Dopaminergic control of speech production in Parkinson's disease–an fMRI study

Introduction: Early on in Parkinson`s disease (PD), patients show hypophonia with the characteristic soft and uniform voice that is not responsive to dopaminergic treatment1. This speech pathology could result from reduced feedforward drive due to hypokinesia or from ineffective sensorimotor integration2 due to insufficient filtering in corticobasal circuits3. More general, akinesia could result from impaired cognitive planning, motor preparation, or both. We thus tested whether PD patients planned less efficiently prior to motor preparation by comparing preparation for covert and overt speech production using f…