Rest tremor: 4 to 5 Hz; usually involves limbs, especially distally; also lips, chin, tongue. Disappears with action, but reemerges with maintained posture. Worsened by stress, walking.

Rigidity: increased resistance to passive movement; equal in all directions; often with palpable “cogwheeling.”

Flexed posture: commonly begins in arms, spreads to body.

Bradykinesia: slow movements, difficulty starting movement, loss of automatic movements (arm-swing).

Hypokinesia: reduced amplitude of movement, particularly repetitive movements (“decrementing” finger or toe-tapping).

Akinesia: reduced frequency of movements.

Examples of bradykinesia, hypokinesia, akinesia: hypomimia (decreased facial expression), decreased blinking, loss of gestures, setting motionless, hypophonia, dysarthria, tachyphemia (rapid speech), aprosody (monotonous speech; loss of rhythm of speech), drooling (impaired swallowing), micrographia, impaired fine motor skills, short stride (festinating gait), difficulty rising from seat. Advanced bradykinesia—major impediment in activities of daily living. If feet involved, should stop driving.

Freezing phenomenon (motor block): transient inability to perform active movements. Manifest in legs (gait freezing), eyelids (apraxia of lid opening), speech (palilalia), writing. Lasts several seconds. Triggers: starting to walk, turning, approaching a destination, revolving doors, elevator doors, crossing heavily trafficked streets. Often overcome by visual clues.