Banca de DEFESA: NATHALIA VANESSA SARAIVA LIMA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : NATHALIA VANESSA SARAIVA LIMA
DATE: 28/03/2024
TIME: 16:00
LOCAL: meet.google.com/hfr-hpqn-rfz
TITLE:

EVALUATION OF VISUAL PATHWAYS IN DOGS USING ELECTROPHYSIOLOGICAL TESTS

KEY WORDS:
PAGES: 49
BIG AREA: Ciências Agrárias
AREA: Medicina Veterinária
SUBÁREA: Clínica e Cirurgia Animal
SPECIALTY: Clínica Veterinária
SUMMARY:

The visual evoked potential (VEP) is an objective electrophysiological test for evaluating visual acuity in non-verbal patients, as its results require minimal collaboration from patients. Assessing the integrity of the retina and optic nerve is essential in the diagnosis of optic pathway disorders, however VEP is still little used in veterinary ophthalmology, requiring further studies and the development of specific protocols for domestic species. The objective of this work was to standardize the visual potential evoked by a flash of white light (VEP-F) in awake dogs, after defining in the skulls of canine cadavers the closest point to the occipital region for the best positioning of the active electrode during the examination. Six heads of dog cadavers were selected, sawn in a sagittal section, the length from the frontonasal joint to the occipital protuberance was measured, and, after visual identification of the occipital region, the location closest to it was externally marked, determining the ideal Oz point. Then, the distance between the inion and Oz was measured, in all skulls, and the average was obtained, in centimeters and percentage, according to the international 10-20 system, of the Oz point. The second part of the experiment consisted of selecting ten animals, males and females, of varying ages and breeds, which were subjected to a light flash-evoked potential examination, using the Nihon Kohdem system, Neuropack 2 MEB-7102A/k , in a dark room, without dark adaptation, the electrodes were arranged in the following sequence: the ground electrode (Fpz) at the frontonasal joint, the active electrode (Oz) at the point previously determined on cadavers and the reference electrode (Cz) halfway between them. The measurement was 1.91 cm from the inion as the closest point to the occipital region, this value being equivalent to 16.16% in the international 10-20 system. When evaluating all animals, the mean latencies of P1, P2 and P3 were 6.69ms, 36.21ms and 104.3ms, respectively; Animals between 2-4 years old showed higher latencies, with 39.65ms in P2, and smaller amplitudes, when compared to animals aged 5-7 years; Males had longer latency than females, with P2 of 43.26ms in males and 26.16ms in females; The amplitudes of all intervals in mesaticephalic animals were higher than in brachycephalic animals. We conclude that the findings of this research serve as a basis for standardizing normal parameters for VEP-F in adult dogs of different breeds and sex, being considered a useful tool to evaluate the integrity of the visual pathway from the retina to the occipital cortex, which can be enrolled in clinical or experimental studies without sedation or anesthesia, dark adaptation or mydriatics.

 

COMMITTEE MEMBERS:
Presidente - FABRICIO BEZERRA DE SA
Externa ao Programa - 2937676 - JEINE EMANUELE SANTOS DA SILVA - UFRPEExterno à Instituição - ROBERIO SILVEIRA DE SIQUEIRA FILHO - UFRPE