The Auditory-Visual Speech Benefit on Working Memory in Older Adults with Hearing Impairment.

The purpose of the study was to investigate the relationship between different exercise modes and visuospatial working memory in healthy older adults. A cross-sectional design was adopted. A total of 111 healthy older adults were enrolled in the study. They were classified by the exercise-related questionnaire to be in an open-skill group, closed-skill group or sedentary group. In experiment 1, the participants performed a visuospatial working memory task. The results indicated that both closed-skill (p < 0.05) and open-skill (p < 0.01) groups reached a higher accuracy than the sedentary group. Experiment 2 examined whether the exercise-induced benefit of working memory was manifested in passive maintenance or active manipulation of working memory which was assessed by visuospatial short-term memory task and visuospatial mental rotation task, respectively. The results showed that the open-skill (p < 0.01) group was more accurate than the sedentary group in the visuospatial short-term memory task, whereas the group difference in the visuospatial mental rotation task was not significant. These findings combined to suggest that physical exercise was associated with better visuospatial working memory in older adults. Furthermore, open-skill exercises that demand higher cognitive processing showed selective benefit for passive maintenance of working memory.

Neural patterns underlying the effect of negative distractors on working memory in older adults

Effects of long-term Wuqinxi exercise on working memory in older adults with mild cognitive impairment.

Working memory (WM), which underlies the temporary storage and manipulation of information, is critical for multiple aspects of cognition and everyday life. Nevertheless, research examining WM specifically in older adults remains limited, despite the global rapid increase in human life expectancy. We examined WM in a large sample ( N = 754) of healthy older adults (aged 58-89) in a non-Western population (Chinese speakers) in Taiwan, on a digit n-back task. We tested not only the influence of age itself and of load (1-back vs. 2-back) but also the effects of both sex and education, which have been shown to modulate WM abilities. Mixed-effects regression revealed that, within older adulthood, age negatively impacted WM abilities (with linear, not nonlinear, effects), as did load (worse performance at 2-back). In contrast, education level was positively associated with WM. Moreover, both age and education interacted with sex. With increasing age, males showed a steeper WM decline than females; with increasing education, females showed greater WM gains than males. Together with other findings, the evidence suggests that age, sex, and education all impact WM in older adults, but interact in particular ways. The results have both basic research and translational implications and are consistent with particular benefits from increased education for women.

This investigation determined the feasibility of using both auditory and visual stimuli in the adaptive testing of speech discrimination. Thirty-six adults with normal hearing and vision were subjects. Using the adaptive methodology known as the Doublet technique, speech-discrimination testing using monosyllabic word lists from the Northwestern University Auditory Test No. 6 (NU-6) (Tillman and Carhart, 1966) was performed at the target levels of 29.3 and 70.7% for both auditory-only and auditory-visual conditions. The results indicated that a specific discrimination score could be obtained under more adverse listening conditions with the addition of visual cues. The contribution of visual cues was constant for the two target scores. The adaptive technique at the 29.3 and 70.7% targets was reliable for both the auditory-only and auditory-visual conditions. Constant level testing showed good agreement with the adaptive technique for the auditory-visual condition. In conclusion, the use of standard error calculations is useful in determining measurement errors and the effects of an aural rehabilitation program.

Cognitive functions decline with age. Declined cognitive functions negatively affect daily behaviors. Previous studies showed the positive effect of spices and herbs on cognition. In this study, we investigated the positive impact of wasabi, which is a traditional Japanese spice, on cognitive functions. The main bioactive compound of wasabi is 6-MSITC (6 methylsulfinyl hexyl isothiocyanate), which has anti-oxidant and anti-inflammatory functions. Anti-oxidants and anti-inflammatories have an important role in cognitive health. Therefore, 6-MSITC is expected to have positive effects on cognitive function. Previous studies showed the beneficial effects on cognitive functions in middle-aged adults. However, it is unclear that 6-MSITC has a positive effect on cognitive functions in healthy older adults aged 60 years and over. Here, we investigated whether 12 weeks' 6-MSITC intervention enhances cognitive performance in older adults using a double-blinded randomized controlled trial (RCT). Seventy-two older adults were randomly assigned to 6-MSITC or placebo groups. Participants were asked to take a supplement (6-MSITC or a placebo) for 12 weeks. We checked a wide range of cognitive performances (e.g., executive function, episodic memory, processing speed, working memory, and attention) at the pre- and post-intervention periods. The 6-MSITC group showed a significant improvement in working and episodic memory performances compared to the placebo group. However, we did not find any significant improvements in other cognitive domains. This study firstly demonstrates scientific evidence that 6-MSITC may enhance working memory and episodic memory in older adults. We discuss the potential mechanism for improving cognitive functions after 6-MSITC intake.

