<p></p>
<p><a name="_Toc29328820">When you come across an abnormal EEG, one where you see epileptiform discharges, etc., its important you refer your patient to a neurologist.&nbsp;</a></p>
<p><a name="_Toc29328820">However, understanding epileptiform EEG and all the different kinds of seizures is a task on its own.&nbsp;</a></p>
<p><a name="_Toc29328820">Here is a two hour long lecture on the EEG of Seizure and epilepsy, full of videos of what various seizures actually <i>look</i>&nbsp;like, in order to help the budding clinician.&nbsp;</a></p><iframe src="https://player.vimeo.com/video/465148872?h=c91f64ca82&amp;color=13979b&amp;title=0&amp;portrait=0" width="640" height="360" frameborder="0" allow="autoplay; fullscreen; picture-in-picture" allowfullscreen=""></iframe>
<p><br></p>
<h2><a name="_Toc29328820">Transient discharges</a> </h2>

<p>Paroxysmal transients in EEG can indicate: </p>

<p>
    <!--[if !supportLists]-->-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
    <!--[endif]-->Epileptogenic activity, indicating a seizure disorder
</p>

<p>
    <!--[if !supportLists]-->-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
    <!--[endif]-->Non-convulsive and non-epileptic activity </p>

<p>
    <!--[if !supportLists]-->-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
    <!--[endif]-->Cerebral vascular issues, tumors, and lesions</p>
<p></p>
<h2><a name="_Toc29328821">A Transient in the EEG</a></h2><br>
<p></p>
<p style="text-align: center;"><span style="font-size: 1rem;">&nbsp;</span><img src="@@PLUGINFILE@@/Transient.png" alt="Transient" width="477" height="443" class="img-responsive atto_image_button_middle" style="font-size: 1rem; text-align: center;"></p>
<p style="text-align: center;"><br></p>
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    <p></p>
    <h2 style="text-align: left;"><a name="_Toc29328822">Focal Slowing</a> </h2>

    <p style="text-align: left;">A focal slowing, if seen in the EEG, can indicate trauma, tumor, a lesion, or a healing grey matter injury. If delta is showing it can indicate an injury where the white matter is damaged and myelination is affected, if theta is showing it could indicate
        a grey matter injury (such as we would see in whiplash or a concussive injury). If the focus is at the posterior temporal lobes, good chance it is a cerebral vascular issue.
    </p>
    <h3 style="text-align: left;"><a name="_Toc29328823"></a><a name="_Toc3535229">Cerebro-vascular disorders</a></h3>

    <p style="text-align: left;">Cerebro-vascular disorders can be indicated by a slowing of alpha at one site. The slow edge of alpha tracks ischemia. An indication of a vascular issue (or impeded flow dynamics) is the presence of headaches or any sort of similar issue.&nbsp; In
        Nuwer et al (1997) there is a finding in cerebrovascular disease that show ischemia-related cerebral impairment to be seen in focal features (perhaps similar to the finding of slowing in the right posterior temporal lobe). </p>

    <p style="text-align: left;">When there is a lack of blood flow and oxygen to the area, there is often a consequential slowing of alpha at the area, sometimes into the theta range. As an area degrades, sometimes the alpha slows considerably below the normal alpha band (i.e. less
        than 8hz). A slowed alpha can represent a compromise of blood flow, and consequentially oxygen, to an area, which will lead to ischemia. The dip in alpha frequency will indicate how severe the ischemia is (Classen and Foreman, 2012). When cerebral
        blood ﬂow (CBF) becomes compromised, changes occur in both the metabolic and electrical activity of cortical neurons, with associated EEG changes.</p>
    <h3 style="text-align: left;"><a name="_Toc29328824">Epileptiform Discharge</a></h3>

    <p style="text-align: left;">A common feature of the epileptic disorders is a paroxysmal excitatory activity.</p>

    <p style="text-align: left;">Epileptogenic activity can be seen in the presence of spike waves, sharp waves, and the presence of spike and slow waves. Additionally, fast beta and gamma can indicate a kindling rhythm in the EEG, reflecting an irritable cortex that is pre-disposed
        towards seizure. Very often seizure will manifest in temporal lobes, which are the most vulnerable lobes for this type of pathology.</p>

