TRANSCRANIAL DIRECT CURRENT STIMULATION (t-DCS) AS ADD-ON TO NEUROREHABILITATION OF PISA SYNDROME IN PARKINSON’S DISEASE: A RANDOMIZED CONTROLLED TRIAL

Background: Pisa Syndrome (PS) is a lateral trunk flexion frequently associated to Parkinson’s disease (PD). The management of PS is still a challenge for the physicians, because it poorly responds to the anti-parkinsonian drugs, and the improvement achieved with neurorehabilitation or botulinum toxin injections tends to fade in 6 months or less. Transcranial direct current stimulation (t-DCS) is a non-invasive neuromodulation technique, which showed promising results in movement disorders. The aim of our study is to evaluate the role of bi-hemispheric t-DCS as add-on to neurorehabilitation in PS. Methods: Twenty-eight patients with PD and PS (21 male, age 72.9±5.1 years, PD duration 9.3±7.4 years, PS duration 3.0±1.9 years) received a 4-week intensive neurorehabilitation treatment and were randomized to receive t-DCS (t-DCS group, n=13), 5 daily sessions (20 minutes - 2 mA) with cathode over the primary motor cortex (M1) contralateral to PS, and anode over the M1 cortex ipsilateral to PS, or sham group (sham group, n=15). At baseline (T0), end of rehabilitation (T1) and 6 months later, patients were evaluated with trunk kinematic analysis in static and dynamic conditions, UPDRS-III, FIM, and VAS for lumbar pain rating. At T0, the evaluations were completed by an EMG study of trunk muscles. Results: The study groups were comparable for clinical/demographic features and EMG phenotypes. When compared to sham group, t-DCS group achieved better results in several variables: overall posture (p=0.014), lateral inclination (p=0.013) of trunk during upright standing position, total range of motion (ROM) of the trunk (p=0.012), ROM of bending ipsilateral to PS (p=0.037), and ROM of anterior trunk flexion (p=0.014). The improvement in the overall trunk posture in upright standing position was persistent in t-DCS group at 6 months (T2 vs. T0: p<0.05). UPDRS-III scores decreased after rehabilitation (p=0.001), without significant differences between t-DCS and sham groups (p=0.942). In contrast, FIM score and lumbar pain intensity improved the most in t-DCS group when compared to sham group (p=0.048, and p=0.017 respectively). The EMG pattern was not a predictor of the efficacy of the t-DCS treatment. Conclusions: Our data supports the use of neuromodulation with t-DCS as add-on to neurorehabilitation for the treatment of patients affected by PS in PD. t-DCS is a non-invasive and repeatable approach that proved effective even in those patients with an EMG pattern not amenable to botulinum toxin injections.