Xinguang Yu

Objective This meta-analysis aimed at evaluating and comparing the efficacy of noninvasive brain stimulation (NIBS) techniques on the behavioral and psychological symptoms of dementia (BPSD). Methods An exhaustive literature retrieval was performed on PubMed, Embase, Cochrane Library, and Web of Science until October 2019. The primary outcome was the relative changes in BPSD severity scores immediately after NIBS and at the last follow-up visit. Subgroup analyses were conducted to compare the efficacy of repetitive transcranial magnetic stimulation (rTMS) and transcranial direct current stimulation (tDCS). Changes in the severity scores after NIBS were also analyzed with restriction to patients with Alzheimer’s disease (AD). Results Ten studies with 324 patients were included, out of which 7 studies involved patients with AD. The analysis results indicated that NIBS significantly improved the BPSD outcome immediately after stimulation (SMD, 0.31; 95% CI, 0.10–0.52; P = 0.005), but not at the last follow-up visit (0.15; − 0.11–0.41; 0.25). Our subgroup analyses suggested that the favorable effects of rTMS remained significant at the last follow-up visit (0.57; 0.18–0.96; 0.004). This discrepancy maybe caused by the continuously insignificant outcomes of tDCS on the whole data. The results for AD patients immediately after stimulation (0.37; 0.12–0.61; 0.003) and at the last follow-up visit (0.29; − 0.19–0.76; 0.24) were both largely similar to those in the whole patient group with dementia. Conclusions rTMS, rather than tDCS, was capable of persistently improving the BPSD at an early stage after treatment. More trials are warranted to confirm our results before the establishment of final conclusions.

Good outcomes have been reported in deep brain stimulation (DBS) for myoclonus-dystonia syndrome (M-D), a heritable disease characterized by childhood-onset myoclonic jerks and dystonia in the upper body. This meta-analysis was to evaluate the clinical outcomes consecutively, compare the stimulation targets, and identify potential prognostic factors. A systematic literature search was performed on PubMed, Web of Science, and Embase. The primary outcome was the percent improvement in Burke–Fahn-Marsden Dystonia Rating Scale movement (BFMDRS-M) scores for dystonia and Unified Myoclonus Rating Scale (UMRS) scores for myoclonus at the last follow-up visit. BFMDRS-disability scores of the patients were also summarized. Pearson correlation analyses were performed to identify the myoclonus and dystonia outcome predictors. Thirty-one studies reporting 71 patients were included. There were significant improvements in BFMDRS-M and BFMDRS-disability scores in each time category and at the last follow-up visit. Mean improvement (%) in UMRS was 79.5 ± 18.2, and 94.1% of the patients showed > 50% improvement in UMRS scores at the last follow-up visit. There was a significant trend toward improved myoclonus outcome with older age at onset and shorter disease duration. Most of the adverse events were mild and transient, and pallidal stimulation seemed to be better with respect to fewer stimulation-induced events. Based on the current data, DBS is effective for even the severe M-D. Surgery at an early stage may predict a better outcome. Although targets do not serve as the outcome predictors, pallidal stimulation may be preferred due to fewer stimulation-induced events.

Repetitive transcranial magnetic stimulation (rTMS) is a noninvasive brain stimulation technique for Alzheimer’s disease (AD). rTMS, with high- or low-frequency, is thought to enhance or inhibit the cortical activities, respectively. This meta-analysis of randomized controlled trials (RCTs) was to summarize the efficacy of the rTMS on the cognition of AD patients and to identify its potential influential factors.

Deep brain stimulation (DBS) is an effective intervention for Meige syndrome, a type of dystonia characterized by blepharospasm, facial, and oromandibular dystonia. This individual patient-level data meta-analysis was to identify the potential outcome predictors, compare the stimulation targets and summarize the efficacy of DBS for Meige syndrome. Three electronic databases (PubMed, Web of Science and Embase) were searched with no publication data restriction to identify studies regarding DBS for Meige syndrome. The primary outcome was the improvement in BFMDRS-M score. Pearson's correlation coefficients and a stepwise multivariate regression analysis were used to identify the potential prognostic factors. Twenty-three studies (115 patients, 94 with pallidal stimulation and 21 with subthalamic stimulation) were eligible. Patients showed significant improvement in Burke-Fahn-Marsden Dystonia Rating Scale movement (BFMDRS-M) (21.5 ± 11.0 vs 8.6 ± 6.9, P < 0.001) and disability (BFMDRS-D) (6.4 ± 5.1 vs 2.9 ± 2.4, P < 0.001) scores at the last follow-up visit (31.9 ± 30.7 months), compared with scores at baseline. Preoperative BFMDRS-M and BFMDRS-D scores were positively correlated with the relative changes in BFMDRS-M score at the last follow-up visit. On the stepwise multivariate regression, only the preoperative BFMDRS remained significant in the best predictive model. Based on the existing evidence, pallidal/subthalamic stimulation is an effective therapy for even the refractory Meige syndrome. Higher preoperative scores probably indicate larger improvement. Stimulation targets or other clinical factors do not constitute the outcome predictive factors.