Silva Filho E.1, Mescouto K.1, Pegado R.1
1Universidade Federal do Rio Grande do Norte, FACISA, Santa Cruz, Brazil
Background: Stroke is a disease that has a great impact worldwide and is a leading cause of adult disability especially in developing countries. Effective cognitive treatments for post-stroke patients are still a main issue in daily clinical practice. The working memory (WM) is associated to temporary storage information, being responsible for many processes of comprehension, language, learning and consolidation of long term memory. A neuromodulatory technique such as Transcranial Direct Current Stimulation (tDCS) on the WM area might be a beneficial adjunct rehabilitation tool to stroke cognitive rehabilitation.
Purpose: The primary aim of this systematic review was to analyse if tDCS had an influence on the WM of post-stroke individuals.
Methods: Assessment of eligibility of articles was made by 2 independent researchers. It was searched the following databases: Cochrane Library via Wiley - CENTRAL, Pubmed, LILACS, SCIELO, Web of Science, Scopus, CINAHL and PEDro. In order to identify further studies, it was searched trials registration, reference lists and contacted authors if needed. The method used to analyze the risk of bias was proposed by Cochrane Collaboration. The inclusion criterias comprised of studies with patients with a diagnosis of stroke without gender restriction, having > 18 years of age, written in any language and year of publication that showed the effects of tDCS on post-stroke adults that used verbal and/or visuospatial WM as outcomes, without limiting the response time.
Results: Three articles were included in the qualitative synthesis with a total amount of 66 post-stroke patients. The interventions were made using the same area for stimulation (dorsolateral area of the prefrontal cortex) with 2mA current intensity and duration of 30 minutes. The verbal WM for intergroup and intragroup analysis showed improvements after intervention using anodic tDCS. The visuospatial WM for intragroup analysis also demonstrated significant improvements. However, for intergroup analysis, only anodic stimulation on the left side of temporal anterior lobe had any statistical differences after tDCS. The methodological variables analysed showed that the randomization, allocation concealment and bliding were not described or done satisfactorily in the articles.
Conclusion(s): The use of tDCS on post-stroke individuals showed improvements on the verbal and visuospatial WM after stimulation, but the methodological quality of the studies are questionable. Better designed studies that have a lower risk of bias are needed.
Implications: Although promissing, future reasearch should focus on investigating tDCS effectiveness on memory in post-stroke patients with better methodological studies designs.
Funding acknowledgements: None
Topic: Neurology: stroke
Ethics approval: Not applicable
All authors, affiliations and abstracts have been published as submitted.
