The function of brainmapping is to gather objective data, the EEG (electrical signals of the brain) (FIGURE 3) that can be processed through a program that displays metrics relevant to functioning in a visual display that facilitates understanding.
Some of the metrics are that individuals brainwaves in amplitude or power, measured in microvolts and seen changing along a y-axis, and frequency measured in hertz (cycles per second) and seen fluctuating along the x-axis. (FIGURE 4) Other metrics look at the individual’s data compared to a normative database, comparing that person to age and gender matches. Here the brainmaps are displayed in z-scores. (FIGURE 5).
The brainmaps are one part of understanding subjective symptoms and finding the possible connection with the objective data collected. Brainmaps are a big part of coordinating a treatment plan toward the desired outcome. They are not necessary but they are useful. The normative database mapping program used is Neuroguide. This requires a full 19 channel assessment.
The LENS map, although not using a normative database, provides a report that assists in guiding treatment, and for those who cannot sit for a full 19 channel mapping, makes a map possible. 1 site at a time, on the average of 4 seconds per site, is recorded with the LENS maps.
The process of brainmapping with a full cap can be intimidating at first but then is often quite interesting for the client. IDEALLY the client has a good night’s sleep the night before and has a clean scalp without products in the hair the day of the recording. A cap will be chosen to fit your head. The 19 electrodes in the cap record the signal coming from your scalp. Nothing is put into your head. A wet gel is put into each electrode. This is a difficult signal to read at the scalp so a lot of care is taken to ensure a ‘clean’ reading. The client will sit still in a comfortable chair and position. The recording takes place at rest and with eyes open and then with eyes closed. It is also possible to record ‘at task’ relevant to the client’s request.
Food and drugs do effect the EEG. Please consult with myself and/or your doctor as certain medications should not be discontinued abruptly. Alcohol, marijuana and other street drugs should not be used before the recording. To the degree that it does not create more anxiety, caffeine and nicotine should also be avoided before the recording. The client is welcome to eat a meal complete with protein and an hour or two before the recording.
The International 10-20 system is a method for describing the location of where electrodes are placed on the scalp and its underlying area of cerebral cortex. The 10 and 20 refer to the distances between adjacent electrodes being either 10% or 20% of the total front-back or right to left distance of the skull.
Each site has a letter to identify the lobe and a number to identify if the site is on the right or left hemisphere.
The numbers:A “z” refers to an electrode placed on the midline. Even numbers (2, 4, 6, 8) refer to electrode positions on the right hemisphere and odd numbers (1, 3, 5, 7) refer to electrode positions on the left hemisphere.
There are certainly associated functions with the varying locations. Additionally, certain brainwave patterns would be expected at some locations and during certain states. It is stated that 50% of the activity we see in the EEG at a specific site is from that neuronal synchrony at that location and the other 50% of the activity we see in the EEG is recruited from the interconnections with other neuronal groups synchronizing.