title: Deficits in audiovisual speech perception in normal aging emerge at the level of whole-word recognition.
abstract: Over the next 2 decades, a dramatic shift in the demographics of society will take place, with a rapid growth in the population of older adults. One of the most common complaints with healthy aging is a decreased ability to successfully perceive speech, particularly in noisy environments. In such noisy environments, the presence of visual speech cues (i.e., lip movements) provide striking benefits for speech perception and comprehension, but previous research suggests that older adults gain less from such audiovisual integration than their younger peers. To determine at what processing level these behavioral differences arise in healthy-aging populations, we administered a speech-in-noise task to younger and older adults. We compared the perceptual benefits of having speech information available in both the auditory and visual modalities and examined both phoneme and whole-word recognition across varying levels of signal-to-noise ratio. For whole-word recognition, older adults relative to younger adults showed greater multisensory gains at intermediate SNRs but reduced benefit at low SNRs. By contrast, at the phoneme level both younger and older adults showed approximately equivalent increases in multisensory gain as signal-to-noise ratio decreased. Collectively, the results provide important insights into both the similarities and differences in how older and younger adults integrate auditory and visual speech cues in noisy environments and help explain some of the conflicting findings in previous studies of multisensory speech perception in healthy aging. These novel findings suggest that audiovisual processing is intact at more elementary levels of speech perception in healthy-aging populations and that deficits begin to emerge only at the more complex word-recognition level of speech signals.
authors.affiliation: Department of Psychology, University of Toronto, Toronto, Ontario, Canada; Department of Hearing and Speech Sciences, Vanderbilt University Medical Center, Nashville, TN, USA; Vanderbilt Brain Institute, Nashville, TN, USA; Vanderbilt Kennedy Center, Nashville, TN, USA. Electronic address: ryan.andrew.stevenson@gmail.com.
authors.forename: Ryan A
authors.initials: RA
authors.lastname: Stevenson
authors.affiliation: Department of Psychology, Austin Peay State University, Clarksville, TN, USA; Department of Communication Sciences and Disorders, University of Memphis, Memphis, TN, USA.
authors.forename: Caitlin E
authors.initials: CE
authors.lastname: Nelms
authors.affiliation: Vanderbilt Brain Institute, Nashville, TN, USA; Department of Neurobiology and Anatomy, University of Texas Medical School at Houston, TX, USA.
authors.forename: Sarah H
authors.initials: SH
authors.lastname: Baum
authors.affiliation: Center for Cognitive Medicine, Department of Psychiatry, Vanderbilt University, Nashville, TN, USA.
authors.forename: Lilia
authors.initials: L
authors.lastname: Zurkovsky
authors.affiliation: Department of Psychology, University of Toronto, Toronto, Ontario, Canada; Rotman Research Institute, Toronto, Ontario, Canada.
authors.forename: Morgan D
authors.initials: MD
authors.lastname: Barense
authors.affiliation: Center for Cognitive Medicine, Department of Psychiatry, Vanderbilt University, Nashville, TN, USA.
authors.forename: Paul A
authors.initials: PA
authors.lastname: Newhouse
authors.affiliation: Department of Hearing and Speech Sciences, Vanderbilt University Medical Center, Nashville, TN, USA; Vanderbilt Brain Institute, Nashville, TN, USA; Vanderbilt Kennedy Center, Nashville, TN, USA; Center for Cognitive Medicine, Department of Psychiatry, Vanderbilt University, Nashville, TN, USA; Department of Psychology, Vanderbilt University, Nashville, TN, USA.
authors.forename: Mark T
authors.initials: MT
authors.lastname: Wallace
mesh_terms: D000161:Acoustic Stimulation; D000328:Adult; D000368:Aged; D000375:Aging / Q000502:physiology* / Q000523:psychology*; D001307:Auditory Perception; D003463:Cues; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010775:Photic Stimulation; D021641:Recognition, Psychology; D013060:Speech / Q000502:physiology*; D013067:Speech Perception; D014796:Visual Perception; D055815:Young Adult
keywords: Aging; Inverse effectiveness; Multisensory; Multisensory integration; Speech perception