Does amantadine maintain function in long-established brain injury? A single case experimental design.

OBJECTIVE: The role of dopamine agonist (DA) in restoring consciousness and cognition in recovery phase following acquired brain injury (ABI) is established (1-5) . The role in later recovery is less well defined. We report a single case experimental design (SCED) trial of amantadine demonstrating improvement in function, six years following ABI.

METHOD: A scoring system based on established abilities in personal care and interaction was used to identify tasks with component actions, 34 actions in total, each ranked in terms of quality of response to a request or prompt. Actions were scored on maintenance dose amantadine; on withdrawal; and after reintroduction. Daytime sleep duration was also recorded.

RESULTS: At 3rd and 5th weeks post withdrawal, deterioration was noted in 27 of 34 graded activities. At 3rd and 5th weeks following reintroduction, all but 3 grades returned to baseline or better. Afternoon sleep duration increased from 35 to 80 minutes during withdrawal period returning towards baseline on amantadine resumption.

CONCLUSION: We believe this provides evidence for benefit of amantadine in sustaining function following ABI. The SCED model used provides a template for others to use to identify comparable change in similar trials.