scholarly journals The effect of transcranial direct current stimulation of dorsolateral prefrontal cortex on performing a sequential dual task: a randomized experimental study

2021 ◽  
Vol 34 (1) ◽  
Author(s):  
Rasool Abedanzadeh ◽  
Saeed Alboghebish ◽  
Parisa Barati

AbstractWhen it comes to simultaneous processing of two tasks, information processing capacity is usually below par and not desirable. Therefore, this preliminary study aimed to investigate the effect of transcranial direct-current stimulation (tDCS) of dorsolateral prefrontal cortex (DLPFC) on performing dual tasks. Twenty-six students (average age 25.2 ± 2.43 years) were selected and then randomly divided into experimental and sham groups. All of the participants conducted the Stroop effect test in a dual task situation before and after the tDCS. This test included two intervals between the stimuli of 100 and 900 ms. The results of mixed-ANOVA showed that the average second reaction time of the experimental stimulated group was reduced (in both dual tasks with congruent and incongruent stimuli) significantly after the tDCS. Therefore, it can be stated that the tDCS of the DLPFC increases the information processing speed and the capacity of attention and, as a result, decreases the effect of the psychological refractory period.

2018 ◽  
Vol 32 (9) ◽  
pp. 788-798 ◽  
Author(s):  
Brad Manor ◽  
Junhong Zhou ◽  
Rachel Harrison ◽  
On-Yee Lo ◽  
Thomas G. Travison ◽  
...  

Objective. To determine the effects of a transcranial direct current stimulation (tDCS) intervention with the anode placed over the left dorsolateral prefrontal cortex (dlPFC) and cathode over the right supraorbital region, on cognition, mobility, and “dual-task” standing and walking in older adults with mild-to-moderate motor and cognitive impairments. Methods. A double-blinded, block-randomized, sham-controlled trial was conducted in 18 nondemented, ambulatory adults aged ⩾65 years with slow walking speed (⩽1.0 m/s) and “executive” dysfunction (Trail Making Test B score ⩽25th percentile of age- and education-matched norms). Interventions included ten 20-minute sessions of tDCS or sham stimulation. Cognition, mobility, and dual-task standing and walking were assessed at baseline, postintervention, and 2 weeks thereafter. Dual tasking was also assessed immediately before and after the first tDCS session. Results. Intervention compliance was high (mean ± SD = 9.5 ± 1.1 sessions) and no unexpected or serious side effects were reported. tDCS, compared with sham, induced improvements in the Montreal Cognitive Assessment total score ( P = .03) and specifically within the executive function subscore of this test ( P = .002), and in several metrics of dual-task standing and walking ( P < .05). Each of these effects persisted for 2 weeks. tDCS had no effect on the Timed Up-and-Go test of mobility or the Geriatric Depression Scale. Those participants who exhibited larger improvements in dual-task standing posture following the first tDCS session exhibited larger cognitive-motor improvements following 2 weeks of tDCS ( P < .04). Interpretation. tDCS intervention designed to stimulate the left dorsolateral prefrontal cortex may improve executive function and dual tasking in older adults with functional limitations.


2020 ◽  
Vol 10 (11) ◽  
pp. 792
Author(s):  
Djamila Bennabi ◽  
Nicolas Carvalho ◽  
Ambra Bisio ◽  
Juliana Teti Mayer ◽  
Thierry Pozzo ◽  
...  

Background: Transcranial direct current stimulation (tDCS) applied to the left dorsolateral prefrontal cortex (dlPFC) might be a promising treatment strategy for depression. As disturbances in psychomotor activity are one of the key features of unipolar depression are, we aimed to evaluate the behavioral effects of ten tDCS sessions over a 5-day period on psychomotor retardation in depressed patients. Methods: Twenty-three treatment-resistant depressed patients received either active or sham anodal tDCS to the left dorsolateral prefrontal cortex (2 mA, 10 sessions over 1 week). Psychomotor functioning was registered by means of observer ratings (Salpêtrière Retardation Rating Scale—SRRS) and objective measures (kinematical analysis of movements, automatic imitation). Results: tDCS sessions resulted in improvements on SRRS scores, although active tDCS was not significantly superior to sham tDCS on the kinematical parameters. Furthermore, no general additional antidepressant effect of tDCS was observed. The relatively small sample size and the short periods of observation should be considered when interpreting these results. Conclusion: tDCS did not induce a clinically relevant effect on psychomotor function in active and sham stimulation groups.


2021 ◽  
pp. 1-11
Author(s):  
Daniela Smirni ◽  
Massimiliano Oliveri ◽  
Eliana Misuraca ◽  
Angela Catania ◽  
Laura Vernuccio ◽  
...  

Background: Recent studies showed that in healthy controls and in aphasic patients, inhibitory trains of repetitive transcranial magnetic stimulation (rTMS) over the right prefrontal cortex can improve phonemic fluency performance, while anodal transcranial direct current stimulation (tDCS) over the left prefrontal cortex can improve performance in naming and semantic fluency tasks. Objective: This study aimed at investigating the effects of cathodal tDCS over the left or the right dorsolateral prefrontal cortex (DLPFC) on verbal fluency tasks (VFT) in patients with mild Alzheimer’s disease (AD). Methods: Forty mild AD patients participated in the study (mean age 73.17±5.61 years). All participants underwent cognitive baseline tasks and a VFT twice. Twenty patients randomly received cathodal tDCS to the left or the right DLPFC, and twenty patients were assigned to a control group in which only the two measures of VFT were taken, without the administration of the tDCS. Results: A significant improvement of performance on the VFT in AD patients was present after tDCS over the right DLPFC (p = 0.001). Instead, no difference was detected between the two VFTs sessions after tDCS over the left DLPFC (p = 0.42). Furthermore, these results cannot be related to task learning effects, since no significant difference was found between the two VFT sessions in the control group (p = 0.73). Conclusion: These data suggest that tDCS over DLPFC can improve VFT performance in AD patients. A hypothesis is that tDCS enhances adaptive patterns of brain activity between functionally connected areas.


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