Cognitive effects of transcranial direct current stimulation combined with working memory training in fibromyalgia: a randomized clinical trial

Vinicius Souza Dos Souza Dos Santos,Wolnei Caumo,Júlia Schirmer Saldanha,Maxciel Zortea,Iraci Lucena Da Silva Torres,Felipe Fregni,Sandra Da Conceição Ribeiro De Carvalho,Cátia Cilene Dos Santos Naziazeno,António Jorge Da Costa Leite,Prisla Ücker Calvetti,Andressa De Souza,Rael Lopes Alves

doi:10.1038/s41598-018-30127-z

Abstract

Cognitive dysfunction in fibromyalgia has been reported, especially memory. Anodal transcranial direct current stimulation (tDCS) over the dorsolateral prefrontal cortex (DLPFC) has been effective in enhancing this function. We tested the effects of eight sessions of tDCS and cognitive training on immediate and delayed memory, verbal fluency and working memory and its association with brain-derived neurotrophic factor (BDNF) levels. Forty females with fibromyalgia were randomized to receive eight sessions of active or sham tDCS. Anodal stimulation (2 mA) was applied over the DLPFC and online combined with a working memory training (WMT) for 20 minutes. Pre and post-treatment neurocognitive tests were administered. Data analysis on deltas considering years of education and BDNF as covariates, indicated active-tDCS + WMT significantly increased immediate memory indexed by Rey Auditory Verbal Learning Test score when compared to sham. This effect was dependent on basal BDNF levels. In addition, the model showed active stimulation increased orthographic and semantic verbal fluency scores (Controlled Oral Word Association Test) and short-term memory (Forward Digit Span). The combination of both techniques seemed to produce effects on specific cognitive functions related to short-term and long-term episodic memory and executive functions, which has clinical relevance for top-down treatment approaches in FM.

Highlights

Cognitive dysfunction in fibromyalgia has been reported, especially memory
Immediate and delayed recall of episodic memory assessed with the Rey Auditory-Verbal Learning Test (RAVLT), orthographic and semantic category verbal fluency assessed with the Controlled Oral Word Association Test (COWAT), the Paced Auditory Serial Addiction Test (PASAT) and short-term and working memory (WM) assessed with the Forward (FDS) and Backward Digit Span (BDS) were compared between treatment groups
The present study aimed to test if a treatment transcranial direct current stimulation (tDCS) coupled with a WM cognitive task would have additive effects that benefit memory, attention and executive functions for patients with FM when compared to cognitive training alone

Summary

Introduction

Cognitive dysfunction in fibromyalgia has been reported, especially memory. Anodal transcranial direct current stimulation (tDCS) over the dorsolateral prefrontal cortex (DLPFC) has been effective in enhancing this function. Data analysis on deltas considering years of education and BDNF as covariates, indicated active-tDCS + WMT significantly increased immediate memory indexed by Rey Auditory Verbal Learning Test score when compared to sham. This effect was dependent on basal BDNF levels. The model showed active stimulation increased orthographic and semantic verbal fluency scores (Controlled Oral Word Association Test) and short-term memory (Forward Digit Span) The combination of both techniques seemed to produce effects on specific cognitive functions related to short-term and long-term episodic memory and executive functions, which has clinical relevance for top-down treatment approaches in FM. Multiples sessions of this combined treatment may have advantages over a singular session

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