Electrical Polarization of the Brain in Corticobasal Syndrome

Objective: In a recent sham-controlled pilot study, we showed that surface anodal direct current (DC) polarization can improve verbal fluency in frontotemporal dementia patients. Corticobasilar syndrome is a related disorder that presents with disordered limb movement, particularly the loss of stored motor programs, (ideational/ideomotor apraxia) and impaired hand function. Conventional neurorehabilitation is typically unsuccessful in this disorder. We wish to see whether anodal polarization of the inferior parietal cortex (IPC) in CBS patients leads to improved movement and whether the improvement is specifically in the generation of stored movements (praxis). We will also apply polarization to the primary sensorimotor area (SM1), where we expect any effects to be on elemental aspects of movement, such as finger tapping speed. Study population: Twenty CBS patients will be enrolled. Design: This single blind crossover study will have three arms: anodal DC to IPC, anodal DC to SM1, and a control condition: polarization with the electrodes placed on the right and left occipital areas. Outcome Measures: The primary outcome measure is a validated test of ideational and ideomotor apraxia. Secondary outcomes are measures of hand dexterity and coordination.