Neurological examination in healthy adult inland bearded dragons (Pogona vitticeps)

Abstract

OBJECTIVE To evaluate neurological tests and expected results in inland bearded dragons (Pogona vitticeps) and generate recommendations for bearded dragon–specific neurological examination. ANIMALS 26 healthy adult inland bearded dragons. PROCEDURES A complete neurological examination utilizing tests described in both mammals and reptiles was performed on each lizard, and test feasibility and outcome were recorded. RESULTS Tests with poor feasibility included oculocardiac reflex (successfully completed in 62% [16/26] of animals) and voluntary ambulation and swallowing by use of a food item (0% [0/26] of animals). Tests with outcomes considered abnormal in mammals but attributable to normal bearded dragon behavior included head position (head tilt present in 12% [3/26]) and head movement (head bob present in 4% [1/26]). Many tests had absent or inconsistent outcomes, including menace response (present in 19% [5/26]), proprioceptive positioning (present in 4% [1/26] in the thoracic limbs and 0% [0/26] in the pelvic limbs), vent reflex (present in 27% [7/26]), and myotatic reflexes (biceps present in 8% [2/26]; patellar, gastrocnemius, and triceps present in 0% [0/26]). Extensor postural thrust was absent in all successfully tested animals, but a novel reflex termed the caudal thoracic extensor reflex was noted instead in all observed animals (100% [21/21]). CLINICAL RELEVANCE Tests with poor feasibility or inconsistent outcomes should have low priority or be excluded from neurological examinations of inland bearded dragons. Normal behaviors should be considered for head position and movement. A bearded dragon–specific neurological examination protocol derived from these findings is described and recommended in order to decrease stress and improve neurolocalization.

Neurological examination of clinically healthy pigeons (Columba livia domestica), mute swans (Cygnus olor), common buzzards (Buteo buteo), common kestrels (Falco tinnunculus) and northern goshawks (Accipiter gentilis)

“…In these studies, certain neurological tests, such as the gag reflex in chinchillas 5 and hedgehogs, 4 were not performable due to anatomical reasons or handling challenges. Additionally, some responses or reflexes, such as the menace response or the perineal/cloacal reflex, were not provokable at all 4–7 or only in a few individuals 8 …”

“…Additionally, some responses or reflexes, such as the menace response or the perineal/cloacal reflex, were not provokable at all [4][5][6][7] or only in a few individuals. 8 Techniques for the neurological examination of birds described by several authors. [9][10][11][12][13] However, normative data from healthy individuals, like they were obtained from the aforementioned small mammal [4][5][6] and reptile 7,8 species, are limited to neuro-ophthalmic tests in various avian species [14][15][16][17][18][19][20] and cranial nerve reflexes in different states of consciousness in turkeys and layer hens.…”

“…8 Techniques for the neurological examination of birds described by several authors. [9][10][11][12][13] However, normative data from healthy individuals, like they were obtained from the aforementioned small mammal [4][5][6] and reptile 7,8 species, are limited to neuro-ophthalmic tests in various avian species [14][15][16][17][18][19][20] and cranial nerve reflexes in different states of consciousness in turkeys and layer hens. 21 Given the differences in anatomy and physiology between birds and mammals, as well as the huge variety of avian species, it is likely that not all tests are equally useful for every species.…”

“…In the recent literature, studies tested the applicability of modified neurological examinations in healthy exotic small mammals 4–6 and reptile species 7,8 . In these studies, certain neurological tests, such as the gag reflex in chinchillas 5 and hedgehogs, 4 were not performable due to anatomical reasons or handling challenges.…”

“…Techniques for the neurological examination of birds described by several authors 9–13 . However, normative data from healthy individuals, like they were obtained from the aforementioned small mammal 4–6 and reptile 7,8 species, are limited to neuro‐ophthalmic tests in various avian species 14–20 and cranial nerve reflexes in different states of consciousness in turkeys and layer hens 21 …”