“All that Spikes is Not Fits,” Mistaking the Woods for the Trees: The Interictal Spikes—An “EEG Chameleon” in the Interface Disorders of Brain and Mind: A Critical Review

Abstract

Recent research into mammalian cortical neurophysiology, after 6 decades of Berger's seminal work on electroencephalography, has shifted the older concept of interictal epileptiform activity (IEA) away from that of a mere electrographic graphoelement of relevance to diagnostic implications in epilepsy. Instead, accumulating information has stressed the neuropsychological implications, cognitive and/or behavioral consequence of these electrophysiological events, which are the phenotypic expression of aberrations of actual biophysical cellular function. We feel that this review is germane to neuropsychiatry, however, a rather neglected area of research. There is a great scope for brain-behavior-EEG research in the future that can be complimented by other techniques of "neurobehavioral electrophysiology". This review does not address the "pearls, perils and pitfalls" in the use of EEG in epilepsy, but critically and systematically reappraises the published electroencephalographic correlates of human behavior. We reiterate that epileptiform and other paroxysmal EEG dysrhythmias unrelated to clinical seizures do have neuropsychological, cognitive and/or behavioral implications as seen in the various neuropsychiatric and neurobehavioral disorders discussed in this article. IEA and EEG dysrhythmias should neither be ignored as irrelevant nor automatically attributed to epilepsy. The relevance of these EEG aberrations in the disorders of the brain-mind interface extend beyond epilepsy, and may be an electrophysiological endophenotype of aberrant neuronal behavior indicative of underlying morpho-functional brain abnormalities. Magnetoencephalography (MEG), data fusion models (EEG-fMRI-BOLD), transcranial magnetic stimulation (TMS), evoked potentials (EP); intracranial electrophysiology, and EEG neurofeedback complemented by current functional neuroimaging techniques (fMRI and PET) would certainly help in further understanding the broader relationship between brain and behavior.

Previously unrecognized behavioral phenotype in Gaucher disease type 3

“…This is far higher than the rate of EEG abnormalities in childhood populations. 36 EEG abnormalities and clinical seizures are associated with a range of behavioral problems, most often internalizing anxiety and depression 27 which may relate to the Cry/Withdrawal pattern of GD3. Spontaneous recovery from childhood seizures is well known.…”

Ambulatory Electroencephalograms in Neuropsychiatric Practice: Opening Pandora’s Jar

“…Nonetheless, a vast number of psychiatric patients have abnormal EEGs. Shelley and Trimble have reviewed these data demonstrating a recurring theme of significant EEG abnormalities in psychiatric populations [10]. One of the major problems in these studies is that there are no uniform criteria for IEAs, and many studies include, normal variants, such as 14 -6 psychomotor variants, small sharp spikes, phantom spikes, wicket rhythms, mid temporal discharges (RMTD), phantom spike waves, as EEG abnormalities [11].…”

“…An EEG is the summation of synchronized potential in the apical dendrites from a large ensemble of cortical neurons. An interictal spike is a brief morphologically defined event generated by synchronous discharges of a group of neurons from an epileptic focus [10] [17]. The relationship between interictal spikes and seizures that define acquired epilepsy has been controversial and has been debated for a number of years [18] [19].…”

Er EEG en nyttig undersøkelse i voksenpsykiatrien?

“…The research literature on the use of QEEG as a method to help diagnose depression, bipolar disorder and schizophrenia is unfortunately dominated by small-scale studies without blinded evaluation, and even in large-scale review papers there has been no attempt to assess the quality of the method (42,43). QEEG is nevertheless a useful research tool because it is difficult to quantify normal limits in a visual EEG interpretation (44).…”