Degeneration of the basal ganglia

Dementia with Lewy bodies

Huntington disease

Parkinson disease

Progressive supranuclear palsy

Multiple system atrophy

Dementias

Alzheimer disease

Creutzfeldt-Jakob disease

Progressive myoclonic encephalopathies (eg, mitochondrial disorders, certain types of epilepsy, such as sialidosis, neuronal ceroid lipofuscinosis, Lafora disease, Unverricht-Lundborg disease)

Metabolic disturbances

Hypercapnia

Hyperglycemia, nonketotic

Hypocalcemia

Hypoglycemia

Hypomagnesemia

Hyponatremia

Liver failure

Uremia

Physical and hypoxic encephalopathies

Electric shock

Heatstroke

Hypoxia

Traumatic brain injury

Toxic encephalopathies

DDT

Heavy metals (including bismuth)

Methyl bromide

Viral encephalopathies

Encephalitis lethargica

Herpes simplex encephalitis

Postinfectious encephalitis

Subacute sclerosing panencephalitis

Drugs at toxic or high doses

Antihistamines

Cephalosporins

MAO inhibitors

Penicillin

Tricyclic antidepressants

SSRIs

Valproate