Abstract
Cognitive functions are often impacted by concussions and neurocognitive tests are used to assess the recovery process. However, these tests lack sensitivity in tracking the recovery process, which may depend on genetic polymorphisms. Brain derived neurotrophic factor (BDNF) is an important nerve growth factor linked with development and neural plasticity. The Val66Met (rs6265) polymorphism has been associated with reduced activity-dependent BDNF secretion, indicating reduced plasticity and greater stability of cortical networks. While most studies found that Met carriers have poorer scores on memory tests, not all studies are in agreement. The purpose of our study was to examine the consequences of Val/Met genotype on the performance of a cognitively demanding dual task, which involved visual spatial working memory (Corsi block test) and an auditory tone discrimination task. Participants were varsity athletes (n=33). All athletes were cleared to play at the time of testing; however, 19 players had a history of at least one concussion. BDNF genotyping was performed using saliva samples, which showed that 18% of athletes were Met allele carriers. The main outcome for the cognitive task was dual task cost (i.e., the percent reduction in performance on the auditory task while concurrently performing the visual task). Since subjects were asked to focus on the Corsi block test, performance on this task was similar during single and dual conditions. Regression analysis revealed that BDNF genotype accounted for 13% of variance in the auditory cost, while the presence of a concussion explained 11% of variance. Met carriers were significantly more accurate in the auditory task in the dual condition in comparison to the Val/Val athletes. These results are in agreement with a recent study which showed that subjects with the Met allele had significantly better performance on a visuomotor adaptation task.1 1Barton et al (2014). J Vis, 14(9): 4; doi:10.1167/14.9.4
Meeting abstract presented at VSS 2015