Electroneurographic examination of the ulnar nerve in the dog: measurements by surface electrodes I. Hájek1, J. Dufek2, I. Uhríková1, P. Schánilec1 1 Faculty of Veterinary Medicine, University of Veterinary and Pharmaceutical Sciences Brno, Czech Republic, 2 Private Neurology/EP Laboratory, Brno, Czech Republic INTRODUCTION Motor nerve conduction testing as a part of electrodiagnostic studies is valuable in the detection of neuromuscular diseases. Velocity is the speed at which an impulse propagates down a nerve. In humans, velocity depends on many factors. Some similarities were described previously in dogs by method which use the needle electrodes. The aim of this study was to perform motor nerve conduction measurements by surface electrodes in healthy dogs and determine correlations of obtained parameters with age and limb length. MATERIAL AND METHODS The ulnar nerve was examined electrophysiologically in 24 clinically healthy dogs. Measurements of motor nerve conduction velocity were performed by surface bipolar stimulating electrodes without anesthesia with Keypoint device (Dantec Dynamics, GB). Proximal stimulation site was at the elbow, distally above the carpus (near the accessory carpal bone). Recording electrodes were placed on palmar interossei muscles. The group of dogs consisted of 12 males and 12 females, aged four month to twelve years, distributed among 16 breeds including four mongrel dogs. Rectal temperature and limb length (distance between two stimulation sites) were measured in all individuals. RESULTS AND DISCUSSION Correlation between duration of action potential and latency in distal stimulation age rectal temperature (RT) length velocity distal latency proximal latency distal duration proximal duration years °C mm m/s ms whole group 5.6±3.7 38.3±0.5 176±46 63.0±9 2.4±0.6 5.3±1.5 2.6±0.6 3.0±0.9 females 4.5±2.5 38.3±0.4 181±28 66.8±6 2.3±0.5 5.0±0.9 2.5±0.4 2.9±0.5 males 6.6±4.5 171±60 59.3±12 2.6±0.8 5.6±1.9 2.7±0.8 3.2±1.2 correlation length, proximal latency, both durations RT, both latencies, both durations length, distal latency, both durations RT, length, both latencies, distal duration CONCLUSION We proved that nerve conduction measurements with surface electrodes provide comparable results to needle electrodes. Moreover, we have found significant correlations between individual parameters in healthy dogs. Only a few studies focused on motor conduction velocity in dogs have been published. Our results showed that the velocity measured with surface electrodes (63±9 m/s) provided similar results to previous reports using needle electrodes (62±6, 60±1, resp. 63±4 m/s).1,2,3 Van Nes and Van den Brom3 found significant difference in velocity and duration of action potential between short-legged and long-legged dogs. In our study, no correlation between limb length and velocity nor amplitude of action potential was found. Contrary, we found significant correlation between latency and duration of action potential in both proximal and distal stimulation. Correlation between age and velocity described previously4 was confirmed as well. REFERENCES 1 Lee, AF, Bowen, JM. Evaluation of Motor Nerve Conduction Velocity in the Dog. Am J Vet Res, 1970; 31:1361-1366. 2 Takakura, Y, Inada, S. Motor Nerve Conduction Velocity of the Ulnar and Tibial Nerves and Characteristics of M Wave of the Interosseous Muscles in the Adult dog. Jpn J Vet Sci, 1983; 45:413-416. 3 Van Nes, JJ, Van Den Brom, WE. Electroneurographic examination of the ulnar and radial nerves in the dog: reference values, biological variation and reproducibility. Res Vet Sci, 1986; 40:189-196. 4 Swallow, JS, Griffiths, IR. Age related changes in the motor nerve conduction velocity in dogs. Res Vet Sci, 1977; 23:29-32.