Transcranial Direct Current Stimulation as Treatment for Auditory Hallucinations (tDCS)

Transcranial Direct Current Stimulation as Treatment for Auditory Hallucinations A Sham-controlled Trial

The present study aims to examine the efficacy of transcranial direct current stimulation on the severity of auditory hallucinations.

Rationale: Auditory hallucinations (AH) are a symptom of several psychiatric disorders, such as schizophrenia. In the majority of patients, these AH respond well to antipsychotic medication. Yet, a significant minority continues to experience frequent AH despite optimal pharmacotherapy and AH severely decrease quality of life in these patients. The number of alternative treatment options for this medication resistant group is currently low and most of them focus on coping with the hallucinations. Transcranial direct current stimulation (tDCS), in contrast, is a safe, non-invasive technique that is able to directly influence cortical excitability through the application of very low electric currents. This technique has only a few transient side-effects and is cheap and portable. To date, only one randomized controlled trial has been published, suggesting high efficacy of tDCS for the treatment of medication-resistant AH in a relatively small sample. We aim to replicate and extend these findings by investigating the efficacy of this technique in a larger sample.

Psychotic Disorders, Mood Disorders, Personality Disorders, Stress Disorders, Post-Traumatic, Hearing Disorders

The anodal electrode will be placed with the middle of the electrode over a point midway between F3 and FP1 (left prefrontal cortex: dorsolateral prefrontal cortex and the cathodal electrode located over a point midway between T3 and P3 (left temporo-parietal junction). Stimulation will consist of 2 mA for 20 minutes per session.

The anodal electrode will be placed with the middle of the electrode over a point midway between F3 and FP1 (left prefrontal cortex: dorsolateral prefrontal cortex and the cathodal electrode located over a point midway between T3 and P3 (left temporo-parietal junction). In the sham condition, after 40 seconds of real stimulation (2 mA), only a small current pulse will occur every 550 msec (110 mA over 15 msec) through the remainder of the 20-minute period.

The primary outcome is the change in the severity of the hallucinations before and after the treatment, as experienced by the participant, measured with the Auditory Hallucination Rating Scale (AHRS)

Changes in severity of hallucinations as assessed by the hallucination change scale (HCS)questionnaire

Changes of positive, negative and disorganized symptomatology as assessed by the positive and negative syndrome scale (PANSS)

The presence and severity of side-effects will be monitored using the tDCS adverse effects questionnaire

Inclusion Criteria: Age over 18. Frequent auditory hallucinations (at least 5 times a week). Patients are on a stable dose of antipsychotic medication (which can also be zero) for at least 2 weeks Mentally competent for informed consent. Provided informed consent. Exclusion Criteria: Metal objects in or around the head that cannot be removed (i.e. cochlear implant, surgical clips, piercing) History of seizures, or a history of seizures in first-degree relatives. History of eye trauma with a metal object or professional metal workers History of brain surgery, brain infarction, head trauma, cerebrovascular accident, broken skull, brain tumour, heart disease, cardiac pacemaker. Skin disease on the scalp on the position of the tDCS electrodes Coercive treatment based on a judicial ruling Pregnancy in female patients

Koops S, Blom JD, Bouachmir O, Slot MI, Neggers B, Sommer IE. Treating auditory hallucinations with transcranial direct current stimulation in a double-blind, randomized trial. Schizophr Res. 2018 Nov;201:329-336. doi: 10.1016/j.schres.2018.06.010. Epub 2018 Jun 20.