tDCS for Cognitive Impairment Associated With Recent-onset Schizophrenia

Condition(s) studied

Investigational drug(s) / intervention(s)

left fronto-temporal transcranial Direct Current Stimulation (tDCS): The study intervention consists of ten 20-minutes sessions of active or sham tDCS. Sessions will be delivered twice daily and separated by at least 2 hours for 5 consecutive weekdays. The electric current will be generated by an electric stimulator (class IIa medical device). During the entire tDCS session, the subject is at "rest", comfortably seated in a chair in a quiet room. A clinician will be present for the entire session duration. The current will be applied via a pair of rubber electrodes (35 cm²) placed on the surface of the scalp. The anode will be placed over the left dorsolateral prefrontal cortex. The cathode will be placed over the left auditory cortex. The stimulation parameters will be set at 2-mA for 20 minutes, with a progressive increase during the first 30-sec and a progressive decrease during the last 30-sec of each session. The impedance of the applied current is monitored by the stimulator during each session.

Study summary

Background: In parallel to the traditional symptomatology, deficits in cognition (memory, attention, reasoning, social functioning) contribute significantly to disability and suffering in individuals with schizophrenia. Cognitive deficits have been closely linked to alterations in early auditory processes (EAP) that occur in auditory cortical areas. Preliminary evidence indicates that cognitive deficits in schizophrenia can be improved with a reliable and safe non-invasive brain stimulation technique called tDCS (transcranial Direct Current Stimulation). However, a significant proportion of patients derive no cognitive benefits after tDCS treatment. Further, the neurobiological mechanisms of cognitive changes after tDCS have been poorly explored in trials and are thus still unclear.

Method: The study is designed as a randomized, double-blind, 2-arm parallel-group, sham controlled, 4-centers trial. Sixty participants with recent-onset schizophrenia and cognitive impairment will be randomly allocated to receive either active (n=30) or sham (n=30) tDCS (20-min, 2-mA, 10 sessions during 5 consecutive weekdays). The anode will be placed over the left dorsolateral prefrontal cortex and the cathode over the left auditory cortex. Cognition, tolerance, symptoms, general outcome and EAP (measured with EEG and multimodal MRI) will be assessed prior to tDCS (baseline), after the 10 sessions, and at 1- and 3-month follow-up. The primary outcome will be the number of responders, defined as participants demonstrating a cognitive improvement ≥Z=0.5 from baseline on the MATRICS Consensus Cognitive Battery total score at 1-month follow-up. Additionally, we will measure how differences in EAP modulate individual cognitive benefits from active tDCS and whether there are changes in EAP measures in responders after active tDCS.

Discussion: Besides proposing a new fronto-temporal tDCS protocol by targeting the auditory cortical areas, we aim to conduct an RCT with follow-up assessments up to 3-months and a large sample size. In addition, this study will allow identifying and assessing the value of a wide range of neurobiological EAP measures for predicting and explaining cognitive deficits improvement after tDCS. The results of this trial will constitute a step toward the use of tDCS as a therapeutic tool for the treatment of cognitive impairment in recent-onset schizophrenia.

Eligibility

Primary outcome measure(s)

• Cognitive response — at 1-month follow-up
  Number of responders at 1-month after tDCS, defined as the proportion of patients demonstrating a cognitive improvement greater than or equal to Z=0.5 from baseline on the MATRICS Consensus Cognitive Battery total score (MCCB). The MCCB is a gold-standard standardized test battery to assess cognitive functions in patients with schizophrenia. This criterion has been used and validated in both antipsychotic and cognitive remediation trials in schizophrenia.

Trial sites (4)

More University Hospital, Grenoble trials in France

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