Although hearing often declines with age, prior research has shown that older adults may benefit from multisensory input to a greater extent when compared to younger adults, a concept known as inverse effectiveness. While there is behavioral evidence in support of this phenomenon, less is known about its neural basis. The present functional MRI (fMRI) study examined how older and younger adults processed multimodal auditory-visual (AV) phonemic stimuli which were either congruent or incongruent across modalities. Incongruent AV pairs were designed to elicit the McGurk effect. Behaviorally, reaction times were significantly faster during congruent trials compared to incongruent trials for both age-groups, and overall older adults responded more slowly. The interaction was not significant, suggesting that older adults processed the AV stimuli similarly to younger adults. Although there were minimal behavioral differences, age-related differences in functional activation were identified: Younger adults elicited greater activation than older adults in primary sensory regions including superior temporal gyrus, the calcarine fissure, and left postcentral gyrus. In contrast, older adults elicited greater activation than younger adults in dorsal frontal regions including middle and superior frontal gyri, as well as dorsal parietal regions. These data suggest that while there is age-related stability in behavioral sensitivity to multimodal stimuli, the neural bases for this effect differed between older and younger adults. Our results demonstrated that older adults underrecruited primary sensory cortices and had increased recruitment of regions involved in executive function, attention, and monitoring processes, which may reflect an attempt to compensate.

Dopamine and training-related working-memory improvement

&lt;p&gt;Objectives: Elementary school classrooms that meet the acoustic requirements for near-optimum speech recognition are extremely scarce. Poor classroom acoustics may become a barrier to speech understanding as children enter school. The purpose of this study was threefold: 1) to quantify the extent to which reverberation, lexical difficulty, and presentation mode affect speech recognition in noise, 2) to examine to what extent auditory-visual (AV) integration assists with the recognition of speech in noisy and reverberant environments typical of elementary school classrooms, 3) to understand the relationship between developing mechanisms of multisensory integration and the concurrently developing linguistic and cognitive abilities.&lt;/p&gt; &lt;p&gt;Design: Twenty-seven typically developing children and 9 young adults participated. Participants repeated short sentences reproduced by 10 speakers on a 30” HDTV and/or over loudspeakers located around the listener in a simulated classroom environment. Signal-to-noise ratio (SNR) for 70 (SNR70) and 30 (SNR30) percent correct performance were measured using an adaptive tracking procedure. Auditory-visual integration was assessed via the SNR difference between AV and auditory-only (AO) conditions, labeled speech-reading benefit (SRB). Linguistic and cognitive aptitude was assessed using the NIH-Toolbox: Cognition Battery (NIH-TB: CB).&lt;/p&gt; &lt;p&gt;Results: Children required more favorable SNRs for equivalent performance when compared to adults. Participants benefited from the reduction in lexical difficulty, and in most cases the reduction in reverberation time. Reverberation affected children’s speech recognition in AO condition and adults in AV condition. At SNR30, SRB was greater than that at SNR70. Adults showed marginally significant increase in AV integration relative to children. Adults also showed increase in SRB for lexically hard versus easy words, at high level of reverberation. Development of linguistic and cognitive aptitude accounts for approximately 35% of the variance in AV integration, with crystalized and fluid cognition composite scores identified as strongest predictors.&lt;/p&gt; &lt;p&gt;Conclusions: The results of this study add to the body of evidence in support of children requiring more favorable SNRs to perform the same speech recognition tasks as adults in simulated listening environments akin to school classrooms. Our findings shed light on the development of AV integration for speech recognition in noise and reverberation during the school years, and provide insight into the balance of cognitive and linguistic underpinnings necessary for AV integration of degraded speech.&lt;/p&gt;

