Consensus statement on Concussion in Sport - The 4th International Conference on Concussion in Sport held in Zurich, November 2012

The new 2012 Zurich Consensus statement is designed to build on the principles outlined in the previous documents and to develop further conceptual understanding of this problem using a formal consensus-based approach. A detailed description of the consensus process is outlined at the end of this document under the Background section. This document is developed primarily for use by physicians and healthcare professionals who are involved in the care of injured athletes, whether at the recreational, elite or professional level.

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Consensus statement on concussion in sport

Since the 1920s, it has been known that the repetitive brain trauma associated with boxing may produce a progressive neurological deterioration, originally termed dementia pugilistica, and more recently, chronic traumatic encephalopathy (CTE). We review 48 cases of neuropathologically verified CTE recorded in the literature and document the detailed findings of CTE in 3 profession althletes, 1 football player and 2 boxers. Clinically, CTE is associated with memory disturbances, behavioral and personality changes, parkinsonism, and speech and gait abnormalities. Neuropathologically, CTE is characterized by atrophy of the cerebral hemispheres, medial temporal lobe, thalamus, mammillary bodies, and brainstem, with ventricular dilatation and a fenestrated cavum septum pellucidum. Microscopically, there are extensive tau-immunoreactive neurofibrillary tangles, astrocytic tangles, and spindle-shaped and threadlike neurites throughout the brain. The neurofibrillary degeneration of CTE is distinguished from other tauopathies by preferential involvement of the superficial cortical layers, irregular patchy distribution in the frontal and temporal cortices, propensity for sulcal depths, prominent perivascular, periventricular, and subpial distribution, and marked accumulation of tau-immunoreactive astrocytes. Deposition of beta-amyloid, most commonly as diffuse plaques, occurs in fewer than half the cases. Chronic traumatic encephalopathy is a neuropathologically distinct slowly progressive tauopathy with a clear environmental etiology.

/pdf/chronic-traumatic-encephalopathy-in-athletes-progressive-2fpvvkc3i3.pdf

Chronic traumatic encephalopathy in athletes: progressive tauopathy after repetitive head injury.

ContextLack of empirical data on recovery time following sport-related concussion
hampers clinical decision making about return to play after injury.ObjectiveTo prospectively measure immediate effects and natural recovery course
relating to symptoms, cognitive functioning, and postural stability following
sport-related concussion.Design, Setting, and ParticipantsProspective cohort study of 1631 football players from 15 US colleges.
All players underwent preseason baseline testing on concussion assessment
measures in 1999, 2000, and 2001. Ninety-four players with concussion (based
on American Academy of Neurology criteria) and 56 noninjured controls underwent
assessment of symptoms, cognitive functioning, and postural stability immediately,
3 hours, and 1, 2, 3, 5, 7, and 90 days after injury.Main Outcome MeasuresScores on the Graded Symptom Checklist (GSC), Standardized Assessment
of Concussion (SAC), Balance Error Scoring System (BESS), and a neuropsychological
test battery.ResultsNo player with concussion was excluded from participation; 79 players
with concussion (84%) completed the protocol through day 90. Players with
concussion exhibited more severe symptoms (mean GSC score 20.93 [95% confidence
interval {CI}, 15.65-26.21] points higher than that of controls), cognitive
impairment (mean SAC score 2.94 [95% CI, 1.50-4.38] points lower than that
of controls), and balance problems (mean BESS score 5.81 [95% CI, –0.67
to 12.30] points higher than that of controls) immediately after concussion.
On average, symptoms gradually resolved by day 7 (GSC mean difference, 0.33;
95% CI, −1.41 to 2.06), cognitive functioning improved to baseline levels
within 5 to 7 days (day 7 SAC mean difference, −0.03; 95% CI, −1.33
to 1.26), and balance deficits dissipated within 3 to 5 days after injury
(day 5 BESS mean difference, −0.31; 95% CI, −3.02 to 2.40). Mild
impairments in cognitive processing and verbal memory evident on neuropsychological
testing 2 days after concussion resolved by day 7. There were no significant
differences in symptoms or functional impairments in the concussion and control
groups 90 days after concussion.ConclusionsCollegiate football players may require several days for recovery of
symptoms, cognitive dysfunction, and postural instability after concussion.
Further research is required to determine factors that predict variability
in recovery time after concussion. Standardized measurement of postconcussive
symptoms, cognitive functioning, and postural stability may enhance clinical
management of athletes recovering from concussion.

