Convergence insufficiency as a predictor of poor prognosis after acute mild traumatic brain injury

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.

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.

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.

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).

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.