Combining HD-tDCS and iTBS in Treating Negative Symptoms of Schizophrenia

Summary

Dysfunction of the dorsolateral prefrontal cortex (DLPFC) is central to the persistence of negative symptoms in schizophrenia. Both HD-tDCS and iTBS targeting the left DLPFC have shown therapeutic benefit. This trial will test the hypothesis that combining HD-tDCS with iTBS yields additive efficacy.

Conditions

• Negative Symptoms in Schizophrenia
• Brain Stimulation Intervention

Interventions

DEVICE

active iTBS followed by active HD-tDCS

The active iTBS sessions will be delivered using the Magstim Rapid2 stimulator. The iTBS protocol consists of 3-pulse 50-Hz bursts given every 200 ms (at 5 Hz) for 2 s at 8-s intervals for 60 cycles. A 2-s train of iTBS will be repeated every 10 s for a total of 1800 pulses per session. The intensity of stimulation will be set at 80% resting motor threshold (RMT). The target will be the left DLPFC with the coil centered at the MNI coordinate \[-38, 44, 26\] calculated from T1-weighted MRI. The active HD-tDCS will be applied by NeuroConn DC Stimulator Plus. The central anode will be placed over the International 10-20 electrode position F3 and the return peripheral electrodes placed at Fp1, Fz, C3 and F7. Stimulation session will be applied at an intensity of 2 mA, 8-sec fade in and 5-sec fade out, for 20 min. During each session, the subject has to perform a computerized working memory task (i.e., 2-back task). The two times daily sessions will be separated by at least 2 hours.

DEVICE

active iTBS followed by sham HD-tDCS

The active iTBS sessions will be delivered using the Magstim Rapid2 stimulator. The iTBS protocol consists of 3-pulse 50-Hz bursts given every 200 ms (at 5 Hz) for 2 s at 8-s intervals for 60 cycles. A 2-s train of iTBS will be repeated every 10 s for a total of 1800 pulses per session. The intensity of stimulation will be set at 80% resting motor threshold (RMT). The target is the left DLPFC with the coil centered at the MNI coordinate \[-38, 44, 26\] calculated from T1-weighted MRI. In the sham HD-tDCS stimulation, short continuous currents without neuromodulatory effects will be applied to mimic real-stimulation sensations. Specifically, sham stimulation will deliver 40-sec, 2 mA normal-like stimulation, followed by a tiny current pulse (110 μA over 15 ms) for impedance control taking place every 550 ms for the remaining time. The other procedure is the same as the active HD-tDCS stimulation.

DEVICE

sham iTBS followed by active HD-tDCS

In the sham iTBS condition, the patients receive the same iTBS regimen and exact positioning of the coil but stimulations will be delivered using a commercial identical looking figure 8 sham coil (Magstim D70 Air film sham coil) that can produce a similar sound and sensation. In the active HD-tDCS condition, stimulation will be applied by a battery-operated device (NeuroConn DC Stimulator Plus) via 5 carbon rubber electrodes (1 cm radius, high-definition 4 × 1 rings configuration). To target the left DLPFC, the central electrode (anode) will be placed over International 10-20 electrode position F3, with return peripheral electrodes at Fp1, Fz, C3 and F7. Stimulation will be applied at an intensity of 2 milliamp (mA), 8-sec fade in and 5-sec fade out, for 20 min. During each session, the subject has to perform a computerized working memory task (i.e., 2-back task). The two times daily sessions will be separated by at least 2 hours.

DEVICE

sham iTBS followed by sham HD-tDCS

In the sham iTBS condition, patients receive the same iTBS regimen and exact positioning of the coil but stimulations will be delivered using a commercial identical looking figure 8 sham coil (Magstim D70 Air film sham coil) that can produce a similar sound and sensation. In the sham HD-tDCS condition, short continuous currents without neuromodulatory effects will be applied to mimic real-stimulation sensations. Specifically, sham stimulation will deliver 40-sec, 2 mA normal-like stimulation, followed by a tiny current pulse (110 μA over 15 ms) for impedance control taking place every 550 ms for the remaining time. The other procedure is the same as the active HD-tDCS stimulation.

Sponsors & Collaborators

• National Science and Technology Council, Taiwan

  collaborator OTHER_GOV

• Tri-Service General Hospital (TSGH)

  lead OTHER

Principal Investigators

• Hsin-An Chang, M.D. · Tri-Service General Hospital (TSGH)

Study Design

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

TRIPLE

Model

PARALLEL

Eligibility

Min Age

18 Years

Max Age

65 Years

Sex

ALL

Healthy Volunteers

No

Timeline & Regulatory

Start

2024-05-06

Primary Completion

2027-12-31

Completion

2028-03-01

Countries

• Taiwan

Study Locations