Methods dictionary
In this page you will find descriptions and explanations about some of the more common procedures used in movement disorders clinical research
The information provided in this page describes common practices and general rules regarding tests and procedures used in clinical research. If you are considering taking part in a research study or trial a member of the respective research team will provide you with detailed information about the specifics of the study and answer any questions.
Have we missed anything? If you would like to suggest additional research methods that should be covered in this page please write to us: movementdisorders@ucl.ac.uk
Biological samples (or Biosamples)
Biological samples might include blood, urine, stool, saliva, skin, cerebral-spinal fluid or even brain tissue which can be collected and used for clinical diagnosis and for research. Biological samples enable clinicians and researchers to perform an in-depth investigation of the collected tissue to get a better understanding of genetics, physiological changes and biological processes which might be related to disease. If needed for research purposes, biological samples will be collected by qualified and experienced personnel who will adhere to strict collection procedures to ensure the safety of research participant and the integrety of the collected samples.
Cognitive Tests
“Cognition” is a general term for a person’s abilities to think, remember things, pay attention, solve problems, etc. Changes in things like memory, attention and other cognitive abilities can sometimes occur in people with Parkinson’s and other movement disorders. Doctors and researchers use standard methods to measure cognition using Neuropsychological tests, which can help identify changes or problems in cognitive abilities over time. Standard cognitive tests will typically require you to answer a series of simple questions and complete a few simple tasks, some in writing and some verbally. As part of these tests you may be asked to do things such as: name objects, memorize and repeat short texts or word lists, count or do other simple numerical tasks, draw simple objects, etc.
DAT Scan (Dopamine Active Transfer scan)
See single photon emission computed tomography imaging using DaT scan.
Deep Brain Stimulation (DBS)
Some people with Parkinson’s are suitable for surgery to help treat and manage their symptoms. DBS is a surgical procedure which involves implanting electrodes into your brain which are connected to a pulse generator. High frequency stimulation are generated and stimulate the target area of the brain. Current research studies aim to improve DBS techniques and its outcome in treating Parkinson’s.
Functional Magnetic Resonance Imaging (fMRI)
fMRI scans are widely used to explore not only the structure but the function of the brain. This method allows us to see what parts of the brain are most active during a specific activity, emotion or behaviour. The methods relies on measuring blood and oxygen levels in the brain to give indications of the levels of activity of different brain region. In movememt disorders research this method can be used to assess functional changes that may occur in the brain as a result of the disease.
The procedure: MRI and fMRI scanner are large cylindrical scanner that you are asked to lie in. You will be asked to remove all jewellery and metal items since these might react with the strong magnetic fields produced during a scan. You wouldn’t feel anything during the scan, but you will be asked to lie still and the machine might make some loud noises. Some people who find it hard to be motionless for extended periods of time or people suffering from claustrophobia (feeling unconfortable in small spaces) might find the process uncomfortable. fMRI scans are usually longer than MRI scans, lasting 30-60 minutes or more. You might be asked to perform certain tasks during the scan to evaluate the changes in brain function that are specifically related to the task.
Lumbar puncture - CSF sample collection
A lumbar puncture collects a small amount of Cerebral Spinal Fluid (CSF) from the spine. CSF is a unique fluid found only in the central nervous system, i.e., in the brain and spinal cord. Substances found in CSF can be a direct indication to biological processes that happen in the brain and may be related to disease. CSF is often used to detect biomarkers, which are different biological substances that can be used as an indication of diagnosis, disease severity, disease stage and more. In clinical trials, CSF might be collected to check whether the drug being tested actually reaches the brain and interacts with its therapeutic targets. Some clinical trials use a lumbar puncture procedure in order to inject the study drug into the Cerebral Spinal Fluid. This route of administration is used to ensure that drugs have a better chance of reaching their therapeutic targets in the brain.
The lumbar puncture procedure might be performed in a sitting or lying position. Local anasthetics and special thin needles are used to minize pain during the injection. You will be monitored following the procedure but typically will be free to get up and move around within minutes or up to one hour following the procedure. A lumbar puncture is considered a generally safe procedure and most common side effects are headaches and/or some local swelling where the needle was inserted.
Magnetic Resonance Imaging (MRI) - structural and connectivity imaging
An MRI is a type of scan that uses strong magnetic fields to produce images of the inside of the body. An MRI can be used to scan any part of the body, but in movement disorders research it is usually used to visualize the structure of the brain. MRI can be used to indicate whether there is any change or abnormality to the structure of the brain, helping to visualize specific parts of the brain which may be affected. A reletively new type of MRI scan is called a “connectivity MRI”, which can create images of the connections between different parts of the brain.
The procedure: An MRI machine is a large cylindrical scanner that you are asked to lie in. You will be asked to remove all jewellery and metal items since these might react with the strong magnetic fields produced during a scan. You wouldn’t feel anything during the scan, but you will be asked to lie still and the machine might make some loud noises. Some people who find it hard to be motionless for extended periods of time or people suffering from claustrophobia (feeling unconfortable in small spaces) might find the process uncomfortable. Connectivity MRI scans are typically longer than the standard structural MRI, and can take up to one hour.
