Abstracts

The purpose of this study was to investigate the role of repetitive transcranial magnetic stimulation (rTMS) as an alternative treatment for 3 dogs suffering from refractory idiopathic epilepsy., Three client-owned epileptic dogs refractory to AED treatment were studied. All dogs were diagnosed with idiopathic epilepsy based on the history of generalized seizures, normal neurological examination, unremarkable brain MRI and EEG features. Affected dogs were followed for at least 60 days before and after rTMS. A calendar of the seizures was kept to evaluate the interval between seizures before and after rTMS. Each dog received multiple AED treatment including phenobarbital, potassium bromide and levetiracetam. No dosage change was made in the two months prior to and following the study. A total amount of five treatments were delivered to each dog over five consecutive days (1 treatment per day). The technique of stimulation consisted in a 9cm focal point coil located over the skull in proximity of the vertex. Different rates of stimulation were used between dog 1 and dogs 2 and 3. In dog 1, each treatment consisted in low-rate rTMS delivered in 20 consecutive trains of 90 pulses each at 1Hz frequency and 60% of the maximal coil output. The inter-train interval (ITI) was 120 seconds. Dog 2 and 3 received a treatment protocol consisting of two consecutive sessions at different rates. The first session consisted of priming the cerebral cortex with high-rate rTMS characterized by 20 trains (40 seconds ITI) of 60 pulses each at 6Hz frequency and 55% of the maximal coil output. The second session of stimulation consisted in low-rate rTMS characterized by 10 trains (60 seconds ITI) of 60 pulses each at 1Hz frequency and 60% of the maximal coil output. The longest seizure-free interval during the pre-rTMS period was compared with the seizure-free interval immediately post-rTMS., Dog 1 and 3 had a short-term improvement of the seizure interval in the immediate post-rTMS period (27 days and 14 days respectively) as compared to the longest seizure-free interval of the pre-rTMS period (20 days and 12 days respectively). Dog 2 had an equal seizure-free interval between the immediate post-rTMS period (19 days) and the longest seizure-free interval of the pre-rTMS period (19 days)., Regardless of the technique of stimulation used in this study (low-rate rTMS versus high-rTMS followed by low-rate rTMS), an equal or prolonged seizure-free interval in the immediate post-rTMS period was observed in all dogs suggesting the possible short-term beneficial effect of rTMS in canine epilepsy., (Supported by Ontario Veterinary College Pet Trust Foundation.)