Background and Objectives: The present study aimed to assess the relative benefits of visual cue supplementation and acoustic enhancement in improving speech perception of individuals with Auditory Neuropathy Spectrum Disorders (ANSD). Methods: The study utilized repeated measure research design. Based on the purposive sampling 40 participants with ANSD were selected. They were assessed for their speech identification of monosyllables in auditory only (A), visual only (V), and auditory-visual (AV) modalities. In the A and AV modalities, the perception of the primary, temporally enhanced, and spectrally enhanced syllables were assessed in quiet as well as 0 dB signal to noise ratio (SNR) conditions. The identification scores were compared across modalities, stimuli, and conditions to derive the relative benefits of visual cues and acoustic enhancement on speech perception of individuals with ANSD. Results: The group data showed a significant effect of modality with the mean identification score being the maximum in AV modality. This was true both in quiet and 0 dB SNR. The mean identification scores in quiet were significantly higher compared to that in 0 dB SNR. However, acoustic enhancement of speech did not significantly enhance speech perception. When acoustic enhancement and visual cues were simultaneously provided, speech perception was determined only by visual cues. The evidence from individual data showed that most of the individuals benefit from AV modality. Conclusions: The findings indicate that both auditory and visual modality needs to be facilitated in ANSD to enhance speech perception. The acoustic enhancements in the current form have negligible influence. However, the inference shall be restricted to the perception of stop consonants.

Working memory (WM) permits maintenance of information over brief delays and is an essential executive function. Unfortunately, WM is subject to age-related decline. Some evidence supports the use of transcranial direct current stimulation (tDCS) to improve visual WM. A gap in knowledge is an understanding of the mechanism characterizing these tDCS linked effects. To address this gap, we compared the effects of two tDCS montages designed on visual working memory (VWM) performance. The bifrontal montage was designed to stimulate the heightened bilateral frontal activity observed in aging adults. The unilateral frontoparietal montage was designed to stimulate activation patterns observed in young adults. Participants completed three sessions (bilateral frontal, right frontoparietal, sham) of anodal tDCS (20 min, 2 mA). During stimulation, participants performed a visual long-term memory (LTM) control task and a visual WM task. There was no effect of tDCS on the LTM task. Participants receiving right unilateral tDCS showed a WM benefit. This pattern was most robust in older adults with low WM capacity. To address the concern that the key difference between the two tDCS montages could be tDCS over the posterior parietal cortex (PPC), we included new analyses from a previous study applying tDCS targeting the PPC paired with a recognition VWM task. No significant main effects were found. A subsequent experiment in young adults found no significant effect of either tDCS montage on either task. These data indicate that tDCS montage, age and WM capacity should be considered when designing tDCS protocols. We interpret these findings as suggestive that protocols designed to restore more youthful patterns of brain activity are superior to those that compensate for age-related changes.

IntroductionMobility and cognitive functions often decline concurrently in older adults, and may be particularly detrimental to walking in complex environments such as uneven terrain. Walking on uneven terrain particularly relies on visuospatial working memory to continuously adjust gait patterns; however, this relationship remains understudied. The objectives of this study are to examine group differences in uneven terrain walking speed and visuospatial n-back task performance across varying task demands among younger adults, and among older adults with high and low physical function and to assess whether uneven terrain-induced reductions in walking speed are associated with declines in n-back performance, particularly among low-functioning older adults. As an exploratory aim, we also examined age-related differences in brain activity during n-back performance to provide additional context for interpreting neural responses across tasks.MethodsThe analysis included 24 younger adults (aged 22.8 ± 3.3) and 44 older adults (aged 74.0 ± 5.6). Using the Short Physical Performance Battery (SPPB), older adults were categorized into high physical function (n = 29) and low physical function (n = 15), with scores below 10 indicating a lower level of physical function. Uneven terrain walking speed was measured as participants traversed four novel custom-made overground surfaces: flat, low, medium, and high terrain unevenness. Visuospatial walking memory was assessed on a spatial n-back task that included four n-back levels, ranging from 0-back to 3-back. Prefrontal cortical activity was measured using functional near-infrared spectroscopy (fNIRS) while participants performed the n-back task.ResultsCompared to younger adults, older adults exhibited poorer working memory performance and slower uneven terrain walking speeds, with both effects being particularly pronounced in low functioning older adults. Slower walking speeds as terrain became more uneven were associated with poorer n-back performance as n-back level increased, with a larger effect size observed in the low physical functioning older adults. fNIRS results revealed comparable levels of prefrontal cortical activity between younger and older groups during the n-back tasks. Prefrontal cortical activity did not increase with higher task demands (i.e., increasing n-back levels) in any of the groups.ConclusionThese findings support a relationship between declines in uneven terrain mobility and n-back cognitive function in older adults; however, this relationship was not observed in younger adults. Further research is needed to understand the shared neural mechanisms underlying age-related declines in mobility and cognitive function.

