1
|
Koo GK, Gaur A, Tumati S, Kusumo RW, Bawa KK, Herrmann N, Gallagher D, Lanctôt KL. Identifying factors influencing cognitive outcomes after anodal transcranial direct current stimulation in older adults with and without cognitive impairment: A systematic review. Neurosci Biobehav Rev 2023; 146:105047. [PMID: 36646259 DOI: 10.1016/j.neubiorev.2023.105047] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Revised: 01/10/2023] [Accepted: 01/12/2023] [Indexed: 01/15/2023]
Abstract
Anodal transcranial direct current stimulation (tDCS) can improve cognition in healthy older adults, those with Alzheimer's disease (AD) and mild cognitive impairment (MCI), albeit with considerable variability in response. This systematic review identifies interindividual factors that may influence tDCS outcomes in older individuals with or without cognitive impairment. Peer-reviewed articles were included if they assessed whether cognitive outcomes (memory or global cognition) after tDCS were associated with pre-intervention factors in healthy older adults or individuals with AD/MCI. We identified eight factors that may affect cognitive outcomes after tDCS. Improved tDCS outcomes were predicted by lower baseline cognitive function when tDCS was combined with a co-intervention (but not when used alone). Preserved brain structure and better baseline functional connectivity, genetic polymorphisms, and the use of concomitant medications may predict better tDCS outcomes, but further research is warranted. tDCS outcomes were not consistently associated with age, cognitive reserve, sex, and AD risk factors. Accounting for individual differences in baseline cognition, particularly for combined interventions, may thus maximize the therapeutic potential of tDCS.
Collapse
Affiliation(s)
- Grace Ky Koo
- Neuropsychopharmacology Research Group, Sunnybrook Research Institute, 2075 Bayview Avenue, Toronto, ON M4N 3M5, Canada; Hurvitz Brain Sciences Program, Sunnybrook Research Institute, 2075 Bayview Avenue, Toronto, ON M4N 3M5, Canada; Department of Pharmacology & Toxicology, University of Toronto, 1 King's College Circle, Toronto, ON M5S 1A8, Canada
| | - Amish Gaur
- Neuropsychopharmacology Research Group, Sunnybrook Research Institute, 2075 Bayview Avenue, Toronto, ON M4N 3M5, Canada; Hurvitz Brain Sciences Program, Sunnybrook Research Institute, 2075 Bayview Avenue, Toronto, ON M4N 3M5, Canada; Department of Pharmacology & Toxicology, University of Toronto, 1 King's College Circle, Toronto, ON M5S 1A8, Canada
| | - Shankar Tumati
- Neuropsychopharmacology Research Group, Sunnybrook Research Institute, 2075 Bayview Avenue, Toronto, ON M4N 3M5, Canada; Hurvitz Brain Sciences Program, Sunnybrook Research Institute, 2075 Bayview Avenue, Toronto, ON M4N 3M5, Canada
| | - Raphael W Kusumo
- Neuropsychopharmacology Research Group, Sunnybrook Research Institute, 2075 Bayview Avenue, Toronto, ON M4N 3M5, Canada; Hurvitz Brain Sciences Program, Sunnybrook Research Institute, 2075 Bayview Avenue, Toronto, ON M4N 3M5, Canada
| | - Kritleen K Bawa
- Neuropsychopharmacology Research Group, Sunnybrook Research Institute, 2075 Bayview Avenue, Toronto, ON M4N 3M5, Canada; Hurvitz Brain Sciences Program, Sunnybrook Research Institute, 2075 Bayview Avenue, Toronto, ON M4N 3M5, Canada
| | - Nathan Herrmann
- Neuropsychopharmacology Research Group, Sunnybrook Research Institute, 2075 Bayview Avenue, Toronto, ON M4N 3M5, Canada; Hurvitz Brain Sciences Program, Sunnybrook Research Institute, 2075 Bayview Avenue, Toronto, ON M4N 3M5, Canada; Department of Psychiatry, Faculty of Medicine, University of Toronto, 250 College Street, 8th floor, Toronto, ON M5T 1R8, Canada
| | - Damien Gallagher
- Neuropsychopharmacology Research Group, Sunnybrook Research Institute, 2075 Bayview Avenue, Toronto, ON M4N 3M5, Canada; Hurvitz Brain Sciences Program, Sunnybrook Research Institute, 2075 Bayview Avenue, Toronto, ON M4N 3M5, Canada; Department of Psychiatry, Faculty of Medicine, University of Toronto, 250 College Street, 8th floor, Toronto, ON M5T 1R8, Canada
| | - Krista L Lanctôt
- Neuropsychopharmacology Research Group, Sunnybrook Research Institute, 2075 Bayview Avenue, Toronto, ON M4N 3M5, Canada; Hurvitz Brain Sciences Program, Sunnybrook Research Institute, 2075 Bayview Avenue, Toronto, ON M4N 3M5, Canada; Department of Pharmacology & Toxicology, University of Toronto, 1 King's College Circle, Toronto, ON M5S 1A8, Canada; Department of Psychiatry, Faculty of Medicine, University of Toronto, 250 College Street, 8th floor, Toronto, ON M5T 1R8, Canada.
