Limits...
'Functional connectivity' is a sensitive predictor of epilepsy diagnosis after the first seizure.

Douw L, de Groot M, van Dellen E, Heimans JJ, Ronner HE, Stam CJ, Reijneveld JC - PLoS ONE (2010)

Bottom Line: The synchronization likelihood (SL) was used as an index of functional connectivity of the EEG, and average SL per patient was calculated in seven frequency bands.In total, 114 patients were selected.Our results indicate that epilepsy diagnosis could be improved by using functional connectivity.

View Article: PubMed Central - PubMed

Affiliation: Department of Neurology, VU University Medical Center, Amsterdam, The Netherlands. l.douw@vumc.nl

ABSTRACT

Background: Although epilepsy affects almost 1% of the world population, diagnosis of this debilitating disease is still difficult. The EEG is an important tool for epilepsy diagnosis and classification, but the sensitivity of interictal epileptiform discharges (IEDs) on the first EEG is only 30-50%. Here we investigate whether using 'functional connectivity' can improve the diagnostic sensitivity of the first interictal EEG in the diagnosis of epilepsy.

Methodology/principal findings: Patients were selected from a database with 390 standard EEGs of patients after a first suspected seizure. Patients who were later diagnosed with epilepsy (i.e. > or = two seizures) were compared to matched non-epilepsy patients (with a minimum follow-up of one year). The synchronization likelihood (SL) was used as an index of functional connectivity of the EEG, and average SL per patient was calculated in seven frequency bands. In total, 114 patients were selected. Fifty-seven patients were diagnosed with epilepsy (20 had IEDs on their EEG) and 57 matched patients had other diagnoses. Epilepsy patients had significantly higher SL in the theta band than non-epilepsy patients. Furthermore, theta band SL proved to be a significant predictor of a diagnosis of epilepsy. When only those epilepsy patients without IEDs were considered (n = 74), theta band SL could predict diagnosis with specificity of 76% and sensitivity of 62%.

Conclusion/significance: Theta band functional connectivity may be a useful diagnostic tool in diagnosing epilepsy, especially in those patients who do not show IEDs on their first EEG. Our results indicate that epilepsy diagnosis could be improved by using functional connectivity.

Show MeSH

Related in: MedlinePlus

Flowchart of included patients.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC2877105&req=5

pone-0010839-g001: Flowchart of included patients.

Mentions: The database with EEG recordings because of suspected epilepsy after a first seizure contained 390 patients. Of this group, 57 patients with a definite diagnosis of epilepsy remained after excluding those who did not meet inclusion criteria (see figure 1). A total of 104 participants were not diagnosed with epilepsy, and 57 participants out of this group were individually matched regarding gender and age to the 57 epilepsy patients. All patients were referred to the VU University Medical Center (which is a tertiary referral center and also has a large emergency department) by their general physician or reported themselves at the emergency department of our hospital, after having one episode that could be explained as an epileptic seizure. All diagnoses were finally reached by the staff neurologists in the VU University Medical Center, also making use of the EEG report of the clinical neurophysiologist of this hospital. Causes for the suspected seizure in these patients are listed in table 1; no other diagnosis was reached in three patients, but epilepsy was ruled out as a diagnosis. No significant differences in age or gender were present between the 57 patients who were included and the 47 who were not. None of the patients used AEDs at the time of the first EEG.


'Functional connectivity' is a sensitive predictor of epilepsy diagnosis after the first seizure.

Douw L, de Groot M, van Dellen E, Heimans JJ, Ronner HE, Stam CJ, Reijneveld JC - PLoS ONE (2010)

Flowchart of included patients.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2877105&req=5

pone-0010839-g001: Flowchart of included patients.
Mentions: The database with EEG recordings because of suspected epilepsy after a first seizure contained 390 patients. Of this group, 57 patients with a definite diagnosis of epilepsy remained after excluding those who did not meet inclusion criteria (see figure 1). A total of 104 participants were not diagnosed with epilepsy, and 57 participants out of this group were individually matched regarding gender and age to the 57 epilepsy patients. All patients were referred to the VU University Medical Center (which is a tertiary referral center and also has a large emergency department) by their general physician or reported themselves at the emergency department of our hospital, after having one episode that could be explained as an epileptic seizure. All diagnoses were finally reached by the staff neurologists in the VU University Medical Center, also making use of the EEG report of the clinical neurophysiologist of this hospital. Causes for the suspected seizure in these patients are listed in table 1; no other diagnosis was reached in three patients, but epilepsy was ruled out as a diagnosis. No significant differences in age or gender were present between the 57 patients who were included and the 47 who were not. None of the patients used AEDs at the time of the first EEG.

Bottom Line: The synchronization likelihood (SL) was used as an index of functional connectivity of the EEG, and average SL per patient was calculated in seven frequency bands.In total, 114 patients were selected.Our results indicate that epilepsy diagnosis could be improved by using functional connectivity.

View Article: PubMed Central - PubMed

Affiliation: Department of Neurology, VU University Medical Center, Amsterdam, The Netherlands. l.douw@vumc.nl

ABSTRACT

Background: Although epilepsy affects almost 1% of the world population, diagnosis of this debilitating disease is still difficult. The EEG is an important tool for epilepsy diagnosis and classification, but the sensitivity of interictal epileptiform discharges (IEDs) on the first EEG is only 30-50%. Here we investigate whether using 'functional connectivity' can improve the diagnostic sensitivity of the first interictal EEG in the diagnosis of epilepsy.

Methodology/principal findings: Patients were selected from a database with 390 standard EEGs of patients after a first suspected seizure. Patients who were later diagnosed with epilepsy (i.e. > or = two seizures) were compared to matched non-epilepsy patients (with a minimum follow-up of one year). The synchronization likelihood (SL) was used as an index of functional connectivity of the EEG, and average SL per patient was calculated in seven frequency bands. In total, 114 patients were selected. Fifty-seven patients were diagnosed with epilepsy (20 had IEDs on their EEG) and 57 matched patients had other diagnoses. Epilepsy patients had significantly higher SL in the theta band than non-epilepsy patients. Furthermore, theta band SL proved to be a significant predictor of a diagnosis of epilepsy. When only those epilepsy patients without IEDs were considered (n = 74), theta band SL could predict diagnosis with specificity of 76% and sensitivity of 62%.

Conclusion/significance: Theta band functional connectivity may be a useful diagnostic tool in diagnosing epilepsy, especially in those patients who do not show IEDs on their first EEG. Our results indicate that epilepsy diagnosis could be improved by using functional connectivity.

Show MeSH
Related in: MedlinePlus