title: Online and offline effects of cerebellar transcranial direct current stimulation on motor learning in healthy older adults: a randomized double-blind sham-controlled study.
abstract: The aim of this randomized double blinded sham-controlled study was to determine the effect of cerebellar anodal transcranial direct current stimulation (a-tDCS) on online and offline motor learning in healthy older individuals. Thirty participants were randomly assigned in experimental (n = 15) or sham tDCS (n = 15) groups. Participants in experimental group received 2 mA cerebellar a-tDCS for 20 min. However, the tDCS was turned off after 30 seconds in sham group. Response time (RT) and error rate (ER) in serial RT test were assessed before, during 35 minutes and 48 h after the intervention. Reduction of RT and ER following the intervention session was considered as short-term (35 min post intervention) and long-term offline learning (48 h post intervention), respectively. Online RT and ER reduction were similar in both groups (P > 0.05). RT was significantly reduced 48 hours post intervention in cerebellar a-tDCS group (P = 0.03). Moreover, RT was significantly increased after 35 minutes and 48 hours in sham tDCS group (P = 0.03, P = 0.007), which indicates a lack of short-term and long-term offline learning in older adults. A-tDCS on cerebellar region produced more short-term and long-term offline improvement in RT (P = 0.014, P = 0.01) compared to sham tDCS. In addition, online, short-term and long-term (48 h) offline error reduced in cerebellar a-tDCS as compared to sham-control group, although this reduction was not significant (P > 0.05). A deficit suggests that a direct comparison to a younger group was made. The findings suggested that cerebellar a-tDCS might be useful for improvement of offline motor learning in older individuals.
authors.affiliation: Neuromuscular Rehabilitation Research Center, Semnan University of Medical Sciences, Semnan, Iran.
authors.forename: Afshin
authors.initials: A
authors.lastname: Samaei
authors.affiliation: Neuromuscular Rehabilitation Research Center, Semnan University of Medical Sciences, Semnan, Iran.
authors.forename: Fatemeh
authors.identifier: 0000-0002-7528-973X
authors.initials: F
authors.lastname: Ehsani
authors.affiliation: Discipline of Physiotherapy, Department of Rehabilitation, Nutrition and Sport, School of Allied Health, La Trobe University, Bundoora, Vic., Australia.
authors.forename: Maryam
authors.initials: M
authors.lastname: Zoghi
authors.affiliation: Student Research Committee, Semnan University of Medical Sciences, Semnan, Iran.
authors.forename: Mohaddese
authors.initials: M
authors.lastname: Hafez Yosephi
authors.affiliation: Department of Physiotherapy, Faculty of Medicine, Nursing and Health Sciences, Monash University, Melbourne, Vic., Australia.
authors.forename: Shapour
authors.initials: S
authors.lastname: Jaberzadeh
mesh_terms: D000818:Animals; D005260:Female; D008297:Male; D002531:Cerebellum / Q000502:physiology; D019054:Evoked Potentials, Motor / Q000502:physiology; D064368:Healthy Volunteers; D007858:Learning / Q000502:physiology; D009048:Motor Skills / Q000502:physiology; D009862:Online Systems; D011930:Reaction Time; D065908:Transcranial Direct Current Stimulation / Q000379:methods; D050781:Transcranial Magnetic Stimulation / Q000379:methods; D006801:Humans
keywords: aging; cerebellum; electrical stimulation; learning; serial reaction time test