Medical procedures available with us

In neurology and psychiatry, technical examinations may be necessary. For example, an EEG can be helpful in cases of temporary confusion or suspected epilepsy. Nerve injuries, on the other hand, can be measured using ENoG and EMG to determine the cause and location of the damage. The nerves in the central nervous system (CNS) that transmit your senses (seeing, feeling, hearing) can also be checked with the so-called evoked potentials. If there is the possibility that the carotid arteries could be constricted or a constriction is already known, sonography is useful (if necessary also for control purposes). A lumbar puncture may be necessary to diagnose dementia or inflammation of the brain. On this page we would like to briefly explain these different techniques to you.

Updated 28th January 2021 — Michael Vorwerg

Table of contents

Electroencephalography (EEG)

The brain (including yours!) works in such a way that small brain cells (we call them ”neurons“) send small currents back and forth along small wires (we call them ”axons“). Since the brain consists of a very large number of brain cells (estimated at least 100 billion, i.e. 100,000,000,000 or 1011 neurons), this creates a complex and intricate network of current-carrying axons. The current flow is not random but finely ordered (otherwise the brain would not work). So if thousands of neurons send currents back and forth together, a ”current pattern“ (actually: voltage differences, but that is not so important here) can be detected above the scalp. This pattern is called an EEG. If the brain is diseased and therefore the currents are no longer in order, you can see this from the EEG pattern (if you know what you are looking for). When you come to the EEG, we will attach many small wires onto your scalp. In order for these to conduct the current well, we have to put a kind of paste under the ends of the wires (we call them "electrodes"). For this reason, it is also important that you come with cleanly washed hair and do not apply hair wax or any other hair products. The EEG is not unpleasant. You sit on a comfortable chair for about 20 minutes and have to open and close your eyes every now and then. During the process you will also be asked to breathe in and out vigorously (we call it ”hyperventilating“) to ”provoke“ the brain. Sometimes it is only through such provocation that changes in the EEG can be detected. That is why you should make an effort with hyperventilation!

Evoked Potentials (SEP, VEP and AEP)

When your senses are stimulated, they send impulses to the brain. However, it takes a short moment (a few milliseconds, i.e. thousandths of a second) before it gets there. The exact duration can be predicted fairly accurately. For example, if you have a picture in front of your eyes, it takes about 100 milliseconds for the information from your eyes to reach the cortex. For each sense there is a different place in the brain where the impulse is sent to. If you hear a sound or feel something on your arm, then after a roughly known time, this stimulus causes a small change in the nerve cells in the cerebral cortex. We can then measure these changes. In other words, we can evoke changes (we call those ”potentials“) in the brain and wait for the answer at the right moment. This is where the term ”evoked potentials“ comes from. Sensory skin stimuli we call ”somatosensory“, eye stimuli ”visual“ and hearing stimuli ”acoustic“. Hence Somatosensory, Visual or Acoustic Evoked Potentials (SEP, VEP and AEP). The measurement itself is done, similar to the EEG, with wires attached onto the scalp (we call them ”surface electrodes“), but only a few. Nevertheless, we will also put a kind of paste under these electrodes. Just as with the EEG, we would like to ask you to come to the examination with cleanly washed hair and without any hair products applied. The measurement will take a while because the evoked potentials are very, very, very small (microvolts, i.e. millionths of a volt). It is therefore necessary to calculate average values from up to 200 measurements in order to ”average out“ the basic electrical brain activity noise. Fortunately, computers do this for us!

Neuronography and Myography (ENoG and EMG)

If you do something, it is with your body, which is controlled by your brain. The brain control is transmitted to the body via small wires (we call them ”nerves“) that run through almost your entire body. The ”thick wires“ conduct enough electricity to be measured from a distance of a few millimetres. If, however, such a wire (let's call it a ”nerve“) is damaged, the measurement will show a change, some of which is very specific. In this way, we can often precisely identify the type and location of the damage. To do this, however, it is necessary to stimulate the nerve with a small impulse. This stimulus may feel a little uncomfortable, but is completely harmless. If the nerve is functioning normally, then the stimulation induces a current that runs along the nerve. It can then be ”received“ at a slightly distant location above another part of the nerve, or a muscle supplied by the nerve, after a short duration. The transmission speed is very fast because a nerve potential can travel up to 120 metres in one second. In nerve measurement (we call it ”electro­neuronography“, abbr. ENoG) the speed can be determined precisely. The derivation on the muscle is called ”electro­myography“ (EMG). Through this examination, we can quickly see, for example, whether you are suffering from carpal tunnel syndrome. However, a measurement inside the muscle can answer further questions. Most nerve and muscle diseases lead to specific changes in the electrical activity of the muscle tissue. For this procedure, a very thin needle-shaped electrode will be inserted into the muscle. The electrical activity of the muscle will be displayed on an oscilloscope and additionally converted into sounds. We can then see and ”listen“ to your muscle at work!

Duplex Ultrasonography of Brain Arteries

Although your brain is only about one-fiftieth (1/50th) of your body weight, it still requires one-fifth (1/5th) of your total body energy. So if you eat 5 rolls a day, one of them is for your brain. Such an energy-hungry organ needs to be well supplied with blood. For this purpose, the blood that is richest in oxygen and nutrients is first of all conducted from the heart to the brain. The blood-carrying vessels (we call them ”arteries“) are subject to a certain amount of pressure due to their location close to the heart. If you then have high blood pressure, the pressure is passed on to these brain-supplying arteries and can damage them. Other known risk factors that can damage your arteries include smoking, diabetes mellitus, high cholesterol, being overweight, poor diet and insufficient physical activity. These lead to deposits, especially at branches of the arteries. Although these initially do not cause any symptoms for years, at some point they can suddenly appear constricted or even occluded and cause strokes. But thanks to ultrasound technology, we can detect even small deposits, initiate a search for your risk factors and, if necessary, counteract them with medication. Severe constrictions can be treated with interventions such as surgery or stent implantation. A hospital stay is required for these procedures. Follow-up ultrasound checks are necessary and can be carried out by us.

Lumbar Puncture (LP) for Cerebrospinal Fluid Analysis

Inside your skull bone lies your brain. More precisely you could say your brain ”floats“ there, because it is completely surrounded by water. This brain-water (we call it ”Cerebrospinal Fluid“) actually looks like clear spring water. However, some neurological conditions, including meningitis or cerebral haemorrhage, can cause turbidity or colouring of the cerebrospinal fluid. These usually have serious symptoms and as such they are nearly always diagnosed and treated in hospitals. However, the examination of the cerebrospinal fluid can also detect less acute, although not necessarily harmless, diseases. For example, this procedure is essential if there is a justified suspicion of Lyme disease or multiple sclerosis. Fortunately, we do not have to drill into your skull to get to your cerebrospinal fluid (that would be too dangerous for us). We will extract the fluid where it is least difficult: at the lower spine using a thin hollow needle. During the puncture of the lumbar spine (hence the name "lumbar puncture" or "LP" for short) you will sit on a stretcher with your back bent. The amount of liquid removed is small, usually 4 to 6 milliliters. There is a total of about 200 millilitres of cerebrospinal fluid (as much as fits in a water glass) in your head and around the spinal cord. Between 600 to 800 millilitres of this fluid is produced daily. Therefore, it can be said that it is exchanged completely 3 to 4 times a day. Despite the small amount we remove you may occasionally have headaches after the lumbar puncture. Side effects can be avoided by drinking plenty of water after the puncture, which is said to facilitate the replacement of your cerebrospinal fluid. We will discuss the procedure with you in detail before the examination.