The term parkinsonism refers to a condition characterized by a combination of at least two of the following clinical signs: resting tremor, rigidity, bradykinesia, and postural instability; no specific etiology is implied by the term (Table 14–1). The term Parkinson's disease refers to levodopa-responsive, idiopathic parkinsonism associated with the presence of Lewy bodies and neuronal degeneration in the substantia nigra pars compacta. Secondary parkinsonism refers to parkinsonism caused by other lesions of the basal ganglia, such as tumors, strokes (vascular parkinsonism), encephalitis, hypoxic or ischemic insult, and toxins (e.g., manganese, carbon monoxide, carbon disulfide). NPH can cause a parkinsonian-like gait disorder, urinary incontinence, and dementia (Table 14–2).