Comparison of Anti-craving Efficacy of Right and Left Prefrontal High Frequency rTMS in Alcohol Dependence: a Randomized Double-blind Study

The patients clinically diagnosed as Alcohol dependence syndrome (F 10.24) according to ICD-10 DCR, fulfilling the inclusion and exclusion criteria will be taken up for the study. A detailed physical examination will be done to rule out any major medical or neurological disease. Written informed consent will be taken after explaining the objectives and procedure of the study in detail. To ensure that the patients selected are right handed, Handedness Preference Schedule will be applied. Socio-demographic data will be collected. Baseline SADQ-C and CIWA-Ar will be administered to determine the severity of alcohol dependence and the intensity of withdrawal symptoms respectively. When the CIWA-Ar score becomes ≤ 10, then they will be taken up for rTMS application. For these patients baseline ACQ-NOW will be administered to measure the baseline craving. Patients will be randomly allocated into two groups using randomization table. The first group will receive active rTMS of the right pre-frontal cortex; the second group will be administered active rTMS of the left pre-frontal cortex. Each patient will receive rTMS sessions 5 days a week for 2 weeks. ACQ-NOW score will again be documented in both the groups after the last rTMS session to observe the changes in craving parameters. The rating will be done by one of the authors who will be blind to the nature of rTMS stimulation being administered to the patients.

The motor threshold (MT) for the left abductor pollicis brevis will be determined by a figure of 8 shaped coil, using the Rossini-Rothwell method. MT will be defined as the lowest intensity, which produces 5 motor evoked potential (MEP) responses of at least 50 µV in 10 trials. The prefrontal cortex rTMS stimulation site will be determined by measuring 5 cm anterior and in a parasagittal line from the point of maximum stimulation of left abductor pollicis muscle. Ten active rTMS treatments will be administered at 10 Hz frequency, over right or left prefrontal cortex at 110% of MT for duration of 5 seconds and 20 trains per session, with the coil-angled tangentially to the head.