Neurocognitive assessment in patients with a minor traumatic brain injury and an abnormal initial CT scan: Can cognitive evaluation assist in identifying patients who require surveillance CT brain imaging?
Introduction
The frequency of traumatic brain injuries is both impressive and non-remitting. More specifically, over 1.5 million Americans suffer a traumatic brain injury annually.1 Though less dramatic in presentation, mild traumatic brain injuries (mTBI) account for approximately 75% of all TBI.2 The increasing research and awareness surrounding the specific effects of repeated mTBI has brought this disease into the limelight in recent years. Emergency department visits have now reached 716/100,000 per year, and admission rates approach 92/100,000.1 While more severe head injuries can necessitate immediate intervention in some cases, mTBI are typically managed using a conservative approach.3
Although the prognostic value of the Glasgow Coma Score (GCS) is well defined,4 patients with mTBI (GCS = 13–15) often present a management dilemma.5 More specifically, while clinical scoring systems (i.e. GCS, Canadian CT head rule) are helpful in determining who requires an initial computerized tomography (CT) of the brain, many mTBI patients who have positive CT findings do not require subsequent neurosurgical intervention. The determination of who will require repeat imaging and a neurosurgical intervention is often unclear early in the inpatient stay.3,6,7 While some risk factors for worsening injury have been identified (i.e. anticoagulation status, age),8, 9, 10, 11 the need for repeat CT brain scans in otherwise healthy patients have been the subject of recent debate.3,6,12,13 Evidence for routine repeat CT of the head in the low-risk patient population is sparse and a more conservative approach has been advocated in the recent literature.3,14
CT scanning provides descriptive structural information about brain injuries, but does not translate well into assessing neuro-cognitive performance.15 Cognitive evaluations (COG) are examinations of higher level brain functioning. When performed by trained personnel, these evaluations are often helpful in regards to discharge planning and determining the need for long-term follow up. Despite its widespread use, there is a paucity of data regarding the usefulness of cognitive testing in the acute and sub-acute management of mTBI.
As some patients may benefit from repeat imaging after minor head trauma,16 a clinical tool to assist in delineating this population would be extremely helpful. The safe and effective reduction of unnecessary repeated CT scans would also benefit both trauma patients and trauma systems by reducing ionizing radiation exposure, length of hospital stay, decreasing costs, and simplifying management of complex patients.13 The aim of this study was therefore to investigate the negative predictive value of a COG examination performed by trained occupational therapists (OT) in patients with mTBI (and an abnormal index CT) for requiring a repeat CT scan of the brain (which would identify a worsening subsequent CT scan, and/or clinical deterioration requiring neurosurgical intervention).
Section snippets
Materials and methods
We conducted a single center retrospective cohort study for patients presenting to the trauma and neurosurgical services at the Foothills Medical Center (FMC) with a mTBI (GCS 13–15) and positive findings on the initial/index CT scan of the brain. Positive findings were defined as the presence of subarachnoid (SAH), subdural (SDH), epidural (EDH) hemorrhage, cerebral contusion, calavarial fracture, intraparenchymal hemorrhage, or evidence of diffuse axonal injury (DAI). GCS included the initial
Results
A total of 247 patients were admitted to the trauma and neurosurgical services at FMC with mTBI and positive finding on their CT head between January 1, 2016 and December 31, 2016. Of these patients, 152 met all inclusion criteria. Demographic and clinical data of this cohort is reported in Table 1. Demographic and clinical data for subgroup analysis of patients passing and failing their COG are available in Table 2.
Discussion
In this retrospective study, successful performance on a COG served as a potentially useful negative predictive tool for patients with mTBI and an abnormality on their index CT brain scan. More specifically, patients who passed their COG rarely required a subsequent neurosurgical intervention (1 patient with an atypical case scenario). It is also of note that patients who were simply able to complete a COG, had little chance of dying. Patients passing their COG left hospital more rapidly and
Conclusion
A passed COG has an acceptable negative predictive value to prompt further investigation of its potential use as a clinical decision making tool in the acute mTBI setting. Standardizing a cognitive assessment and ensuring its rapid and reliable administration to brain injured patients will provide the primary focus of further studies. In summary, our future goal is to elucidate the specific relationship between neurocognitive testing and subsequent deterioration requiring neurosurgical
Conflict of interest
The authors have no conflicts of interest that are relevant to this project.
Funding
This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.
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