Pragmatic Trial of Remote tDCS and Somatosensory Training for Phantom Limb Pain With Machine Learning to Predict Treatment Response

During tDCS, low amplitude direct currents are applied via scalp electrodes and penetrate the skull to enter the brain. Direct current will be transferred by a saline-soaked pair of surface sponge electrodes (35 cm2) and delivered by a specially developed, battery-driven, constant current stimulator with a maximum output of 10 mA.

The somatosensory training will be performed during the self-administration of tDCS, including 20 sessions over 4 weeks. Sessions will start with relaxation exercises using a body scan technique, whereby subjects in a relaxed state will be instructed to sequentially interchange their mind to different regions of the body while perceiving it and establishing contact with the body part. Subjects will be asked to concentrate on any feeling (kinetic, kinesthetic or exteroceptive) related to each body part. Phantom exercises will involve the use of imagined movements of the phantom limb. Therefore, patients will be asked to perform general exercises with their phantom limb. Exercises will include hip, knee, ankle, and toe movements.

Usual care includes pharmacological treatments, physical therapy, occupational therapy and/or behavioral therapy that the subject is receiving.