scholarly journals Evidence of degraded representation of speech in noise, in the aging midbrain and cortex

2016 ◽  
Vol 116 (5) ◽  
pp. 2346-2355 ◽  
Author(s):  
Alessandro Presacco ◽  
Jonathan Z. Simon ◽  
Samira Anderson

Humans have a remarkable ability to track and understand speech in unfavorable conditions, such as in background noise, but speech understanding in noise does deteriorate with age. Results from several studies have shown that in younger adults, low-frequency auditory cortical activity reliably synchronizes to the speech envelope, even when the background noise is considerably louder than the speech signal. However, cortical speech processing may be limited by age-related decreases in the precision of neural synchronization in the midbrain. To understand better the neural mechanisms contributing to impaired speech perception in older adults, we investigated how aging affects midbrain and cortical encoding of speech when presented in quiet and in the presence of a single-competing talker. Our results suggest that central auditory temporal processing deficits in older adults manifest in both the midbrain and in the cortex. Specifically, midbrain frequency following responses to a speech syllable are more degraded in noise in older adults than in younger adults. This suggests a failure of the midbrain auditory mechanisms needed to compensate for the presence of a competing talker. Similarly, in cortical responses, older adults show larger reductions than younger adults in their ability to encode the speech envelope when a competing talker is added. Interestingly, older adults showed an exaggerated cortical representation of speech in both quiet and noise conditions, suggesting a possible imbalance between inhibitory and excitatory processes, or diminished network connectivity that may impair their ability to encode speech efficiently.

2019 ◽  
Author(s):  
C.A. Crowell ◽  
S.W. Davis ◽  
L. Beynel ◽  
L. Deng ◽  
D. Lakhlani ◽  
...  

AbstractNeuroimaging evidence suggests that the aging brain relies on a more distributed set of cortical regions than younger adults in order to maintain successful levels of performance during demanding cognitive tasks. However, it remains unclear how task demands give rise to this age-related expansion in cortical networks. To investigate this issue, we used functional magnetic resonance imaging to measure univariate activity, network connectivity, and cognitive performance in younger and older adults during a working memory (WM) task. In the WM task investigated, participants hold letters online (maintenance) while reordering them alphabetically (manipulation). WM load was titrated to obtain four individualized difficulty levels. Network integration—defined as the ratio of within-versus between-network connectivity—was linked to individual differences in WM capacity. The study yielded three main findings. First, as task difficulty increased, network integration decreased in younger adults, whereas it increased in older adults. Second, age-related increases in network integration were driven by increases in right hemispheric connectivity to both left and right cortical regions, a finding that helps to reconcile extant theories of compensatory recruitment in aging to address the multivariate dynamics of global network functioning. Lastly, older adults with higher WM capacity demonstrated higher levels of network integration in the most difficult condition. These results shed light on the mechanisms of age-related network reorganization by suggesting that changes in network connectivity may act as an adaptive form of compensation, with older adults recruiting a more distributed cortical network as task demands increase.Significance statementOlder adults often activate brain regions not engaged by younger adults, but the circumstances under which this widespread network emerges are unclear. Here, we examined the effects of aging on network connectivity between task regions recruited during a working memory (WM) manipulation task, and the rest of the brain. We found an age-related increase in the more global network integration in older adults, and an association between this integration and working memory capacity in older adults. The findings are generally consistent with the compensatory interpretation of these effects.


