The first part of any clinical assessment is the consultation. This involves a visit to the clinic during which I will take your history and perform the physical examination. The initial clinical impression will be discussed as well as the proposed plan of action. This may involve a treatment with medication or there may be the need for a clinical test (described below). Following that the tests will be scheduled and once they have been done I will discuss the results and treatment plan from there.
If you feel your main issue is memory then I will schedule you for a formal memory assessment. During this consultation I will assess you and perform memory tests and then I will interview your carer (spouse, sibling etc). I find this the best way to get an accurate history and sense of what the main issue may be (see dementia page). I will then schedule you for an MRI brain scan with a special sequence that evaluates the memory areas of the brain. We will then meet again and discuss the treatment plan from there. If you are diagnosed with a cognitive impairment we will chat about how to improve memory and the value of medication if that is what is necessary.
EMG and NCS are done together. The nerve conduction studies portion involves stimulating nerves and looking at the responses generated. Depending on your symptoms nerves from the arm, leg or both are studied. Every nerve has both a sensory and motor portion and testing each portion of the nerve gives useful information. The stimulation can be quite uncomfortable but the discomfort only lasts for the duration of each stimulation.
The EMG portion involves sticking a small needle into various muscles- the combination of muscles tested will depend on symptoms you have presented with. The needle is similar in size to an acupuncture needle. It can cause discomfort. If the needle hits off a nerve twig there can be a dart of pain. The needle will be in each muscle for approximately one minute.
If you have symptoms such as numbness or tingling in the hands or feet or weakness in the arms and legs your doctor might send you for this test.
There are many different ways of testing the autonomic nervous system. The main testing involves what is called a tilt table test. This simply involves measuring the blood pressure and heart rate while you are lying flat and then when you are tilted to 60 degrees. There are straps on the table so you won’t feel like you are going to topple over. When you are tilted up to 60 degrees you will remain in that position for 40 minutes or until you experience symptoms. There is a blood pressure monitor on your finger- this measures your blood pressure every time your heart beats. Therefore your finger may feel a bit numb at the end of the test. There is also a regular blood pressure monitor on your arm. There is a heart monitor with 3 electrodes on your chest. In addition to looking at the blood pressure and heart rate in the lying down and tilted positions we also check how your heart rate varies with a deep breathing test and how your heart rate and blood pressure varies with another breathing test. (called a Valsalva manoeuver). At the very end of the test you will be asked to stand for 5 minutes again during which your heart rate and blood pressure will be monitored.
If you have symptoms such as lightheadedness, dizziness or fainting episodes you may be sent for this test.
EEG stands for electroencephalography.
Your doctor might want you to have this if you have an episode that could be a seizure.
It is a means of looking at your brain wave in real time. It involves sticking electrodes on your head with an electrode paste. The electrodes are connected to a machine through wires that then measures your brain wave for around 20-40 minutes. There are certain situations in which your neurologist will want a more prolonged monitoring of your brain wave. In this situation you will be admitted to the hospital overnight and the electrodes will be applied and left on overnight.
A lumbar puncture is a procedure whereby a sample of the fluid surrounding your brain and spinal cord is taken. This is called cerebrospinal fluid.
Your doctor might want you to have this test if there is a chance of inflammation or infection that is involving your brain or spinal cord.
It involves introducing a needle in to the lower back beneath where the spinal cord ends. The area is cleaned with an iodine solution which feels cold. Then a small needle is used to introduce local anaesthetic. Then after a few minutes the lumbar puncture needle is introduced in to the spinal canal. When the needle goes in you may feel a dart of pain or a tingling that goes down one leg. This is because at the base of the spinal cord the nerves come out in to what is called a “horses hair” and when the needle touches these fibres it can cause a dart of pain- this will not last or cause any harm. After the procedure you may be asked to lie flat for a few hours. The reason for this is to reduce the chance of developing a post lumbar puncture headache. There is a very small chance of bleeding or infection at the site where the needle is introduced however a sterile technique is used to minimise this risk.
The post lumbar puncture headache is the most common side effect of having a lumbar puncture. It occurs because after the needle is put in to take the fluid it may leave a tiny hole and before that naturally closes up more fluid leaks out and this causes a “low pressure” headache. This means the headache will become worse on standing up. Drinking plenty of fluid and caffeine usually helps this headache. If it occurs it should settle within a week to 10 days. If it persists beyond this you may need what is referred to a blood patch. This involves taking a sample of your own blood and reintroduce it in to the spinal canal in order to close up the hole.
These are types of scans of the brain and spinal cord. Depending on what you have presented with I may suggest you have one or other.
The CT scan gives a broad picture of the brain and is useful in emergency types of situations. For example, if you think you may be having a stroke then the first test you will have once you arrive at the hospital will be a CT of your brain- this is because it is quick (it takes about 3-4 minutes) and is available in almost every hospital. It gives quick information such as whether or not your stroke is from a bleed or clot (see stroke page).
An MRI brain gives a much more detailed picture of the brain. It is the test of choice for most non-emergency neurological issues. It would be the test used in the diagnosis of multiple sclerosis for example or to look at the memory structures in the brain as well as in many other conditions. The MRI of brain takes between 20 and 40 minutes depending on the clinical question. It can be quite noisy. The MRI scan may be of the brain alone or may include all or some of your spine. Occasionally you may receive an injection of a contrast “dye” for the scan. This is because in certain conditions whether or not the contrast is taken up by certain brain structures is important.
During both the MRI and CT scans you may also have an image to look at the vessels in the brain- this is called an angiogram. This won’t make any difference to the scan in terms of how it is done- at most it will add on an extra 5 or 10 minutes.
If you are anxious about going in to the MRI scanner then you can ask your GP to give you a low dose of Valium to take half an hour before the scan.