Faculty Bibliography

OBJECTIVE:This study aimed to identify predictors of brain CT abnormalities in patients who sustained a mild traumatic brain injury (mTBI). METHODS:Retrospective observational cohort of adult patients with mTBI (Glasgow Coma Score 13-15) that occurred within the preceding 24 h. RESULTS:2548 (91%) of the cohort had a brain CT and 698 (27%) demonstrated abnormal findings. The most frequently observed CT abnormalities were bleeding (638, 25%) and fractures (190, 7.4%). Multivariate logistic regression analysis revealed several significant predictors associated with the presence of brain CT abnormalities including older age [P < 0.0001], male sex [P < 0.0001], loss of consciousness [P = 0.0041], associated vomiting [P = 0.0011], alteration of consciousness (AOC) [P = 0102], and GCS score [P < 0.0001]. This was a robust model with an R² of 14.2%. CONCLUSION/CONCLUSIONS:In this retrospective analysis, older age, male sex, the presence of loss of consciousness or alteration in consciousness, lower GCS score, and associated vomiting were found to be significant predictors of having an abnormal brain CT. These findings highlight the importance of considering these factors when determining the necessity of brain CT scans in patients with mTBI and suggest that existing clinical decision rules may be limited. These findings may also help to inform clinical decision rules. Early identification of individuals at a higher risk of CT abnormalities may assist in appropriate management and allocation of healthcare resources.

BACKGROUND:Mild traumatic brain injury (mTBI) is becoming a more common emergency department (ED) presentation. Towards this end, many types of testing in the acute setting are being investigated. One of these is screening for convergence insufficiency (CI) symptoms. These are common problems reported by patients with mTBI, but such oculomotor testing is rarely performed in the ED. OBJECTIVE:To assess the feasibility of convergence insufficiency screening in the ED and investigate whether CI is associated with adverse events such as post-concussive symptoms or hospital admission. METHODS:Written informed consent was obtained from patients age 18 years or older who experienced a mild head injury from any mechanism resulting in an mTBI. Patients underwent screening for CI symptoms using a standardized instrument of 15 questions, known as the convergence insufficiency symptom survey (CISS), with responses based on the Likert scale. These data were correlated to outcomes of hospital admission, occurrence of post-concussive symptoms, and 30-day hospital re-admission. RESULTS:A total of 116 patients were prospectively enrolled, of which 58 were male. The median age was 31 years, with a range of 18 to 95 years of age. The median CISS score was 13, with an interquartile range (IQR) of 6 to 21 and an overall range of 0 to 53. Females presented with a median CISS score of 14, which was higher compared to the male median score of 10. The higher the CISS score, the more likely the patient was to be admitted to the hospital (p = 0.0378), develop symptoms of post-concussive syndrome at 30-day follow up (p = 0.0322), and be readmitted within 30 days (p = 0.0098). CONCLUSIONS:Screening for CI symptoms using the CISS can be a solid adjunct in the evaluation of mTBI in the ED. The CISS is easy and fast to administer, and it is a useful tool to stratify patients in terms of who is at the highest risk of developing complications related to the mTBI.

PURPOSE/OBJECTIVE:This pilot study sought to determine the efficacy of using the Developmental Eye Movement (DEM) test in the adult, acquired brain injury (ABI) population to quantify clinically the effects of controlled, laboratory-performed, oculomotor-based vision therapy/vision rehabilitation. METHODS:Nine adult subjects with mild traumatic brain injury (mTBI) and five with stroke were assessed before and after an eight-week, computer-based, versional oculomotor (fixation, saccades, pursuit, and simulated reading) training program (9.6h total). The protocol incorporated a cross-over, interventional design with and without the addition of auditory feedback regarding two-dimensional eye position. The clinical outcome measure was the Developmental Eye Movement (DEM) test score (ratio, errors) taken before, midway, and immediately following training. RESULTS:For the DEM ratio parameter, improvements were found in 80-89% of the subjects. For the DEM error parameter, improvements were found in 100% of the subjects. Incorporation of the auditory feedback component revealed a trend toward enhanced performance. The findings were similar for both DEM parameters, as well as for incorporation of the auditory feedback, in both diagnostic groups. DISCUSSION/CONCLUSIONS:The results of the present study demonstrated considerable improvements in the DEM test scores following the oculomotor-based training, thus reflecting more time-optimal and accurate saccadic tracking after the training. The DEM test should be considered as another clinical test of global saccadic tracking performance in the ABI population.

