ABSTRACT
Because Parkinson’s disease (PD) is an extrapyramidal motor disorder,
leading to rigidity, bradykinesia, tremor, and postural instability, the bulk of
research on PD has focused on the movement disorder. Accompanying the
increasing recognition that PD often involves a compromise of non-motor
functions (such as cognition, affect, and sleep),1 is research showing that
non-motor dysfunction seriously detracts from patient and caregiver quality
of life2-4 and increases complexity and cost of treatment.5 Consequently,
there is great interest in understanding the mechanisms underlying the
cognitive deficits and how such deficits might be detected and treated early.
