Can normal EEG have spikes?
Some waveforms or activity on an EEG are normal, while others may be within normal limits for some people but not others. Spikes or sharp waves are terms commonly seen in EEG reports. If these happen only once in a while or at certain times of day, they may not mean anything.
What is spike-and-wave in EEG?
Spike-and-wave is a pattern of the electroencephalogram (EEG) typically observed during epileptic seizures. A spike-and-wave discharge is a regular, symmetrical, generalized EEG pattern seen particularly during absence epilepsy, also known as ‘petit mal’ epilepsy.
What are wicket waves EEG?
Wicket waves are by far the most commonly encountered benign variant and a frequent source of overinterpretation and mistaken diagnosis of epilepsy on EEG. Wicket waves are single waveforms that occur in brief trains or clusters.
What is a phantom spike-and-wave?
Phantom spike-and-wave bursts or 6Hz spike-and-wave bursts consist of brief bursts of spikes of very low amplitude with a repetition range of 5 to 7Hz. This pattern usually occurs bilaterally and synchronously during relaxed wakefulness, drowsiness or light sleep. Bursts disappear during deeper levels of sleep.
Are EEGs always accurate?
A normal EEG does not mean that you did not have a seizure. Approximately one-half of all EEGs done for patients with seizures are interpreted as normal. Even someone who has seizures every week can have a normal EEG test. This is because the EEG only shows brain activity during the time of the test.
What is a Persyst seizure?
The Persyst Seizure Detector neural network uses a wide range of inputs from the EEG in order to determine the probability that the data in a particular segment represents an electrographic seizure. These inputs include the background activity, Artifact Reduction, Rhythmicity, Amplitude, Symmetry, and many more.
What is sharp transient?
Positive occipital sharp transients can mimic occipital spikes. These are most highly present in the adolescent EEG. They have a characteristic checkmark appearance with an initial positive deflection in the occipital leads followed by a rapid surface negative deflection.
What is Spike waveform?
Spike sorting is a class of techniques used in the analysis of electrophysiological data. Spike sorting algorithms use the shape(s) of waveforms collected with one or more electrodes in the brain to distinguish the activity of one or more neurons from background electrical noise.
What are wicket spikes?
Wicket spikes occur both in the awake state and in light sleep. Their frequency is 6-11 Hz, and they usually occur in short runs (wicket rhythm) but may also appear as single sharp transients. The location is temporal, usually bilateral and independent.
What is ciganek rhythm?
Answer. Midline theta rhythm (ie, Ciganek rhythm) may be observed during wakefulness or drowsiness. The frequency is 4-7 Hz, and the location is midline (ie, vertex). The morphology is rhythmic, smooth, sinusoidal, arciform, spiky, or mu-like.
What causes PLEDs?
The cause of PLEDs was ischemic cerebral infarction in 11 patients; hemorrhagic cerebral infarction, central nervous system infection, and tumor in 3 patients; traumatic brain injury in 2 patients; limbic encephalitis in 2 patients; central nervous system vasculitis in 1 patient; and cerebral venous infarction in 1 …
Can you have an abnormal EEG and not have seizures?
To complicate this further, some people have ‘abnormal’ EEGs but do not have epilepsy. Also, many people who do have epilepsy will only have ‘abnormal’ activity on the EEG if they have a seizure at the time the test is happening.
What causes a sharp spike on the EEG?
Mesial temporal lobe epilepsy, a common type of focal epilepsy, often lacks scalp EEG correlates. Small sharp spikes on EEG were time-locked to hippocampal discharges recorded on intracranial electrodes. Small sharp spikes can be EEG markers of mesiotemporal lobe epilepsy rather than normal variants.
Where are small sharp spikes in the electroencephalogram?
The terms small sharp spikes (SSS) and benign epilepti – form transients of sleep (BETS) are synonymous. These quick, low-voltage spikes are usually seen in the tempo- ral areas with a broad gradient across the temporal chain. The upward and downward phases of the tran- sients are usually of similar amplitude.
When do small sharp spikes occur in sleep?
Small sharp spikes (SSS) Synonymes: BETS (Benign Epileptiform Transients of Sleep) and benign sporadic sleep spikes. Occur in light sleep (non-REM 1 and 2 sleep) Amplitude of <50 microV and duration of <50 ms. Usually monophasic, occasionally diphasic. Occasionally followed by a slow wave, however do not disturb the background.
Which is the normal variant of the EEG?
NORMAL VARIANTS THAT MIMIC SINGLE EPILEPTIFORM WAVES Posterior Occipital Sharp Transients of Sleep Posterior occipital sharp transients of sleep (POSTS) are one of the most common normal variants seen in the EEG and can be considered one of the normal elements of sleep.