Objective: Quantitative Encephalography (QEEG) represents synthetically the features of EEG signal, and thus is a promising tool in the assessment of neurophysiological changes induced by anti-seizure medications (ASMs). In this study, we characterized QEEG chronic modifications brought by the first ASM (fASM) in a population of 17 drug-naïve patients with drug-responsive Temporal Lobe Epilepsy (TLE). Methods: We analysed standard 19-channel EEG from 17 patients with drug-responsive TLE both before (T0) and after (T1, from 4 to 8 months) the introduction of the fASM. We investigated the spectral properties in the classical frequency bands, such as δ (1–3 Hz), θ (4–7 Hz), α (8–13 Hz), β (14–30 Hz) and γ (31–45 Hz) bands, and the individual alpha frequency (IAF). Moreover, we estimated the fractal dimension (FD) values and then compared these features between T0 and T1. Results: in drug-responder TLE patients, the fASM induces a decrease in Theta power (p = 0.012) and an increase in the FD (p=0.002) and IAF (p = 0.007). Bayesian analysis was used to compare the Bayes Factors (BF) across the three indexes used (Theta (BF=1.131), IAF (BF=4.414), and FD (BF=10.660)). Based on the magnitude of the BF, we found that FD was 9.4 times more sensitive than theta band and 2.4 times respect to IAF. Discussion: in drug-responder TLE patients, the fASM induces EEG modifications that can be measured and subtend an increase in the complexity of functional patterns of the patient’s brain after drug administration. Conclusions: QEEG may help to understand the effect of ASMs in the central nervous system and offer new prognostic biomarkers for patients with epilepsy.
Obbiettivo: l’Elettroencefalografia Quantitativa (QEEG) rappresenta sinteticamente le caratteristiche del segnale EEG ed è pertanto uno strumento promettente nella determinazione dei cambiamenti neurofisiologici indotti dai farmaci anti-crisi (‘anti-seizure medications’, ASM). In questo studio abbiamo caratterizzato le modificazioni croniche della QEEG indotte dal primo ASM (‘first ASM’, fASM) in una popolazione di 17 pazienti farmaco-naïve presentanti una Epilessia Lobare Temporale (‘Temporal Lobe Epilepsy’, TLE) farmaco-responsiva. Metodi: abbiamo analizzato EEG standard a 19 canali di pazienti con TLE farmaco-responsiva, sia prima (T0) che dopo (T1, da 4 a 8 mesi) l’introduzione del fASM. Abbiamo investigato le proprietà spettrali nelle classiche bande di frequenza, quali le bande δ (1–3 Hz), τ (4–7 Hz), α (8–13 Hz), β (14–30 Hz) e γ (31–45 Hz), oltre che la Frequenza dell’Alpha Individuale (‘Individual Alpha Frequency’, IAF). Inoltre, abbiamo stimato i valori della dimensione frattale (Fractal Dimension, FD) ed abbiamo poi comparato i nostri risultati tra T0 e T1. Risultati: in pazienti con TLE farmaco-responsiva, l’fASM ha indotto una decrescita nella potenza della banda Theta (p=0.012) e un aumento della dimensione frattale (p=0.002) e della IAF (p=0.007). L’analisi Bayesiana è stata usata per comparare i Fattori Bayesiani (Bayesian Factors, BF) a livello di tutti e tre gli indici usati: Theta (BF=1.131), IAF (BF=4.414) e FD (BF=10.660). Basandoci sulla magnitudo dei BF, abbiamo trovato che la FD era 9.4 volte più sensibile nell’analisi della banda theta e 2.4 volte più sensibile rispetto alla IAF nell’identificare i cambiamenti neurofisiologici tra T0 e T1. Discussione: in pazienti con TLE farmaco-responsiva, l’fASM induce modificazioni dell’EEG che possono essere misurate e che sottendono un incremento della complessità dei pattern funzionali del cervello dei pazienti dopo somministrazione del farmaco. Conclusioni: QEEG potrebbe aiutare a comprendere gli effetti degli ASM sul sistema nervoso centrale, e offrire nuovi marcatori prognostici per pazienti con epilessia.
CHARACTERIZATION OF EEG PATTERN COMPLEXITY IN TEMPORAL EPILEPSY BY MEANS OF FRACTAL ANALYSIS
ZACCHELLO, MARCO
2021/2022
Abstract
Objective: Quantitative Encephalography (QEEG) represents synthetically the features of EEG signal, and thus is a promising tool in the assessment of neurophysiological changes induced by anti-seizure medications (ASMs). In this study, we characterized QEEG chronic modifications brought by the first ASM (fASM) in a population of 17 drug-naïve patients with drug-responsive Temporal Lobe Epilepsy (TLE). Methods: We analysed standard 19-channel EEG from 17 patients with drug-responsive TLE both before (T0) and after (T1, from 4 to 8 months) the introduction of the fASM. We investigated the spectral properties in the classical frequency bands, such as δ (1–3 Hz), θ (4–7 Hz), α (8–13 Hz), β (14–30 Hz) and γ (31–45 Hz) bands, and the individual alpha frequency (IAF). Moreover, we estimated the fractal dimension (FD) values and then compared these features between T0 and T1. Results: in drug-responder TLE patients, the fASM induces a decrease in Theta power (p = 0.012) and an increase in the FD (p=0.002) and IAF (p = 0.007). Bayesian analysis was used to compare the Bayes Factors (BF) across the three indexes used (Theta (BF=1.131), IAF (BF=4.414), and FD (BF=10.660)). Based on the magnitude of the BF, we found that FD was 9.4 times more sensitive than theta band and 2.4 times respect to IAF. Discussion: in drug-responder TLE patients, the fASM induces EEG modifications that can be measured and subtend an increase in the complexity of functional patterns of the patient’s brain after drug administration. Conclusions: QEEG may help to understand the effect of ASMs in the central nervous system and offer new prognostic biomarkers for patients with epilepsy.File | Dimensione | Formato | |
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https://hdl.handle.net/20.500.12608/30786