Parkinson disease

Parkinson disease (PD) is a progressive, neurodegenerative disease that affects between 1 and 2 percent of individuals over 65 years of age and 3-5 percent of those aged 85 or older (Fahn, 2003). PD is the second most common neurodegenerative disorder after Alzheimer’s disease. Currently, approximately six million people are affected by PD worldwide (Viartis, 2008). PD was originally attributed to neuronal loss within the substantia nigra pars compacta, and a concomitant loss of dopamine. PD is now thought to be a multi-system disorder that involves not only the dopaminergic system, but other neurotransmitter systems, whose role may become more prominent as the disease progresses (Perry et al., 1991). There are four cardinal features of PD: rest tremor, rigidity, bradykinesia and postural instability, all of which are motor symptoms. However, PD also may include any combination of a myriad of non-motor symptoms including autonomic disruptions, orthostatic hypotension, sweating dysfunction, pain, sensory symptoms, cognitive changes, sleep disorders, fatigue, loss of motivation, anxiety and depression (Fahn, 2003). Both motor and non-motor aspects of PD may impact upon the ability of those with PD to participate in exercise and/or the effects that exercise might have on those with PD.