Long-term consequences of repetitive traumatic brain injury (TBI) have been described for decades. The available evidence suggests that participation in collision and contact sports and the military may increase the risk of neurodegenerative diseases, however the data is conflicting. Presently, the cases of chronic traumatic encephalopathy (CTE) in professional football players are at the forefront of societal awareness; however CTE can only be definitively diagnosed post-mortem. As a result, physicians are seeing an increasing number of athletes who participated in collision and contact sports or military veterans seeking evaluation for persistent neurobehavioral symptoms. It is important to objectively determine the diagnoses and optimal interventions for these persistent neurobehavioral symptoms, and the rate of TBI-attributed cognitive impairment.
The goal of this study is to determine the rate of treatable diagnoses in patients with a history of repeated TBI and persistent symptoms upon presentation to a multidisciplinary concussion clinic.
We conducted retrospective chart reviews on 126 military veterans and 41 collegiate and professional athletes seen in the UCLA Steve Tisch BrainSPORT Concussion Clinic in the past 5 years for diagnosis of chronic neurobehavioral symptoms. Male or female patients greater than 18 years of age who reported at least 1 year of neurobehavioral symptoms were included in the data. All patients were evaluated by a multidisciplinary team that included experienced neurologists and neuropsychologists. All patients were consented into a registry that allows chart review and/or research data review as well as the potential to be contacted for follow-up if needed.
There were 167 patients (157 males, 10 females) ranging from 18-64 years old (mean age 38.8 years). 41 collegiate and professional athletes were included, in which 14 were active and 27 were retired. The mean age of the athletes was 36.6 years. 126 military veterans were included with an average age of 39.5 years. 79 of the 126 military veterans were provided with a comprehensive neuropsychology evaluation and assessment. 74/79 patients (93.6%) were diagnosed with post-traumatic stress disorder and 51 (64.5%) were diagnosed with varying levels (mild to severe) of Major Depressive Disorder. 61 of the 79 (77.2%) patients that underwent neurological and neuropsychological evaluation, were found to have a medical history of TBI. However, only 21/61 (34.4%) of these TBI patients were diagnosed with the TBI being a contributing factor of their present cognitive, behavioral, sleep and pain symptoms. During their neuropsychological evaluation, 73 of 79 patients (92.4%) endorsed sleep symptoms that consisted of insomnia, sleep apnea, nightmares, sleep disturbances, and trouble falling asleep after awakening in the middle of sleep. 72 of 79 patients (91.1%) endorsed pain due to headaches, while 46 of 79 patients (58.2%) endorsed other chronic pain symptoms. 14 (17.7%) patients were diagnosed with a substance abuse disorder which included either alcohol, cocaine, opioid, or cannabis abuse. 5 out of 79 patients (6.3%) were diagnosed with mild cognitive impairment (MCI) and no patients were diagnosed with major cognitive impairment or dementia. Inter-rater reliability was also determined using the Cohen’s kappa coefficient for a value of 0.66.
While 61 of the 79 neuropsychology-assessed, military patients had a medical history of either single or multiple TBIs, only 21 had a formal Axis I diagnosis of TBI as a contributor to their current symptoms. Thus, objective determination of TBI using neuropsychological testing suggested that a majority of persistent symptoms were associated with comorbid conditions. Only 5/79 (6.3%) of these patients were diagnosed with mild cognitive impairment, while none were diagnosed with major cognitive impairment, or dementia. Further studies will investigate the effect that the length of exposure in military or athletic participation has on the rate of neurocognition and comorbid conditions.
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