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Greater BOLD variability in older compared with younger adults during audiovisual speech perception.

Baum SH, Beauchamp MS - PLoS ONE (2014)

Bottom Line: While mean response amplitudes were moderately greater in younger adults, older adults had much greater within-subject variability.The greatly increased variability in older adults was observed for both individual voxels in the whole-brain analysis and for ROIs in the left superior temporal sulcus, the left auditory cortex, and the left visual cortex.Increased variability in older adults could not be attributed to differences in head movements between the groups.

View Article: PubMed Central - PubMed

Affiliation: Department of Neurobiology and Anatomy, University of Texas Medical School at Houston, Houston, Texas, United States of America; Vanderbilt Brain Institute, Vanderbilt University, Nashville, Tennessee, United States of America.

ABSTRACT
Older adults exhibit decreased performance and increased trial-to-trial variability on a range of cognitive tasks, including speech perception. We used blood oxygen level dependent functional magnetic resonance imaging (BOLD fMRI) to search for neural correlates of these behavioral phenomena. We compared brain responses to simple speech stimuli (audiovisual syllables) in 24 healthy older adults (53 to 70 years old) and 14 younger adults (23 to 39 years old) using two independent analysis strategies: region-of-interest (ROI) and voxel-wise whole-brain analysis. While mean response amplitudes were moderately greater in younger adults, older adults had much greater within-subject variability. The greatly increased variability in older adults was observed for both individual voxels in the whole-brain analysis and for ROIs in the left superior temporal sulcus, the left auditory cortex, and the left visual cortex. Increased variability in older adults could not be attributed to differences in head movements between the groups. Increased neural variability may be related to the performance declines and increased behavioral variability that occur with aging.

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Mean and standard deviation of BOLD responses to audiovisual speech across subjects.A: Average hemodynamic response to audiovisual syllables in the left STS for older adults (red) and younger adults (blue). Shaded region indicates standard deviation of the group response (intersubject variability). B: Response amplitudes in the left STS (STS), left auditory cortex (Aud), and left visual cortex (Vis) across all older adults (red) and younger adults (blue). Error bars show the complete range of data (subjects with maximum and minimum response); middle bar shows median subject.
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pone-0111121-g002: Mean and standard deviation of BOLD responses to audiovisual speech across subjects.A: Average hemodynamic response to audiovisual syllables in the left STS for older adults (red) and younger adults (blue). Shaded region indicates standard deviation of the group response (intersubject variability). B: Response amplitudes in the left STS (STS), left auditory cortex (Aud), and left visual cortex (Vis) across all older adults (red) and younger adults (blue). Error bars show the complete range of data (subjects with maximum and minimum response); middle bar shows median subject.

Mentions: The standard deviation of the response across subjects was also similar between groups (Figure 2; left STS: SD of 0.08% for younger adults vs. 0.12% for older adults, Bartlett’s multiple sample test for equal variances χ21 = 2.5, p = 0.12; left auditory cortex: 0.14% vs. 0.12%, χ21 = 0.7, p = 0.41; left visual cortex: 0.08% vs. 0.12%, χ21 = 2.3, p = 0.13).


Greater BOLD variability in older compared with younger adults during audiovisual speech perception.

Baum SH, Beauchamp MS - PLoS ONE (2014)

Mean and standard deviation of BOLD responses to audiovisual speech across subjects.A: Average hemodynamic response to audiovisual syllables in the left STS for older adults (red) and younger adults (blue). Shaded region indicates standard deviation of the group response (intersubject variability). B: Response amplitudes in the left STS (STS), left auditory cortex (Aud), and left visual cortex (Vis) across all older adults (red) and younger adults (blue). Error bars show the complete range of data (subjects with maximum and minimum response); middle bar shows median subject.
© Copyright Policy
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4206517&req=5

pone-0111121-g002: Mean and standard deviation of BOLD responses to audiovisual speech across subjects.A: Average hemodynamic response to audiovisual syllables in the left STS for older adults (red) and younger adults (blue). Shaded region indicates standard deviation of the group response (intersubject variability). B: Response amplitudes in the left STS (STS), left auditory cortex (Aud), and left visual cortex (Vis) across all older adults (red) and younger adults (blue). Error bars show the complete range of data (subjects with maximum and minimum response); middle bar shows median subject.
Mentions: The standard deviation of the response across subjects was also similar between groups (Figure 2; left STS: SD of 0.08% for younger adults vs. 0.12% for older adults, Bartlett’s multiple sample test for equal variances χ21 = 2.5, p = 0.12; left auditory cortex: 0.14% vs. 0.12%, χ21 = 0.7, p = 0.41; left visual cortex: 0.08% vs. 0.12%, χ21 = 2.3, p = 0.13).

Bottom Line: While mean response amplitudes were moderately greater in younger adults, older adults had much greater within-subject variability.The greatly increased variability in older adults was observed for both individual voxels in the whole-brain analysis and for ROIs in the left superior temporal sulcus, the left auditory cortex, and the left visual cortex.Increased variability in older adults could not be attributed to differences in head movements between the groups.

View Article: PubMed Central - PubMed

Affiliation: Department of Neurobiology and Anatomy, University of Texas Medical School at Houston, Houston, Texas, United States of America; Vanderbilt Brain Institute, Vanderbilt University, Nashville, Tennessee, United States of America.

ABSTRACT
Older adults exhibit decreased performance and increased trial-to-trial variability on a range of cognitive tasks, including speech perception. We used blood oxygen level dependent functional magnetic resonance imaging (BOLD fMRI) to search for neural correlates of these behavioral phenomena. We compared brain responses to simple speech stimuli (audiovisual syllables) in 24 healthy older adults (53 to 70 years old) and 14 younger adults (23 to 39 years old) using two independent analysis strategies: region-of-interest (ROI) and voxel-wise whole-brain analysis. While mean response amplitudes were moderately greater in younger adults, older adults had much greater within-subject variability. The greatly increased variability in older adults was observed for both individual voxels in the whole-brain analysis and for ROIs in the left superior temporal sulcus, the left auditory cortex, and the left visual cortex. Increased variability in older adults could not be attributed to differences in head movements between the groups. Increased neural variability may be related to the performance declines and increased behavioral variability that occur with aging.

Show MeSH