Global Journal of NeuroEngineering

Global Journal of NeuroEngineering - Volume 1

Asymmetry of Permutation Entropy in Early Creutzfeldt-Jakob Disease: A Clue to a Specific Pathological Process?

Published on: 18 December 2015

Pages: 7-10

Edoardo Ferlazzo1,2, Sara Gasparini1,2, Chiara Sueri2, SilvanaFranceschetti3, Fabrizio Tagliavini3, Vito Sofia4, Daniela Fatuzzo4, Antonio Gambardella1, Angelo Labate1, Laura Mumoli1, GiovanbattistaGaspare Tripodi2, Domenico Labate5, Francesco Carlo Morabito5 and Umberto Aguglia1,2

1Magna Græcia University, Catanzaro, Italy; 2Regional Epilepsy Centre, Bianchi-Melacrino-Morelli Hospital, Reggio Calabria, Italy; 3Neurologic Institute “Carlo Besta”, Milan, Italy; 4Institute of Neurology, University of Catania, Italy and 5University Mediterranea of Reggio Calabria, Italy


Objective: We used permutation entropy (PE) to disclose abnormalities of cerebral activity in patients with early genetic or sporadic Creutzfeldt-Jakob disease (CJD), as compared to patients with steroid-sensitive subacuteencephalopathies (SSE) and healthy volunteers (HV).

Methods: We evaluated 16 EEG of CJD patients, 21 of SSE patients and 33 of HV. EEG of CJD patients were performed at an early stage and didn’t show periodic sharp wave complexes. Diagnosis of SSE was established on clinical and laboratory data. PE was estimated channel by channel. Average PE of all channels and the mean PE values of channels belonging to right and left hemispheres were calculated. The following variables were analysed: age at inclusion, sex, total average PE and mean interhemispheric PE differences.

Results: Average PE was significantly lower in CJD patients as compared to HV (mean 0.72, SD 0.03 vs. mean 0.75, SD 0.02, p=0.01). Mean interhemispheric PE difference was higher (mean 0.009, SD 0.006) in CJD patients as compared to both SSE (mean 0.005, SD 0.003) and HV groups (mean 0.004, SD 0.004) (p=0.02).

Discussion: The lower average PE value in CJD compared to HV group demonstrates a reduction of EEG complexity that suggests disruption of thalamo-cortical connection since the early phases of disease. Moreover, subjects with CJD showed a significant interhemispheric asymmetry in PE values, indicating that the pathological process of CJD may be initially asymmetric. This study confirms that PE may represent a useful tool to reveal abnormalities of cerebral electric activity not revealed by conventional EEG recordings.

Keywords: Signal, Analysis, EEG, Degenerative, Prion, Hashimoto’s encephalopathy.

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