Duration of Parkinson disease is associated with an increased propensity for "reinvestment"

Background. As a consequence of difficulties in movement initiation and execution, people with Parkinson's disease (PD) are typically encouraged to consciously monitor and control the mechanics of their actions. This is described as 'reinvestment' and has been shown to help mediate effective motor output. Paradoxically, in situations where people with PD are particularly motivated to move effectively, reinvestment may exacerbate existing movement deficits. Objective. To examine the propensity for reinvestment in a sample of people with PD. Methods. A volunteer sample of 55 people with PD was asked to complete a previously validated measure, the Reinvestment Scale. A sub-sample (and age matched controls) was asked to complete a recently developed, movement specific, version of the Scale. Data was collected on Mini Mental State Examination and the Hoehn & Yahr Scale. Participant demographics, including age of onset and duration of disease, were also collated. Results. Multiple regression analyses showed that duration of disease was associated with reinvestment score on both the Reinvestment Scale and the Movement Specific Reinvestment Scale. Conclusions. Participants appeared to become more aware of the mechanics of their actions over time. Possible explanations for this finding are discussed with reference to rehabilitation.