Modified neurologic examination is feasible in healthy Puerto Rican crested toads (Peltophryne lemur)

To evaluate commonly used neurologic tests in mammals, reptiles, and birds and establish expected results in Puerto Rican crested toads to generate recommendations for toad-specific neurologic examinations.

A breeding population of healthy Puerto Rican crested toads (Peltophryne lemur) was used in April 2024. Neurologic examination based on standard tests described in other species was performed on each individual. Test feasibility and outcome were recorded independently by 3 observers.

Twelve toads were included. Tests with poor feasibility included respiratory rate (successfully completed in 17% [2 of 12] of toads) and swallowing (8% [1 of 12]). Many tests had absent or inconsistent outcomes, or lack of consensus between observers, including menace response (present in 55% [6 of 11]), ocular tracking (present in 0% [0 of 11]), pupillary light reflex (present in 8% [1 of 11]), physiologic nystagmus (present in 0% [0 of 12]), corneal sensation in response to air (present in 50% [5 of 10]), oculocardiac reflex (present in 36% [4 of 11]), tactile placing (present in 67% [6 of 9]), skin twitch (present in 0% [0 of 12]), and patellar reflex (present in 0% [0 of 12]). The most consistent tests, where test completion and the expected result were 100% successful as determined by all observers, were palpebral reflex, nasocortical and facial stimulation, corneal sensation (direct contact), hemiwalking, wheelbarrow, and pelvic limb withdrawal.

Some neurologic tests used in other species are potentially useful in Puerto Rican crested toads. Tests with low feasibility or inconsistent results should be given lower priority.

A toad-specific neurologic examination protocol is outlined minimizing stress and enhancing neurolocalization. However, differences between species may impact results.