Sharp Slow Waves in the EEG

Janati, Abdorasool; ALGhasab, Naif Saad; Alshammari, Raed Ayed; AlGhassab, Abdulmohsen saad; Fahad, Al-Aslami Yossef

doi:10.1080/21646821.2016.1151311

Cited by 3 publications

(5 citation statements)

References 19 publications

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“…The high incidence of congenital CNS anomalies in the aIED group (39%) versus the IED group (6%) is in accord with previous findings published in the literature 14–18. For example, FTSW are characteristic of Rolandic epilepsy whereas ND was originally thought to be pathognomonic of Angelman syndrome.…”

Section: Discussionsupporting

confidence: 89%

“…Similarly, cortical deafferentation has been implicated in the genesis of FTSWs, where pacemakers located in deeper structures of the brain, such as the entorhinal-hippocampus complex may be the source of this activity 15. SSWs are thought to originate in lower cortical layers where augmentation of deep cortical EPSPs occurs 16. This is followed by widespread projection of this activity to the surface, inducing SSWs.…”

Section: Discussionmentioning

confidence: 99%

“…Theoretically, this process is triggered by cortical deafferentation due to a sub-cortical pathology. Bifid spikes17 and “notched” delta18 are presumed to emanate from conduction defects in projection fibers, resulting in the electrical signals reaching the scalp with different latencies, configuring a “notched” appearance.…”

Section: Discussionmentioning

confidence: 99%

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Atypical Interictal Epileptiform Discharges in Electroencephalography

Janati¹,

ALGhasab²,

Aldaife³

et al. 2018

J Epilepsy Res

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Background and Purpose A great deal of attention has been focused on “typical” interictal epileptiform discharges (IEDs) in the electroencephalography (EEG) literature. However, there is a paucity of data on “atypical” IEDs, namely, positive sharp waves (PSWs), focal triphasic sharp waves and spikes (FTSWs), sharp slow waves (SSWs), bifid spikes, and “notched” delta. In this present study, we sought to address the pathophysiology, characteristics, and diagnostic significance of “atypical” IEDs in clinical neuroscience. Methods We prospectively reviewed the EEGs of 1,250 patients from a heterogeneous population over a period of 2 years. We also documented demographic, clinical, and neuroimaging data. Results Thirty-one patients had PSWs, 26 had FTSWs, 30 had SSWs, 24 had notched delta, and four had bifid spikes in their EEG data. Ninety-six percent of patients with PSWs had epilepsy whereas 100% of the FTSW and SSW groups had this diagnosis. In the ND group the rate of epilepsy was 95% and in the bifid spike group 75%. Accordingly, “atypical” IEDs are potentially epileptogenic patterns with localizing significance, occurring primarily in younger age groups. We also found that a significant number of these patients had congenital central nervous system anomalies. Conclusions We conclude that “atypical” IEDs are rare and under-reported EEG patterns that potentially signify focal epileptogenicity. Our data also stresses the significance of neuroimaging in investigating the possibility of an underlying congenital central nervous system anomaly in this population.

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Section: Discussionsupporting

confidence: 89%

Section: Discussionmentioning

confidence: 99%

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Atypical Interictal Epileptiform Discharges in Electroencephalography

Janati¹,

ALGhasab²,

Aldaife³

et al. 2018

J Epilepsy Res

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“…Hence, we ruled out possible risk factors for the development of new seizures like substance use or withdrawal, sleep deprivation, and nutritional deficiencies. However, the finding of sharp and slow waves on the EEG after a week of the incident may indicate the possibility of an underlying epileptogenic focus [ 10 , 11 ]. Although, the CT scan ruled out gross structural anomalies, a high resolution MRI would have been the ideal imaging modality.…”

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confidence: 99%

Generalized seizure induced by continuous theta-burst stimulation (cTBS) in a patient with bipolar depression: A case report

Kelkar¹,

Sreeraj²,

Mehta³

et al. 2023

Brain Stimulation

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“…6 Deep layers of the cortex may also be the source of other atypical IEDs (e.g., focal triphasic and sharp slow waves), 7,8 where cortical deafferentation due to a subcortical pathology (e.g., heterotopias) may theoretically produce such patterns. Atypical IEDs are generally rare and probably underreported EEG patterns with focal and epileptogenic significance.…”

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confidence: 99%

EEG spikes resembling cardiac M-shaped waves in the EKG: the cerebral M pattern

Janati¹,

ALGhasab

Aziz

et al. 2017

Ann Clin Neurophysiol

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Interictal epileptiform discharges (IEDs) in the electroencephalogram (EEG) are electroclinical patterns typified by sharp waves and spikes, and defined as waveforms that are distinct from the background activity due to their high amplitude (typically 2.5-fold higher than the background voltage). Their duration may vary from less than 70 ms (classified as spikes) to 70-200 ms (classified as sharp waves). There is a large body of literature on the characteristics of typical IEDs 1-5 but a paucity of data on atypical IEDs.All scalp-recorded electrical activities are generated by postsynaptic potentials in cortical neurons. It is hypothesized that IEDs represent the summation of excitatory postsynaptic potentials (EPSPs) and inhibitory postsynaptic potentials in the cortex. IEDs in scalp recordings typically have a negative polarity that reflects the action of perpendicularly oriented neurons in the cortex. However, it is noteworthy that in certain types of cerebral insult (particularly congenital CNS anomalies), augmentation of the deep cortical EPSPs may Studies of interictal epileptiform discharges are essential for improving the diagnosis, classification, and management of epilepsy. In this case series we sought to identify the clinical and neurophysiological significance of bifid spikes, whose pattern bears a strong resemblance to the cardiac M pattern. We hypothesize that, analogous to the cardiac M pattern, the cerebral M pattern is generated by a conduction defect associated with asynchronous spatiotemporal averaging of electrical signals in the cortex, resulting in the signals reaching the scalp with different latencies. Unlike the cardiac M pattern, the pathology underlying the cerebral M pattern is unknown, although congenital CNS anomalies may be a culprit.

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Sharp Slow Waves in the EEG

Cited by 3 publications

References 19 publications

Atypical Interictal Epileptiform Discharges in Electroencephalography

Atypical Interictal Epileptiform Discharges in Electroencephalography

Generalized seizure induced by continuous theta-burst stimulation (cTBS) in a patient with bipolar depression: A case report

EEG spikes resembling cardiac M-shaped waves in the EKG: the cerebral M pattern

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