Junhong Zhou1,2,3, Brad Manor1,2,3, Wanting Yu1, On-Yee Lo1,2,3, Natalia Gouskova1, Ricardo Salvador4, Racheli Katz5, Pablo Cornejo Thumm6, Marina Brozgol6, Giulio Ruffini4, Alvaro Pascual-Leone1,3,7, Lewis A Lipsitz1,2,3, Jeffrey M Hausdorff6,8,9. 1. Hinda and Arthur Marcus Institute for Aging Research, Hebrew SeniorLife, Boston, MA. 2. Beth Israel Deaconess Medical Center, Boston, MA. 3. Harvard Medical School, Boston, MA. 4. Neuroelectrics Corporation, Cambridge, MA. 5. Tel Aviv University, Tel Aviv, Israel. 6. Center for the Study of Movement, Cognition, and Mobility, Neurological Institute, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel. 7. Guttman Brain Health Institute, Institut Guttmann de Neurorehabilitació, Universitat Autónoma de Barcelona, Barcelona, Spain. 8. Sagol School of Neuroscience and Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel. 9. Rush Alzheimer's Disease Center and Department of Orthopedic Surgery, Rush University Medical Center, Chicago, IL.
Abstract
OBJECTIVE: Among older adults, the ability to stand or walk while performing cognitive tasks (ie, dual-tasking) requires coordinated activation of several brain networks. In this multicenter, double-blinded, randomized, and sham-controlled study, we examined the effects of modulating the excitability of the left dorsolateral prefrontal cortex (L-DLPFC) and the primary sensorimotor cortex (SM1) on dual-task performance "costs" to standing and walking. METHODS: Fifty-seven older adults without overt illness or disease completed 4 separate study visits during which they received 20 minutes of transcranial direct current stimulation (tDCS) optimized to facilitate the excitability of the L-DLPFC and SM1 simultaneously, or each region separately, or neither region (sham). Before and immediately after stimulation, participants completed a dual-task paradigm in which they were asked to stand and walk with and without concurrent performance of a serial-subtraction task. RESULTS: tDCS simultaneously targeting the L-DLPFC and SM1, as well as tDCS targeting the L-DLPFC alone, mitigated dual-task costs to standing and walking to a greater extent than tDCS targeting SM1 alone or sham (p < 0.02). Blinding efficacy was excellent and participant subjective belief in the type of stimulation received (real or sham) did not contribute to the observed functional benefits of tDCS. INTERPRETATION: These results demonstrate that in older adults, dual-task decrements may be amenable to change and implicate L-DPFC excitability as a modifiable component of the control system that enables dual-task standing and walking. tDCS may be used to improve resilience and the ability of older results to walk and stand under challenging conditions, potentially enhancing everyday functioning and reducing fall risks. ANN NEUROL 2021;90:428-439.
OBJECTIVE: Among older adults, the ability to stand or walk while performing cognitive tasks (ie, dual-tasking) requires coordinated activation of several brain networks. In this multicenter, double-blinded, randomized, and sham-controlled study, we examined the effects of modulating the excitability of the left dorsolateral prefrontal cortex (L-DLPFC) and the primary sensorimotor cortex (SM1) on dual-task performance "costs" to standing and walking. METHODS: Fifty-seven older adults without overt illness or disease completed 4 separate study visits during which they received 20 minutes of transcranial direct current stimulation (tDCS) optimized to facilitate the excitability of the L-DLPFC and SM1 simultaneously, or each region separately, or neither region (sham). Before and immediately after stimulation, participants completed a dual-task paradigm in which they were asked to stand and walk with and without concurrent performance of a serial-subtraction task. RESULTS: tDCS simultaneously targeting the L-DLPFC and SM1, as well as tDCS targeting the L-DLPFC alone, mitigated dual-task costs to standing and walking to a greater extent than tDCS targeting SM1 alone or sham (p < 0.02). Blinding efficacy was excellent and participant subjective belief in the type of stimulation received (real or sham) did not contribute to the observed functional benefits of tDCS. INTERPRETATION: These results demonstrate that in older adults, dual-task decrements may be amenable to change and implicate L-DPFC excitability as a modifiable component of the control system that enables dual-task standing and walking. tDCS may be used to improve resilience and the ability of older results to walk and stand under challenging conditions, potentially enhancing everyday functioning and reducing fall risks. ANN NEUROL 2021;90:428-439.
Authors: D B Fischer; P J Fried; G Ruffini; O Ripolles; R Salvador; J Banus; W T Ketchabaw; E Santarnecchi; A Pascual-Leone; M D Fox Journal: Neuroimage Date: 2017-05-29 Impact factor: 6.556
Authors: M J Angevaare; J Roberts; H P J van Hout; K J Joling; M Smalbrugge; L J Schoonmade; G Windle; C M P M Hertogh Journal: Ageing Res Rev Date: 2020-08-22 Impact factor: 10.895