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Balanced bifrontal transcranial direct current stimulation enhances working memory in adults with high-functioning autism: a sham-controlled crossover study.
Mol Autism 2017; 8:40MA

Abstract

BACKGROUND

Working memory (WM) often is impaired in autism spectrum disorder (ASD). Such impairment may underlie core deficits in cognition and social functioning. Transcranial direct current stimulation (tDCS) has been shown to enhance WM in both healthy adults and clinical populations, but its efficacy in ASD is unknown. We predicted that bifrontal tDCS would improve WM performances of adults with high-functioning autism during active stimulation compared to sham stimulation and that such enhancement would generalize to an untrained task.

METHODS

Twelve adults with high-functioning ASD engaged in a battery of WM tasks that included backward spatial span, backward digit span, spatial n-back and letter n-back. While engaged, 40 min of 1.5 mA bifrontal stimulation was applied over the left and the right dorsolateral prefrontal cortices (DLPFC). Using a single-blind crossover design, each participant received left anodal/right cathodal stimulation, right anodal/left cathodal stimulation, or sham stimulation, in randomized counterbalanced order on three separate days. Following tDCS, participants again engaged in letter and spatial n-back tasks before taking the Brief Test of Attention (BTA). We used repeated-measures ANOVA to compare overall performance on the WM battery as measured by a composite of z-scores for all five measures. Post hoc ANOVAs, t tests, Friedman's tests, and Wilcoxon signed-rank tests were used to measure the online and offline effects of tDCS and to assess performances on individual measures.

RESULTS

Compared to sham stimulation, both left DLPFC anodal stimulation (t11 = 5.4, p = 0.0002) and right DLPFC anodal stimulation (t11 = 3.57, p = 0.004) improved overall WM performance. Left anodal stimulation (t11 = 3.9, p = 0.003) and right anodal stimulation (t11 = 2.7, p = 0.019) enhanced performances during stimulation. Enhancement transferred to an untrained task 50 min after right anodal stimulation (z11 = 2.263, p = 0.024). The tasks that showed the largest effects of active stimulation were spatial span backward (z11 = 2.39, p = 0.017) and BTA (z11 = 2.263, p = 0.024).

CONCLUSIONS

In adults with high-functioning ASD, active bifrontal tDCS given during WM tasks appears to improve performance. TDCS benefits also transferred to an untrained task completed shortly after stimulation. These results suggest that tDCS can improve WM task performance and could reduce some core deficits of autism.

TRIAL REGISTRATION

NCT01602263.

Authors+Show Affiliations

Department of Neurology, The Johns Hopkins University School of Medicine, 1629 Thames Street, Suite 350, Baltimore, MD 21231 USA.Department of Neurology, The Johns Hopkins University School of Medicine, 1629 Thames Street, Suite 350, Baltimore, MD 21231 USA.Department of Psychiatry and Behavioral Sciences, The Johns Hopkins University School of Medicine, 600 N. Wolfe Street, Baltimore, MD 21287 USA. Division of MR Research, Russell H. Morgan Department of Radiology and Radiological Science, 600 N. Wolfe Street, Baltimore, MD 21287 USA.Department of Psychiatry and Behavioral Sciences, The Johns Hopkins University School of Medicine, 600 N. Wolfe Street, Baltimore, MD 21287 USA. Department of Neurology, The Johns Hopkins University School of Medicine, 600 N. Wolfe Street, Baltimore, MD 21287 USA.Department of Neurology, The Johns Hopkins University School of Medicine, 1629 Thames Street, Suite 350, Baltimore, MD 21231 USA.