2018 ◽  
Vol 29 (10) ◽  
pp. 909-916 ◽  
Author(s):  
Jennifer McCullagh ◽  
Jennifer B. Shinn

AbstractOlder adults often report difficulty hearing in background noise which is not completely attributable to peripheral hearing loss. Although age-related declines in cognition and hearing in background noise occur, the underlying age-related changes in processing of auditory stimuli in background noise has yet to be fully understood. The auditory P300 has the potential to elucidate the effects of age on auditory and cognitive processing of stimuli in background noise, but additional research is warranted.The purpose of this study was to investigate age-related differences in cognitive processing of auditory stimuli by evoking the auditory P300 at multiple signal-to-noise ratios (SNRs).A two-group, repeated measures study design was used.A convenience sample of 35 participants, 15 older adults (mean age of 66.4 yr) and 20 younger adults (mean age of 21.1 yr), participated in the study. All participants had negative otologic and neurological histories.The auditory P300 was evoked using an oddball paradigm with 500 (frequent) and 1000 Hz (target) tonal stimuli in quiet and in the presence of background noise at +20, +10, and 0 SNRs. P300 amplitudes and latencies were measured in each condition for every participant. Repeated measures analyses of variance were conducted for the amplitude and latency measures of the P300 for each group.Results from this study demonstrated P300 latencies were significantly longer in older adults in noise at the most challenging condition (0 SNR) compared with the quiet condition and between the +10 SNR and 0 SNR conditions. Although older adults had significantly longer P300 latencies compared with younger adults, no significant group by listening condition interaction existed. No significant P300 amplitude differences were found for group, noise, or group × listening condition interactions.Results provide evidence that auditory cortical processing, regardless of age, is poorer at more difficult SNRs. However, results also demonstrate that older adults perform significantly poorer than younger adults. This supports the notion that some degree of age-related decline in synchronous firing and rate of transmission of the auditory cortical neurons contributing to the auditory P300 exists. Studies are needed to further understand the impact of noise on auditory cortical processing across populations.


2019 ◽  
Author(s):  
Debbie Marianne Yee ◽  
Sarah L Adams ◽  
Asad Beck ◽  
Todd Samuel Braver

Motivational incentives play an influential role in value-based decision-making and cognitive control. A compelling hypothesis in the literature suggests that the brain integrates the motivational value of diverse incentives (e.g., motivational integration) into a common currency value signal that influences decision-making and behavior. To investigate whether motivational integration processes change during healthy aging, we tested older (N=44) and younger (N=54) adults in an innovative incentive integration task paradigm that establishes dissociable and additive effects of liquid (e.g., juice, neutral, saltwater) and monetary incentives on cognitive task performance. The results reveal that motivational incentives improve cognitive task performance in both older and younger adults, providing novel evidence demonstrating that age-related cognitive control deficits can be ameliorated with sufficient incentive motivation. Additional analyses revealed clear age-related differences in motivational integration. Younger adult task performance was modulated by both monetary and liquid incentives, whereas monetary reward effects were more gradual in older adults and more strongly impacted by trial-by-trial performance feedback. A surprising discovery was that older adults shifted attention from liquid valence toward monetary reward throughout task performance, but younger adults shifted attention from monetary reward toward integrating both monetary reward and liquid valence by the end of the task, suggesting differential strategic utilization of incentives. Together these data suggest that older adults may have impairments in incentive integration, and employ different motivational strategies to improve cognitive task performance. The findings suggest potential candidate neural mechanisms that may serve as the locus of age-related change, providing targets for future cognitive neuroscience investigations.


2020 ◽  
Author(s):  
Samina Rahman ◽  
Victoria Kordovski ◽  
Savanna Tierney ◽  
Steven Paul Woods

Objective: Online banking is becoming increasingly common among older adults, whomay experience difficulties effectively navigating this instrumental technology. Thisstudy examined age effects on a performance-based Internet banking task and itsassociation with neurocognitive ability and functional capacity in older and youngeradults. Method: Thirty-five older adults and 50 younger adults completed anexperimenter-controlled online banking measure in which they independentlyperformed a series of naturalistic financial tasks (e.g., account transfers, bill paying).Participants also completed a standardized battery of neuropsychological tests andmeasures of functional capacity. Results: Older adults were markedly slower and lessaccurate in completing the Internet-based banking task, which was not confounded byother demographic, mood, or computer use factors. Higher scores on measures ofneurocognition and financial functional capacity were both strongly associated withhigher Internet-based banking task accuracy scores and quicker completion times inthe older, but not the younger adults. Conclusions: Findings suggest that older adultsexperience difficultly quickly and accurately navigating online banking platforms, whichmay be partly related to age-related declines in neurocognitive functions and basicfinancial capacity. Future studies might examine whether neurocognitive approaches toremediation and compensation can be used to improve online banking capacity inolder adults.


