Effect of tDCS on Cognition, Symptoms in Chronic Schizophrenia Patients With Tardive Dyskinesia

Effect of tDCS on Cognition, Symptoms in Chronic Schizophrenia Patients With Tardive dyskinesia_a Randomized, Double-blind, Sham-controlled Trial

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).

This study is a randomized, double-blind, sham-controlled clinical trial. 60 patients with TD were randomly allocated to active (n=30) or sham tDCS groups (n=30). All patients received 2-mA anodal left/cathodal right prefrontal tDCS treatment (fifteen 30-minutes sessions: Monday to Friday once daily, every other week to do a group of treatment). Abnormal Involuntary Movements Scale (AIMS), Tardive Dyskinesia Rating Scale (TDRS), Assessment of Negative Symptoms(SANS), the Positive and Negative symptom scale(PANSS), and the Cambridge Neuropsychological Test Automatic Battery (CANTAB) were assessed in patients. All evaluations were scored at baseline, the end of 3rd weeks, 5th weeks, and 7th weeks. Side effects of tDCS were assessed with an experimenter-administered open-ended questionnaire during the whole experiment.

transcranial Direct Current Stimulation, Randomized Controlled Trial, Schizophrenia, Tardive Dyskinesia, Abnormal Involuntary Movements Scale, Tardive Dyskinesia Rating Scale, Cognition

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).

This study is a randomized, double-blind, sham-controlled clinical trial.All patients received 2-mA anodal left/cathodal right prefrontal tDCS treatment (fifteen 30-minutes sessions: Monday to Friday once daily, every other week to do a group of treatment). All evaluations were performed at baseline, the end of 3rd weeks, 5th weeks, and 7th weeks by 2 psychiatrists blinded to the treatment assigned. Inter-rater reliability was satisfactory(ka=0.86).

All patients received 2-mA anodal left/cathodal right prefrontal tDCS treatment (fifteen 30-minutes sessions: Monday to Friday once daily, every other week to do a group of treatment).

All patients received 2-mA anodal left/cathodal right prefrontal tDCS treatment (fifteen 30-minutes sessions: Monday to Friday once daily, every other week to do a group of treatment).

The primary outcome measure was the severity of TD symptoms, which was measured by the AIMS total score(the sum of items 1-7).The range for subscale scores(items1-7) is between 0-28 scores and the higher values represent a worse outcome.

The severity of TD symptoms were also measured by the total TDRS score and the orofacial dyskinesia subscale scores, trunk and limb dyskinesia subscale scores. The range for TDRS total score is between 44-264 scores and the orofacial dyskinesia subscale scores are between16-96 scores , the trunk and limb dyskinesia subscale scores are between 24-144 scores.The higher values represent a worse outcome.

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.

Negative symptoms were assessed with SANS. The range for SANS total scores is between 0-120 scores and the higher values represent a worse outcome.

Psychopathology was measured by the total PANSS score and the positive, negative, and general psychopathology subscale scores. The range for PANSS total score is between 30-210 scores and the positive subscale scores are between 7-49 scores and the negative subscale scores are between 7-49 scores and the general psychopathology total scores are between 16-112 scores.

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.

Inclusion Criteria: Right-handed; meeting the diagnosis of schizophrania; had been receiving antipsychotic drugs for at least 12 months; at least one AIMS item rated(moderate) or at least two AIMS items rated ≥2(mild); All patients volunteered to participate in this study. Exclusion Criteria: organic disorder that could cause movement disorders, mental retardation,and a history of substance dependence(except nicotine); with serious physical illness(e.g.severe cardiovascular diseases); with color blindness/weakness, stuttering, deafness.