Like any other organ of our body the brain is
also prone to a number of disturbances exerted by inner and external influences. Internal reasons might be disturbances of the blood flow and by
it supplementation of oxygen. External influences might come from intrusion of
bacteria and viruses. But also traumatic influences are of considerable
meaning. As multifunctional disturbances can be, as heterogeneous are the
consequences. This is a trivial statement, which shows special consequences,
since we are dealing with a highly complex system. In many organs partial
disturbance of a particular region only leads to quantitative diminution of
total organ capacity. With respect to the brain one might suffer from a variety
of different qualitative and quantitative failures. This is quite obvious in
the case of stroke or tumors, where particular regions suffer from local
disturbances, or even lack their function totally. This high complexity together
with the network structure as mentioned above asks for evaluation of its total
functionality. Traditionally, one discriminates between the so called “somatic”
part of the brain and its “psychic” components. Breakdown of the former part is
covered by the field of neurology, whereas breakdown or disturbances of the
latter are covered by the field of psychiatry. Fortunately, both areas are very
often covered by one and the same doctor, at least within Germany. Differences
are also reflected by different diagnostic tools. Neurologists mainly use methods based on the visualization of the
brain`s “hardware”, but psychiatrists still depend on the verbal communication
of subjectively experienced symptoms.
Broadest use in neurology is made of x-ray,
computer tomography and magnetic resonance tomography (MRT). In the second case
electroencephalography (inclusive evoked potentials, see later) and functional
MRT. In addition, ultra sound technologies are used currently more and more. I
mention this because the development of technical methods for assessment of
possible “somatic” causes of disease has made large progress, whereas for
example electroencephalography as “software check” remained far behind its
possibilities. The mathematical description of the electric brain activity by
means of the Fast Fourier Transformation (FFT) as well as the definition of
particular frequency ranges according to their physiological meanings, as
realized in the CATEEM system, seem to be very promising.
After extensive use of the CATEEM system for
characterization of drugs and after its successful use in sleep research it was
decided to learn more about disturbances of electric brain activity during
disease processes. Based on the assumption, that disease origins from
disturbances of electrochemical communication within the brain, the goal
emerged to describe the current state of the brain in terms of changed local frequency
patterns. All what was needed now was a data base of healthy subjects characterized
in the same manner giving median numbers of all six frequency ranges at each of
the 17 locations. A total of 500 healthy volunteers of both sexes aged 18 to 80
participating in our medication studies were used to construct a “normal”
database. The distribution of these 102 values (17 electrode positions times 6
frequency ranges) now serves for comparison of single patients to this data
base. According to the distribution function, error probabilities for each single
value are calculated and given as numbers from 1 to 4 representing error
probabilities from 10:1 to 10000 to 1. Fig. 1 documents the mathematical base
of the calculation.
Fig. 1 Calculation of the aberration index
This value is called “aberration index”. In
medicine “normal values” are based on averaged mean numbers collected from a larger
population. Even if your blood pressure is not exactly 120 to 80, it can still
be normal. But the larger the deviation of individual values, the higher the
probability of having a pathological feature. For mapping the same type of
color code is used as for depiction of the original data, but now they
represent the statistical deviation from normality. Fig. 2 shows examples of
the recorded electric disturbances during different diseases.
With this index an objective measure for the
occurrence of a functional disturbance of the brain was developed, which not
only can be used as a diagnostic aid, but also could serve as control for a
therapeutic success. If the aberration index becomes smaller this is
interpreted as an approach to normality. During the course of degenerative
disease also a progressive development can be detected using this parameter.
From this is becomes obvious that this parameter is useful for the evaluation
of the effect of medications as could be shown recently in patients suffering
from Parkinson`s disease (Dimpfel et. al. ,2014).
Consequently, a large number of patients have
been recorded using the CATEEM technology in numerous hospitals. We always made
the experience, that discoveries of “hardware” abnormalities were accompanied
by disturbances of electric activity. Of special interest were disturbances of
electric brain communication, which up to now have escaped objective
quantitative measurements. I like to mention headache and especially migraine,
since we – using the method developed by us – succeeded for the first time to
record clear, statistically significant, reproducible changes of electric
patterns of this disease. Recording from more than 600 patients suffering from
migraine indicated that in about 90% of the cases a deviation from normality
was detected. But results also revealed the heterogeneity of headache and
migraine, since deviations form normality not only occurred within different
brain areas but also with respect to different frequencies. These deviant
electric patterns were recorded during the ache-free interval and support the
neurogenic origin of the disease. However, many textbooks refer to the vascular
origin of migraine, based on disturbance of the blood flow. Since higher
nervous systems activity at the same time recommends higher oxygen demand, it
is very difficult to see where the original disturbance comes from, the famous
egg-hen problem. Thus, quantitative assessment of EEG recordings using neo-CATEEM
(http://www.mewicon.at) provides an entirely
new approach in objectifying pathological disturbances of the brain during
disease.
Examples of quantitative assessment of
pathological electric brain activity using CATEEM.
Reference
Dimpfel W, Öhlwein C, Hoffmann JA, Müller T (2014) Parkinson`s Disease during Therapy with Rasagilin. Advances in Parkinson`s Diesease 3: 22-34
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