What Is Essential Tremor And How Is It Different To A Parkinsons Tremor
A tremor is a rhythmical, involuntary movement that affects a part of the body, such as the hand.
Essential tremor is the most common type of tremor. Its most noticeable when your hands are doing something and it usually affects both the right and left sides of the body equally. Essential tremors often lessen when your body is resting.
Unlike an essential tremor, a Parkinsons tremor is most obvious when the affected body part is resting and tends to be less noticeable with movement. It usually starts on one side of the body and may progress to the other side as Parkinsons develops.
The time it takes to get a diagnosis can vary from person to person. Some people may receive a diagnosis of Parkinsons quite quickly, but for others it may be a long process. This can be due to a number of things, including your medical history, your age and what symptoms you have.
Your specialist may wish to rule out other causes of your symptoms first and see how you respond to treatment. This may take some time, and, as already mentioned, there is currently no definitive test for Parkinsons.
How you respond to treatment may help your specialist make a diagnosis. Keeping a diary or record of your symptoms will give the specialist more information to guide their decision.
Because the symptoms of Parkinsons are sometimes similar to other forms of parkinsonism, people can sometimes be misdiagnosed.
What Is A Nuclear Medicine Datscan
The DaTscan is a safe nuclear medicine study used to evaluate the brain for tremors and/or Parkinsons Disease. It utilizes the injection of a material called Ioflupane I123 into the bloodstream, where it travels to the brain and highlights the neurons responsible for controlling movement. From there an RAO imaging expert will take pictures of the affected area using a gamma camera, a device designed to capture detailed pictures of the brain and its neurons for assessment.
This revolutionary procedure is FDA approved to help your referring physician and RAO radiologist determine if you suffer from a Parkinsonian syndrome or from a relatively benign nervous system disorder known as essential tremor. Fortunately, results are available in only weeks instead of months or years, as with previous tests.
If your doctor has referred you for this test, it is because you have symptoms that suggest the possibility of a Parkinsonian syndrome. The sooner the cause has been identified, the sooner your doctor can proceed with treatment.
Should I Get A Datscan Or Pet Scan To Confirm My Diagnosis Of Parkinsons Disease
You can find out more about NPFs National Medical Director, Dr. Michael S. Okun, by also visiting the NPF Center of Excellence, University of Florida Center for Movement Disorders & Neurorestoration.
This past month, the FDA approved DaTscan , a radiopharmaceutical agent which is injected into a patients veins in a procedure referred to as SPECT imaging. DaTscan is an important addition because it is anticipated to be more widely available than other techniques and it has received several major endorsements from leading scientists.
One of the most frequently asked questions about Parkinsons disease on NPFs Ask the Doctor web-based forum is whether or not to pursue DaT or PET scanning to confirm a diagnosis of Parkinsons disease. In this months Whats Hot column, we offer a review of the subject in light of the recent FDA approval.
The new DaT scans use a substance that tags a part of a neuron in the brain where dopamine attaches to it, showing the density of healthy dopamine neurons. Thus, the more of the picture that lights up, the more surviving brain cells. If the parts of the brain where dopamine cells should be remain dark in the scan, an expert reader may diagnose early brain degeneration. This could mean either Parkinsons disease or parkinsonism.
An example DaTscan is shown below and it demonstrates essential tremor on the left , and a parkinsonian syndrome on the right .
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Datscan Imaging: A Clearer Picture Of Parkinsons
Parkinsons disease affects one in every hundred people over the age of 60. Until recently, however, doctors had to rely on a clinical evaluation, combined with blood tests and brain studies, to diagnose this common movement disorder. But the results were often inconclusive because there was no test to distinguish Parkinsons disease and related disorders from other conditions that have similar symptoms. As a result, effective treatment could sometimes be delayed while the patient and physician searched for answers.
Timely Diagnosis
Now, a recently introduced nuclear imaging test called DaTscan is helping specialists at Orange Coast Memorial evaluate patients with suspected parkinsonian syndromes, of which PD is the most common. The test is especially important because it helps distinguish PD and allied disorders from a look-alike condition called essential tremora disorder characterized by trembling of the hands, head, and occasionally the arms and legs. Although Parkinsons disease and essential tremor both involve involuntary shaking movements that are similar, these disorders require very different treatments, says Daniel Truong, M.D., a internationally known neurologist and medical director of The Parkinsons and Movement Disorder Institute at Orange Coast Medical Center. DaTscan allows us to rule out essential tremor and other non-parkinsonian conditions, which can help lead to a more accurate and timely diagnosis and treatment.
Changes In The Brain
Would I Still Have Gotten A Datscan
It was important for me to have confirmation other than my symptoms of abnormalities in my brain. I think this scan can be used as a baseline to follow my disease progression.
So, yes, I would have still gotten this test, although the $2,000 out-of-pocket cost upfront may have given me pause.
Note: Parkinsons News Today is strictly a news and information website about the disease. It does not provide medical advice, diagnosis or treatment. This content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or another qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this website. The opinions expressed in this column are not those of Parkinsons News Today or its parent company, BioNews Services, and are intended to spark discussion about issues pertaining to Parkinsons disease.
