My research focuses on individuals with Parkinson’s disease (PD). I am primarily interested in determining whether speech motor programming deficits exist in this population and contribute to the known problems with motor speech execution.

It has been suggested in studies of limb movement that people with PD have two potential problems: (1) reduced ability to maintain a prepared response before the “program” begins to degrade and (2) impaired ability to switch from a programmed response to a novel response without getting “stuck” on the initial response. Importantly, these motor programming impairments have parallels in the cognitive domain. That is, individuals with PD are well known to have difficulty maintaining a cognitive set, or mental state, and switching between cognitive sets.

If problems with the maintenance or switching of a response do indeed exist, how then do we know whether to attribute these difficulties to motor programming disruption or cognitive disruption? By using two comparable reaction time tasks that differ in the required level of speech motor programming versus cognitive processing, we can begin to isolate motor programming deficits that cannot be attributed to cognitive “maintenance” or “set switching” deficits. Moreover, as participants complete the reaction time protocol while on and off of their anti-Parkinson’s medications, we can achieve a deeper understanding of the unmasked effects of PD on these particular aspects of response preparation.

This medication withdrawal period also allows us to investigate changes to speech and cognitive-linguistic ability as a function of medication state—a topic that is poorly understood at present.