| |
Collapse
|
2
|
Liu M, Tian H, Sun S, Tian X, Wang W, Wu Y. The association of pulse pressure change with memory decline in middle-aged and older adults. J Am Geriatr Soc 2023; 71:423-431. [PMID: 36289057 DOI: 10.1111/jgs.18095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Revised: 09/24/2022] [Accepted: 10/01/2022] [Indexed: 11/28/2022]
Abstract
BACKGROUND Less is known regarding the association of pulse pressure (PP) with memory function. This study aimed to characterize long-term patterns of PP in middle-aged and older adults and explore their impact on subsequent change in memory function. METHODS Data from the English Longitudinal Study of Ageing (ELSA, 2004-2018), were analyzed. Totally, 3587 dementia-free participants with three measurements of BP were included. All three visits of PP (2004-2012) were used to characterize longitudinal patterns of PP by group-based trajectory modeling (GBTM). Generalized estimating equation (GEE) models were fitted to explore the impact of PP trajectories on change in memory over a subsequent 6-year period (2012-2018). RESULTS Using GBTM, three distinct trajectories of PP were identified: low-stable (38.1%), moderate-stable (48.6%), and elevated-increasing group (13.3%). GEE model suggested that memory declined over a 6-year period in all PP trajectories (all Ptime <0.001). The overall interactions between patterns of PP changes and time with memory were statistically significant (χ2 interaction = 20.69, p = 0.002). Compared to participants in the low-stable group, those in the moderate-stable and elevated-increasing group exhibited a faster decline in memory. CONCLUSIONS Longitudinal patterns of moderate-stable and elevated-increasing PP were associated with an accelerated decrease in memory. Controlling BP instability may be a promising interventional strategy for preventing cognitive decline among older adults.
Collapse
Affiliation(s)
- Mengli Liu
- Department of Epidemiology and Health Statistics, Public Health College, Qingdao University, Qingdao, China.,Nanjing Municipal Center for Disease Control and Prevention, Nanjing, China
| | - Huimin Tian
- Department of Epidemiology and Health Statistics, Public Health College, Qingdao University, Qingdao, China
| | - Shuqin Sun
- Department of Geriatrics, Affiliated Hospital of Qingdao University, Qingdao, China
| | - Xiaocao Tian
- Department of Chronic Noncommunicable Disease Control and Prevention, Qingdao Municipal Center for Disease Control and Prevention, Qingdao, China
| | - Weijing Wang
- Department of Epidemiology and Health Statistics, Public Health College, Qingdao University, Qingdao, China
| | - Yili Wu
- Department of Epidemiology and Health Statistics, Public Health College, Qingdao University, Qingdao, China
| |
Collapse
|
3
|
Left Prefrontal tDCS during Learning Does Not Enhance Subsequent Verbal Episodic Memory in Young Adults: Results from Two Double-Blind and Sham-Controlled Experiments. Brain Sci 2023; 13:brainsci13020241. [PMID: 36831783 PMCID: PMC9954521 DOI: 10.3390/brainsci13020241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 01/21/2023] [Accepted: 01/28/2023] [Indexed: 02/04/2023] Open
Abstract
Recent studies suggest that transcranial direct current stimulation (tDCS) applied over the prefrontal cortex (PFaC) may enhance episodic memory ability. As such, there is ongoing interest in the therapeutic potential of this technique in age-related memory decline. At the same time, the findings are not yet conclusive regarding the magnitude of this effect, and assumptions regarding underlying brain mechanisms of stimulation-induced changes in behaviour are yet to be tested in detail. Here, we evaluated the effect of tDCS over left PFC on verbal episodic memory in young adults. Two separate randomized, double-blind, sham-controlled experiments were carried out using (1) incidental learning followed by a recognition test and (2) intentional learning followed by a free recall. In both studies, participants performed a learning task with active or sham tDCS during the encoding period, followed by retrieval tasks on the same day and the next day. The results suggest that, contrary to expectations, active tDCS did not enhance memory performance relative to sham tDCS. Possible reasons behind the lack of enhancement effects are discussed, including the possibility that memory enhancement effects of tDCS may be smaller than first thought. Scientific practices that could improve estimation accuracy in the field are also discussed.