The effects of acoustic confusion (phonological similarity), word length, and concurrent articulation (articulatory suppression) are cited as support for Working Memory's phonological loop component (e.g., Baddeley, 2000, Psychonomic Bulletin and Review, 7, 544). Research has focused on younger adults, with no studies examining whether concurrent articulation reduces the word length and acoustic confusion effects among older adults. In the current study, younger and older adults were given lists of similar and dissimilar letters (Experiment 1) or long and short words (Experiment 2) for immediate serial reconstruction of order. Items were presented visually or auditorily, with or without concurrent articulation. As expected, younger and older adults demonstrated effects of acoustic confusion, word length, and concurrent articulation. Further, concurrent articulation reduced the effects of acoustic confusion and word length equally for younger and older adults. This suggests that age-related differences occur in overall performance, but do not reflect an age-related deficiency in the functioning of the phonological loop component of working memory.

Current models of brain organization include multisensory interactions at early processing stages and within low-level, including primary, cortices. Embracing this model with regard to auditory-visual (AV) interactions in humans remains problematic. Controversy surrounds the application of an additive model to the analysis of event-related potentials (ERPs), and conventional ERP analysis methods have yielded discordant latencies of effects and permitted limited neurophysiologic interpretability. While hemodynamic imaging and transcranial magnetic stimulation studies provide general support for the above model, the precise timing, superadditive/subadditive directionality, topographic stability, and sources remain unresolved. We recorded ERPs in humans to attended, but task-irrelevant stimuli that did not require an overt motor response, thereby circumventing paradigmatic caveats. We applied novel ERP signal analysis methods to provide details concerning the likely bases of AV interactions. First, nonlinear interactions occur at 60-95 ms after stimulus and are the consequence of topographic, rather than pure strength, modulations in the ERP. AV stimuli engage distinct configurations of intracranial generators, rather than simply modulating the amplitude of unisensory responses. Second, source estimations (and statistical analyses thereof) identified primary visual, primary auditory, and posterior superior temporal regions as mediating these effects. Finally, scalar values of current densities in all of these regions exhibited functionally coupled, subadditive nonlinear effects, a pattern increasingly consistent with the mounting evidence in nonhuman primates. In these ways, we demonstrate how neurophysiologic bases of multisensory interactions can be noninvasively identified in humans, allowing for a synthesis across imaging methods on the one hand and species on the other.

Working memory performance can be influenced by motivational factors, which may be associated with specific brain activities, including suppression of alpha oscillations. We investigated whether providing individuals online feedback about their ongoing oscillations (EEG-neurofeedback) can improve working memory under high and low reward expectancies. We combined working memory training with neurofeedback to enhance alpha suppression in a monetary-rewarded delayed match-to-sample task for visual objects. Along with alpha, we considered the neighbouring theta and beta bands. In a double-blind experiment, individuals were trained over 5 days to suppress alpha power by receiving real-time neurofeedback or control neurofeedback (placebo) in reward and no-reward trials. We investigated (i) whether neurofeedback enhances alpha suppression, (ii) whether monetary reward enhances alpha suppression and working memory, and (iii) whether any performance benefits of neurofeedback-training would transfer to unrelated cognitive tasks. With the same experimental design, we conducted two studies with differing instructions given at the maintenance, yielding together 300 EEG recording sessions. In Study I, participants were engaged in a mental calculation task during maintenance. In Study II, they were instructed to visually rehearse the sample image. Results from Study I demonstrated a significant training and reward-anticipation effect on working memory accuracy and reaction times over 5 days. Neurofeedback and reward anticipation showed effects on theta suppression but not on alpha suppression. Moreover, a cognitive training effect was observed on beta suppression. Thus, neurofeedback-training of alpha was unrelated to working memory performance. Study II replicated the training and reward-anticipation effect on working memory but without any effects of neurofeedback-training on oscillations or working memory. Neither study showed transfer effects of either working memory or neurofeedback-training. A linear mixed-effect model analysis of neurofeedback-independent training-related improvement of working memory combining both studies showed that improved working memory performance was related to oscillatory changes over training days in the encoding and maintenance phases. Improvements in accuracy were related to increasing beta amplitude in reward trials over right parietal electrodes. Improvements in reaction times were related to increases in right parietal theta amplitude during encoding and increased right parietal and decreased left parietal beta amplitudes during maintenance. Thus, while our study provided no evidence that neurofeedback targeting alpha improved the efficacy of working memory training or evidence for transfer, it showed a relationship between training-related changes in parietal beta oscillations during encoding and improvements in accuracy. Right parietal beta oscillations could be an intervention target for improving working memory accuracy.