2020 ◽  
Vol 4 (Supplement_1) ◽  
pp. 653-653
Author(s):  
Lizbeth Benson ◽  
Anthony Ong

Abstract Intensive measurements of individuals’ experiences allow for identifying patterns of functioning that may be markers of resilience, and whether such patterns differ across the life span. Using 8 daily diary reports collected in the second burst of the National Study of Daily Experiences (NSDE, n=848, age 34-84; 55%female), we examined whether positive emodiversity (Shannon’s entropy) attenuated the association between cumulative stressor exposure and depressive symptoms, and age-related differences therein. Results indicated age moderated the extent to which positive emodiversity attenuated the association between stress and depressive symptoms (b=0.11, p < .05). The attenuated association was strongest for younger adults with higher positive emodiversity, compared to those with lower positive emodiversity. For older adults, the association between stress and depressive symptoms was relatively similar regardless of their positive emodiversity. Implications pertain to for whom and in what contexts specific types of dynamic emotion experiences may promote optimal functioning and resilience.


2015 ◽  
Vol 113 (7) ◽  
pp. 2127-2136 ◽  
Author(s):  
Chia-Cheng Lin ◽  
Susan L. Whitney ◽  
Patrick J. Loughlin ◽  
Joseph M. Furman ◽  
Mark S. Redfern ◽  
...  

Vibrotactile feedback (VTF) has been shown to improve balance performance in healthy people and people with vestibular disorders in a single-task experimental condition. It is unclear how age-related changes in balance affect the ability to use VTF and if there are different attentional requirements for old and young adults when using VTF. Twenty younger and 20 older subjects participated in this two-visit study to examine the effect of age, VTF, sensory condition, cognitive task, duration of time, and visit on postural and cognitive performance. Postural performance outcome measures included root mean square of center of pressure (COP) and trunk tilt, and cognitive performance was assessed using the reaction time (RT) from an auditory choice RT task. The results showed that compared with younger adults, older adults had an increase in COP in fixed platform conditions when using VTF, although they were able to reduce COP during sway-referenced platform conditions. Older adults also did not benefit fully from using VTF in their first session. The RTs for the secondary cognitive tasks increased significantly while using the VTF in both younger and older adults. Older adults had a larger increase compared with younger adults, suggesting that greater attentional demands were required in older adults when using VTF information. Future training protocols for VTF should take into consideration the effect of aging.


2022 ◽  
Author(s):  
Kendra Leigh Seaman ◽  
Alexander P. Christensen ◽  
Katherine Senn ◽  
Jessica Cooper ◽  
Brittany Shane Cassidy

Trust is a key component of social interaction. Older adults, however, often exhibit excessive trust relative to younger adults. One explanation is that older adults may learn to trust differently than younger adults. Here, we examine how younger (N=33) and older adults (N=30) learn to trust over time. Participants completed a classic iterative trust game with three partners. Younger and older adults shared similar amounts but differed in how they shared money. Compared to younger adults, older adults invested more with untrustworthy partners and less with trustworthy partners. As a group, older adults displayed less learning than younger adults. However, computational modeling shows that this is because older adults are more likely to forget what they have learned over time. Model-based fMRI analyses revealed several age-related differences in neural processing. Younger adults showed prediction error signals in social processing areas while older adults showed over-recruitment of several cortical areas. Collectively, these findings suggest that older adults attend to and learn from social cues differently from younger adults.


