Reexamining the Added Value of Intermittent Photic Stimulation and Hyperventilation in Routine EEG Practice

Abstract

Objective: Investigate the added value of hyperventilation (HV) and intermittent photic stimulation (IPS) to the routine electroencephalogram (EEG). Method: This is a retrospective review of 1,172 successive EEGs. The records with evidence of epileptogenic activity were identified and further analyzed to identify if the activation techniques could trigger the expression of epileptic activity not seen otherwise in the nonactivated tracing. Results: Activation procedures provided additional information in 9.5% of the abnormal EEG files. They helped establish the diagnosis of an epileptic disorder or further characterize the epileptic syndrome. This occurred exclusively in the younger age group (age <36 years), and predominantly in women. Conclusion: IPS and HV are easy to perform and remain important adjuncts to routine EEG. They may trigger the expression of epileptogenic activity in an otherwise uneventful EEG. Whereas their diagnostic value was obvious in the younger age group, we found no evidence to support their usefulness in the middle-age and elderly groups.

Altered Intermittent Rhythmic Delta and Theta Activity in the Electroencephalographies of High Functioning Adult Patients with Autism Spectrum Disorder

“…This might result in EEG changes, such as physiological slowing, IRDA/IRTA, or epileptiform activity (Siddiqui et al, 2011 ; Barker et al, 2012 ). Interictal epileptiform activity was found particularly in patients with generalized epilepsy, but also in patients with focal epilepsy (Ahdab and Riachi, 2014 ; Kane et al, 2014 ). The role of EEG changes in patients without epileptic seizures is still unresolved.…”

Standardization and quality assurance in clinical electroencephalography

“…Even though some studies have reported that HV can be more effective in female patients 18,28 , our findings were inconclusive. The number of women with abnormalities or seizures during HV was higher than the number of men, but this was not statistically significant.…”

“…Hyperventilation is the oldest provocation methods, its efficiency in triggering absence seizures being observed even before the use of EEG, while the effect it has on cerebral electric activity has been observed by Berger in 1934 and further studied by Gibbs et al in 1935. [15][16][17] Over time, its diagnostic value has been certified by several studies and it has become a part of most standard EEG recordings [16][17][18][19][20][21][22][23][24][25] and it is also of use in intracranial EEG recordings 26 .…”

“…As a provocation method, it has proven to be more useful in generalized epilepsy, and especially in absence seizures 16,17,[19][20][21][27][28][29] , but also in Juvenile Myoclonic Epilepsy [29][30][31] . Nevertheless, some studies have shown that it can also trigger focal seizures, especially those with a temporal lobe onset 17,22,23,26,28 while others question its value for focal epilepsy 18,24,27 In addition to epileptiform discharges, HV can also elicit slow activity. Sometimes this is a normal phenomenon, especially in children or young adults, but it can also point to a specific cerebral disease.…”

Hyperventilation maneuver during EEG in children with epilepsy after the COVID‐19 pandemic. Is a routine procedure necessary?

“…Other studies have shown that HV has added information in very few patients, Ahdab and Riachi 21 described that only 8 patients out of 1172 did the HV add additional information.…”