Published: Monday, October 24th, 2011
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In this publication we will give you a general overview of Neurotrophic Factors and the Neurophysiological Evaluation we applied.
Studies are being made for consistency and power analysis relating to events, this is a test that evaluates the answers or voltages generated by each region of the brain when performing a task or activity that requires cognitive effort.
The neurophysiological evaluation includes the following studies:
-Frequency analysis of EEG
- EEG coherence Analysis
-EVOKED POTENTIALS RELATED TO EVENTS INCLUDING P300
- Topographical visual Potential -
- Audio Potential for Long-Latency
- Coherence Analyses of related events
Next is a brief description of the different neurophysiological tests that can be applied to the patient.
P300: The P300 wave (P3) is a power related to a cognitive event obtained by an infrequent stimulus, relevant to a task. It is considered as a potential endogenous because its occurrence is due to the subject’s reaction to the stimulus and not the physical attributes of the stimulus. To be more specific, the P300 reflects processes involved in stimulus evaluation and categorization. A typical procedure is the oddball paradigm, in which a target stimulus (target or goal) occurs from more frequent background stimuli. A distractor stimulus can also be used to ensure that the response is due to the target in place rather than a change in the background pattern. We use an audio stimulus for the frequent and distracting stimuli. When recording using an electroencephalogram (EEG), this wave appears as a positive voltage deflection with latency (delay between stimulus and response) of about 300 to 600 ms. The presence, magnitude, topography and time of this signal are used to measure cognitive function.
ATTENTION (Contingent CPT): This test is a visual continuous performance task in which the answer depends on the appearance of two consecutive letters (S-T). Conditional execution tests have a long and rich history in the evaluation process trials (Rosvold, 1955). Certain parameters of this task, such as stimulus characteristics, number of trials and blocks and external triggers are controlled by the subject. In the continuous subject tested the patient is presented with random letters. The patient’s goal is to press a button on the mouse only when a specified letter appears to be used as a target.
MEMORY SPACE NOTICE: The test based on a visual spatial memory is a task that can be configured at various levels of difficulty. The number of location of the objects can be changed, the time between the presentation of the stimulus (simultaneously or sequentially) and the time between stimulus presentation and response. The visual memory test requires that the patient retains the location of the objects presented on the screen.
MENTAL FLEXIBILITY (CARDS): The card sorting test is inspired by the Wisconsin Card Sorting Test (Berg. 1948, D.A. Grant and Berg, 1948) which was designed to analyze the “abstract behavior” and “mental flexibility”. The test is sensitive to frontal lobe damage shown by the difficulty to classify according to a category (Drewe, 1974) and a non-specific brain damage, according to persistent errors (Robinson, 1980).