The Effects of tDCS on Auditory Hallucination, Insight, Neurocognitive Function and HRV in Patients With Schizophrenia
Condition: Schizophrenia; Schizoaffective Disorder; Auditory Hallucination, Verbal; Neurocognitive Dysfunction; Autonomic Imbalance; Psychosocial Impairment; Quality of Life
MeSH terms: Hallucinations; Schizophrenia; Psychotic Disorders; Cognitive Dysfunction
Study type: Interventional

Summary: 
      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.
    

Detailed 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.
    

Intervention name(s): tDCS
Intervention type(s): Device
Allocation: Randomized
Intervention model: Parallel Assignment
Intervention model 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.
Masking: Double (Participant, Outcomes Assessor)
Primary purpose: Treatment