While the motor cortex is the part of the brain that controls movement, the basal ganglia provide input so that voluntary movements are done at the right speed. Thus, damage to or degeneration of the basal ganglia results in abnormal movement and movement disorders such as parkinsonism. Dopamine deficiency is why all parkinsonisms can exhibit symptoms of tremors (shaking), bradykinesia (slow movement), rigidity (stiffness), and postural instability (poor balance) — no matter what the diagnosis is. For many parkinsonisms, the cause of the underlying disease process leading to dopamine deficiency is not known or not fully understood. Indeed, even classic Parkinson’s disease is referred to as idiopathic Parkinson’s disease because it has no known cause.
Lewy Body Dementia
Other symptoms of LBD include parkinsonism — rigidity, unusually slow movement, and impaired balance and coordination — but generally, LBD begins with cognitive symptoms, and the motor symptoms start later. Lewy bodies may also be found in the brains of those with Parkinson’s disease and those with a condition called Parkinson’s dementia, in which problems with memory and thinking develop in a person who has had motor symptoms typical of Parkinson’s disease for at least a year. In spite of the overlap in both symptoms and the presence of Lewy bodies, Lewy body dementia and Parkinson’s dementia are considered two different conditions.
Multiple System Atrophy
Multiple system atrophy (MSA) is a degenerative neurologic disease characterized by parkinsonism or ataxia (clumsiness and trouble with balance) along with autonomic dysfunction, which includes erratic blood pressure levels sometimes resulting in fainting, bladder dysfunction, erectile dysfunction, and abnormal sweating. The cause of MSA is unknown.
Progressive Supranuclear Palsy
Progressive supranuclear palsy (PSP) is a rare brain disorder in which abnormal deposits of the protein tau accumulate in nerve cells in the brain, although it’s not known whether that’s the actual cause of the disorder. That being said, falls are almost always the first noticeable symptom and the reason for referral to a neurologist. Other common symptoms include symmetric limb stiffness and much more arm, neck, and trunk rigidity than would be expected in idiopathic Parkinson’s disease. In people with PSP, problems with eye movement can lead to difficulty directing one’s gaze, especially looking down or up at something.
Corticobasal Degeneration
In corticobasal degeneration (CPD), the tissues of the cerebral cortex and basal ganglia progressively deteriorate for reasons that are not completely understood. CBD can also cause thinking and memory difficulties, or cognitive dysfunction, that impact decision-making, attention, and performing learned or skilled movements; speech and language difficulties; and visuospatial impairments. Certain medications may help treat muscle rigidity and other symptoms of corticobasal degeneration, but there is no treatment to slow progression of the underlying disease.
Vascular Parkinsonism
However, postural tremor, which occurs when a person attempts to hold a body part still against the force of gravity, is common. An example of this would be extending the arms in front of the body and holding them there.
Post-Traumatic Parkinsonism
Post-traumatic parkinsonism may be caused by a severe head injury or by frequent head trauma, such as from boxing or playing football.
Essential Tremor
In contrast, the type of tremor associated with Parkinson’s disease is resting tremor, which occurs when a hand or limb is at rest. Essential tremor does not cause the slowness, stiffness, or walking difficulties that are seen in other parkinsonisms.
Drug-Induced Parkinsonism
Drug-induced parkinsonism sometimes disappears when a person stops taking the drug that’s causing it, but it can also persist or even worsen after the drug is stopped. In some cases, it disappears only to reappear later after discontinuing the drug. The following substances can cause drug-induced parkinsonism:
Typical antipsychotics, such as Haldol (haloperidol) and Thorazine (chlorpromazine)Atypical antipsychotics, including Risperdal (risperidone) and Zyprexa (olanzapine)Reserpine, a drug used to treat high blood pressure and, historically, agitation in people with mental disordersXenazine (tetrabenazine) and Austedo (deutetrabenazine), which are used to reduce involuntary movements associated with Huntington’s disease and tardive dyskinesiaGut motility stimulators and antiemetics, such as Reglan (metoclopramide)Antiepileptic drugs, such as Depakote (valproic acid)Stimulants, including amphetamines and cocaine
Postencephalitic Parkinsonism
Sometimes called sleeping sickness or sleepy sickness, postencephalitic parkinsonism was possibly related to the influenza pandemic of that era or an enterovirus. Enteroviruses are a group of viruses that usually cause mild illness but can cause serious illness if they infect the central nervous system. An estimated 1 million people were affected by encephalitis lethargica, and some of those who survived it entered into a chronic phase of the disorder characterized by parkinsonism. Drug-induced parkinsonism can sometimes be reversed when a person stops taking the drug responsible for it. But other non-PD parkinsonisms tend to be progressive, often rapidly so. Unlike with Parkinson’s disease, medications to increase dopamine in the brain — notably levodopa (Duopa, Rytary, Sinemet) — often provide little benefit for other parkinsonisms. Speech therapy, physical therapy, and antidepressants may help manage the symptoms of these conditions. Additional reporting by Ingrid Strauch.
