Single Dose 4-Aminopyridine for Diagnosing Recurrent Laryngeal Nerve Paralysis Continuity After Trauma

Inclusion Criteria: * Recurrent Laryngeal Nerve injury (including acute unilateral, and bilateral vocal cord paralysis) following trauma, surgery or intubation * Closed soft tissue envelope obscuring direct observation of the continuity of the affected nerve * Cognitive ability to report sensory and motor deficit during examination * Able to complete single day dosing within 4 months of the inciting event * Eligible for standard of care plan of monitoring * Adults subject aged 18+ * Availability for main trial day within 1 week of diagnosis and follow-up visits as needed Exclusion Criteria: * History of multiple sclerosis, stroke or any other diagnosed neurological or central nervous system disorder or injury * History of intercranial surgery * History of hypersensitivity to AMPYRA® or 4-aminopyridine * Current use of aminopyridine medications, including other compounded 4-AP, e.g. fampridine, dalfampridine * Patients with known history of renal impairment (calculated GFR (GFR\<80 mL/min)) within 6 months time * Patients with a known history of a seizure disorder (4-AP overdose can, in selected cases, result in limited seizure activity). * Patients unable to communicate return or loss of sensation. * Patients with injuries too extensive to isolate a single nerve(s) for testing. * Patients currently taking organic cat-ion transporter 2 (OCT2) inhibitors, e.g. Cimetidine, dolutegravir, isavuconazole, ranolazine. * Patients who had a direct transection or sacrifice of the nerve * Patients who are pregnant * History of direct laryngeal trauma * Intolerance of exam or study procedures * Inability to visualize the larynx upon scope exam * Procedural or other pharmacological treatments of RLN paralysis prior to enrollment