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

To conduct an initial neurological assessment, a penlight is essential because it allows the healthcare provider to evaluate pupillary response, which is a critical component of assessing neurological function. By shining the penlight into the patient's eyes, a clinician can observe the constriction of the pupils in response to light, which helps to gauge the integrity of the brain and optic pathways. This is particularly important in identifying any signs of neurological impairment or changes in consciousness.

The other options, while potentially useful in various assessments, do not directly evaluate neurological status in the same way. A tongue blade is typically used for oral examinations or to assess throat conditions, a cotton swab is generally used for sampling or cleaning, and a stethoscope is primarily used for auscultation of heart and lung sounds rather than neurological assessment. Therefore, the penlight is the most relevant and necessary tool for this specific task.