Electroencephaloghic Findings of Encephalitis in Beagle Dogs Experimentally Infected with Canine Distemper Virus (CDV)

Abstract

The present research study had two goals. Firstly, the effect of medetomidine/propofol on the electroencephalographic (EEG) recordings of nine SPF dogs was analysed. It was found that the basic pooled pattern of EEG recordings was characterized by a mean amplitude of 28 uV (range = 15-70 uV) and mean frequency of 1.8 Hz (range = 1-2.5 Hz), with superimposed low voltage (amplitude range = 4-20 uV; mean 14 uV) and fast activity (frequency range = 10-27 Hz; mean 18 Hz). All results were significantly constant (P < 0.05) and accurately reproducible (R = 0.70). The second goal was to investigate the value of EEG findings from dogs experimentally infected with canine distemper virus (CDV) under the same anaesthetic conditions, for the diagnosis of encephalitis. It was found that the EEG traces were characterized by high voltage, slow activity (HVSA) with superimposed low voltage, fast activity (LVFA). By comparing the mean values of amplitude and frequency for each single phase at different time intervals, it was found that only the mean value of the superimposed frequency was linearly distributed and changed significantly (P < 0.001). Thus, at least three readings should be taken from phase III of the EEG recording in order to obtain accurate values. The study has shown that electroencephalography can supply valuable information in cases of CDV encephalitis and can assist greatly in the differential diagnosis.