Diagnosing dementia
AS THE MEDICAL PROFESSION WORKS TO DEFEAT DEMENTIA,
DIETER GROSSEGGER
OF ALPHA TRACE EXPLAINS THE BENEFITS OF BETTER
MEDICAL DIAGNOSIS IN DETECTING FUNCTIONAL CHANGES IN THE BRAIN
Pan European Networks: Science & Technology
06
Dieter Grossegger PhD
Chief Executive Officer
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The next consequent step will be a comparison
of calculated EEG parameters with a normative
database. Since a person’s EEG signature
changes over its course of life, the database will
either be age matched or specifically generated
for a certain age group. The letter will be
an appropriate concept, since the dementia
issue typically concerns people aged 60 and
more. The crucial statistical step follows next to
the extraction of key parameters from a
multitude of calculated EEG parameters, to
achieve physiological evidence for the diagnosis
of the most common diseases causing dementia,
which are: Alzheimer’s disease, dementia of Lewy
bodies type, vascular dementia, fronto-temporal
lobe dementia, mild cognitive impairment
and depression.
This is a call for neurologists to exploit the power
of EEG with quantitative and statistical methods
to position their services at the forefront of
affordable, non-invasive, and diagnostically
conclusive differential diagnosis of dementia.
T
he term dementia subscribes various diseases and conditions
arising from malfunctioning or dying nerve cells in the brain.
As a consequence changes in one’s memory, ability to think
clearly, and also behaviour may occur. When diagnosing dementia, many
symptoms as well as co-morbidities need to be assessed independently
with adequate diagnostic methods. Different diseases causing dementia
show different symptoms, but it is difficult to diagnose the types of
dementia from symptoms alone since there is considerable overlap.
Imaging techniques and/or invasive biomarker tests in cerebrospinal fluid
are common techniques to enhance diagnostic discriminatory power.
These techniques are expensive and/or invasive and not indicated as
standard diagnostic tools for dementia.
Since dementia is associated with functional changes in the brain, it is
indicated to intensify the consideration and inclusion of EEG-based tools
for differential dementia diagnosis. The Electroencephalogram (EEG) is a
non-invasive low cost diagnostic technique to record (with high temporal
resolution) brain-cortical function. In the typical EEG laboratory, the EEG
is recorded on PC-based systems and visually reviewed by trained
neurologists. A visual inspection of the routinely recorded EEG will expose
some information to the specialist suitable for a basic assertion of a
patient’s brain activity. However a differential dementia diagnosis cannot
be obtained from visual EEG review alone. The next and decisive step will
be a quantitative computer analysis of specific parameters calculated from
the EEG in question. Typically, such parameters are absolute/relative power
values per frequency band, coherence measures, and many more. Results
of such calculations may be presented as graphs and topographic
mappings already much more suitable to pick-up specific changes
indicative of dementia related processes.
EEG raw data, left:
topographic mapping of
absolute power values
per frequency band,
delta, theta, alpha, beta
Dementiagram
NEURODEGENERATIVE RESEARCH
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