Background Past work has shown that low-rate frequency modulation (FM) may

Background Past work has shown that low-rate frequency modulation (FM) may help preserve signal coherence aid segmentation at word and syllable boundaries and benefit speech intelligibility in Cilengitide the presence of a masker. stochastic patterns of low-rate FM and the intelligibility of speech in noise. Study Sample Thirteen postlingually deafened adult CI users participated in this study. Data Collection and Analysis Using modulators derived from 5-Hz lowpass noise applied to a 1-kHz carrier thresholds were measured in terms of frequency excursion both inquiet and with a speech-babble masker present stimulus duration and signal-to-noise ratio in the presence of a speech-babble masker. Speech perception ability was assessed in the presence of the same speech-babble masker. Associations were evaluated with Pearson product-moment correlation analysis with correction for family-wise error and commonality analysis to determine the unique and common contributions across psychoacoustic variables to the association with speech ability. Results Significant correlations were obtained between masked speech intelligibility and three metrics of FM discrimination involving either signal-to-noise ratio or stimulus duration with shared variance among the three steps accounting for much of the effect. Compared to past results from young normal-hearing adults and older adults with either normal hearing or a mild-to-moderate hearing loss mean FM discrimination thresholds obtained from CI users were higher in all conditions. Conclusions The ability to process the pattern of frequency excursions of stochastic FM may in part have a common basis with speech perception in noise. Discrimination of differences in the temporally distributed place coding of the stimulus could serve as this common basis for CI users. value saved from each random ordering. Following 10 0 iterations the proportion of times that these saved values were less than the value of the original data were used as the value adjusted for multiple comparisons. For psychoacoustic steps that showed significant pairwise correlation to BKB-SIN SNR-50 thresholds the combined prediction by Cilengitide these variables of speech thresholds was assessed with multiple linear regression. Finally commonality analysis (Nimon 2010 was used to determine the unique and common contributions among the psychoacoustic variables in accounting for the relationship to speech performance. RESULTS Results from the psychoacoustic testing are shown as box plots in Physique 2. In general there was a wide performance range across participants in all conditions. For the two Delta F conditions (left panel) in silent individual thresholds varied by a factor of nearly 18 from under 30 Hz to almost 480 Cilengitide Hz with the addition of the speech-babble masker at an SNR of 16 dB shifting the range to roughly 100-650 Hz. Average threshold as assessed by geometric mean was 125.4 Hz in quiet and 265.1 Hz in the presence of the masker. Significance of the masking effect was confirmed by a paired-samples = 0.019 = 0.99]. In the FM SNR condition (middle panel) thresholds spanned a range of almost 16 dB with a mean value of 2.36 dB. For the two Duration conditions (right panel) thresholds varied by a factor of roughly 10 and 14 in the Duration Down and Duration Up conditions respectively. Though the two Duration conditions were identical except for starting stimulus duration the geometric mean threshold was much larger in the Duration Down (91.9 msec) than Duration Up (21.5 msec) condition. A paired-samples < .001 = 1.64]. Physique 2 Box plots showing FM discrimination thresholds from each condition. The line through each box is the median threshold; the upper and lower box edges indicate the 25th and 75th percentiles with error bars showing the 10th and 90th percentiles. Speech-in-babble thresholds from BKB-SIN testing ranged from 6.75 to 20 dB (Table 1) with the average threshold 14.70 dB. The same babble masker was Cilengitide used in the FM SNR condition as in the speech testing with both assessing a threshold value in dB. Possible power of FM cues to Ccr7 benefit performance in the speech condition requires that FM discrimination thresholds are at worst no poorer than the speech thresholds. The average FM SNR threshold was 12.36 dB lower than the average BKB-SIN SNR-50 threshold with a paired-samples Cilengitide < 0.001 = 2.61]. It is important to keep in Cilengitide mind that this difference on its own does not demonstrate involvement of FM discrimination ability in the speech task. Furthermore the comparison between speech and FM SNR thresholds reflects not only difference in signal type but also in procedure with BKB-SIN testing using an open-set response format in.