Modulation of Adaptive Cognitive Control by Prefrontal High-Definition Transcranial Direct Current Stimulation in Older Adults

2019 ◽  
Vol 74 (7) ◽  
pp. 1174-1183 ◽  
Author(s):  
Oyetunde Gbadeyan ◽  
Marco Steinhauser ◽  
Alexander Hunold ◽  
Andrew K Martin ◽  
Jens Haueisen ◽  
...  
Keyword(s):  
Older Adults ◽  
Young Adults ◽  
Cognitive Control ◽  
Direct Current ◽  
Transcranial Direct Current Stimulation ◽  
Error Rates ◽  
Advanced Age ◽  
Induced Current ◽  
High Definition ◽  
Direct Current Stimulation

Abstract Objective Adaptive cognitive control frequently declines in advanced age. Because high-definition transcranial direct current stimulation (HD-tDCS) of the right dorsolateral prefrontal cortex (DLPFC) improved cognitive control in young adults, we investigated if this montage can also improve cognitive control in older individuals. Method In a double-blind, sham HD-tDCS controlled, cross-over design, 36 older participants received right DLPFC HD-tDCS during a visual flanker task. Conflict adaptation (CA) effects on response time (RT) and error rates (ER) assessed adaptive cognitive control. Biophysical modeling assessed the magnitude and distribution of induced current in older adults. Results Active HD-tDCS enhanced CA in older adults. However, this positive behavioral effect was limited to CA in ER. Similar to results obtained in healthy young adults, current modeling analysis demonstrated focal current delivery to the DLPFC with sufficient magnitude of the induced current to modulate neural function in older adults. Discussion This study confirms the effectiveness of HD-tDCS to modulate adaptive cognitive control in advanced age.

Effects of High Definition-Transcranial Direct Current Stimulation on Local GABA and Glutamate Levels Among Older Adults with and without Mild Cognitive Impairment: An Exploratory Study

2021 ◽  
pp. 1-12
Author(s):  
Ketrin Lengu ◽  
Shannon Ryan ◽  
Scott J. Peltier ◽  
Troy Tyszkowski ◽  
Anson Kairys ◽  
...  
Keyword(s):  
Older Adults ◽  
Cognitive Impairment ◽  
Mild Cognitive Impairment ◽  
Parietal Cortex ◽  
Direct Current ◽  
Transcranial Direct Current Stimulation ◽  
Resonance Spectroscopy ◽  
High Definition ◽  
Direct Current Stimulation ◽  
Superior Parietal Cortex

Background: Prior research, primarily with young adults, suggests transcranial direct current stimulation (tDCS) effects are driven by the primary excitatory and/or inhibitory neurotransmitters, glutamate, and gamma-aminobutyric acid (GABA), respectively. Objective: We examined the neurometabolic mechanisms of tDCS in older adults with and without mild cognitive impairment (MCI). Methods: We used data from a double-blind, cross-over, randomized controlled trial (NCT01958437) in 32 older adults to evaluate high definition (HD)-tDCS-induced changes in glutamate and GABA via magnetic resonance spectroscopy (MRS). Participants underwent MRS following two counterbalanced HD-tDCS sessions (one active, one sham) that targeted the right superior parietal cortex (center anode at P2) and delivered 2mA for 20 minutes. Results: Relative to sham, and when co-varying for MRS voxel overlap and right superior parietal volume, active HD-tDCS significantly increased GABA and decreased the ratio of glutamate to GABA. No changes were observed in a left prefrontal control MRS voxel. Although we did not find a significant correlation between strength of delivered current (measured via MRI-based computational modeling) and neurometabolite change, there was a robust positive relationship between the volume of right superior parietal cortex and neurometabolite change. Conclusion: Our preliminary findings of increased GABA and reduced glutamate/GABA ratio raise the possibility that (HD-)tDCS effects differ by age. Moreover, age- and disease-related regional brain volume loss may be especially important to consider when planning future studies. Replication would emphasize the importance of developing population-specific tDCS parameters that consider structural and physiologic changes associated with “normal” and pathological aging.

scholarly journals Age-related differences in the role of the prefrontal cortex in sensory-motor training gains: A tDCS study

2020 ◽  
Author(s):  
Si Jing Tan ◽  
Hannah L. Filmer ◽  
Paul E. Dux
Keyword(s):  
Older Adults ◽  
Young Adults ◽  
Prefrontal Cortex ◽  
Direct Current ◽  
Transcranial Direct Current Stimulation ◽  
Response Selection ◽  
Sources Of Information ◽  
Multiple Sources ◽  
Direct Current Stimulation ◽  
Age Related

