Noninvasive Brain Stimulations for Unilateral Spatial Neglect after Stroke: A Systematic Review and Meta-Analysis of Randomized and Nonrandomized Controlled Trials

Hindawi Neural Plasticity Volume 2018, Article ID 1638763, 25 pages https://doi.org/10.1155/2018/1638763 Review Article Noninvasive Brain Stimulations for Unilateral Spatial Neglect after Stroke: A Systematic Review and Meta-Analysis of Randomized and Nonrandomized Controlled Trials Flávio Taira Kashiwagi,1 Regina El Dib,2 Huda Gomaa,3 Nermeen Gawish,3 Erica Aranha Suzumura,4 Taís Regina da Silva,1 Fernanda Cristina Winckler,1 Juli Thomaz de Souza,2 Adriana Bastos Conforto ,5 Gustavo José Luvizutto ,6 and Rodrigo Bazan1 1 Neurology Department, Botucatu Medical School, Universidade Estadual Paulista (UNESP), Botucatu, SP, Brazil Science and Technology Institute, Universidade Estadual Paulista (UNESP), São José dos Campos, SP, Brazil 3 Department of Pharmacy, Tanta Chest Hospital, Tanta, Egypt 4 Research Institute, Hospital do Coração (HCor), São Paulo, SP, Brazil 5 Neurostimulation Laboratory, University of São Paulo (USP), São Paulo, SP, Brazil 6 Department of Applied Physical Therapy, Federal University of Triângulo Mineiro (UFTM), Uberaba, MG, Brazil 2 Correspondence should be addressed to Gustavo José Luvizutto; Received 7 September 2017; Accepted 15 April 2018; Published 28 June 2018 Academic Editor: Michele Fornaro Copyright © 2018 Flávio Taira Kashiwagi et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Background. Unilateral spatial neglect (USN) is the most frequent perceptual disorder after stroke. Noninvasive brain stimulation (NIBS) is a tool that has been used in the rehabilitation process to modify cortical excitability and improve perception and functional capacity. Objective. To assess the impact of NIBS on USN after stroke. Methods. An extensive search was conducted up to July 2016. Studies were selected if they were controlled and noncontrolled trials examining transcranial direct current stimulation (tDCS), repetitive transcranial magnetic stimulation (rTMS), and theta burst stimulation (TBS) in USN after stroke, with outcomes measured by standardized USN and functional tests. Results. Twelve RCTs (273 participants) and 4 non-RCTs (94 participants) proved eligible. We observed a benefit in overall USN measured by the line bisection test with NIBS in comparison to sham (SMD −2.35, 95% CI −3.72, −0.98; p = 0 0001); the rTMS yielded results that were consistent with the overall meta-analysis (SMD −2.82, 95% CI −3.66, −1.98; p = 0 09). The rTMS compared with sham also suggested a benefit in overall USN measured by Motor-Free Visual Perception Test at both 1 Hz (SMD 1.46, 95% CI 0.73, 2.20; p < 0 0001) and 10 Hz (SMD 1.19, 95% CI 0.48, 1.89; p = 0 54). There was also a benefit in overall USN measured by Albert’s test and the line crossing test with 1 Hz rTMS compared to sham (SMD 2.04, 95% CI 1.14, 2.95; p < 0 0001). Conclusions. The results suggest a benefit of NIBS on overall USN, and we conclude that rTMS is more efficacious compared to sham for USN after stroke. 1. Background Stroke is the second leading cause of death worldwide and the primary cause of chronic disability in adults [1]. In the United States, it is the fourth leading cause of death overall [2]. Among people who survive a stroke, unilateral spatial neglect (USN) is the most frequent disorder for right hemisphere lesions [3]. The incidence of USN varies widely from 10% to 82% [4, 5]. USN is characterized by the inability to report or respond to people or objects presented on the side contralateral to the lesioned side of the brain and has been associated 2 with poor functional outcomes and long stays in hospitals and rehabilitation centers [6]. Pharmacological interventions such as dopamine and noradrenergic agonists or procholinergic treatment have been used in people affected by USN after stroke, but the evidence derived from a Cochrane systematic review that included only two available RCTs was very low and inconclusive [7]. Other nonpharmacological rehabilitation techniques have been explored for USN with the aim to facilitate the recovery of perception and behavior, which include right half-field eye-patching [8], mirror therapy [9], prism adaptation [10], left-hand somatosensory stimulation with visual scanning training [11], contralateral transcutaneous electrical nerve stimulation and optokinetic stimulation [12], trunk rotation [13], repetitive transcranial magnetic stimulation [14], galvanic vestibular stimulation [15], and dressing practice [16]. However, their results do not support the use of these techniques in isolation for improvement of secondary outcomes such as performance and sensorimotor functions, activities of daily living (ADLs), or quality of life [9, 14, 17]. Noninvasive brain stimulations (transcranial direct current stimulation (tDCS) and repetitive transcranial magnetic stimulation (rTMS)) have already shown their ability to modify cortical excitability [18]. tDCS is a noninvasive method used to modulate cortical excitability by applying a direct current to the brain that is less expensive than repetitive transcranial magnetic stimulation (rTMS). The latter is an electric current that creates magnetic fields that penetrate the brain and can modulate cortical excitability by decreasing or increasing it and potentially improve perceptual and cognitive abilities [19, 20]. A previous Cochrane systematic review summarized results about the effects of tDCS versus control (sham/any other intervention) on activities of daily living (ADLs) among stroke survivors. The authors included 32 randomized controlled trials (RCTs) and concluded that tDCS might enhance ADLs, but upper and lower limb function, muscle strength, and cognitive abilities should be further explored [21]. Another Cochrane systematic review assessed the efficacy of repetitive transcranial magnetic stimulation (rTMS) compared to sham therapy or no therapy for improving function in people with stroke. The 19 included trials showed that rTMS was not associated with a significant increase in ADLs or in motor function; therefore, the authors do not support the use of rTMS for the treatment of stroke, and they plan to complete further trials to confirm their findings [22]. Previous reviews were, however, limited in that they did not include non-RCT studies nor did they evaluate the newest noninvasive brain stimulation—theta burst. We therefore conducted a systematic review of RCT and non-RCT studies that assessed the impact of tDCS, rTMS, and TBS for unilateral spatial neglect after stroke. 2. Methods We adhered to methods described in the Cochrane Handbook for Intervention Reviews [23]. Our reporting also adheres to the Preferred Reporting Items for Systematic Neural Plasticity Reviews and Meta-Analyses (PRISMA) [24] and MetaAnalysis of Observational Studies in Epidemiology (MOOSE) statements [25]. 2.1. Eligibility Criteria. The eligibility cri (...truncated)