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. Author manuscript; available in PMC: 2025 Mar 18.
Published in final edited form as: J Head Trauma Rehabil. 2024 Mar 18;39(2):121–139. doi: 10.1097/HTR.0000000000000901

TABLE 2.

TBI indicators of severity by TBI tier.; most recent head injury, National Concussion Surveillance System Pilota

Probable TBI (tier 3), n = 716
Possible TBI (tier 2), n = 343
Delayed Possible TBI (tier 1), n = 93
Noncases (tier 0), n = 212
Statistically significant differences between tiers
Count Weightedb, % or mean 95% Cl Count Weightedb, % or mean 95% Cl Count Weightedb, % or mean 95% Cl Count Weightedb, % or mean 95% Cl

Evaluated for TBI Yes 319 45.4% 40.8%-50.1% 74 20.9% 15.5%-26.2% 21 23.8% 12.6%-35.1% 32 14.5% 8.6%-20.4% c, d, e
Time to symptom resolution 1 day of symptoms 133 15.8% 12.7%-18.8% 141 41.5% 34.9%-48.2% 41 42.0% 29.9%-54.2% f f f c, d, e
 Still having symptom OR had symptoms for 8+ days 338 46.5% 41.9%-51.1% 72 18.9% 14.0%-23.9% 14 15.8% 5.8%-25.8% f f f c, d, e
Extent of Impact: social functioning (mean) 657 2.1 2.0–2.2 327 1.3 1.2–1.4 85 1.1 1.0–1.2 207 1.0 1.0–1.1 c, d, e, g, h
Extent of Impact: work functioning (mean) 659 2.2 2.1–2.3 329 1.4 1.3–1.5 83 1.2 1.1–1.3 207 1.1 1.0–1.1 c, d, e, g, h

Abbreviations: Cl, confidence interval; TBI, traumatic brain Injury.

a

Palrwlse differences between groups were tested using a univariate f statistic for continuous severity Indicators and χ2 tests for categorical severity Indicators.

b

Estlmates were weighted to correct for disproportionate sampling probabilities Introduced by the sampling design and to correct for differences in the demographic characteristics of the sample versus the population. Weighted estimates from this pilot work were not specifically Intended to produce nationally representative estimates of TBI.

c

Statistically significant difference (P < .05) between tiers 3 and 2.

d

Statistically significant difference (P < .05) between tiers 3 and 1.

e

Statlstlcally significant difference (P < .05) between tiers 3 and 0.

f

Not applicable. No analysis was conducted because no data were collected for these cases.

g

Statistical ly significant difference (P < .05) between tiers 2 and 1.

h

Statistically significant difference (P < .05) between tiers 2 and 0.