ELECTROENCEPHALOGRAPHY AS DIAGNOSTIC METHOD IN EPILEPTIC DOGS
DOI:
https://doi.org/10.31548/dopovidi2016.04.024Keywords:
dogs, epilepsy, diagnostics, electroencephalographyAbstract
In human medicine electroencephalography (EEG) is an important sensitive non invasive diagnostic method which is used when examining patients with the history of cerebral paroxysms.
The epilepsy is the most widespread chronic neurological disorders among animals, as well as among people. The diagnostic approach to epilepsy has always been challenging.
There have already been a lot of investigations aimed to estimate the expediency of conducting EEG in dogs and elaborate the specific technique for this species. Nevertheless, to authors’ mind the amount of available information is not enough and feather investigations should be conducted.
The aim of our investigation was to analyze results of short-lasting interictal electroencephalograms of epileptic dogs.
Eight dogs of different breeds with generalized or secondary generalized epileptic seizures which were diagnosed as such that had probably or possibly symptomatic epilepsy («unknown cause epilepsy» in correspondence to IVETF) were engaged in the experiment. The control group was represented by five healthy dogs.
The electroencephalography was conducted under sedation with medetomidine in dosed as 40 μg/kg administrated 20-30 minutes prior to electroencephalography. The EEG was conducted with the help of DX NT 32v19 complex using eight noninvasive electrodes (Fp1, Fp2, C3, C4, O1, O2, T3, T4).
Analysis of electroencephalogram was performed by visual detection of paroxysmal activity and quantitative electroencephalography (QEEG) using fast Fourier transformation (FFT) to the frequency range of bands corresponding 0.5–3.0 Hz for delta, 4.0– 7.0 Hz for theta, 8.0–13.0 Hz for alpha and β 14.0–40.0 Hz for beta bands.
During visual analyze intrerictal paroxysmal activity was registered in 5 sick dogs, three of which demonstrated epileptiform activity represented by sharp waves, spikes and slow wave-sharp wave complexes. No paroxysmal activity was noticed in healthy dogs.
During the analyze of results obtained with the help of fast Fuorier transformation it was estimated that sick dogs demonstrated higher frequency range of delta, theta and alpha bands and lower frequency range of beta band comparing to healthy dogs.
According to obtained results paroxysmal activity during electroencephalography was registered in 62,5% of sick dogs whereas epileptiform activity was registered in 37,5% of them.
These results demonstrate high specificity but low sensibility of electroencephalography used with diagnostic purpose in epileptic dogs.
The analysis of electroencephalograms obtained during photostimulation evidences the absence of efficacy of this method in dogs.
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