflecting the phase-locking activity from ensemble neurons in brainstem area; • Can be evoked by toneburst, two tones, tonal sweeps and speech (Hoormann, 1992; Krishnan et al., 2002, 2004; Galbraith et al., 1995; Cunningham et al., 2001; Russo et al., 2004). • FFR preserved pitch-related information; assess pitch perception (Krishnan et al., 2004).

  4. Effects of noise on scalp-recorded response • on auditory brainstem response (ABR) (Burkard and Hecox, 1983) Both noise level and intensity level showed effects; • on cortical P1-N1-P2 complex (Billings, 2009) Response was mainly affected by SNR;

  5. Mechanism of pitch perception in noise • Another benefit of studying this topic was to learn the effects of broadband noise on pitch perception; • Previous studies on speech evoked ABR (Cunningham et al., 2001; Russo et al., 2004): • response degraded in noisy condition (SNR+5 dB): rms amplitdue decreased; latency delayed; • FFR part sustained;

  6. Hypothesis • FFR originates from brainstem area (Snyder and Schreiner, 1984; Hooremann et al., 1992) • Broadband noise would have the effects on FFR similar as on ABR. • It was hypothesized that SNR and intensity level should have a combined effect on FFR.

  7. Method • Subjects: • 9 native Chinese speakers (5 males, 4 females) aged between 20 to 30 years old; • All subjects were with normal hearing.

  8. Method • Stimuli: • Mandarin i2 tone plus background noise at various conditions: intensity level conditions: 70, 55, 40 dB SPL; SNR level conditions: Quiet, +12 dB, +6 dB, 0 dB, -6 dB and -12 dB. • Conditions were presented randomly; • One condition 2000 sweeps recorded.

  9. Method • Recording: • Bipolar montage: lower forehead (Fz) as positive, right mastoid bone (M2) as reference, left mastoid bone (M1) as ground;

  10. Method • Data Analysis: • Preprocessing: band pass filtered (100 to 1500 Hz), segmented, baseline corrected, criterion rejected(±25 μV) and averaged; • For each condition, spectrograms were averaged across subjects; • Three parameters quantified for evaluation: frequency error, slope error and pitch tracking accuracy.

  11. Method Response contour

  12. Method response stimuli

  13. Method Correlation Pitch tracking accuracy ∑ ∆ frequency Frequency error Time bin ∆ slope Slope error

  14. Results – frequency error

  15. Results – frequency error

  16. Results – frequency error

  17. Results – frequency error

  18. Results – slope error

  19. Results – pitch tracking accuracy

  20. Results • The 0 dB SNR point is a key point; • When SNR is larger or equal to 0 dB, the intensity level dose not show large effect on response; • When SNR is less than 0 dB, the response becomes worse as SNR decreases and is largely affected by intensity level.

  21. Thanks a lot!!

More Related