Evaluation of the diagnostic value of transcranial electrical stimulation (TES) to assess neuronal functional integrity in horses.

Unlabelled: Medical imaging allows for the visualization of spinal cord compression sites; however, it is impossible to assess the impact of visible stenotic sites on neuronal functioning, which is crucial information to formulate a correct prognosis and install targeted therapy. It is hypothesized that with the transcranial electrical stimulation (TES) technique, neurological impairment can be reliably diagnosed.

Objective: To evaluate the ability of the TES technique to assess neuronal functional integrity in ataxic horses by recording TES-induced muscular evoked potentials (MEPs) in three different muscles and to structurally involve multiple ancillary diagnostic techniques, such as clinical neurological examination, plain radiography (RX) with ratio assessment, contrast myelography, and post-mortem gross and histopathological examination.

Transcranial Magnetic Stimulation and Transcranial Electrical Stimulation in Horses.

Depending on the localization of the lesion, spinal cord ataxia is the most common type of ataxia in horses. Most prevalent diagnoses include cervical vertebral stenotic myelopathy (CVSM), equine protozoal myeloencephalitis (EPM), trauma and equine degenerative myeloencephalopathy (EDM). Other causes of ataxia and weakness are associated with infectious causes, trauma and neoplasia.

Trapezius Motor Evoked Potentials From Transcranial Electrical Stimulation and Transcranial Magnetic Stimulation: Reference Data, Characteristic Differences and Intradural Motor Velocities in Horses.

Reason For Performing Study: So far, only transcranial motor evoked potentials (MEP) of the extensor carpi radialis and tibialis cranialis have been documented for diagnostic evaluation in horses. These allow for differentiating whether lesions are located in either the thoraco-lumbar region or in the cervical myelum and/or brain. Transcranial trapezius MEPs further enable to distinguish between spinal and supraspinal located lesions.

Comparison of Muscle MEPs From Transcranial Magnetic and Electrical Stimulation and Appearance of Reflexes in Horses.

Introduction: Transcranial electrical (TES) and magnetic stimulation (TMS) are both used for assessment of the motor function of the spinal cord in horses. Muscular motor evoked potentials (mMEP) were compared intra-individually for both techniques in five healthy horses. mMEPs were measured twice at increasing stimulation intensity steps over the extensor carpi radialis (ECR), tibialis cranialis (TC), and caninus muscles.

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.

Introduction: Adhesive surface electrodes are worthwhile to explore in detail as alternative to subcutaneous needle electrodes to assess myogenic evoked potentials (MEP) in human and horses. Extramuscular characteristics of both electrode types and different brands are compared in simultaneous recordings by also considering electrode impedances and background noise under not mechanically secured (not taped) and taped conditions.

Methods: In five ataxic and one non-ataxic horses, transcranial electrical MEPs, myographic activity, and noise were simultaneously recorded from subcutaneous needle (three brands) together with pre-gelled surface electrodes (five brands) on four extremities.

State-of-the-Art Diagnostic Methods to Diagnose Equine Spinal Disorders, With Special Reference to Transcranial Magnetic Stimulation and Transcranial Electrical Stimulation.

Spinal cord disorders are a common problem in equine medicine. However, finding the site of the lesion is challenging for veterinarians because of a lack of sensitive diagnostic methods that can assess neuronal functional integrity in horses. Although medical imaging is frequently applied to help diagnose corticospinal disorders, this approach does not reveal functional information.

Multipulse transcranial electrical stimulation (TES): normative data for motor evoked potentials in healthy horses.

Background: There are indications that transcranial electrical stimulation (TES) assesses the motor function of the spinal cord in horses in a more sensitive and reproducible fashion than transcranial magnetic stimulation (TMS). However, no normative data of TES evoked motor potentials (MEP) is available.

Results: In this prospective study normative data of TES induced MEP wave characteristics (motor latency times (MLT); amplitude and waveform) was obtained from the extensor carpi radialis (ECR) and tibial cranialis (TC) muscles in a group of healthy horses to create a reference frame for functional diagnostic purposes.