Use of video-electroencephalography as a first-line examination in veterinary neurology: development and standardization of electroencephalography in unsedated dogs and cats.

Objective: To assess the feasibility and validate the use of video-electroencephalography (EEG) in conscious dogs and cats and to propose guidelines of routine EEG in veterinary clinical practice. Design: Prospective clinical study. Data: One hundred and fifty EEG recordings were carried out to validate the clinical adding-value, reproducibility, and guidelines on 140 owned animals. One hundred and one EEGs were performed on dogs and 49 on cats. Procedures: We compared recordings performed with 8 EEG unwired stud Ag/AgCl electrodes held by elastic straps and 8 EEG wired cup Ag electrodes held by a tailor-made manufactured headset combined with a wired video-EEG device. Electrodes placement was determined according to previously published animal EEG protocols. Physiological sensors, such as electrocardiography, electromyography, and respiratory sensors were added. Stimulation protocols were tested. Quality and interpretability were evaluated. Results: Headsets and recording procedures appeared suitable for all skull shapes and sizes. Video-EEG recordings were successfully performed without tranquilization or anesthesia except for 9 animals. Median EEG recordings time was 40 min. Impedance remained below 20 kΩ in 99% of dog EEGs and 98% of cat EEGs. Isosynchrony was reported in 6% of the channels. Seventy-five percent of dog EEGs and 83% of cat EEGs were readable for more than 50% (to 100%) of their duration. Successful discrimination of vigilance states from rhythm analysis (wakefulness, drowsiness, and sleepiness) was possible in 99% of dog EEGs and 91% of cat EEGs. Photic driving responses during photic stimulations were observed in 11% of dog EEGs and 85% of cat EEGs. Electroencephalography recordings were directly informative in 32% of the examinations: in 25% EEG abnormalities were associated with clinical signs and 7% concerned EEG abnormalities without clinical symptoms during recording. Thirteen percent of dogs subjected to photic stimulation exhibited epileptic anomalies. Among 9 EEGs with other history-based stimulations, three displayed epileptic graphoelements. Conclusions: We have developed a standardized unanesthetized video-EEG procedure easily performed and reproducible in dogs and cats. Qualitative and quantitative technical and medical criteria were evaluated and were in accordance with human EEG recommendations. Moreover, we have demonstrated its relevance and accuracy for diagnostic purposes, providing further arguments for the use of EEG as a first-line neurological functional exploration test.

Immune-mediated polyneuropathy in cats: Clinical description, electrodiagnostic assessment, and treatment.

BACKGROUND: Suspected immune-mediated polyneuropathy has been increasingly reported in cats, especially in the last decade, but the condition remains poorly understood. OBJECTIVES: Refine the clinical description and review the classification of this condition based on electrodiagnostic investigation and evaluate the benefit of corticosteroid treatment and L-carnitine supplementation. ANIMALS: Fifty-five cats presented with signs of muscular weakness and electrodiagnostic findings consistent with polyneuropathy of unknown origin. METHODS: Retrospective, multicenter study. Data from the medical records were reviewed. The owners were contacted by phone for follow-up at the time of the study. RESULTS: The male-to-female ratio was 2.2. The median age of onset was 10 months, with 91% of affected cats being <3 years of age. Fourteen breeds were represented in the study. The electrodiagnostic findings supported purely motor axonal polyneuropathy. Histological findings from nerve biopsies were consistent with immune-mediated neuropathy in 87% of the tested cats. The overall prognosis for recovery was good to excellent, as all but 1 cat achieved clinical recovery, with 12% having mild sequelae and 28% having multiple episodes during their lifetime. The outcome was similar in cats with no treatment when compared with cats receiving corticosteroids or L-carnitine supplementation. CONCLUSIONS AND CLINICAL IMPORTANCE: Immune-mediated motor axonal polyneuropathy should be considered in young cats with muscle weakness. This condition may be similar to acute motor axonal neuropathy in Guillain-Barré syndrome patients. Based on our results, diagnostic criteria have been proposed.