2020 ◽  
Author(s):  
Sade J Abiodun ◽  
Galen McAllister ◽  
Gregory Russell Samanez-Larkin ◽  
Kendra Leigh Seaman

Facial expressions are powerful communicative social signals that motivate feelings and action in the observer. However, research on incentive motivation has overwhelmingly focused on money and points and the limited research on social incentives has been mostly focused on responses in young adulthood. Previous research on the age-related positivity effect and adult age differences in social motivation suggest that older adults might experience higher levels of positive arousal to socioemotional stimuli than younger adults. Affect ratings following dynamic emotional expressions (anger, happiness, sadness) varying in magnitude of expression showed that higher magnitude expressions elicited higher arousal and valence ratings. Older adults did not differ significantly in levels of arousal when compared to younger adults, however their ratings of emotional valence were significantly higher as the magnitude of expressions increased. The findings provide novel evidence that socioemotional incentives may be relatively more reinforcing as adults age. More generally, these dynamic socioemotional stimuli that vary in magnitude are ideal for future studies of more naturalistic affect elicitation, studies of social incentive processing, and use in incentive-driven choice tasks.


2018 ◽  
Author(s):  
Dirk U. Wulff ◽  
Thomas Hills ◽  
Rui Mata

Cognitive science invokes semantic networks to explain diverse phenomena from reasoning to memory retrieval and creativity. While diverse approaches are available, researchers commonly assume a single underlying semantic network that is shared across individuals. Yet, semantic networks are considered the product of experience implying that individuals who make different experiences should possess different semantic networks. By studying differences between younger and older adults, we demonstrate that this is the case. Using a network analytic approach and diverse empirical data, we present converging evidence of age-related differences in semantic networks of groups and, for the first time, individuals. Specifically, semantic networks of older adults exhibited larger degrees, less clustering, and longer path lengths. Furthermore, the edge weight distributions of older adults individual networks exhibited significantly more skew and higher entropy across node pairs and, except for unrelated node pairs, less inter-individual agreement, suggesting that older adults networks are generally more distinct than younger adults networks. Our results challenge the common conception of a single semantic network shared by individuals and highlight the importance of individual differences in cognitive modeling. They also present valuable benchmarks to discern between theories of age-related changes in cognitive performance.


2019 ◽  
Vol 5 (1) ◽  
Author(s):  
Michiko Sakaki ◽  
Jasmine A. L. Raw ◽  
Jamie Findlay ◽  
Mariel Thottam

Older adults typically remember more positive than negative information compared to their younger counterparts; a phenomenon referred to as the ‘positivity effect.’ According to the socioemotional selectivity theory (SST), the positivity effect derives from the age-related motivational shift towards attaining emotionally meaningful goals which become more important as the perception of future time becomes more limited. Cognitive control mechanisms are critical in achieving such goals and therefore SST predicts that the positivity effect is associated with preserved cognitive control mechanisms in older adults. In contrast, the aging-brain model suggests that the positivity effect is driven by an age-related decline in the amygdala which is responsible for emotional processing and emotional learning. The aim of the current research was to address whether the age-related positivity effect is associated with cognitive control or impaired emotional processing associated with aging. We included older old adults, younger old adults and younger adults and tested their memory for emotional stimuli, cognitive control and amygdala-dependent fear conditioned responses. Consistent with prior research, older adults, relative to younger adults, demonstrate better memory for positive over negative images. We further found that within a group of older adults, the positivity effect increases as a function of age, such that older old adults demonstrated a greater positivity effect compared to younger older adults. Furthermore, the positivity effect in older old adults was associated with preserved cognitive control, supporting the prediction of SST. Contrary to the prediction of the aging-brain model, participants across all groups demonstrated similar enhanced skin conductance responses to fear conditioned stimuli – responses known to rely on the amygdala. Our results support SST and suggest that the positivity effect in older adults is achieved by the preserved cognitive control mechanisms and is not a reflection of the impaired emotional function associated with age.


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