Transcranial Electrical Stimulation (TES)
Two decades ago, transcranial stimulation was introduced as a technique to elicit motor potentials in muscles in all limbs in horses. The technique was based on transcranial stimulation by a magnetic coil (TMS) placed over the head and can be used to diagnose spinal ataxia. Since horses need to be sedated anyway, this also allows to use transcranial electrical stimulation (TES).
This alternative method looked more accurate since, as shown in human and primates, TES activates spinal tracts directly beyond the motor cortex while, in contrast, TMS primarily activates the brain before the motor activity is conveyed to the spinal cord. Conduction times will then be prolonged while evoked muscle potentials (MEP) are more affected by brain activity.
However, little comparative neuro-anatomical and physiological knowledge in horses is available. This challenged to start a scientific study in a PhD program of Sanne Journée where the experience of multipulse TES in intraoperative monitoring is elaborated and implemented in a diagnostic TES-MEP method for horses. Its features in practice are evaluated. Scientific peer reviewed publications concern the design of the method [1, 6], an elaborative study for selection and use of electrodes for extramuscular MEPs , a study on normative data of MEP parameters of the TES method , a comparative study of TMS and TES in horses with normal  and compromised spinal cords , a study in horses with a compromised spinal cord in which the results of necropsy, radiological findings including myelography are compared at different ataxia scores  and finally a review study describing the State-of-the-Art diagnostic methods to diagnose equine spinal disorders, with special reference to TMS and TES .
TES is of a welcome complementary value in state-of-the-art diagnostic methods on equine spinal disorders. The study results confirm the expected features of TES by revealing significant shorter MLTs, higher conduction velocities and better reproducibility than TMS while both techniques are useful for assessing functional integrity of motor functions of the spinal cord. A striking difference with human is the pivotal presence of elicited reflexes in horses in both stimulation techniques.
The clinical relevance of TES in equine practice is presented at three BEVA congresses describing the method in 2014 , the comparison between TES and TMS in horses with spinal cord pathology in 2016  and the comparison of necropsy, radiology including myelography and ataxia scores in 2018 
Peer reviewed publications
 Sanne Lotte Journée, Henricus Louis Journée, Cornelis Marinus de Bruijn, Catherine John Ghislaine Delesalle (2015) Design and optimization of a novel method for assessment of the motor function of the spinal cord by multipulse transcranial electrical stimulation (TES) in horses Journal of Equine Veterinary Scienceˇ35 (2015) pp. 793-800
 Sanne Lotte Journée, Henricus Louis Journée, Cornelis Marinus de Bruijn, CathÇrine John Ghislaine Delesalle. Multipulse transcranial electrical stimulation (TES): normative data for motor evoked potentials in healthy horses BMC Veterinary Research (2018) 14:121
 Sanne L. Journee, Constance de Meeus d’Argenteuil, Lorie De Mare, Berit Boshuizen, Katrien Vanderperren, Louis H. Journée, Marco de Bruijn, Wilhelmina Bergmann, Catherine Delesalle. State-of-the-Art Diagnostic Methods to Diagnose Equine Spinal Disorders, With Special Reference to Transcranial Magnetic Stimulation and Transcranial Electrical Stimulation. Journal of Equine Veterinary Science 81 (2019) 102790
 Journée SL, Journée HL, Reed SM, Berends HI, de Bruijn CM and Delesalle CJG (2020) Extramuscular Recording of Spontaneous EMG Activity and Transcranial Electrical Elicited Motor Potentials in Horses: Characteristics of Different Subcutaneous and Surface Electrode Types and Practical Guidelines. Front. Neurosci. 14:652. doi: 10.3389/fnins.2020.00652
2020 Journee elektrodes.pdf
 Journée SL, Journée HL, Berends HI, Reed SM, de Bruijn CM and Delesalle CJG (2020) Comparison of Muscle MEPs From Transcranial Magnetic and Electrical Stimulation and Appearance of Reflexes in Horses. Front. Neurosci. 14:570372. doi: 10.3389/fnins.2020.570372 25 September 2020
 Journée S.L., C. J. G. Delesalle, C. M. De Bruijn, W. Bergmann and H. L. Journée. Transcranial electrical stimulation (TES) as a possible novel alternative to transcranial magnetic stimulation (TMS) to assess the motor function of the spinal cord for clinical diagnosis in horses Equine Veterinary Journal 46, Suppl. 47 (2014) 1
 Journée S., Journée H., de Bruijn M. Delesalle C. (2016) Intra-Individual Comparison of Motor Latency Times (MLTs) of Muscular Motor Evoked Potentials (MEP) of Transcranial Magnetic (TMS) and Electrical Stimulation (TES) in Horses with Neurological Motor Symptoms. Equine Veterinary journal 48, Suppl. 50 (2016): 10.
 S.L. Journée, C.J.G. Delesalle, C.M. de Bruijn, W. Bergmann and H.L. Journée. Multipulse transcranial electrical stimulation (TES) to diagnose spinal injury in horses. Equine Veterinary Journal 50, Suppl. 52 (2018) 5-35 14.20.