Suspected spontaneous early hemorrhagic transformation of multiple ischemic strokes secondary to primary splenic torsion in a German Shepherd dog.

A 3-year-old female German Shepherd dog was presented with generalized tonic-clonic epileptic seizures, right-sided central vestibular syndrome, and right trigeminal nerve dysfunction. Acute lacunar ischemic strokes within both thalami, right side of the mesencephalon, left side of the myelencephalon, both sides of the cervical spinal cord, and acute hemorrhagic strokes within the rostral part of the right cerebellar hemisphere and right rostral colliculus were identified on magnetic resonance imaging. Additional evaluation identified multiple renal infarcts and complete splenic torsion, with entrapment of the left pancreatic lobe. Medical management, splenectomy, partial pancreatectomy, and intensive physical rehabilitation led to clinical improvement. The histology of the spleen was consistent with hemorrhagic infarction. Three months after onset, neurological examination identified only mild vestibular sequelae. The final diagnosis was multiple ischemic strokes secondary to primary splenic torsion. Spontaneous early hemorrhagic transformation, a well-known condition in human medicine, also was found in this case.

A PNPLA8 frameshift variant in Australian shepherd dogs with hereditary ataxia.

Hereditary ataxias are common among canine breeds with various molecular etiology. We identified a hereditary ataxia in young-adult Australian Shepherd dogs characterized by uncoordinated movements and spasticity, worsening progressively and leading to inability to walk. Pedigree analysis suggested an autosomal recessive transmission. By whole genome sequencing and variant filtering of an affected dog we identified a PNPLA8:c.1169_1170dupTT variant. This variant, located in PNPLA8 (Patatin Like Phospholipase Domain Containing 8), was predicted to induce a PNPLA8:p.(His391PhefsTer394) frameshift, leading to a premature stop codon in the protein. The truncated protein was predicted to lack the functional patatin catalytic domain of PNPLA8, a calcium-independent phospholipase. PNPLA8 is known to be essential for maintaining mitochondrial energy production through tailoring mitochondrial membrane lipid metabolism and composition. The Australian Shepherd ataxia shares molecular and clinical features with Weaver syndrome in cattle and the mitochondrial-related neurodegeneration associated with PNPLA8 loss-of-function variants in humans. By genotyping a cohort of 85 control Australian Shepherd dogs sampled in France, we found a 4.7% carrier frequency. The PNPLA8:c.[1169_1170dupTT] allele is easily detectable with a genetic test to avoid at-risk matings.

Epidemiological, clinical, and electrophysiological findings in dogs and cats with traumatic brachial plexus injury: A retrospective study of 226 cases.

BACKGROUND: The imaging and electrodiagnostic (EDX) characteristics of traumatic brachial plexus injury (TBPI) are incompletely reported. OBJECTIVES: To describe the epidemiological, clinical, and EDX characteristics of TBPIs in a series of cases in dogs and cats; to determine the association between clinical data, EDX findings, and clinical outcomes; and to assess the sensitivity and specificity of EDX studies to classify nerve lesions. ANIMALS: One hundred and seventy-five dogs and 51 cats with TBPI and EDX exploration of radial nerve, ulnar nerve, or both nerves. METHODS: Retrospective case series. All medical records were searched for dogs and cats presenting with TBPIs that underwent EDX exploration. Epidemiological, clinical, EDX, and follow-up data were extracted. Association between clinical data, EDX findings, and clinical outcomes was explored. RESULTS: Forty-six percent of affected animals were injured before 2 years of age and 57% of dogs weighed more than 20 kg. The radial compound muscle action potential (CMAP) amplitude for dogs and cats that had clinical improvement was higher than in animals without improvement (4.3 mV [0-23.6] vs 0 mV [0-2.4], respectively, P = .02). A discriminating radial CMAP amplitude threshold value of 5 mV had a specificity of 93% (95% CI [80-100]) to predict recovery. CONCLUSIONS AND CLINICAL IMPORTANCE: Electrodiagnostic studies, particularly measurement of radial CMAP amplitude, are valuable diagnostic tests to refine the prognosis of these animals.