Assessing Repetitive Transcranial Magnetic Stimulation as a Treatment for Refractory Depression (rTMS)

Assessing Repetitive Transcranial Magnetic Stimulation as a Treatment for Refractory Depression

The hypothesis of this study was that transcranial magnetic stimulation (TMS) focused on hyperfunctional cerebral areas should be more effective in treating depressive symptoms than stimulations not taking into account the functional specificity of the patient. The goal was to compare the effects of "guided" TMS, using neuroimaging to guide TMS on dysfunctional cortical regions individually detected by neuroimaging, with "standard TMS", as used in most studies, over the left prefrontal cortex, and with sham TMS, in patients with resistant depression.

The objectives of the study were :

• To localize the site of lowest frontal activity in each patient with resistant depression, using PET to measure regional cerebral metabolic rates for glucose (rCMRGlu).
• To demonstrate that high-frequency TMS (10Hz) guided on that site is more effective than standard or sham TMS, in resistant depressed patients, using a doubled blind controlled procedure.
• To assess the effects of TMS on regional cerebral metabolism using rCMRGlu PET after 10 sessions of TMS treatments.

Depressed patients meeting DSM-IV criteria for Major Depressive Disorder, aged between 18 and 55, have been included. They met criteria for depression resistant to antidepressant drugs They were randomised in 3 groups: guided prefrontal TMS, standard left prefrontal and sham left prefrontal TMS.

rTMS was administered daily on working days, for two weeks. Ten stimuli per second (10Hz) were applied in 20 courses so that patients received 1600 stimuli per day. Guided TMS was on a prefrontal target corresponding to the highest statistically significant hyperfunctional cluster determined with rCMRGlu PET. Standard stimulation was left pre-frontal, 5 cm anterior to the optimal stimulation point of the abductor pollices brevis. Stimulation strength was chosen at 90% relative to motor threshold. Sham rTMS used a procedure identical to the real standard treatment, but using a sham coil.

Inclusion Criteria:

• Major depression (according to DSM-IV)resistant to at least two medical antidepressant treatment of different pharmacological action, prescribed for at least one month each at an effective dosage, without therapeutical result.
• Hospitalisation in the service of an investigator
• Informed consent signed

Exclusion Criteria:

• Presence of metallic parts inside the body (pace-maker, vascular clip, cardiac valve, prothesis...)
• Severe somatic or central nervous system disease
• Familial history of comitiality
• Pregnancy