AbstractThe ability to process multiple sources of information concurrently is particularly impaired as individuals age and such age-related increases in multitasking costs have been linked to impairments in response selection. Previous neuroimaging studies with young adults have implicated the left hemisphere prefrontal cortex (PFC) as a key neural substrate of response selection. In addition, several transcranial direct current stimulation studies (tDCS) have provided causal evidence implicating this region in response selection and multitasking operations. For example, Filmer at al. (2013b) demonstrated that typically observed response selection learning/training gains in young adults were disrupted via offline transcranial direct current stimulation (tDCS) of left, but not right, PFC. Here, considering evidence of functional dedifferentiation in the brains of older adults, we assessed if this pattern of response selection learning disruption via tDCS to the left PFC is observed in older adults, testing if this region remains a key response selection node as individuals age. In a pre-registered study with 58 older adults, we applied anodal, cathodal, and sham stimulation to left and right PFC, and measured performance as participants trained on low- and high-response selection load tasks. Active stimulation did not disrupt training in older adults as compared to younger adults. However, there was evidence of enhanced training gains via tDCS, which scaled with response selection task difficulty. The results highlight age-related differences in the casual neural substrates that subserve response selection and learning.

scholarly journals Can Transcranial Direct Current Stimulation Enhance Functionality in Older Adults? A Systematic Review

2021 ◽  
Vol 10 (13) ◽  
pp. 2981
Author(s):  
Andrés Pino-Esteban ◽  
Álvaro Megía-García ◽  
David Martín-Caro Álvarez ◽  
Hector Beltran-Alacreu ◽  
Juan Avendaño-Coy ◽  
...  
Keyword(s):  
Systematic Review ◽  
Older Adults ◽  
Direct Current ◽  
Transcranial Direct Current Stimulation ◽  
Randomized Clinical Trials ◽  
Scientific Evidence ◽  
Healthy Older Adults ◽  
Sham Stimulation ◽  
Direct Current Stimulation ◽  
Potential Benefits

Transcranial direct current stimulation (tDCS) is a non-invasive, easy to administer, well-tolerated, and safe technique capable of affecting brain excitability, both at the cortical and cerebellum levels. However, its effectiveness has not been sufficiently assessed in all population segments or clinical applications. This systematic review aimed at compiling and summarizing the currently available scientific evidence about the effect of tDCS on functionality in older adults over 60 years of age. A search of databases was conducted to find randomized clinical trials that applied tDCS versus sham stimulation in the above-mentioned population. No limits were established in terms of date of publication. A total of 237 trials were found, of which 24 met the inclusion criteria. Finally, nine studies were analyzed, including 260 healthy subjects with average age between 61.0 and 85.8 years. Seven of the nine included studies reported superior improvements in functionality variables following the application of tDCS compared to sham stimulation. Anodal tDCS applied over the motor cortex may be an effective technique for improving balance and posture control in healthy older adults. However, further high-quality randomized controlled trials are required to determine the most effective protocols and to clarify potential benefits for older adults.

scholarly journals Effects of transcranial direct current stimulation combined with listening to preferred music on memory in older adults

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ricky Chow ◽  
Alix Noly-Gandon ◽  
Aline Moussard ◽  
Jennifer D. Ryan ◽  
Claude Alain
Keyword(s):  
Older Adults ◽  
Working Memory ◽  
Recognition Memory ◽  
Direct Current ◽  
Transcranial Direct Current Stimulation ◽  
Digit Span ◽  
Recognition Task ◽  
Music Listening ◽  
Subsequent Performance ◽  
Direct Current Stimulation

AbstractListening to autobiographically-salient music (i.e., music evoking personal memories from the past), and transcranial direct current stimulation (tDCS) have each been suggested to temporarily improve older adults’ subsequent performance on memory tasks. Limited research has investigated the effects of combining both tDCS and music listening together on cognition. The present study examined whether anodal tDCS stimulation over the left dorsolateral prefrontal cortex (2 mA, 20 min) with concurrent listening to autobiographically-salient music amplified subsequent changes in working memory and recognition memory in older adults than either tDCS or music listening alone. In a randomized sham-controlled crossover study, 14 healthy older adults (64–81 years) participated in three neurostimulation conditions: tDCS with music listening (tDCS + Music), tDCS in silence (tDCS-only), or sham-tDCS with music listening (Sham + Music), each separated by at least a week. Working memory was assessed pre- and post-stimulation using a digit span task, and recognition memory was assessed post-stimulation using an auditory word recognition task (WRT) during which electroencephalography (EEG) was recorded. Performance on the backwards digit span showed improvement in tDCS + Music, but not in tDCS-only or Sham + Music conditions. Although no differences in behavioural performance were observed in the auditory WRT, changes in neural correlates underlying recognition memory were observed following tDCS + Music compared to Sham + Music. Findings suggest listening to autobiographically-salient music may amplify the effects of tDCS for working memory, and highlight the potential utility of neurostimulation combined with personalized music to improve cognitive performance in the aging population.

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