Marij Bär - Counseling en Coaching

We conducted a double-blind, placebo-controlled trial of rTMS in 55 patients for 2 weeks, with a 12-week follow up, using random effects regression analysis to correct for unbalanced data, a common problem in longitudinal medical research.

Methods and Materials

Subjects / design
This study was designed as a double-blind placebo-controlled study, conducted over a 4-year period from 1997 to 2001. All inpatients and outpatients who met the DSM-IV criteria for major depressive episode were included. Further inclusion criteria were age over 16 and a score of 20 or higher on the 17-item Hamilton Depression Rating Scale (HDRS). Exclusion criteria were a history of epilepsy and a medical disorder that would preclude the administration of rTMS (Wassermann, 1998). Psychotropic medication was accepted if the dosage of antidepressive medication had not been changed for 6 weeks, and if the dosage of benzodiazepines had not been changed for 2 weeks prior to inclusion. For details of the psychotropic medication received see table 1.
Antidepressive medication had to remain stable during the 14 weeks of the study. Written informed consent was obtained. The ethics committee of the hospital approved the protocol.
Prior to treatment, all patients were assessed with standard clinical, psychiatric, and laboratory tests. Trained medical practitioners rated depression at baseline with the HDRS. Ratings were repeated at weeks 1, 2, 4, 8, and 14, with weeks 1 and 2 being the actual weeks of treatment. Patients were randomly assigned to rTMS or sham condition. Only the neurophysiologist applying the magnetic stimulation knew the chosen condition. All other members of the medical staff, as well as the patients and the data manager were blind to the treatment modality. Only after entering of all data into the data file the code for Sham / rTMS was revealed. Thus this study was double blind and placebo-controlled.

Table 1. Psychotropic medication received during the study.
Some patients received more than one medication.
MAO = monoamine oxidase inhibitor, TCA = tricyclic antidepressant, SSRI = selective serotonine re-uptake inhibitor, rTMS = repetitive transcranial magnetic stimulation.

Procedure rTMS

Subjects received rTMS daily on 10 consecutive weekdays (five sessions per week). The Maglite™ with a round stimulating coil MC-125 (Dantec Medical A/S. Skovlunde, Denmark) for biphasic pulses was used. Stimulation parameters were 20 Hz, 20 trains of 2 seconds, 30 seconds between trains, and 80% motor threshold. Before the first session, the optimal motor point and stimulation threshold for activating the right thenar muscles were determined for each patient by applying a single stimulus on the left side of the scalp. The left dorsolateral prefrontal cortex (left DLPFC) stimulation site was defined as being 5 cm anterior to this optimal motor point, according to the technique of Pascual-Leone et al (1996). This site was marked. During the rTMS session, the coil was centered flat over the left DLPFC. The small hole in the center of the coil permitted exact positioning by visual control of the mark. The sham treatment was performed by angling the outer edge of the coil 45˚ with the inner edge resting on the vertex, thereby inducing a contraction of the scalp and face muscles.