Collapse
|
4
|
Bagattini C, Cid-Fernández S, Bulgari M, Miniussi C, Bortoletto M. Opposite pattern of transcranial direct current stimulation effects in middle-aged and older adults: Behavioral and neurophysiological evidence. Front Aging Neurosci 2023; 15:1087749. [PMID: 36761183 PMCID: PMC9905246 DOI: 10.3389/fnagi.2023.1087749] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Accepted: 01/04/2023] [Indexed: 01/27/2023] Open
Abstract
Introduction Episodic memory (EM) exhibits an age-related decline, with overall increased impairment after the age of 65. The application of transcranial direct current stimulation (tDCS) to ameliorate cognitive decline in ageing has been extensively investigated, but its efficacy has been reported with mixed results. In this study, we aimed to assess whether age contributes to interindividual variability in tDCS efficacy. Methods Thirty-eight healthy adults between 50 and 81 years old received anodal tDCS over the left prefrontal cortex during images encoding and then performed an EM recognition task while event-related potentials (ERPs) were recorded. Results Our results showed an opposite pattern of effect between middle-aged (50-64 years) and older (65-81 years) adults. Specifically, performance in the recognition task after tDCS was enhanced in older adults and was worsened in middle-aged adults. Moreover, ERPs acquired during the recognition task showed that two EM components related to familiarity and post-retrieval monitoring, i.e., Early Frontal and Late Frontal Old-New effects, respectively, were significantly reduced in middle-aged adults after anodal tDCS. Discussion These results support an age-dependent effect of prefrontal tDCS on EM processes and its underlying electrophysiological substrate, with opposing modulatory trajectories along the aging lifespan.
Collapse
Affiliation(s)
- Chiara Bagattini
- Neurophysiology Lab, IRCCS Istituto Centro San Giovanni di Dio Fatebenefratelli, Brescia, Italy,Section of Neurosurgery, Department of Neuroscience Biomedicine and Movement Sciences, University of Verona, Verona, Italy,*Correspondence: Chiara Bagattini,
| | - Susana Cid-Fernández
- Department of Developmental and Educational Psychology, University of Santiago de Compostela, Santiago de Compostela, Galicia, Spain
| | - Martina Bulgari
- Neurophysiology Lab, IRCCS Istituto Centro San Giovanni di Dio Fatebenefratelli, Brescia, Italy
| | - Carlo Miniussi
- Center for Mind/Brain Sciences (CIMeC), University of Trento, Rovereto, Italy
| | - Marta Bortoletto
- Neurophysiology Lab, IRCCS Istituto Centro San Giovanni di Dio Fatebenefratelli, Brescia, Italy
| |
Collapse
|
5
|
Greeley B, Barnhoorn JS, Verwey WB, Seidler RD. Anodal Transcranial Direct Current Stimulation Over Prefrontal Cortex Slows Sequence Learning in Older Adults. Front Hum Neurosci 2022; 16:814204. [PMID: 35280208 PMCID: PMC8907426 DOI: 10.3389/fnhum.2022.814204] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Accepted: 01/25/2022] [Indexed: 11/13/2022] Open
Abstract
Aging is associated with declines in sensorimotor function. Several studies have demonstrated that transcranial direct current stimulation (tDCS), a form of non-invasive brain stimulation, can be combined with training to mitigate age-related cognitive and motor declines. However, in some cases, the application of tDCS disrupts performance and learning. Here, we applied anodal tDCS either over the left prefrontal cortex (PFC), right PFC, supplementary motor complex (SMC), the left M1, or in a sham condition while older adults (n = 63) practiced a Discrete Sequence Production (DSP), an explicit motor sequence, task across 3 days. We hypothesized that stimulation to either the right or left PFC would enhance motor learning for older adults, based on the extensive literature showing increased prefrontal cortical activity during motor task performance in older adults. Contrary to our predictions, stimulation to the right and left PFC resulted in slowed motor learning, as evidenced by a slower reduction rate of reduction of reaction time and the number of sequence chunks across trials relative to sham in session one and session two, respectively. These findings suggest an integral role of the right PFC early in sequence learning and a role of the left PFC in chunking in older adults, and contribute to mounting evidence of the difficultly of using tDCS in an aging population.
