A functional abnormality of the autonomic nervous system.

A motor disorder characterized by a velocity-dependent increase in tonic stretch reflexes with increased muscle tone, exaggerated (hyperexcitable) tendon reflexes.

Intracytoplasmic, eosinophilic, round to elongated inclusions found in vacuoles of injured or fragmented neurons. The presence of Lewy bodies is the histological marker of the degenerative changes in LEWY BODY DISEASE and PARKINSON DISEASE but they may be seen in other neurological conditions. They are typically found in the substantia nigra and locus coeruleus but they are also seen in the basal forebrain, hypothalamic nuclei, and neocortex.

Pathological protein aggregates formed by hyperphosphorylation of a microtubule-associated protein known as tau, causing it to aggregate in an insoluble form.

Inability to initiate changes in activity or movement and to perform ordinary volitional movements rapidly and easily.

Hyperreflexia is the presence of hyperactive stretch reflexes of the muscles.

Functional neurological abnormalities related to dysfunction of the pyramidal tract.

A resting tremor occurs when muscles are at rest and becomes less noticeable or disappears when the affected muscles are moved. Resting tremors are often slow and coarse.

Loss of previously present mental abilities, generally in adults.

Characteristic neurologic anomaly resulting from degeneration of dopamine-generating cells in the substantia nigra, a region of the midbrain, characterized clinically by shaking, rigidity, slowness of movement and difficulty with walking and gait.

A loss of global cognitive ability of sufficient amount to interfere with normal social or occupational function. Dementia represents a loss of previously present cognitive abilities, generally in adults, and can affect memory, thinking, language, judgment, and behavior.

A type of dystonia (abnormally increased muscular tone causing fixed abnormal postures) that affects muscles of the limbs.

Atrophy of the cortex of the cerebrum.

Continuous involuntary sustained muscle contraction. When an affected muscle is passively stretched, the degree of resistance remains constant regardless of the rate at which the muscle is stretched. This feature helps to distinguish rigidity from muscle spasticity.