tDCS in Post-stroke Neglect Rehabilitation

Introduction Stroke is the main cause of disability in the world and its sequelae have a great impact in the functional independence and quality of life of patients and families. Unilateral spatial neglect is one of the most frequent cognitive deficits after stroke, and its maintenance is associated with poor functional outcome of the rehabilitation process. For many years clinical research has been conducted to develop new and effective rehabilitation strategies for neglect. Noninvasive brain stimulation (NIBS) techniques are important tools in this regard, and it should be considered as a therapeutic intervention used in combination with conventional neuropsychological approaches. Transcranial direct current stimulation (tDCS) is a noninvasive, safe, neurophysiological technique able to modulate cortical activity by inducing a weak electric current into the brain. The studies focused on neglect symptoms treatment by means of tDCS over the lesional and contralesional hemisphere have shown promising results and its combination with conventional neglect therapies may enhance treatment efficacy and speed the recovery. Objectives To improve neglect symptoms by reducing the pathological hyperactivity of the undamaged hemisphere after right medial cerebral artery stroke, through the application of multisite tDCS, and to validate a NIBS protocol for the enhancement of conventional neuropsychological rehabilitation outcome. Methods The sample will be composed by 30 patients with spatial neglect secondary to a ischemic stroke in the middle cerebral artery in subacute stage (3 to 12 months since the event). The patients will be randomly assigned to one experimental group (Active, Sham, and Control). The intervention protocol consists in a two weeks intervention (10 sessions, 45 min, Monday to Friday) of tDCS and neuropsychological rehabilitation applied concurrently. In each session a 20 min tDCS at 2 milliamps (m will be applied over P3 according to 10/20 EEG international system (cathodal) with return electrodes placed in C3,CP5,CP1,Pz,PO3,PO7,P7 (10/20 EEG). StarStim® tDCS 8 channels Multisite device will be used.

Inclusion Criteria: * Hemorrhagic or ischemic stroke in the right hemisphere. * Stroke 3 to 12 months since the event (regardless of whether or not they have received prior rehabilitation). * 18 to 99 years-old. * Neuroimaging study. * Absence of previous strokes. * Functional capacity that allows him/her to remain seated and active for one hour (Barthel Index score greater than 5 in the item of transfers between chair and bed; this item can be scored from 0 to 15, being 0 totally dependent and 15 totally independent). * Right-handed manual dominance * Neglect scores on at least two of the three tests administered for the assessment of visuospatial neglect. * Signature of informed consent by the patient or his/her legal guardian. Exclusion Criteria: * Dermatological problems (psoriasis, dermatitis on the scalp or face). * Presence of implants or metal parts in the head excluding fillings. * Pacemakers, medication pumps, stimulators (vagal, cerebral, transcutaneous), ventriculoperitoneal shunts or aneurysm clips. * Presence of previous strokes. * Neurological disease other than stroke described in the inclusion criteria. * Severe cognitive impairment assessed using the Mini-mental state examination (MMSE), excluding patients with scores under 24 (the score of MMSE are between 0 and 30, being 0 severe cognitive impairment and 30 no cognitive impairment). * Significant language difficulties that not allow proper understanding of activities or severely limit expression. * History of alcohol or drug abuse. * Moderate or severe active depression. * Uncontrolled medical problems (pathologies in acute phase without medical or pharmacological treatment with proven efficacy or pathologies with imminent life risk). * Pregnancy or suspected pregnancy that will be checked by pregnancy test at the beginning of the study in patients of childbearing age and with the recommendation of the use of contraceptive methods until the end of the intervention.