BACKGROUND: Considering the extensive neural network of the oculomotor subsystems, traumatic brain injury (TBI) could affect oculomotor control and related reading dysfunction. OBJECTIVE: To evaluate comprehensively the effect of oculomotor-based vision rehabilitation (OBVR) in individuals with mTBI. METHODS: Twelve subjects with mTBI participated in a cross-over, interventional study involving oculomotor training (OMT) and sham training (ST). Each training was performed for 6 weeks, 2 sessions a week. During each training session, all three oculomotor subsystems (vergence/accommodation/version) were trained in a randomized order across sessions. All laboratory and clinical parameters were determined before and after OMT and ST. In addition, nearvision-related symptoms using the Convergence Insufficiency Symptom Survey (CISS) scale and subjective visual attention using the Visual Search and Attention Test (VSAT) were assessed. RESULTS: Following the OMT, over 80% of the abnormal parameters significantly improved. Reading rate, along with the amplitudes of vergence and accommodation, improved markedly. Saccadic eye movements demonstrated enhanced rhythmicity and accuracy. The improved reading-related oculomotor behavior was reflected in reduced symptoms and increased visual attention. None of the parameters changed with ST. CONCLUSIONS: OBVR had a strong positive effect on oculomotor control, reading rate, and overall reading ability. This oculomotor learning effect suggests considerable residual neuroplasticity following mTBI.

Vergence dysfunction in individuals with mild traumatic brain injury (mTBI) may have a negative effect on quality of life, functional abilities, and rehabilitative progress. In this study, we used a range of dynamic and static objective and subjective measures of vergence to assess 21 adult patients with mTBI and nearwork symptoms. The results were compared with 10 control adult subjects. With respect to dynamic parameters, responses in those with mTBI were slowed, variable, and delayed. With respect to static parameters, reduced near point of convergence and restricted near vergence ranges were found in those with mTBI. The present results provide evidence for the substantial adverse effect of mTBI on vergence function.

BACKGROUND: This article reviews literature regarding individuals with traumatic brain injury who have vision related impairments up to one year, post-injury. Such impairments may impact rehabilitation of activities of daily living and mobility since vision is integral in much of what one does on a daily basis. METHODS: Search of Medline, Ovid, and PubMed was performed using terms including: traumatic brain injury, visual deficits after brain injury, vision and traumatic brain injury, and ADLs after brain injury. RESULTS: Eighteen studies were analyzed and reviewed. A range of visual and visual-motor impairments are seen across the severity of traumatic brain injury. Visual impairment negatively impacts independence in mobility and activities of daily living. Common sensorimotor visual symptoms reported by those with traumatic brain injury include blurred vision, reading problems, double vision or eyestrain, dizziness or disequilibrium in visually-crowded environments, visual field defects, light sensitivity, and color blindness. CONCLUSIONS: This review should alert the reader to common visual complaints and defects seen after traumatic brain injury. It is important to screen persons who have suffered traumatic brain injury for sensorimotor vision deficits early on in recovery so that these issues may be addressed and recovery of function and independence in the community are not delayed.

PURPOSE: Individuals with mild traumatic brain injury (mTBI) frequently complain of increased sensitivity to visual motion. Thus, the purpose of this study was to assess the coherent motion threshold (CMT) in subjects with mTBI and reported visual motion sensitivity. METHODS: Fourteen adult subjects with mTBI and symptoms of motion sensitivity were tested. They were compared with 40 age-matched asymptomatic visually normal individuals. CMT was assessed using a 2-alternative, forced choice paradigm. A symptom rating-scale questionnaire related to motion and light sensitivity, vertigo, and self-reported reading ability was also administered to the mTBI group. RESULTS: Mean CMTs were significantly elevated in the mTBI (8.81%) versus the normal subjects (6.53%). There was a trend for a progressive increase in mean CMT in mTBI with increased symptoms related to visual motion sensitivity and vertigo. However, there was no apparent relation to either light sensitivity or self-reported reading ability in mTBI. There was no significant age effect in either group. CONCLUSIONS: The elevated CMT in mTBI suggests damage to the magnocellular pathway, such as extrastriate visual cortical area V5, visual area medial temporal, and the medial superior temporal cortex, which is involved directly in various aspects of motion processing. These findings are consistent with the subjects' symptoms of motion sensitivity and vertigo in their natural environments.

Accommodation refers to the process of obtaining and maintaining a focused foveal retinal image of an object of interest. It involves optical, sensory, motor, perceptual, cognitive, pharmacologic, and biomechanical aspects, and hence represents a complex, multilevel neurologic control process. In patients with mild traumatic brain injury (mTBI), this process frequently is disrupted and compromised neurologically because of the pervasiveness of the coup-contrecoup, swelling, and shearing aspects of the brain injury. In this report, we review the earlier literature on accommodation in mTBI and then present several new findings from our clinical research unit, along with their clinical implications.