Presentation level effects on listeners' weighting strategies for speech
High presentation levels have been shown to negatively effect listeners’ recognition scores (Molis and Summers, 2003). The effect has been reported to be greater for some phonemes (e.g., alveolars /t, d, s, z, n, and l) more than others (Hornsby, Trine and Ohde, 2005). We conducted two studies to further investigate the effect of presentation level on  speech recognition. In the first study, we found that as presentation level (50, 75 and 95 dB SPL) increased, listeners with normal hearing placed a greater weight on the higher frequency energy in sentences. In the second study, listeners with normal hearing did not change how they weighted the frequency energy in nonsense syllables when presentation level (45 dB, 65 dB, 75 dB and 85 dB SPL) was increased. However, spectral weighting strategies were different across speech features and were consistent with their high recognition of /m, n/ and low recognition of /p, f, θ, ð/.

Age effects on listening strategies used to process time-compressed sentences
Speech recognition in noise, regardless of hearing thresholds, declines with age. Reduced temporal and/or frequency resolution have been the most common explanations for these age-related differences. However, it is clear these two measures alone cannot fully account for the decline in older listeners’ ability to identify speech in the presence of noise. In our current work an alternative explanation related to how listeners use or weight information in speech is being examined.

Use of fMRI to assess how older listeners process complex auditory signals
Poor performance of elderly listeners on temporal processing tasks, such as time-compressed speech, has been linked to age-related changes in the central auditory system. We use fMRI to determine if cortical representation of specific neuroanatomical areas are responsible for the differences between young and older listeners behavioral performance on a time-compressed sentence recognition task.