Visual Dysfunction in Combat-related Mild Traumatic Brain Injury—A Review

Abstract

Approximately half of all military personnel who have served in the conflicts in Iraq and Afghanistan are reported to have some degree of combat-related mild traumatic brain injury (TBI). Although in civilian concussion injuries symptoms typically resolve within several weeks, blast-induced mild TBI may be accompanied by prolonged symptoms and afferent and efferent visual dysfunction. Most commonly near vision problems and photophobia are the presenting symptoms. A complete eye exam including vision testing, oculomotor function, and near tasking, is highly recommended after blast-induced mild TBI to detect and improve symptoms in this young patient population. A review of the current literature is presented. KeywordsMild TBI, visual dysfunction, combat-related injuries, TBI Disclosure: The authors have no conflicts of interest to declare. Blast Injury MechanismsThere are several factors that can affect the degree of brain injury. At the time of the explosion a shock front is created followed by a blast wave, which expands until the pressure falls below atmospheric pressure. 16,17 Initially, the primary blast wave passes through body armor and bone, and is able to disrupt underlying tissues through embedded shear and stress waves. 13,22 Organ systems with high air content such as the pulmonary, gastrointestinal and auditory systems are the most susceptible, but overpressure also causes damage to the central nervous system, visual system, musculoskeletal and cardiovascular systems. 23 Secondary damage occurs when debris or fragmentation from the explosive device or surrounding objects penetrate the body. 24 Tertiary blast injury involves acceleration and deceleration forces, such as occur when a body is propelled and crashes into a fixed structure or the ground. 15 Quaternary injury occurs

Deficits in Visual System Functional Connectivity after Blast‐Related Mild TBI are Associated with Injury Severity and Executive Dysfunction

“…; Magone et al. ). In a recent study of combat‐injured service members with reported histories of TBI, the majority of those with blast‐related mTBI reported visual complaints and presented with visual dysfunctions (Brahm et al.…”

Olfactory and executive dysfunctions following orbito-basal lesions in traumatic brain injury

“…Traumatic brain injury (TBI) can cause cognitive [1][2][3], psychological and behavioural disorders [4] as well as functional [5] and sensory dysfunction [6][7][8]. These impairments can be, depending on the severity of the trauma, of variable intensity and duration.…”

“…These impairments can be, depending on the severity of the trauma, of variable intensity and duration. Some studies on visual [6,7] and auditory functions [8] have been conducted with patients following TBI, but few studies are currently available on posttraumatic olfactory impairment, especially within the first few days following a TBI. The goal of the present study was to assess olfaction in patients with mild-to-severe TBI in an acute care setting.…”