https://jamanetwork.com/journals/jama/articlepdf/197668/JOC30118.pdf

Acute Effects and Recovery Time Following Concussion in Collegiate Football Players: The NCAA Concussion Study

ContextApproximately 300 000 sport-related concussions occur annually
in the United States, and the likelihood of serious sequelae may increase
with repeated head injury.ObjectiveTo estimate the incidence of concussion and time to recovery after concussion
in collegiate football players.Design, Setting, and ParticipantsProspective cohort study of 2905 football players from 25 US colleges
were tested at preseason baseline in 1999, 2000, and 2001 on a variety of
measures and followed up prospectively to ascertain concussion occurrence.
Players injured with a concussion were monitored until their concussion symptoms
resolved and were followed up for repeat concussions until completion of their
collegiate football career or until the end of the 2001 football season.Main Outcome MeasuresIncidence of concussion and repeat concusion; type and duration of symptoms
and course of recovery among players who were injured with a concussion during
the seasons.ResultsDuring follow-up of 4251 player-seasons, 184 players (6.3%) had a concussion,
and 12 (6.5%) of these players had a repeat concussion within the same season.
There was an association between reported number of previous concussions and
likelihood of incident concussion. Players reporting a history of 3 or more
previous concussions were 3.0 (95% confidence interval, 1.6-5.6) times more
likely to have an incident concussion than players with no concussion history.
Headache was the most commonly reported symptom at the time of injury (85.2%),
and mean overall symptom duration was 82 hours. Slowed recovery was associated
with a history of multiple previous concussions (30.0% of those with ≥3
previous concussions had symptoms lasting >1 week compared with 14.6% of those
with 1 previous concussion). Of the 12 incident within-season repeat concussions,
11 (91.7%) occurred within 10 days of the first injury, and 9 (75.0%) occurred
within 7 days of the first injury.ConclusionsOur study suggests that players with a history of previous concussions
are more likely to have future concussive injuries than those with no history;
1 in 15 players with a concussion may have additional concussions in the same
playing season; and previous concussions may be associated with slower recovery
of neurological function.

https://jamanetwork.com/journals/jama/articlepdf/197667/JOC30117.pdf

Cumulative Effects Associated With Recurrent Concussion in Collegiate Football Players: The NCAA Concussion Study

The authors studied 538 patients who had sustained minor head trauma, which was defined as a history of unconsciousness of 20 minutes or less, a Glasgow Coma Scale score of 13 to 15, and hospitalization not exceeding 48 hours. Of these patients, 424 were evaluated 3 months after injury. The follow-u

Disability Caused by Minor Head Injury

OBJECTIVE:This study prospectively examined neuropsychological functioning in 2300 collegiate football players from 10 National Collegiate Athletic Association Division A universities. The study was designed to determine the presence and duration of neuropsychological symptoms after mild head injury

Neuropsychological functioning and recovery after mild head injury in collegiate athletes

This paper describes the pilot phase of the National Traumatic Coma Data Bank, a cooperative effort of six clinical head-injury centers in the United States. Data were collected on 581 hospitalized patients with severe non-penetrating traumatic head injury. Severe head injury was defined on the basis of a Glasgow Coma Scale (GCS) score of 8 or less following nonsurgical resuscitation or deterioration to a GCS score of 8 or less within 48 hours after head injury. A common data collection protocol, definitions, and data collection instruments were developed and put into use by all centers commencing in June, 1979. Extensive information was collected on pre-hospital, emergency room, intensive care, and recovery phases of patient care. Data were obtained on all patients from the time of injury until the end of the pilot study. The pilot phase of the Data Bank provides data germane to questions of interest to neurosurgeons and to the lay public. Questions are as diverse as: what is the prognosis of severe brain injury; what is the impact of emergency care; and what is the role of rehabilitation in the recovery of the severely head-injured patient?

Rebecca W. Rimel

Papers

Disability Caused by Minor Head Injury

Neuropsychological functioning and recovery after mild head injury in collegiate athletes

The National Traumatic Coma Data Bank. Part 1: Design, purpose, goals, and results.

Mild head injury in sports: Neuropsychological sequelae and recovery of function.

Understanding posttraumatic symptoms after minor head injury