ABSTRACT
OBJECTIVE: The purpose of the study was to test the ability of oculomotor, vestibular, and reaction time (OVRT) metrics to serve as a concussion assessment or diagnostic tool for general clinical use. SETTING AND PARTICIPANTS: Patients with concussion were high school-aged athletes clinically diagnosed in a hospital setting with a sports-related concussion (n = 50). Control subjects were previously recruited male and female high school student athletes from 3 local high schools (n = 170). DESIGN: Video-oculography was used to acquire eye movement metrics during OVRT tasks, combined with other measures. Measures were compared between groups, and a subset was incorporated into linear regression models that could serve as indicators of concussion. MEASURES: The OVRT test battery included multiple metrics of saccades, smooth pursuit tracking, nystagmoid movements, vestibular function, and reaction time latencies. RESULTS: Some OVRT metrics were significantly different between groups. Linear regression models distinguished control subjects from concussion subjects with high accuracy. Metrics included changes in smooth pursuit tracking, increased reaction time and reduced saccade velocity in a complex motor task, and decreased optokinetic nystagmus (OKN) gain. In addition, optokinetic gain was reduced and more variable in subjects assessed 22 or more days after injury. CONCLUSION: These results indicate that OVRT tests can be used as a reliable adjunctive tool in the assessment of concussion and that OKN results appear to be associated with a prolonged expression of concussion symptoms.
Subject(s)
Athletic Injuries/diagnosis , Athletic Injuries/physiopathology , Brain Concussion/diagnosis , Brain Concussion/physiopathology , Eye Movements/physiology , Adolescent , Eye Movement Measurements , Female , Humans , Male , Predictive Value of Tests , Reaction Time/physiology , Reproducibility of Results , Vestibular Function Tests , Video RecordingABSTRACT
PURPOSE: We describe infrared regional pupillometry as an objective comparative assessment of midperipheral to central retinal sensitivity and to correlate with midperipheral retinal ischemia in diabetic subjects. METHODS: We tested 12 normal and 17 diabetic subjects using bilateral infrared pupillometry. The diabetic cohort included seven subjects without, five with mild, three with moderate, and two with severe non-proliferative diabetic retinopathy (NPDR). Central and annular stimuli of varying intensity were presented to one eye, and pupillary amplitude and constriction velocity were measured from both eyes. Light stimulus of increasing intensity was presented as 20 consecutive trials (stimulus duration of 300 ms with 3000 ms intervals). The ratio of central to peripheral responses (Q values) was calculated for each stimulus configuration. Average responses with respect to the stimulus strength were regressed with Gompertz sigmoid function. RESULTS: Control and moderate/severe NPDR cases comparison showed statistically significant differences in amplitude (Q(A)) and constriction velocity (Q(CV)) (Wilcoxon rank sum test P = 0.002, respectively). Age difference for these groups was not statistically significant (Wilcoxon rank sum test P = 0.15). The comparison of control and diabetic subjects without NPDR/mild NPDR was statistically significant for Q(A) and Q(CV) (Wilcoxon rank sum test P = 0.0002 and P = 0.001, respectively). Q(A) and Q(CV) differences were statistically significant between moderate/severe NPDR cases and subjects without or mild NPDR cases (Wilcoxon rank sum test P = 0.013). CONCLUSIONS: Q(A) and Q(CV) values correlated highly with the severity of diabetic retinopathy, but not with the duration of diabetes.
