I have written before about the difficulty of diagnosing Parkinson’s disease. There is no blood test where you can just measure the quantity of dopamine in your brain. Instead, diagnosis is dependent on family history and clinical exam. And once the clinician (typically a neurologist) determines you have “Parkisonisms”, diagnosis could go many directions, not necessarily “Parkinson’s disease”.
First, what are the signs of “Parkisonisms”? Four motor symptoms: tremor, muscle rigidity, bradykinesia (slow movement, e.g., your handwriting gets smaller, or you start scuffling when you walk), and postural instability. (This last one is classically tested by the doctor pulling you forward by your shoulders and seeing if you can catch your balance.) To complicate diagnosis further, you don’t need to have all these symptoms and there’s also a host of non-motor symptoms you may display. (Drooling is my personal favorite.)
So, now you have “Parkinsonisms”. Parkinson’s Disease is the usual explanation but frequently, the clinician needs other confirmations to deliver a diagnosis of Parkinson’s Disease, for instance, how you respond to PD medication.
You could have something else. I was astounded when I participated in various research projects, and the questionnaires
included a long list of “movement disorders”. Here’s some of them:
—Essential Tremors — See my earlier post for differences from PD. Typically, tremors occur on both sides of the body (not starting on the dominant side like PD), tremor is the primary symptom, and you’re more likely to have a family history of the disorder.
—Multiple System Atrophy (MSA) — Red flag for diagnosis is parkinsonisms combined with early and severe trouble controlling blood pressure and/or urination. The disorder’s symptoms reflect the loss of nerve cells in several different areas in the brain and spinal cord that control the autonomic nervous system and coordinate muscle movements.
—Progressive Supranuclear Palsy (PSP) — Red flag for diagnosis is parkinsonisms combined with severe trouble controlling eye movements. One of the classic signs of the disease is an inability to aim the eyes properly, which occurs because of lesions in the area of the brain that coordinates eye movements.
—Dementia with Lewy Bodies (DLB) — Lewy bodies are the protein clumps that show up in brain autopsies of people with PD. These are analagous to the amyloid clumps found in brain autopsies of Alzheimer’s patients. Red flag for diagnosis is parkinsonisms combined with early dementia and severe hallucinations. If you’ve caught the TV series Boss starring Kelsey Grammer, this is what the fictitious Chicago mayor suffers from. (There’s some creative/scary cinematography showing his hallucinations.) This also was the diagnosis for the late comedian, Robin Williams.
—Pick’s disease — I keep getting this mixed up with Pickett’s Charge, and certainly both terms are challenging to work into a conversation. The much drearier contemporary name is frontotemporal dementia (FTD) which describes a clinical syndrome associated with shrinking of the frontal and temporal anterior lobes of the brain. The main symptom is problems with language.
—Spinal cerebella ataxia (SCA) — Ataxia often occurs when parts of the nervous system that control movement are damaged. People with ataxia experience a failure of muscle control in their arms and legs, resulting in a lack of balance and coordination or a disturbance of gait.
—Corticobasal degeneration (CBD) — This is a progressive neurological disorder characterized by nerve cell loss and atrophy (shrinkage) of multiple areas of the brain including the cerebral cortex and the basal ganglia. This is an example where the clinician may rule this in or out based on response to PD drugs. Symptoms of CBD are similar to PD, but this disorder does not respond to PD drug therapies.
—Olivopontocerebellar atrophy (OPCA) — While this sounds like an obscure Italian dish, it is a term that describes the degeneration of neurons in specific areas of the brain – the cerebellum, pons, and inferior olives. (The inferior olives are located right next to the subpar martinis — sorry, seriously, this is a brain part involved in motor control.) The characteristic areas of brain damage that indicate OPCA can be seen by imaging the brain using CT scans or MRI studies. MRIs are more often used to rule things out (in my case, they ruled out a stroke), but OPCA is an example where technology may be used to confirm a diagnosis.
Another diagnostic technology is DaTScan, which is a nuclear medicine scan that looks for degeneration in the brain indicative of certain parkinsonian syndromes. It can distinguish a brain with a normal number of dopamine transporters from a brain with fewer dopamine transporters. This is not the magic blood test: it can distinguish between Essential Tremors and PD, but not PD and (say) DLB.
Check out the helpful article (on which much of this post is based) Diagnosing Parkinson Disease by Daniel Burdick, MD in Parkinson Pathfinder magazine(APDA, Washington Chapter), Summer 2015, . Dr. Burdick is a movement disorder neurologist at the Booth Gardner Parkinson’s Care Center in Kirkland, WA.
If you want to scare the beejeezus out of yourself and find out all the possible neurological ailments you could be afflicted with (conveniently listed in alphabetical order!), check out the website of the National Institute of Neurological Disorders and Stroke (NINDS), an institute under the National Institute of Health (NIH). I relied primarily on this site for definitions.