In the present study, the investigators intend to investigate whether anodal transcranial direct current stimulation (tDCS) may be effective in reducing pain in chronic pain patients.

tDCS is a noninvasive brain stimulation technique that utilizes low amplitude direct currents applied via scalp electrodes to modulate the level of cortical excitability.Several studies have demonstrated that tDCS applied over the sensory-motor cortex has been able to decrease pain sensation and to increase pain threshold in healthy subjects and in chronic pain patients.

The aim of this study was to test whether daily sessions of anodal tDCS repeated for 5 consecutive days may be effective in reducing pain in a large number of chronic pain patients.

Patients will receive sham tDCS or real tDCS in a 5-day period of treatment in a randomized, sham controlled study. The participants will be divided to 2 groups of 50 each. One group will receive 5 days period of 20 min 2mA tDCS over the lt M1 and the other will receive sham stimulation. X week later the groups will switch to the other arm.

Pain will be measured using visual analog scale (VAS) for pain and the short form McGill questionnaire (SF-MPQ). Disability will be measured using the ( Pain Disability Index (PDI) of Life-54 scale (MSQoL-54). Depressive symptoms and anxiety will also be evaluated using the Center for Epidemiological Studies-Depression Scale and the State-trait Anxiety Inventory (STAI). Cognitive function will be mesured using minimental test. Evaluations will be performed at baseline, immediately after the end of treatment, and once a week during a 3-week follow-up period.

Inclusion Criteria:

• over 18
• chronic pain patients VAS > 4

Exclusion Criteria:

• pregnancy
• scalp lacerations
• History of seizures
• metal implants in the head
• heart pace maker