The Effects of tDCS on Auditory Hallucination, Insight, Neurocognitive Function and HRV in Patients With Schizophrenia

Tri-Service General Hospital

Status: Completed

Conditions: Auditory Hallucination, Verbal; Quality of Life; Schizophrenia; Autonomic Imbalance; Schizoaffective Disorder; Psychosocial Impairment; Neurocognitive Dysfunction

Treatments: Device: tDCS

Study type: Interventional

Funder types: Other

Identifiers

NCT03388554

2-103-03-002-2

Details and patient eligibility

About

The study aimed to investigate whether transcranial direct current stimulation could modify auditory hallucination, insight, neurocognitive function, heart rate variability, psychosocial functioning and quality of life in patients with schizophrenia.

Full description

Transcranial direct current stimulation (tDCS), a novel, non-invasive and safe neuro-modulating technique, has been developed as a new therapeutic option for neuropsychiatric disorders. It encompasses the induction of a relatively weak constant current flow through the cerebral cortex via scalp electrodes. Dependent on stimulation polarity, this results in a modulation of cortical excitability and spontaneous neural activity. The technique was established in the 1950s and 1960s primarily in animals. In these early studies it was shown that subthreshold DC stimulation increases spontaneous neuronal activity if the anode is placed above or within the cortex, while exposure to cathodal polarity results in reduced activity. This is caused by a subthreshold membrane depolarization by anodal and a hyperpolarization by cathodal stimulation. It was demonstrated in humans that the after-effects of tDCS depend on modifications of NMDA receptor-efficacy. The after-effects of tDCS are blocked by the NMDA receptor antagonist dextromethorphan, and prolonged by the partial NMDA receptor-agonist D-cycloserine. This tDCS polarity-dependent alteration of NMDA receptor function seems to be initiated by the respective membrane potential shift and probably by the accompanying cortical activity modification,because it is prevented by the sodium channel blocker carbamazepine. Intraneuronal calcium concentration also contributes, because calcium channel antagonists eliminate the excitability-enhancing aftereffects of anodal tDCS. Recently, tDCS has been found to improve psychopathological symptoms (auditory hallucination in particular), cognitive deficits and insight of schizophrenia and also strengthen cardiac autonomic function in healthy subjects. Further replication studies are needed.

The study aimed to investigate whether transcranial direct current stimulation could modify auditory hallucination, insight, neurocognitive function, heart rate variability, psychosocial functioning and quality of life in patients with schizophrenia.

Study design: randomized double-blind, sham-controlled study design.

Participants: 60 patients having a diagnosis of schizophrenia or schizoaffective with refractory auditory verbal hallucinations (defined as the persistence of daily auditory verbal hallucinations without remission in spite of antipsychotic medications at an adequate dosage for at least 3 months), aged 20-65 years.

Others: see Arms and Interventions, Eligibility Criteria or Outcome Measures.

Enrollment: 60 patients

Sex: All

Ages: 20 to 65 years old

Volunteers: No Healthy Volunteers

Inclusion criteria

• Patients who met DSM-IV-TR criteria for schizophrenia or schizoaffective disorder were included in the study. All these patients showed refractory auditory verbal hallucinations,which are defined as the persistence of daily auditory verbal hallucinations without remission in spite of antipsychotic medications at an adequate dosage for at least 3 months.

Exclusion criteria

1. Pregnancy or breastfeeding.
2. Having epilepsy, severe physical illness, any current psychiatric comorbidity or history of substance dependence.
3. Having contraindications for transcranial electrical/magnetic stimulation.
4. Having intracranial metal foreign bodies.
5. Having a history of intracranial neoplasms or surgery, or a history of severe head injuries or cerebrovascular diseases.

Trial design

Primary purpose: Treatment

Allocation: Randomized

Interventional model: Parallel Assignment

Masking: Double Blind

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60 participants in 2 patient groups

Active tDCS

Active Comparator group

Description:

Direct current (DC) generated by a DC stimulator (Eldith DC stimulator: www. neuroconn.de/dc-stimulator_plus_en/) was bilaterally delivered through a pair of saline-soaked surface sponge electrodes (35 square centimeter). The anode was placed with the middle of the electrode over a point midway between F3 and FP1 (left dorsolateral prefrontal cortex and left prefrontal cortex). The cathode was located over a point midway between T3 and P3 (left temporo-parietal junction). Stimulation was applied at an intensity of 2 mA for 20 min, twice-daily on 5 consecutive weekdays. The twice daily sessions were separated by at least 3 hours. All patients in the active tDCS group were maintained on their antipsychotic medications throughout the study period.

Treatment:

Device: tDCS

Sham tDCS

Sham Comparator group

Description:

In sham stimulation, the current was turned on for 30 sec and then ramped down to 0 mA. All patients in the sham tDCS group were maintained on their antipsychotic medications throughout the study period.

Treatment:

Device: tDCS