TY - JOUR

T1 - Stimulating aged brains with transcranial direct current stimulation

T2 - Opportunities and challenges

AU - Habich, Annegret

AU - Fehér, Kristoffer D.

AU - Antonenko, Daria

AU - Boraxbekk, Carl Johan

AU - Flöel, Agnes

AU - Nissen, Christoph

AU - Siebner, Hartwig Roman

AU - Thielscher, Axel

AU - Klöppel, Stefan

PY - 2020

Y1 - 2020

N2 - Ageing involves significant neurophysiological changes that are both systematic while at the same time exhibiting divergent trajectories across individuals. These changes underlie cognitive impairments in elderly while also affecting the response of aged brains to interventions like transcranial direct current stimulation (tDCS). While the cognitive benefits of tDCS are more variable in elderly, older adults also respond differently to stimulation protocols compared to young adults. The age-related neurophysiological changes influencing the responsiveness to tDCS remain to be addressed in-depth. We review and discuss the premise that, in comparison to the better calibrated brain networks present in young adults, aged systems perform further away from a homoeostatic set-point. We argue that this age-related neurophysiological deviation from the homoeostatic optimum extends the leeway for tDCS to modulate the aged brain. This promotes the potency of immediate tDCS effects to induce directional plastic changes towards the homoeostatic equilibrium despite the impaired plasticity induction in elderly. We also consider how age-related neurophysiological changes pose specific challenges for tDCS that necessitate proper adaptations of stimulation protocols. Appreciating the distinctive properties of aged brains and the accompanying adjustment of stimulation parameters can increase the potency and reliability of tDCS as a treatment avenue in older adults.

AB - Ageing involves significant neurophysiological changes that are both systematic while at the same time exhibiting divergent trajectories across individuals. These changes underlie cognitive impairments in elderly while also affecting the response of aged brains to interventions like transcranial direct current stimulation (tDCS). While the cognitive benefits of tDCS are more variable in elderly, older adults also respond differently to stimulation protocols compared to young adults. The age-related neurophysiological changes influencing the responsiveness to tDCS remain to be addressed in-depth. We review and discuss the premise that, in comparison to the better calibrated brain networks present in young adults, aged systems perform further away from a homoeostatic set-point. We argue that this age-related neurophysiological deviation from the homoeostatic optimum extends the leeway for tDCS to modulate the aged brain. This promotes the potency of immediate tDCS effects to induce directional plastic changes towards the homoeostatic equilibrium despite the impaired plasticity induction in elderly. We also consider how age-related neurophysiological changes pose specific challenges for tDCS that necessitate proper adaptations of stimulation protocols. Appreciating the distinctive properties of aged brains and the accompanying adjustment of stimulation parameters can increase the potency and reliability of tDCS as a treatment avenue in older adults.

KW - Ageing

KW - Cognition

KW - Neurophysiology

KW - Transcranial direct current stimulation

U2 - 10.1016/j.pscychresns.2020.111179

DO - 10.1016/j.pscychresns.2020.111179

M3 - Journal article

C2 - 32972813

AN - SCOPUS:85090746251

VL - 306

JO - Psychiatry Research: Neuroimaging

JF - Psychiatry Research: Neuroimaging

SN - 0925-4927

M1 - 111179

ER -