Two experiments in which time was restored to artificially accelerated (time-compressed) speech are reported. Experiment 1 showed that although both young and older adults' recall of the speech benefited from the restoration of time, time restoration failed to boost the older adults to their baseline levels for unaltered speech. In Experiment 2, either 100% or 125% of lost time was restored by inserting pauses, either at linguistic boundaries or at random points within the passages. Experiment 2 showed that the beneficial effects of time restoration depended on where processing time was inserted, as well as how much time was restored. Results are interpreted in terms of age-related slowing in speech processing moderated by preserved linguistic knowledge and short-term conceptual memory.

Two experiments examined whether young and older adults differ in comprehending sentences that contain temporary syntactic closure ambiguities. Experiment 1 examined age-related differences using the Auditory Moving Window (AMW) task, in which sentences were presented in a segment-by-segment self-paced fashion. Experiment 2 examined age-related differences using a sentence recall task, in which sentences were presented in their entirety. Sentences were constructed to have cooperating prosody (i.e., where prosody is consistent with the syntactic boundaries), baseline prosody (i.e., where prosody is ambiguous in the syntactically ambiguous region), and conflicting prosody (i.e., where cross-splicing relocates the prosodic phrase break at a misleading point in syntactic structure). The results showed that both young and older adults make comparable use of prosodic information to interpret temporary syntactic ambiguities, although younger adults may make use of this information more quickly than older adults. In addition, older adults appeared to be less able than young adults to revise initial syntactic misinterpretations caused by conflicting prosodic information. These results are interpreted with respect to age-related impairments in the allocation of working memory resources and inefficient inhibitory function during spoken language processing.

The distinction between the processing of musical information and segmental speech information (i.e., consonants and vowels) has been much explored. In contrast, the relationship between the processing of music and prosodic speech information (e.g., intonation) has been largely ignored. We report an assessment of prosodic perception for an amateur musician, KB, who became amusic following a right-hemisphere stroke. Relative to matched controls, KB's segmental speech perception was preserved. However, KB was unable to discriminate pitch or rhythm patterns in linguistic or musical stimuli. He was also impaired on prosodic perception tasks (e.g., discriminating statements from questions). Results are discussed in terms of common neural mechanisms that may underlie the processing of some aspects of both music and speech prosody.

It is well known that damage to the peripheral auditory system causes deficits in tone detection as well as pitch and loudness perception across a wide range of frequencies. However, the extent to which to which the auditory cortex plays a critical role in these basic aspects of spectral processing, especially with regard to speech, music, and environmental sound perception, remains unclear. Recent experiments indicate that primary auditory cortex is necessary for the normally-high perceptual acuity exhibited by humans in pure-tone frequency discrimination. The present study assessed whether the auditory cortex plays a similar role in the intensity domain and contrasted its contribution to sensory versus discriminative aspects of intensity processing. We measured intensity thresholds for pure-tone detection and pure-tone loudness discrimination in a population of healthy adults and a middle-aged man with complete or near-complete lesions of the auditory cortex bilaterally. Detection thresholds in his left and right ears were 16 and 7 dB HL, respectively, within clinically-defined normal limits. In contrast, the intensity threshold for monaural loudness discrimination at 1 kHz was 6.5±2.1 dB in the left ear and 6.5±1.9 dB in the right ear at 40 dB sensation level, well above the means of the control population (left ear: 1.6±0.22 dB; right ear: 1.7±0.19 dB). The results indicate that auditory cortex lowers just-noticeable differences for loudness discrimination by approximately 5 dB but is not necessary for tone detection in quiet. Previous human and Old-world monkey experiments employing lesion-effect, neurophysiology, and neuroimaging methods to investigate the role of auditory cortex in intensity processing are reviewed.