Collapse
Affiliation(s)
- Brian Greeley
- Department of Physical Therapy, University of British Columbia, Vancouver, BC, Canada
| | - Jonathan S. Barnhoorn
- Department of Learning, Data-Analytics and Technology, University of Twente, Enschede, Netherlands
| | - Willem B. Verwey
- Department of Learning, Data-Analytics and Technology, University of Twente, Enschede, Netherlands
| | - Rachael D. Seidler
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, United States
- *Correspondence: Rachael D. Seidler,
| |
Collapse
|
6
|
Lee JH, Lee TL, Kang N. Transcranial direct current stimulation decreased cognition-related reaction time in older adults: A systematic review and meta-analysis. Ageing Res Rev 2021; 70:101377. [PMID: 34089900 DOI: 10.1016/j.arr.2021.101377] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Revised: 04/18/2021] [Accepted: 05/31/2021] [Indexed: 01/01/2023]
Abstract
BACKGROUND This systematic review and meta-analysis investigated the effects of transcranial direct current stimulation (tDCS) on the cognitive functions of healthy older adults by focusing on the changes in reaction time during cognitive tasks. METHOD A total of 31 studies qualified for this meta-analysis, and we acquired 36 comparisons from the included studies for data synthesis. The individual effect sizes were calculated by comparing the altered reaction time during the performance of a specific cognitive task between the active tDCS and sham groups. In two moderator variable analyses, we examined the potentially different effects of the tDCS protocols on the cognition-related reaction time based on the tDCS protocol used (i.e., online vs. offline tDCS) and the five cognitive domains: (a) perceptual-motor function, (b) learning and memory, (c) executive function / complex attention, (d) language, and (e) social cognition. Meta-regression analyses were conducted to estimate the relationship between demographic and tDCS parameter characteristics and the changes in reaction time. RESULTS The random-effects model meta-analysis revealed significant small effects of tDCS on cognition-related reaction time. Specifically, providing online tDCS significantly reduced the reaction time, and these patterns were observed during learning and memory and executive function / complex attention tasks. However, applying offline tDCS failed to find any significant reduction of reaction time across various cognitive tasks. The meta-regression analysis revealed that the effects of tDCS on the reaction time during the performance of cognitive tasks increased for the older people. CONCLUSIONS These findings suggest that providing online tDCS may effectively improve the ageing-induced reaction time related to specific cognitive functions of elderly people.
Collapse
|
7
|
Figeys M, Zeeman M, Kim ES. Effects of Transcranial Direct Current Stimulation (tDCS) on Cognitive Performance and Cerebral Oxygen Hemodynamics: A Systematic Review. Front Hum Neurosci 2021; 15:623315. [PMID: 33897392 PMCID: PMC8058208 DOI: 10.3389/fnhum.2021.623315] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Accepted: 03/11/2021] [Indexed: 11/24/2022] Open
Abstract
Background: There is increasing evidence to support the efficacy of transcranial direct current stimulation (tDCS) applications in cognitive augmentation and rehabilitation. Neuromodulation achieved with tDCS may further regulate regional cerebral perfusion affiliated through the neurovascular unit; however, components of cerebral perfusion decrease across aging. A novel neuroimaging approach, functional near-infrared spectroscopy (fNIRS), can aid in quantifying these regional perfusional changes. To date, the interaction of the effects of tDCS on cognitive performance across the lifespan and obtained fNIRS hemodynamic responses remain unknown. Objective: This review aims to examine the effects of tDCS on cognitive performance and fNIRS hemodynamic responses within the context of cognitive aging. Methods: Six databases were searched for studies. Quality appraisal and data extraction were conducted by two independent reviewers. Meta-analysis was carried out to determine overall and subgroup effect sizes. Results: Eight studies met inclusion criteria. The overall effect size demonstrates that tDCS can alter cognitive performance and fNIRS signals, with aging being a potential intermediary in tDCS efficacy. Conclusion: From the studies included, the effects of tDCS on cognitive performance and fNIRS metrics are most prominent in young healthy adults and appear to become less robust with increasing age. Given the small number of studies included in this review further investigation is recommended.
Collapse
Affiliation(s)
- Mathieu Figeys
- Faculty of Rehabilitation Medicine, University of Alberta, Edmonton, AB, Canada
| | - Michael Zeeman
- Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
| | - Esther Sung Kim
- Faculty of Rehabilitation Medicine, University of Alberta, Edmonton, AB, Canada.,Department of Communication Sciences and Disorders, University of Alberta, Edmonton, AB, Canada
| |
Collapse
|