1560
The idiopathic epilepsy, as much in veterinary medicine, as in human medicine, is a disease that affects a great amount of individuals. It is\ncharacterized by seizures without any provable reason, more than a possible\ngenetic predisposition.\nFor both cases the classification of the seizures and t...
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| Formato: | Tesis doctoral acceptedVersion |
| Lenguaje: | Español |
| Publicado: |
Universidad de Buenos Aires. Facultad de Ciencias Veterinarias
2012
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| Acceso en línea: | http://repositoriouba.sisbi.uba.ar/gsdl/cgi-bin/library.cgi?a=d&c=avaposgra&cl=CL1&d=HWA_1560 https://repositoriouba.sisbi.uba.ar/gsdl/collect/avaposgra/index/assoc/HWA_1560.dir/1560.PDF |
| Aporte de: |
| Sumario: | The idiopathic epilepsy, as much in veterinary medicine, as in human medicine, is a disease that affects a great amount of individuals. It is\ncharacterized by seizures without any provable reason, more than a possible\ngenetic predisposition.\nFor both cases the classification of the seizures and the epilepsies is based\non the use of phenotypic criteria like for example the semiological characteristics, the type of stimulus induces that them and the age in which they appear for the first time.In veterinary medicine, it is mentioned that in the majority of the patients the cause of the epilepsy is not identified and consequently, is assumed that they suffer idiopathic epilepsy, by absence of positive findings. From the\nmoment in which their methodology of registry and analyses has been\nstandardized, the EEG plays a fundamental role in the diagnosis of the epilepsies. Nevertheless only it displays pathological graphoelements in 33% of the cases.\nThe neurophysiologists insist on which there is no nervous function exist without a time metric of the signal, be it one simpler motor act or the most complex cognitive act. On the basis of this, the mathematical analysis of the\nEEG, denominated quantified \n electroencephalogram (EEGq) and, in particular,\nthe cerebral coherence would be able to discriminate between the normal and pathological electrical activity.\nThe purpose of this study was to obtain the values normal of cerebral\ncoherence in adult dogs healthy and to evaluate the differences that existed\nwith the values of cerebral coherence in dogs that suffer idiopathic epilepsy,\nto evaluate the possibility of incorporate this study to the diagnosis of the\nidiopathic epilepsy protocol in dogs. For such aim EEG of healthy adult dogs and idiopathic epilepsy adult dogs free of medication at the time of the study were obtained. We worked with\n12 channels electroencephalographic equipment. In order to obtain the EEG registries it was used a program especially designed for computed\nelectroencephalography and reconstruction by brain mapping. The minimum\ntime of registry was of 30 minutes. Restriction of the animal was realized with\nxylazina, in dose of 1 mg/kg. Was utilized for the analysis only electroencephalograms that presented normal plot to the visual analysis,\nwhich is without pathological graphoelements.\nNext at least 15 stationary segments of 2 seconds of duration (epochs)\nfree of artifices were selected. The values of cerebral coherence for\ninterhemispherical combinations (T3-T4 Fp1-Fp2; F3-F4; P3-P4; O1-O2) and intrahemispherical combinations (O-P; O-F; O-Fp; Fp-T; T-O) were obtained. The values of cerebral coherence were obtained from two different ways: a) of the normal form, that is to say cross power spectrum, coherence spectrum (cross correlation) and, phase spectrum b) the average of the coherence of\nthe electroencephalographic alpha and theta bands.\nAccording to our studies, we can describe in the healthy adult dogs the\nexistence of two groups of channels with electrical dynamics different for the\nanalysis from the interhemispherical coherence as much for the\nintrahemispherical analysis of coherence: A) for the interhemispherical\nanalysis the group of dorsal channels (Fp1-Fp2; F3-F4; P3-P4; O1-O2) display the\nPPC in 7,62 Hz.; whereas the group of temporary channels (T3-T4) the value\nof the frequency in which the PPC appears is 5,25 Hz. B) For the intrahemispherical analysis the group of dorsal channels (O-P; O-F; O-Fp)\npresents the PPC to a frequency of 7,58 Hz. and in the group of halo\nchannels (Fp-T and T-O) the value of frequency to which the PPC appears is\n6,30 Hertz. In the idiopathic epileptic dogs we have found that the value of the\nfrequency in which the PPC appears is minor who in the healthy dogs. In all\nevaluated channels the value of the frequency is included within the value of\nthe electroencephalographic theta band (4-7 Hz); nevertheless the differences\nbetween the groups of channels described previously for the\ninterhemispherical and intrahemispherical combinations remain.\nEven though the analysis of the electroencephalographic bands (alpha and theta) show similar data to the classic form of obtain data, work with a great number of values does of this very troublesome analysis and makes difficult the use as daily tool of use in the routine diagnosis.\nThe study of cerebral coherence appears like a useful tool of the EEGq to\ndescribe the cerebral activity, identifying the specific oscillating of the\ncerebral areas, allowing to establish the anatomical connections among them.\nIn this aspect it is able to recognize alterations in the oscillator, in their\nconnections and the participation of them in pathological events, so that it\ncan be used like tool for the diagnosis of electrical alterations. For this reason\ncould be incorporate without difficulty to the protocol of diagnosis of idiopathic epilepsy in dogs.\nFinally we have found that the idiopathic epileptic dogs present a showy\nsimilarity with the findings that have been reported in humans, reason why\ncould be used as model of study of the epilepsy in humans, especially in the\nreferred thing to an instrument of electrical diagnosis. |
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