Title: Effects of amantadine on post-concussion symptoms and neurocognitive performance in concussed adolescents
Cara Camiolo Reddy, Michael Collins, Mark Lovell
University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA
Objective: Amantadine, a dopaminergic agent with pre- and post-synaptic CNS effect, has been used for the treatment of arousal, executive functioning, and agitation following brain injury in adult and pediatric populations. To date, there has been no report of its use in the treatment of deficits following concussive injury. The aim of this study is to evaluate the effect of amantadine on post-concussion symptoms and neurocognitive performance in adolescents.
Method: This is a retrospective study utilizing a convenience sample of 29 consecutive male and female subjects undergoing evaluation and treatment through the University of Pittsburgh Medical Center Sports Medicine Concussion Program from 2006 through 2008. The subject pool consisted of individuals treated with amantadine after failing to recover following a prolonged period of rest. Following injury, all subjects underwent a clinical interview and completed the ImPACT computerized neurocognitive test battery. The neuropsychological testing modules of ImPACT are comprised of a series of 6 tests to yield four composite scores: Verbal Memory, Visual Memory, Processing Speed, and Reaction time. The ImPACT battery also includes a symptom inventory with a seven point Likert scale on twenty-two concussive symptoms. The athletes' self-reported symptoms and neurocognitive test scores were tracked until the time of recovery. All statistical analyses were conducted utilizing Statistica version 6.0. A repeated Measures of Analysis of Variance (ANOVA) design was utilized to evaluate change in ImPACT composite scores at different points in time.
Results: The sample consisted of 12 males and 17 females with an average age of 15.7 years (range = 13 to 18 years). The male and female groups did not differ significantly with regard to age, level of education, or prior concussion history. The average time post-injury for initiation of amantadine was 102 days (range = 14 to 544 days). Following the introduction of amantadine, test performance improved from pre-treatment levels on all ImPACT composite measures. In addition, subjects demonstrated a significant decrease in post-concussive symptoms following the introduction of amantadine.
Discussion: The majority of concussed individuals spontaneously recover following a period of cognitive and physical rest. There are no widely accepted interventions for those individuals with persistent neurocognitive deficits and post-concussive symptoms. In this study, amantadine was initiated for subjects who were not exhibiting spontaneous recovery following prolonged periods of physical and cognitive rest. Amantadine treatment resulted in a significant decrease in symptoms as well as improvement in all aspects of ImPACT.