title: A meta-analysis of site-specific effects of cathodal transcranial direct current stimulation on sensory perception and pain.
abstract: The primary aim of our meta-analysis was to evaluate the effects of cathodal transcranial direct current stimulation (c-tDCS) on sensory and pain thresholds (STh and PTh) in healthy individuals and pain level (PL) in patients with chronic pain. Electronic databases were searched for c-tDCS studies. Methodological quality was evaluated using the PEDro and Downs and Black (D&B) assessment tools. C-tDCS of the primary motor cortex (S1) increases both STh (P<0.001, effect size of 26.84%) and PTh (P<0.001, effect size of 11.62%). In addition, c-tDCS over M1 led to STh increase (P<0.005, effect size of 30.44%). Likewise, PL decreased significantly in the patient group following application of c-tDCS. The small number of studies precluded subgroup analysis. Nevertheless, meta-analysis showed that in all groups (except c-tDCS of S1) active c-tDCS and sham stimulation produced significant differences in STh/PTh in healthy and PL in patient group. This review provides evidence for the site-specific effectiveness of c-tDCS in increasing STh/PTh in healthy individuals and decreasing PL in patients with chronic pain. However, due to small sample sizes in the included studies, our results should be interpreted with caution. Given that the level of blinding was not considered in the inclusion criteria, the results of the current study should be interpreted with caution.
authors.affiliation: Department of Physiotherapy, School of Primary Health Care, Faculty of Medicine, Nursing and Health Sciences, Monash University, Melbourne, Australia.
authors.forename: Bita
authors.initials: B
authors.lastname: Vaseghi
authors.affiliation: Department of Medicine, Royal Melbourne Hospital, The University of Melbourne, Melbourne, Australia.
authors.forename: Maryam
authors.initials: M
authors.lastname: Zoghi
authors.affiliation: Department of Physiotherapy, School of Primary Health Care, Faculty of Medicine, Nursing and Health Sciences, Monash University, Melbourne, Australia.
authors.forename: Shapour
authors.initials: S
authors.lastname: Jaberzadeh
mesh_terms: D000328:Adult; D059350:Chronic Pain / Q000175:diagnosis; D006801:Humans; D010146:Pain / Q000175:diagnosis*; D017288:Pain Threshold; D012677:Sensation / Q000502:physiology*; D065908:Transcranial Direct Current Stimulation / Q000009:adverse effects*; D055815:Young Adult