Parkinson's disease and parkinsonism in the elderly: A glossary of terms

A clinical syndrome of akinesia accompanied by rigidity and often tremor. Akinesia includes difficulty with voluntary motor actions, difficulty performing sequential or concurrent motor actions, slowness of voluntary movement, and abnormal fatigability of repetitive motor actions. Rigidity, or ‘stiffness’, can be defined as the resistance encountered by an examiner when passively stretching relaxed muscles around a joint. Rigidity in parkinsonism can often be detected in the axial skeleton and upper limbs by the examiner performing passive flexion/extension movements of the neck and wrist joint. Tremor is often present at rest when the muscles are fully relaxed and is usually first noted in the upper limb involving the hand and fingers. Leg and jaw tremor may less commonly occur. Parkinson’s disease is the most common cause of parkinsonism and arises sporadically and is of unknown cause. Known causes of parkinsonism include drugs, cerebrovascular disease, other sporadic and inherited neurodegenerative disease, infections, head trauma, hydrocephalus, and metabolic diseases, amongst others.