Parkinson’s Differentials

What Parkinson’s is Not: Parkinsonian Look-Alikes

With so many people who show Parkinsonian symptoms not being correctly diagnosed as having Parkinson’s, it is also worthwhile noting that a number of people initially diagnosed with Parkinson’s have another disease, a “Parkinson’s look-alike,” instead. Most often these people are still considered to have Parkinsonism by the community, but their treatment protocol may be substantially different from that of persons who have idiopathic Parkinson’s.

Here are some of the conditions with which Parkinson’s may be initially confused:

Benign Essential Tremor

  • A common condition that may appear in the elderly and slowly progress over the years. The tremor is usually equal in both hands and increases when the hands are stretched out in front of the patient or when the hands are moving. The tremor may involve the head but spares the legs. Patients with Benign Tremor have no other Parkinson’s features, and there is usually a family history of tremor. Parkinsonian Tremor and Benign Tremor generally respond to different drugs. A small number of patients with Benign Essential Tremor (less than five percent) develop PD.


Shy Drager Syndrome

  • A condition in which the earliest and most severe symptoms are those of insufficiency of the Autonomic Nervous System: dizziness on standing, bladder difficulty, and impotence. These autonomic symptoms are followed by PD symptoms such as rigidity, tremor, bradykinesia, postural instability, and gait difficulty. There is some question among neurologists as to whether the Shy Drager Syndrome is a form of PD or a separate disease.


Normal Pressure Hydrocephalus

  • An uncommon condition that consists of difficulty walking resembling PD), mental changes (resembling senility), and urinary incontinence. The condition is caused by an enlargement of the fluid cavities (Ventricles) in the brain that compress the parts of the brain that regulate walking and thinking. Normal Pressure Hydrocephalus differs from the more familiar hydrocephalus of childhood, which results from the blockage to the flow of spinal fluid. No such blockage is found in patients with Normal Pressure Hydrocephalus. There is no known cause of Normal Pressure Hydrocephalus. The Condition may respond to a shunt: a tube placed in the ventricle which drains off the excessive fluid and carries it away.


Striato-Nigral Degeneration

  • An uncommon disorder in which patients become stiff and slow and develop difficulty with balance and walking. Usually patients do not have tremor and cannot be distinguished from patients with PD on the basis of a neurological exam. Patients with Striato-Nigral Degeneration however do not respond to Levadopa. Only after death can this disorder be distinguished from PD because in Striato-Nigral Degeneration most of the damage is in the Striatum and not the Substantia Nigra. This is the reverse of the situation with PD.


Pseudobulbar Palsy

  • A common disorder that occurs in patients with disease of the blood vessels of the brain (Arteriosclerosis). Arteriosclerosis is especially likely to occur in patients with high blood pressure or diabetes. Patients who develop Pseudobulbar Palsy do so because they suffer numerous small strokes (ministrokes), many of which are so mild that patients are unaware of them. The ministrokes usually damage the part of the brain that controls balance and walking, the same area involved in PD. The two disorders may not be distinguished on the basis of a neurological examination alone. Patients with Pseudobulbar Palsy do not respond to antiparkinsonian drugs. In the past, many patients were thought to have PD on the basis of Arteriosclerosis alone (arteriosclerotic PD). Currently, Arteriosclerosis is not believed to be the cause of PD.


Progressive Supernuclear Palsy

  • An uncommon disorder in which patients develop Paralysis of their eye movements, difficulty in speaking, rigidity, and senility. This disorder causes changes in the brain that are similar to those of PD, but are even more extensive. Patients with this condition do not respond to antiparkinson drugs.


Wilson’s Disease

  • A rare inherited disorder that appears in patients below the age of 40. This disease involves the brain and the liver. This excess results in damage to these two organs. Early diagnosis is important in this disease as treatment prevents further damage to the brain and liver.


Hallervorden Spatz Disease

  • Also a rare, inherited progressive disease that begins in late childhood. Hallervorden Spatz Disease is associated with the accumulation of excessive iron in certain parts of the brain. There is no treatment for this disease.


Olivopontocerebellar Degeneration

  • An uncommon disorder in which patients have difficulty with balance and walking, often called Ataxia. The patients may have an action or sustention tremor, but do not have rigidity or bradykinesia. The disorder results from a deterioration of the nervous system, including the Cerebellum, the Pons (a part of the brain stem), and the Olives (a part of the Brain Stem and Spinal Cord). Olivopontocerebellar Degeneration does not respond to antiparkinson drugs.


Huntington’s Disease

  • An inherited disease which usually begins early in middle life. It is characterized by involuntary movements (dyskinesias, chorea) associated with changes in behavior, personality, and mood. The chorea (which resembles the involuntary movements caused by Levedopa) may precede, occur simultaneously, or follow the mental changes. The disease, when fully developed, is easily distinguished from PD. However, the symptoms of a childhood form of Huntington’s disease may resemble PD. Levadopa usually worsens the symptoms of Huntington’s disease…



  • An inherited disease that begins in childhood and is progressive. The patients develop unusual postures of the head and neck, arms and legs. This is called Generalized Dystonia (Dystonia Musculorum Deformans). A variation of the disease, Segmental Dystonia, develops in adulthood and involves only one part of the body, e.g. the head and neck (Torticollis or Wryneck). …


Brain Tumors

  • Tumors of the brain that are close to the substantia nigra or the striatum may exert local pressure on these structures. This local pressure may, in turn, result in the appearance of symptoms that resemble PD. A CT or NMR scan of the brain will exclude the possibility of a brain tumor as the cause of the Parkinsonian symptoms