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New Diagnostic Standards For Parkinsons
Until recently, the gold-standard checklist for diagnosis came from the U.K.s Parkinsons Disease Society Brain Bank. It was a checklist that doctors followed to determine if the symptoms they saw fit the disease. But thats now considered outdated. Recently, new criteria from the International Parkinson and Movement Disorder Society have come into use. This list reflects the most current understanding of the condition. It allows doctors to reach a more accurate diagnosis so patients can begin treatment at earlier stages.
How Do I Prepare For My Datscan
Your doctor will review your medical history, and provide general instructions before scheduling your procedure. There is no specific prep for DaTSCAN, and there are only 3 simple instructions. Youll need to drink plenty of fluids the day before and the day of your procedure. The day before your procedure youll need to pick up your medication, and youll need to take your medication as prescribed the night before your procedure. On the day of your procedure, you will arrive early for an injection. After receiving your injection, you may leave and return when scheduled for your procedure.
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Whats Hot In Pd An Update On Dat Scanning For Parkinsons Disease Diagnosis
In 2011, the FDA approved a diagnostic test for Parkinsons disease. The DaTscan is a radiopharmaceutical agent which is injected into a patients veins in a procedure referred to as SPECT imaging. DaTscan, when it was approved, was considered an important addition to the armamentarium of the bedside clinician. In 2011 I wrote a Whats Hot column on DAT scanning, and this month I will update that posting and bring everyone up to date on the impact of this test.
One of the most frequently asked questions about Parkinsons disease on NPFs Ask the Doctor web-based forum is whether or not to pursue DaT or PET scan to confirm a diagnosis of Parkinsons disease. The short answer is that the DaT test is over-used in clinical practice, and is only FDA approved to distinguish potential Parkinsons disease from essential tremor. In fact, the test only tells the clinician if there is an abnormality in the dopamine transporter, and does not actually diagnose Parkinsons disease . PET is also overused, though it can be a more powerful diagnostic tool when in the right expert hands.
The new DaT scans use a substance that tags a part of a neuron in the brain where dopamine attaches to it, thus showing the density of healthy dopamine neurons. Thus, the more of the picture that lights up, the more surviving brain cells. Dark areas could mean either Parkinsons disease or parkinsonism.
Selected References
Accuracy Of A Clinical Diagnosis Of Et
In the general population, 40% of cases of ET are misdiagnosed and up to 50% of patients diagnosed with ET do not have it. Jain et al applied Movement Disorder Society Consensus Statement Criteria to 71 consecutive patients at the Neurological Institute of New York with a pre-evaluation diagnosis of ET., Sixty-three per cent were found to have true ET and 37% were found to have false ET. Eighty-eight per cent of the patients with false ET had been evaluated by a neurologist. Of the 26 patients found to have false ET, 11 met clinical criteria for PD. An area of controversy attracting much recent discussion is the breadth of the definition of ET, and whether or not it should include asymmetrical tremor, parkinsonism or dystonia. Clearly, extending the clinical definition too widely is bound to reduce diagnostic specificity while increasing sensitivity of detection. Appropriate use of ioflupane scan in cases of possible ET with marked asymmetry or other parkinsonian features is recommended and would help in detection of tremulous PD cases or cases of PD with additional ET.
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Limitations And Pitfalls Of Ioflupane
In most cases the visual interpretation of ioflupane SPECT is simple and straightforward. However, the ease of visual interpretation may be challenged by patient positioning, motion, use of different colour scales and the lack of experience of some readers with subtle anatomical asymmetry as pathological uptake. Mild anatomical asymmetry of the striata may results in subtle asymmetric appearance on ioflupane scans and can be observed in normal healthy controls. In some cases this can mimic the diagnostic asymmetry due to neurodegenerative process in PS.
In such challenging cases, quantitative assessment could be used as a diagnostic adjunct to improve the diagnostic confidence in addition to the visual read. There are several commercial software packagessome under development for full FDA 510 submissionthat will analyse ioflupane scans and from which striatal binding ratios may be compared against a standard age-matched and gender-matched database of healthy controls. Efforts in this direction will be extremely important, given that there is normal loss of DaT receptor density with aging. However, without a formal validation of software in clinical trials and regulatory approval, the routine clinical use of quantification as a stand-alone approach remains challenging and cannot be recommended for current clinical practice without a visual read.
What To Expect During A Datscan
Before the DaTscan, it is essential to discuss the patients medical history with the doctor. For instance, some medications may interfere with the imaging and may need to be discontinued.
The radioactive agent that is injected into the patients bloodstream before the imaging takes some time to reach the striatum region of the brain where cells carrying DaT are usually found. After injection, the patient may need to wait for three to six hours before receiving the SPECT scan to visualize DaT distribution in the brain. The scan itself can take 45 minutes to an hour.
The radiologist will then send the brain scans to the neurologist who will explain the results to the patient.
