Staging neurological disorders: expressions of cognitive and motor disorder.

In neurologic disorders, there are progressive losses in regional brain structural integrity, circuitry, and neuronal process that threaten individuals' ability to express functional capacity at several levels of severity. The classification of (a) patients on the basis of diagnosis, risk prognosis, and intervention outcome forms the basis of clinical staging and (b) laboratory animals on the basis of animal model of brain disorder, extent of insult and dysfunctional expression, provides the components for the clinical staging and preclinical staging, respectively, of the disease state with certain associated epidemiological, biological, and genetic characteristics. The investigation of epigenetics and biomarkers is intrinsic to any analysis of the progressive nature of the neurogenerative disorders, in the present account disorders relating to Alzheimer's disease, Parkinson's disease, depression, and diabetes.