Can an early 24-hour EEG predict the response to the ketogenic diet? A prospective study in 34 children and adults with refractory epilepsy treated with the ketogenic diet.
OBJECTIVE
We examined whether early EEG changes in a 24-h EEG at 6 weeks of treatment were related to the later clinical response to the ketogenic diet (KD) in a 6-month period of treatment.


METHODS
We examined 34 patients with heterogeneous epilepsy syndromes (21 children, 13 adults) and found 9 clinical responders (≥50% seizure reduction); this is a responder rate of 26%. We visually counted the interictal epileptic discharge index (IED index) in % during 2h of wakefulness and in the first hour of sleep (method 1), and also globally reviewed EEG changes (method 2), while blinded to the effect of the KD.


RESULTS
At group level we saw a correlation between nocturnal reduction of IED-index at 6 weeks and seizure reduction in the follow-up period. A proportional reduction in IED index of 30% from baseline in the sleep EEG, was associated with being a responder to the diet (Pearson Chi-square p=0.04). EEG scoring method 2 observed a significantly larger proportion of patients with EEG-improvement in sleep in KD responders than in non-responders (p=0.03). At individual level, however, EEG changes did not correlate very strongly to the response to the diet, as IED reduction in sleep was also seen in 15% (method 1) to 26% (method 2) of the non-responders.


CONCLUSIONS
Nocturnal reduction of IEDs is related to the response to the KD, however in daily clinical practice, an early EEG to predict seizure reduction should not be advised for individual patients.
Department of Neurology, Epilepsy Centre Kempenhaeghe, Heeze, The Netherlands.
Saskia C M
SC
Ebus
Department of Neurology, Epilepsy Centre Kempenhaeghe, Heeze, The Netherlands. Electronic address: lambrechtsd@kempenhaeghe.nl.
Danielle A J E
DA
Lambrechts
Department of Neurology, Epilepsy Centre Kempenhaeghe, Heeze, The Netherlands.
Ingrid J T
IJ
Herraets
Department of Neurology, Epilepsy Centre Kempenhaeghe, Heeze, The Netherlands; Research School of Mental Health & Neuroscience, Maastricht University, The Netherlands.
Marian J M
MJ
Majoie
Department of Neurology, Epilepsy Centre Kempenhaeghe, Heeze, The Netherlands.
Anton J
AJ
de Louw
Department of Neurology, Epilepsy Centre Kempenhaeghe, Heeze, The Netherlands; Department of Neurology, Ghent University Hospital, Belgium.
Paul J
PJ
Boon
Research School of Mental Health & Neuroscience, Maastricht University, The Netherlands; Department of Behavioural Sciences, Epilepsy Centre Kempenhaeghe, Heeze, The Netherlands; Department of Neurology, Maastricht University Medical Centre, The Netherlands.
Albert P
AP
Aldenkamp
Department of Neurology, Epilepsy Centre Kempenhaeghe, Heeze, The Netherlands; Department of Electrical Engineering (Signal Processing Systems Group), University of Technology, Eindhoven, The Netherlands.
Johan B
JB
Arends
D000293:Adolescent; D000328:Adult; D000927:Anticonvulsants / Q000627:therapeutic use; D001921:Brain / Q000503:physiopathology*; D002648:Child; D002675:Child, Preschool; D055423:Diet, Ketogenic; D004569:Electroencephalography / Q000379:methods*; D004827:Epilepsy / Q000175:diagnosis / Q000178:diet therapy* / Q000188:drug therapy / Q000503:physiopathology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007223:Infant; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D011446:Prospective Studies; D012640:Seizures / Q000175:diagnosis / Q000178:diet therapy / Q000188:drug therapy / Q000503:physiopathology; D012890:Sleep / Q000502:physiology; D016896:Treatment Outcome; D014851:Wakefulness / Q000502:physiology; D055815:Young Adult
D000927:Anticonvulsants
Adults; Children; EEG; Epilepsy; Interictal epileptic discharges; Ketogenic diet