What essential supply is needed to conduct an initial neurological assessment for Mr. Wiggins?

The essential supply needed to conduct an initial neurological assessment is a penlight. This tool is particularly important for assessing pupillary response, which is a key component of a neurological examination. The reaction of the pupils to light can provide valuable information about the neurological function and potential brain injuries of a patient.

Using a penlight, the healthcare professional checks for direct and consensual reactions of the pupils when light is shone in each eye. This assessment helps in understanding the function of the optic nerve and the brain's ability to process visual information.

Other instruments, while useful in various examinations, do not specifically provide the same critical insights into neurological function as a penlight does.