Can Anyone In The Medical Field or Anyone Read This, And Tell Me What It Mean?
I had an EEG done on 12/13-14/2007, I got a copy of my medical records and was reading this but I don't know what it means. This what is says word for word. CLINICAL INFORMATION A 24-hour extended ambulatory EEG recording had been requested for evaluation of syncope. The patient has fetal alcohol syndrome. A previous ambulatory EEG was unsuccessful because three electrodes fell off. Routine EEG done on 10-19-07 has been interpreted as being suspicious of epilepticform activity because of generalize slowing seen during hyperventilation amd because of frequent focal beta and delta waves the left temporal head area. No medications are listed. EEG DESCRIPTIONS This is a 24-hour ambulatory EEG obtained as an outpatient utilizing standard 10-20 international electrode system with accompany EKG lead. It is obtained with the patient awake, drowsy and asleep. During the awake records there is considerable amount scalp muscle artifacts as is usual for ambulatory recordings. C3 and C4 electrode artifacts are particularly prominent but do not interfere with interpretation. The dominant posterior awake rhythm is a symmetrical 8-cycle per second (Hz) alpha with low voltage fast frequency beta rhythm seen over both hemispheres. During sleep vertex sharp waves, K complex and symmetrical sleep spindles are noted. Numerous localizing montage fail to reveal any abnormalities including epileptic abnormalities. There were no patient marked events. Thank you all for the help. Please don't tell me to take it to a doctor. If you want to you may e-mail your take on it, at juju.bigley@yahoo.com
What are your brainwaves on weed?
Here’s an article from VICE on the very subject. It’s a very small sample and not a scientific study but still it’s very interesting.There are pretty dramatic effects visible on an EEG.Apparently after smoking a spliff or eating a cookie the two participants had much more higher, frequency, higher amplitude, and more chaotic brainwaves. There seems to be some left hemisphere / right hemisphere differences too.They had also been drinking a bit so it’s a possibility that it’s not purely the weed.This Is What Your Brain Looks Like After You Smoke Weed | VICE | United StatesHere are the conclusions of a more controlled study of acute THC use and it's effects on EEG.Results: Recreational smokers scaled significantly higher than the controls on both psychometric scales. Cannabis induced a moderate increase of the mean EEG power in the alpha1 band a8–10Hz), a robust increase of the power in the gamma band a30–40Hz) and on the contrary a moderate decrease in the alpha2 band a10–12Hz). EEG coherence was mainly decreased across the whole spectrum, with the most robust changes being present in the beta a12–25Hz) and high beta a25–30Hz) bands. sLORETA analysis showed a robust gamma current density increase in the frontal and temporal lobes and a small decrease of alpha2 activity in the middle cingulate and premotor cortex aBrodman area 6 and 24). Changes were much less pronounced in chronic users. None of the PPI parameters were significantly affected by the drug; however the startle reaction in chronic users tended to be increased compared to other groups.Conclusion: Some parallels can be seen compared to EEG and psychometric findings in acutely psychotic patients. These findings may imply that acute THC can serve as a model of psychosis. On the other hand, the ineffectiveness of cannabis to disrupt PPI is contradictory and its value as a translational parameter in human models is disputable.http://www.ecnp-congress.eu/pres...So this seems to confirm the impression from the VICE article that the high frequency beta activity becomes more incoherent. There is a moderate increase in alpha1 band power and a decrease in alpha2 band, but more prominent is a strong increase in the higher frequency gamma band power.
What is the significance of having coherence and phase synchronization in signals with respect to EEG? What is the meaning of presence of phase synchronization in EEG signals?
Any signal (biomedical here) has a few basic components. They are wave amplitude, frequency and phase. The waves of the brain are mainly divided into a few well known frequency bandwidths, alpha, beta, theta, delta, gamma and most of these oscillations tend to have a particular area in the brain there they are predominant. Like the alpha rhythm being prominent in the occipital cortex and it’s variants oscillating in the temporal and sensorimotor cortices, beta being in the sensorimotor cortex etc etc.However, just self sufficient and independent regions of oscillations are not enough to provide the rich dynamical structure of the brain. For any meaningful interpretation of stimulus and for exerting a meaningful behavior, these rhythms communicate with each other. And the manner in which they communicate is what we see with coherence and phase synchronization.Looking at any such measure between different brain regions is what we call functional connectivity. Which translates to communication between two regions which may or may not have any structural connection.Cxy(f)=|Gxy(f)|^2/Gxx(f)Gyy(f)Coherence mainly deals with the correlation of the power spectral densities. In simple terms, coherence looks at communication between any two regions of the brain in terms of frequency and therefore ignores the other two measures of amplitude and phase which tends to make it an unsatisfactory computation if we want to look at functional connectivity.Phase synchronization or phase based measures in general look at the correlation between phases which is supposedly more in tune with how the brain looks at information. Of course, it’s not the entire picture. Communication happens between different areas and across different frequency bandwidths. So, to get a better estimate, we tend to look at cross frequency communication i.e. how the amplitude or phase of one frequency is en-trained by the other frequency bandwidth.Buzsáki, Gyorgy. (2009). Rhythms of The Brain. Rhythms of the Brain.. xiv, 448 p.. 10.1093/acprof:oso/9780195301069.001.0001.