Movement Disorders Society-Unified Parkinson’s Disease Rating Scale (MDS-UPDRS)
The MDS-UPDRS is a commonly used scale to measure motor symptoms and disease severity in Parkinson’s disease. There are four parts to this rating scale which assess: motor function, motor symptoms, non-motor symptoms and motor complications (including medication wearing off symptoms and dyskinesia). The scale is given in the form of a questionnaire, partly to be completed by the researcher (or doctor/nurse) making the assessment and partly to be completed by the patient. The questionnaire asks about your experiences of daily living and you will be asked to assess the severity and frequency of different problems you may experience. The MDS-UPDRS also includes an assessment of motor function, for which the examiner will ask you to perform a few simple motor tasks, such as moving your hands and legs in certain ways, tapping your fingers, rising from a chair, walking a short distance, etc. The full MDS-UPDRS scale will take about 20-40 min to complete.
Neuroimaging
Neuroimaging is a widely used method which allows us to see the effect of Parkinson’s disease and other Movement Disorders on the brain. There are different neuroimaging techniques we use to gather information on the structure and/or function of the brain. A few commonly used neuroimaging techniques include: MRI, fMRI, PET, SPECT
Neurological examination
A neurological examination is performed by a trained clinician and designed to assess you reflexes, sensory and motor function. This assessment gives a first indication of the function of the nervous system, without a more detailed investigation (e.g., neuroimaging). A neurological examination can help with the clinical diagnoses process and if often used in research to review the presentation of symptoms and to assess the severity of disease. A neurological examination will include a review of your medical history and current symptoms as well as a physical examination. The examiner will ask you to answer some questions about yourself and your past and current symptoms as well as some general questions evaluating your mental state. The examiner will check your reflexes and ask you to perform some simple tasks such as tracking on abject with your eyes, moving your hands and legs in certain ways, tapping your fingers, standing up and walking a short distance, etc.
Non-motor symptoms scale
People with Parkinson’s might experience a range of non-motor symptoms, such as sleep problems, dizziness and falls, feelings of depression or anxiety, hallucinations, constipation, urinary and sexual problems, problems with memory or attention and more. There are a number of ways to measure these symptoms but one of the most commonly used is the Non-Motor Symptoms Scale (NMSS). This is a questionnaire in which the examiner will take you through a list of about 30 non-motor symptoms to check whether you have experienced any of them. You will be asked to evaluae the severity of each symptom and how often you have been experiencing it.
Positron Emission Tomography (PET)
PET scan is very similar to a SPECT scan: both imaging technoques involve the injection of a radioactive tracer and the use of specialized scanners to visualize structure and function of specific parts of the brain. There are a number of technical differences between PET and SPECT but the overall procedure and information gained from the test is generally similar.
You can watch this video outlining the PET procedure (courtesy of UCL/UCLH NIHR Biomedical Research Centre).
For more information on a type of PET specifically used to diagnose and study movement disorders please see single photon emission computed tomography imaging using DaT scan.
Single Photon Emission Computed Tomography (SPECT) imaging and DAT scans
Single photon emission computer tomography, commonly known as SPECT, is a type of neuroimaging which can give information on both the structure and the function of different parts of the brain. SPECT neuroimaging uses radioactive substances (called “tracers”) which connect to specific cells or parts in the brain. A specialized camera detects the radioactive radiation the tracers emit and uses it to re-consutruct an image of the relevant brain region. Dopamine is a major brain chemical and the loss of brain cells responsible for producing dopamine is believed to be the main cause of Parkinson’s disease. A special type of SPECT scan, called Dopamine Active Transfer scan (DAT scan) uses a tracer which labels dopamine-producing cells in the brain. This procedure can therefore be used to assess the number and activity levels of dopamine-producing brain cells. DAT scans can be used as part of the clinical diagnostic process for Parkinson’s and may be used in research to look at disease-related changes over time and to assess the effects of new potential treatments.
The procedure: SPECT and DAT scans require the injection or infusion of a radioactive tracer. The test requires only a small amount of radiation which is not associated with any long-term health risks. Following the injection you will be asked to wait approximately 3-4 hours before the scan can start. For the scan itself you will be asked to lie perfectly still on your back for the duration of the scan, which is typically 30-60 min. The images are taken with specialized cameras which can rotate all around you but will not touch you and you will not be enclosed in a tunnel-like scanner. Most of the radioactive tracer leaves your body through your urine within a few hours after the scan and your body breaks down the remaining tracer over the next few days.
Some medications may affect the results of the DAT scan and you will be asked to stop taking them at least 2 days before the scan. Most anti-parkinsonian medications do not interfere with the test and can be taken regularly but others, including many anti-depressants, anti-anxiety and other medication will need to be stopped for a few days. In any case you should discuss your full list of medications with the doctor or researcher who referred you to the scan ahead of time.