Nathan R. D’Amico1, Katie Stephenson-Brown1, R.J. Elbin1, M. Womble2

1University of Arkansas, Fayetteville, AR; 2INOVA Sports Medicine, Fairfax, VA

The assessment of near-point of convergence (NPC) is a component of the Vestibular Ocular Motor Screening (VOMS) for sport-related concussion (SRC). The NPC distance measurement is obtained by the patient and assesses his/her ability to view a near target without diplopia. A NPC measure > 5cm is predictive of SRC. The VOMS requires NPC distance to be measured by the patient and then recorded by the clinician. However, some clinicians prefer to measure NPC distance themselves and anecdotally report that they get a more accurate and consistent measurement due to their training and experience. No study to date has compared NPC distance measures between patient and clinician administration. PURPOSE: To examine differences in NPC distance measurements between patient and clinician administration. METHODS: Sixty-six concussed patients (22.2 ± 10.1 years) participated in this study. To assess NPC distance, the patient focused his/her eyes on a size 14-point font target (i.e., fixation stick) that slowly moved toward the center of the patient’s eyes, held by the clinician or patient, until the patient reported diplopia. The distance from the end of the patient’s nose to the fixation stick was measured by the clinician and recorded in cm. The NPC distance was recorded as the average of three trials and was administered twice in this study, first by the patient and second by the clinician. Paired-samples t-tests were performed to examine differences in NPC distance between patient and clinician administration. Chi-square analyses were performed to examine the association between patient and clinician administration for detecting impairment over clinical cutoffs (NPC > 5cm). RESULTS: There were no significant differences between patient administered (3.58 ± 3.01 cm) and clinician administered NPC distance measures (3.88 ± 3.52 cm) (t [67] = -1.52, p = .13). The number of NPC distance measures that exceeded clinical cutoffs (> 5cm) were not significantly different between patient (n= 27) and clinician administrations (n= 27) (χ2 [1, 136] = .08, p = 1.0). CONCLUSION: The NPC distance measures did not significantly differ between patient and clinician administration. Despite clinicians’ training and experience, these results suggest that patients can get as accurate and consistent NPC distance measurements as clinicians.

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