Pub Type(s)

Journal Article
Randomized Controlled Trial
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

28775825

Citation

van Steenburgh, J Jason, et al. "Balanced Bifrontal Transcranial Direct Current Stimulation Enhances Working Memory in Adults With High-functioning Autism: a Sham-controlled Crossover Study." Molecular Autism, vol. 8, 2017, p. 40.
van Steenburgh JJ, Varvaris M, Schretlen DJ, et al. Balanced bifrontal transcranial direct current stimulation enhances working memory in adults with high-functioning autism: a sham-controlled crossover study. Mol Autism. 2017;8:40.
van Steenburgh, J. J., Varvaris, M., Schretlen, D. J., Vannorsdall, T. D., & Gordon, B. (2017). Balanced bifrontal transcranial direct current stimulation enhances working memory in adults with high-functioning autism: a sham-controlled crossover study. Molecular Autism, 8, p. 40. doi:10.1186/s13229-017-0152-x.
van Steenburgh JJ, et al. Balanced Bifrontal Transcranial Direct Current Stimulation Enhances Working Memory in Adults With High-functioning Autism: a Sham-controlled Crossover Study. Mol Autism. 2017;8:40. PubMed PMID: 28775825.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Balanced bifrontal transcranial direct current stimulation enhances working memory in adults with high-functioning autism: a sham-controlled crossover study. AU - van Steenburgh,J Jason, AU - Varvaris,Mark, AU - Schretlen,David J, AU - Vannorsdall,Tracy D, AU - Gordon,Barry, Y1 - 2017/07/28/ PY - 2016/11/02/received PY - 2017/06/16/accepted PY - 2017/8/5/entrez PY - 2017/8/5/pubmed PY - 2018/4/24/medline KW - Autism KW - Dorsolateral prefrontal cortex KW - Transcranial direct current stimulation KW - Working memory SP - 40 EP - 40 JF - Molecular autism JO - Mol Autism VL - 8 N2 - BACKGROUND: Working memory (WM) often is impaired in autism spectrum disorder (ASD). Such impairment may underlie core deficits in cognition and social functioning. Transcranial direct current stimulation (tDCS) has been shown to enhance WM in both healthy adults and clinical populations, but its efficacy in ASD is unknown. We predicted that bifrontal tDCS would improve WM performances of adults with high-functioning autism during active stimulation compared to sham stimulation and that such enhancement would generalize to an untrained task. METHODS: Twelve adults with high-functioning ASD engaged in a battery of WM tasks that included backward spatial span, backward digit span, spatial n-back and letter n-back. While engaged, 40 min of 1.5 mA bifrontal stimulation was applied over the left and the right dorsolateral prefrontal cortices (DLPFC). Using a single-blind crossover design, each participant received left anodal/right cathodal stimulation, right anodal/left cathodal stimulation, or sham stimulation, in randomized counterbalanced order on three separate days. Following tDCS, participants again engaged in letter and spatial n-back tasks before taking the Brief Test of Attention (BTA). We used repeated-measures ANOVA to compare overall performance on the WM battery as measured by a composite of z-scores for all five measures. Post hoc ANOVAs, t tests, Friedman's tests, and Wilcoxon signed-rank tests were used to measure the online and offline effects of tDCS and to assess performances on individual measures. RESULTS: Compared to sham stimulation, both left DLPFC anodal stimulation (t11 = 5.4, p = 0.0002) and right DLPFC anodal stimulation (t11 = 3.57, p = 0.004) improved overall WM performance. Left anodal stimulation (t11 = 3.9, p = 0.003) and right anodal stimulation (t11 = 2.7, p = 0.019) enhanced performances during stimulation. Enhancement transferred to an untrained task 50 min after right anodal stimulation (z11 = 2.263, p = 0.024). The tasks that showed the largest effects of active stimulation were spatial span backward (z11 = 2.39, p = 0.017) and BTA (z11 = 2.263, p = 0.024). CONCLUSIONS: In adults with high-functioning ASD, active bifrontal tDCS given during WM tasks appears to improve performance. TDCS benefits also transferred to an untrained task completed shortly after stimulation. These results suggest that tDCS can improve WM task performance and could reduce some core deficits of autism. TRIAL REGISTRATION: NCT01602263. SN - 2040-2392 UR - https://www.unboundmedicine.com/medline/citation/28775825/Balanced_bifrontal_transcranial_direct_current_stimulation_enhances_working_memory_in_adults_with_high_functioning_autism:_a_sham_controlled_crossover_study_ L2 - https://molecularautism.biomedcentral.com/articles/10.1186/s13229-017-0152-x DB - PRIME DP - Unbound Medicine ER -