1550 - Progressive Cognitive Decline Following Two Mild Traumatic Brain Injury (mTBI) Exposures During Middle Age

Case Diagnosis:
Progressive cognitive decline following two mTBI exposures

Case Description:
51-year-old male combat veteran presented with progressive cognitive impairment following two mTBI exposures (initial at age 43, blast-related mTBI during combat; second at age 45, motor vehicle accident). Comprehensive neuropsychological testing demonstrated objective cognitive impairments in immediate and delayed auditory memory, delayed visual memory, visual spatial perception, visual-motor construction, motor function, visual-spatial sequencing and scanning speed, cognitive flexibility, semantic fluency, and processing speed. MRI of the brain demonstrated minimal scattered foci of T2/FLAIR hyperintensity in the periventricular white matter and was otherwise normal. Comorbidities included hypertension, hyperlipidemia, diabetes mellitus type 2, coronary artery disease, bilateral sensorineural hearing loss, obstructive sleep apnea, generalized partial seizures, post-traumatic stress disorder and depression. Over the next 5 years, the patient progressed from mild cognitive impairment to dementia by clinical criteria. He is currently treated with both donepezil and memantine, underwent medical retirement, and requires a formal caregiver.

Discussions:
Long-term neurological consequences of TBI – a signature injury of modern warfare – may be the most critical issue facing Veterans over the next 50 years, given that large cohort studies in both civilian and Veteran populations have demonstrated an association between TBI and an increased incidence of dementia diagnosis. Thus, there is a critical need to identify modifiable risk factors that increase the risk for secondary neurocognitive decline following TBI exposure. As summarized in the 2020 Lancet Commission on Dementia Prevention, Intervention, and Care report, multiple modifiable risk factors have been objectively demonstrated to increase the risk of cognitive decline and dementia, including hearing loss, obesity, physical inactivity, hypertension, diabetes, and depression, amongst others. While the presented patient’s TBI exposure history was limited to two mTBI’s, his multiple modifiable risk factors likely accelerated his neurocognitive decline.

Conclusions:
Neurorehabilitation should include aggressive management of modifiable risk factors following TBI exposure.