No Difference In Emotional Response Between Threatening Sport And Non-sport Images In Individuals After Anterior Cruciate Ligament Reconstruction

After anterior cruciate ligament reconstruction (ACLR), individuals experience injury-related fear which is associated with secondary ACL injury risk. Electroencephalogram (EEG) assessments examining the late positive potential (LPP), an index of emotional perception, can help identify underlying neural consequences of fear that may influence secondary ACL injury risk. PURPOSE: To examine if individuals after ACLR exhibit different neural processing across sport and non-sport stimuli. METHODS: EEG was completed on 9 females (age = 21.4 ± 4.8 years [range: 14-35], time since surgery = 27.2 ± 13.9 months [range: 4-60]). Inclusion criteria was a primary, unilateral ACL injury sustained during sport or activity. Participants viewed sport and non-sport picture stimuli in three conditions: Neutral, Threatening, and Mutilation (Table 1). Participants were instructed to view the pictures and EEG activity was recorded from 32 electrode sites arranged in an extended montage based on the International 10-10 system. LPP was measured in response to all images using the mean voltage within the 400-1000 millisecond time window following stimuli presentation. A repeated measures 3x2 ANOVA was conducted to examine difference in LPP amplitude across all conditions. A priori alpha was set to p ≤ 0.05. Post hoc analysis was conducted as needed. RESULTS: There was a significant difference in LPP amplitude from Neutral to Threat to Mutilation images (p ≤ 0.003), indexing the most intense responses to Mutilation and least intense to Neutral images. There were no differences in LPP amplitude between sport and non-sport images (p = 0.1). CONCLUSIONS: After ACLR, individuals appear to exhibit similar neural processing of images of actions that could induce potential knee injury and images of clear non-sport related threat. This population may subconsciously perceive sport activities as harmful or threatening which may explain the increased risk of secondary ACL injury. - Table 1. Stimuli Descriptions Condition Non-Sport Image Examples Sport Image Examples Neutral (n = 40) IAPS: clock, bucket IAPS: person painting, person sitting, person on phone Threatening (n = 40) IAPS: snarling dog, person with gun, building on fire PHOSA-ACLR: running, lunging, jumping IAPS: sprinting, skiing, diving, gymnastics Mutilation (n = 40) IAPS: bloody face, burned body Google Images: knee with obvious deformity or mispositioned (no blood) Abbreviations: International Affective Picture System (IAPS), Photographic Series of Sports Activities for Anterior Cruciate Ligament Reconstruction (PHOSA-ACLR). The list of examples provided is not comprehensive. No picture was shown twice.