Concussion guidelines step 1: Systematic review of prevalent indicators

Neurosurgery, 75 (3): September 2014Neurosurgery IF (2013) = 3.013

Authors

Nancy Carney, PhD: Dept of medical informatics and clinical

epidemiology; Oregon Health and Science University, Oregon, US.

Associate Prof at Brain Trauma Foundation Centre for Guidelines Management

Silvana Riggio, MD: Dept of Psychiatry and Neurology, Mount

Sinai, New York Anxiety disorders, stress management, TBIs

Disclosure

“Brain Trauma Foundation Concussion Guidelines project is supported by the US Army Contracting Command.”

Introduction

First in a series of reports Step 1 goal: “evidence-based definition for

concussion using highest quality published literature”

No uniform definition for research/clinical purposes

Definition = Prevalence of signs, symptoms, neurological deficits and cognitive deficits (SSDs).

Prevalence = proportion in “concussed population” – proportion in control(or self) population

In absence of physiological measure, evidence of concussion

are signs, symptoms and objective measures of neurologic or cognitive

dysfunction

Zurich consensus statement 2014

Introduction (cont)

Once it is know who had what and when they had it, one would have a concreted evidence-based foundation on which to develop a defn.

Studies which examined concussion, but also those with potential concussive events (PCE) were included: therefore potential for inclusion on non-concussed individuals.

Following attributes: Change in brain function Follows a force to the head May be accompanied by temporary LOC Is identified in awake individuals Includes measures of neurological and cognitive dysfunction

? Would a better way not be to compare asymptomatic and symptomatic head knocks?

Methods

Research team:

Funding from US Army (Dept Defense) and Brain Trauma Foundation (1st author dept.)

Executive Committee

Methods GroupPanel of Technical

Experts

Six meetings to discuss project parameters:1. Clinical/research expertise in

concussion2. Dept of Defense3. Centers for Disease Control and

Prevention

Methods cont.

Objectives: identify most prevalent indicators of concussion and their associations.

Key questions1. What are most common signs, symptoms, and neuro

and cog deficits within 3 months post PCE?2. Does presences of signs, symptoms and deficits

within 3 months post PCE vary by factors (demo, etc)

3. What is the association between different or the same SSDs at different time points for the same patient post-PCE (???)

4. What is the relationship between SSDs and imaging/biomarkers after a PCE?

Methods cont (2)

Strategy PhD-level (?) librarian 1980 – Sept 2012 (post-CT scan) Medline, Sports Discus, PsychINFO,

Cochrane Review articles used as comparison Abstracts read by two assessors from

Methods Group: differences resolved through comparison or 3rd assessor

Methods cont (3)

Quality Assessment Assessment for bias and confound, based on seven

domains (YES, NO, UNCLEAR)1. Selection bias2. Bias resulting from MD3. Ascertainment bias: case definition and ID4. Ascertainment bias: case assessment5. Ascertainment bias: SSD description and evaluation6. Ascertainment bias: SSD assessment7. Confounding

Performed by 2 members or Methods Group (blinded to each other’s work). Discrepancies resolved by third member

Overall assessment – not addidive for 7 domains, but contextual based on purpose of paper▪ = Low, medium or high potential for bias

Methods cont (4)

Identification of Prevalent Indicators: Information across studies combined to

answer key (4) questions. ▪ Only high quality reports used for this (> 1

independent sample, studies with inclusive case definitions, studies with fixed time points)▪ Only if report’s findings were consistent▪ Only if > 1 study

Results

5592 abstracts -> 1362 full text met inclusions -> 231 met criteria -> 62 were rated as medium (not low??) potential for bias.

Of the 62, 26 satisfied strict criteria for prevalent indicators: Eleven independent samples from 8

publications contributed to findings▪ All were athletic populations▪ 5 in adults only▪ 1 adolescents only▪ 5 both

Results (cont.)

Discussion – key indicators

Discussion – less “key”

Recovery pattern in cog test: Majority of cases with cog deficit resolve within 1 week

Deficits in cog function Consistent deficits in tests of RT, memory,

Att/processing/speed/working memory Subgroups

Previous concussion Associations

Severity (amnesia or LOC/PTA) assocaited with cog deficits 7 days post PCE

Self-reported symptoms correlate with neuro and cog deficit tests (48 hrs)

Discussion – poor indicators

CT scan Learning disability (1 study!)

Discussion limitations

Mainly athletic population (+ve!) Studies call condition “concussion”,

but may not be due to nonspecific defn.

Practice effect on neuropysch tests PCE vs concussion:

Lacerated forehead post-fall is evidence of PCE but not necessarily concussion

Don’t mention false positives?

Discussion – proposed study NB to elucidate PCE from concussion “In absence of physiological measure, evidence of

concussion are signs, symptoms and objective measures of neurologic or cognitive dysfunction”

“In addition, brain imaging, biomarkers, helmet accelerometer studies and other objective methods are being explored for their ability to detect concussion”

“However, studies have not examined the links among these measures in a way that distinguished evidence for concussion from evidence for a PCE”

THUS, their study design couldn’t either

Take home message

“Prevalent and consistent indicators of a concussion include observing disorientation or confusion immediately after the injury, and slower reaction time, poor balance, and impaired verbal learning and memory within 2 days after the injury.” (SMR)