1-2 of 2 Results  for:

  • Keywords: speech perception x
  • Neurolinguistics x
Clear all

Article

The Motor Theory of Speech Perception  

D. H. Whalen

The Motor Theory of Speech Perception is a proposed explanation of the fundamental relationship between the way speech is produced and the way it is perceived. Associated primarily with the work of Liberman and colleagues, it posited the active participation of the motor system in the perception of speech. Early versions of the theory contained elements that later proved untenable, such as the expectation that the neural commands to the muscles (as seen in electromyography) would be more invariant than the acoustics. Support drawn from categorical perception (in which discrimination is quite poor within linguistic categories but excellent across boundaries) was called into question by studies showing means of improving within-category discrimination and finding similar results for nonspeech sounds and for animals perceiving speech. Evidence for motor involvement in perceptual processes nonetheless continued to accrue, and related motor theories have been proposed. Neurological and neuroimaging results have yielded a great deal of evidence consistent with variants of the theory, but they highlight the issue that there is no single “motor system,” and so different components appear in different contexts. Assigning the appropriate amount of effort to the various systems that interact to result in the perception of speech is an ongoing process, but it is clear that some of the systems will reflect the motor control of speech.

Article

Cochlear Implants  

Matthew B. Winn and Peggy B. Nelson

Cochlear implants (CIs) are the most successful sensory implant in history, restoring the sensation of sound to thousands of persons who have severe to profound hearing loss. Implants do not recreate acoustic sound as most of us know it, but they instead convey a rough representation of the temporal envelope of signals. This sparse signal, derived from the envelopes of narrowband frequency filters, is sufficient for enabling speech understanding in quiet environments for those who lose hearing as adults and is enough for most children to develop spoken language skills. The variability between users is huge, however, and is only partially understood. CIs provide acoustic information that is sufficient for the recognition of some aspects of spoken language, especially information that can be conveyed by temporal patterns, such as syllable timing, consonant voicing, and manner of articulation. They are insufficient for conveying pitch cues and separating speech from noise. There is a great need for improving our understanding of functional outcomes of CI success beyond measuring percent correct for word and sentence recognitions. Moreover, greater understanding of the variability experienced by children, especially children and families from various social and cultural backgrounds, is of paramount importance. Future developments will no doubt expand the use of this remarkable device.