    <p style="text-align: left;"><b>Spike:</b> An epileptogenic transient can be seen in a spike (a transient with a duration of less than 70 msec, but more than 20 msec and commonly negative in polarity. Spike morphology has a step incline. </p>

    <p style="text-align: left;"><b>Sharp Wave</b>: A transient that is 80 – 200msec. Morphology is usually pointed and voltage is usually high.</p>
    <h4 style="text-align: left;">Here is an EEG of an individual going through an absence seizure:<br>&nbsp;&nbsp;<video controls="true"><source src="@@PLUGINFILE@@/Seizure%20video.mp4?time=1597384319251">@@PLUGINFILE@@/Seizure%20video.mp4?time=1597384319251</video>&nbsp;<br></h4>
    <h4 style="text-align: center; ">Widespread epileptogenic discharge, affecting the EEG due to shared variance via the ear electrodes</h4>
        <p></p>
        <p style="text-align: center;"><span style="font-size: 1rem;">&nbsp;</span><img src="@@PLUGINFILE@@/Epileptiform.png" alt="Epileptiform Content" width="531" height="723" class="img-responsive atto_image_button_middle" style="font-size: 1rem; text-align: center;"></p>
        <p style="text-align: center;"><br></p>
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        <h3 style="text-align: left;"><a name="_Toc29328825">Epileptiform Discharge as seen in classic
Spike and Wave Phenomena</a></h3>
        <p style="text-align: center;"><span style="font-size: 1rem;">&nbsp;</span><img src="@@PLUGINFILE@@/Epileptiform%202.png" alt="Epileptiform 2" width="500" height="671" class="atto_image_button_middle" style="font-size: 1rem; text-align: center;"></p>
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            <h3 style="text-align: left;"><a name="_Toc29328826">Phase Reversals</a></h3>

            <p style="text-align: left;">Phase reversals are a focal finding in the EEG where the waveforms go electro-positive and electro-negative, looking as though they are pointing to each other. This is a marker of a physical abnormality and can point to the seizure focus,
                a lesion, hypoperfusion, localized infarct (a small localized area of dead tissue), or white matter ischemia. This is an “X marks the spot” type of finding. Phase Reversals can be seen using bi-polar montages.</p>
            <h3></h3>
            <h2 style="text-align: left;"><a name="_Toc29328827">Multi-focal spikes in the EEG</a></h2>
            <p style="text-align: center;"><span style="font-size: 1rem;">&nbsp;</span><img src="@@PLUGINFILE@@/multi%20focal%20spike.png" alt="Mulit focal spike" width="672" height="1097" class="img-responsive atto_image_button_middle" style="font-size: 1rem; text-align: center;"></p>
            <p style="text-align: center;"><br></p>
            <p></p>
            <h3 style="text-align: left;">Phase Reversals</h3>
            <p style="text-align: center;"><br></p>
            <h2 style="text-align: center;"><br></h2>
            <p></p>
            <p style="text-align: center;"><a name="_Toc29328827" style="background-color: rgb(255, 255, 255); color: rgb(82, 96, 105); font-size: 1rem;">&nbsp;<img src="@@PLUGINFILE@@/Phase%20Reversals.png" alt="Phase Reversals" width="772" height="1104" style="text-align: center;" class="atto_image_button_middle"></a></p>
            <a name="_Toc29328827">
                <p style="text-align: center;"><br></p>
                </a>
                <p style="text-align: center; "><br></p>
                <p style="text-align: left;"><a name="_Toc29328829" style="color: rgb(55, 71, 79); font-family: &quot;Open Sans&quot;; font-size: 1.715rem; background-color: rgb(255, 255, 255);">Encephalopathy</a><br></p>

                <p style="text-align: left;">Encephalopathy (low voltage slow)—you must also find the etiology, see if it is metabolic, toxic, traumatic, anoxic, electrolytic—no medication will work as long a there is insufficient support for brain function. You will treat this by
                    identifying and rectifying the root of the problem.
                </p>

                <h3 style="text-align: left;">Low Voltage Slow Profile</h3>
                <p style="text-align: center; "><img src="data:image/png;base64,[encoded data, 285864 characters]" alt=""><br></p>
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