Effect of tDCS on Cognition, Symptoms in Chronic Schizophrenia Patients With Tardive dyskinesia_a Randomized, Double-blind, Sham-controlled Trial
Phase: NA
Conditions: Tardive Dyskinesia
Sponsor: Suzhou Psychiatric Hospital

 
Effect of tDCS on Cognition, Symptoms in Chronic Schizophrenia 
Patients With Tardive Dyskinesia 
 
 
 
NCT03497013 
August 11, 2020 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

Study Protocol and Statistical Analysis Plan 
1.Objective 
The aim of the study was to evaluate the efficacy, safety, and cognitive function of transcranial 
direct current stimulation (tDCS) in chronic schizophrenia patients with tardive dyskinesia (TD). 
2.Methods 
2.1. Subjects 
Between July 2017 and August 2020, 64 schizophrenic inpatients with TD were recruited from 
four different psychiatric hospitals, in mainland China. All of the subjects satisfied the following 
inclusion criteria: (1) aged from 18 to 70 years old; (2) clinical diagnosis of schizophrenia according 
to the criteria of Diagnostic and Statistical Manual of Mental Disorder, Fourth Edition (DSM-IV) 
and had been receiving antipsychotic drugs for at least 12 months; (3) diagnosis of TD based on the 
Schooler-Kane criteria, that is, at least one AIMS item rated (moderate) or at least two AIMS items 
rated ≥2 (mild), confirmed independently by 2 trained psychiatrists; (4) right-handed; (5) all patients 
volunteered to participate in this study. The exclusion criteria included (1) organic disorder that 
could cause movement disorders, mental retardation, and a history of substance dependence (except 
nicotine); (2) with serious physical illness (e.g. severe cardiovascular diseases); (3) with color 
blindness/weakness, stuttering, deafness. 
The patients were screened and given a complete clinical evaluation, including medical and 
neurologic examinations and laboratory tests, before they were included in the study. The study was 
approved by the Institute Review Board Committees. Written informed consent was obtained from 
the subjects prior to entry after they had been provided with a detailed explanation of the study. The 
trial was registered with ClinicalTrials.gov (NCT03497013). 
2.2. Procedures 
2.2.1. Overall design 
This study is a randomized, double-blind, sham-controlled clinical trial. Patients with TD were 
randomly allocated to active or sham tDCS groups by computer software based on a simple 
randomization method. All patients received 15 tDCS sessions. The participants would not know 
the tDCS status. The assessors for clinical outcomes would be blinded to the randomization status. 
The person who perform the intervention would not know the assessment results. 
2.2.2. transcranial Direct Current Stimulation (tDCS)  

tDCS is a Transcranial Electrical Stimulation (tES) technique that delivered by Soterix Medical 
1×1 Low-Intensity Transcranial Electrical Stimiulator (tES) Model 2001. It sends a small current 
across the scalp to modulate brain function. All patients received 2-mA anodal left dorsolateral 
prefrontal cortex/cathode right contralateral supraorbital area tDCS treatment (fifteen 30-minutes 
sessions: Monday to Friday once daily, every other week to do a group of treatment). Electrodes are 
encased with 5×7 cm sponges and moistened with saline (0.9% NaCl). For sham stimulation, the 
current will stop after 30 seconds from the start of stimulation. In this way, the patients would 
experience the same initial sensation of slight tingling and it is a blinding method considered reliable 
for several previous studies. 
2.2.3. Primary outcomes 
The primary outcome measure was the severity of TD symptoms, which was measured by the 
Abnormal Involuntary Movements Scale (AIMS) and Tardive Dyskinesia Rating Scale (TDRS). All 
evaluations were scored at baseline, the end of 3rd weeks, 5th weeks, and 7th weeks. 
2.2.4. Other clinical assessments 
Side effects of tDCS were assessed with an experimenter-administered open-ended 
questionnaire during the whole experiment. The questionnaire contained rating scales regarding the 
presence and severity of headache, difficulties in concentrating, acute mood changes, visual 
perceptual changes and any discomforting sensation like pain, tingling, itching or burning under the 
electrodes.  
Each patient was given a series of computerized tests from the Cambridge Neuropsychological 
Test Automated Battery. The language-independent tests and touch screen technology deliver rapid 
and non-invasive cognitive assessment. Executive and memory function were assessed with the 
following three tasks: The Pattern Recognition Memory (PRM), Intra/Extradimensional Set Shift 
(IED), and Spatial Working Memory.  
Negative symptoms were assessed with the scale for assessment of Negative Symptoms (SANS) 
and Psychopathology was measured by the Positive and Negative symptom scale (PANSS). These 
assessments were performed at baseline, the end of 3rd weeks, 5th weeks, and 7th weeks. 
2.3. Statistical analysis 
The entire statistical analysis was performed using the Statistical Package for Social Sciences 
(SPSS), version 23.0. The Kolmogorov-Smirnov nonparametric test was used to test the normality 

of continuous variables. The continuous variables were described using summary statistics, such as 
the means and standard deviations. The categorical variables were described using frequencies and 
percentages. The baseline characteristics of each group were compared using a t test for the 
continuous variables and the 2 test for the categorical variables. Repeated-measures analysis of 
variance (ANOVA) was used to analysis the repeated measurement data. P＜0.05 was considered 
statistically significant.