phaidra.vetmeduni.ac.at o:4636 DOI 10.1016/j.bbi.2025.02.018 Distinctive seizure signature in the first video case-control study of a naturally-occurring feline autoimmune encephalitis model Background and objective Autoimmune encephalitis (AE) is a form of brain inflammation where pathogenic autoantibodies bind surface proteins. In humans, AE is at least as common as infective encephalitis, and seizures are a prominent manifestation. The most common adult human AE is associated with antibodies to leucine-rich glioma-inactivated 1 (LGI1-Ab-E). AE in non-human mammals is also recognised, notably the polar bear ‘Knut’, diagnosed with N-methyl D-aspartate receptor antibody encephalitis. LGI1-Ab-E is an emerging cause of spontaneously-arising AE in domestic cats. Our objective was to phenotype the seizure profile of feline LGI1-Ab-E and probe parallels to its human counterpart. Methods We characterised seizures in naturally-occurring feline LGI1-Ab-E. Three veterinary and two human neurologists independently blind-rated 35 LGI1-antibody positive and negative feline seizure videos from 24 cats (16 LGI1-Ab-E positive, 8 negative). Data analysed included seizure frequency, semiologies and their co-occurrence, localisation, inter-rater agreement, and predictive factors. Results The mean number of daily seizures at peak was significantly higher in LGI1-antibody positive compared to LGI1-antibody-negative cats (12.6 vs. 1.9/day, pcorr = 0.011). Semiologies statistically significantly enriched in LGI1-Ab-E observations included orofacial automatisms (88/120, 73 % vs. 26/55, 47 %, pcorr = 0.024), salivation (87/120, 73 % vs. 23/55, 42 %, pcorr = 0.004); and mydriasis (79/120, 66 % vs 19/55, 35 %, pcorr = 0.004), and almost exclusively seen in LGI1-Ab-E were circling (39/120, 33 % vs. 1/55, 2 %, pcorr=<0.001) and aggression (14/120, 12 % vs. 0/55, 0 %, non significant after correction). A temporal lobe onset was proposed in 67 % (80/120) of seropositive ratings, compared to 28 % (15/55) LGI1-Ab-E negative (p < 0.0001). Network analysis depicted complex and overlapping relationships between features, akin to the frequent and multifaceted seizures of human LGI1-Ab-E. Orofacial automatisms, mydriasis and temporal lobe localisation were predictive semiological features of feline LGI1-Ab-E. Significance Feline LGI1-Ab-E represents a clinically distinctive seizure disorder. Our findings highlight the value of studying naturally-occurring, biologically representative animal models which closely mimic human diseases. This bidirectional translational approach confers benefits across species and unites human and veterinary neurology. Autoimmune Cats Encephalitis Leucine-rich Glioma-inactivated 1 (LGI1) Orofacial Seizures 2025-11-28T09:18:27.436Z LOMv1.0 Author BEGIN:VCARD VERSION:3.0 N:Binks;S. N. M.; FN:S. N. M. Binks END:VCARD BEGIN:VCARD VERSION:3.0 N:Crawford;Abbe; FN:Abbe Crawford END:VCARD BEGIN:VCARD VERSION:3.0 N:Ives;E.; FN:E. Ives END:VCARD BEGIN:VCARD VERSION:3.0 N:Davison;L. J.; FN:L. J. Davison END:VCARD BEGIN:VCARD VERSION:3.0 N:Fower;Andrew; FN:Andrew Fower END:VCARD BEGIN:VCARD VERSION:3.0 N:Fox;H.; FN:H. Fox END:VCARD BEGIN:VCARD VERSION:3.0 N:Kaczmarska;A.; FN:A. Kaczmarska END:VCARD BEGIN:VCARD VERSION:3.0 N:Woodhall;M.; FN:M. Woodhall END:VCARD BEGIN:VCARD VERSION:3.0 N:Waters;P.; FN:P. Waters END:VCARD BEGIN:VCARD VERSION:3.0 N:Handel;Adam; FN:Adam Handel END:VCARD BEGIN:VCARD VERSION:3.0 N:Irani;Sarosh; FN:Sarosh Irani END:VCARD BEGIN:VCARD VERSION:3.0 N:Gutierrez-Quintana;Rodrigo; FN:Rodrigo Gutierrez-Quintana END:VCARD BEGIN:VCARD VERSION:3.0 N:Chowdhury;F. A.; FN:F. A. Chowdhury END:VCARD BEGIN:VCARD VERSION:3.0 N:Eriksson;S. H.; FN:S. H. Eriksson END:VCARD BEGIN:VCARD VERSION:3.0 N:Pakozdy;Akos; FN:Akos Pakozdy END:VCARD https://w3id.org/kim/hcrt/scheme https://w3id.org/kim/hcrt/text Textdokument Text LOMv1.0 yes https://creativecommons.org/licenses/by/4.0 application/pdf 1932385 https://phaidra.vetmeduni.ac.at/o:4636 https://phaidra.vetmeduni.ac.at/api/object/o:4636/thumbnail LOMv1.0 discipline