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What Happens During A Datscan
During a DaTSCAN, a very small amount of tracer, specific for the organ or tissue to be scanned, is injected into a vein by a nuclear medicine technologist. Images may be taken during the injection, immediately after the injection, or following a delayed period to allow the tracer to distribute to the organ or tissue of interest. The gamma rays emitted by the tracer are detected by a special camera that is positioned near the organ or part of the body being imaged.
You will need to remain very still for the camera, but it will not touch you. The radiation from a nuclear medicine procedure is comparable to that received during a routine X-ray. The tracer only remains in the body for a short period of time before being eliminated in the urine or stool.
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Effective And Efficient Diagnosis Of Parkinsonism: The Role Of Dopamine Transporter Spect Imaging With Ioflupane I
DaSupplements and Featured Publications
Am J Manag Care. 2004 20:S97-S109 Parkinsons disease is a common neurological illness associated with significant patient and payer burden. Its accurate diagnosis is challenging and misdiagnosis is common.1-3 Additionally, overdiagnosis of PD has been observed when only clinical symptoms were used to assess uncertain cases.4 Although experts in movement disorders are able to achieve greater diagnostic accuracy than their primary care or general neurology counterparts, they are still uncertain about the diagnosis in many patients. Adding to this, access to experts may be limited, thus further reducing opportunities for diagnosis.5 Imaging technology has improved considerably in recent years. The 2011 approval by the US Food and Drug Administration of the radiopharmaceutical ioflupane I-123 injection for striatal dopamine transporter visualization using single-photon emission computed tomography offers a new biomarker that can assist in differentiating conditions associated with nigrostriatal degeneration from those movement disorders without this degeneration .6 This publication is based on a roundtable discussion involving a multidisciplinary panel of experts with experience in movement disorders, nuclear imaging, managed care, and patient advocacy, and provides clinical criteria and algorithms to help guide managed care organizations and practitioners in the appropriate use of DaTscan imaging.
Overview of Parkinsons Disease
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When Do You Get Results From A Pet Scan For Parkinsons
PET scans are usually more extensive and detailed than similar tests that are available. Despite this, test results can usually be given within one to two days after the scan. National Parkinson Foundation: Should I get a DaT scan or PET scan to confirm my diagnosis of Parkinsons disease? Radiology-Info.org: PET Scan and Parkinson Disease.
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Datscan Imaging: A Clearer Picture Of Parkinson’s
Parkinsons disease affects one in every hundred people over the age of 60. Until recently, however, doctors had to rely on a clinical evaluation, combined with blood tests and brain studies, to diagnose this common movement disorder. But the results were often inconclusive because there was no test to distinguish Parkinsons disease and related disorders from other conditions that have similar symptoms. As a result, effective treatment could sometimes be delayed while the patient and physician searched for answers.
Timely Diagnosis
Now, a recently introduced nuclear imaging test called DaTscan is helping specialists at Orange Coast Memorial evaluate patients with suspected parkinsonian syndromes, of which PD is the most common. The test is especially important because it helps distinguish PD and allied disorders from a look-alike condition called essential tremora disorder characterized by trembling of the hands, head, and occasionally the arms and legs. Although Parkinsons disease and essential tremor both involve involuntary shaking movements that are similar, these disorders require very different treatments, says Daniel Truong, M.D., a internationally known neurologist and medical director of The Parkinsons and Movement Disorder Institute at Orange Coast Medical Center. DaTscan allows us to rule out essential tremor and other non-parkinsonian conditions, which can help lead to a more accurate and timely diagnosis and treatment.
Changes In The Brain
FDA Approved
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Diagnosis And Medication Response
The widely held clinical view is that if a patient responds adequately to a treatment trial of a drug for a hypothesised condition, the patient drug response is confirmatory of the proposed diagnosis. Although there is ample common sense inherent in this view, medication challenges have their own complications and are not necessarily straightforward. For instance, there has been little work on defining the magnitude of a significant clinical response. Alternatively, if a patient shows little clinical response to a drug, does it mean he does not have that condition or is simply unresponsive to that particular drug? The placebo response is particularly problematic when dealing with dopaminergic therapies, given that dopamine forms part of the reward mechanism of the brain.
Similarly, in ET, appropriate medications commonly have no appreciable effect. In one study, propranolol was found to be of no benefit in 30% of patients with ET while primidone was of no benefit in 32%. To make matters even more confusing, PD tremor may improve with propranolol.
In some cases, it is when the response to medication is less than expected that diagnostic uncertainty emerges. In these cases, it may not be clear whether the diagnosis is wrong or the patient is simply one of those who does not respond as well as expected to the chosen medication. In some of these patients, functional dopaminergic radioimaging may be useful to help guide further treatment decisions.
Humanistic Considerations In Ioflupane Imaging
SPECT imaging with ioflupane may have an impact on patient-reported quality of life through enabling timely diagnosis that can lead to prompt and appropriate treatment. Patients who remained untreated after a PD diagnosis experienced deteriorations in mobility, activities of daily living, emotional well-being, social support and bodily discomfort.,
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