Table 3 Psychometric evidence of concussion symptom measures in the student-athlete age 13–22, published studies
StudyStudy objectiveStudy designStudy populationSymptom measurePsychometric evidence
McCaffrey (2007)30Determine the relation between force caused by head impact and subsequent neurocognitive or balance symptomsDouble-blind, repeated measures43 non-concussed college athletes (age mean = 20.7, SD = 1.62)Sport: footballGSC; 18 itemsReliability: not reportedValidity: increase in number of symptoms (but not severity) following 90 g force taken but not “low impact” (<60 g force); 2 symptoms on average. Minimal change in symptoms following >90 g of force was not corroborated by change in balance or cognitionSerial use: two administrations, 2 week interval. No RCI
Register-Mihalik (2007)31Examine the effects of pre-season baseline headaches and post-traumatic headaches on neurocognitive performanceRetrospective repeated measures study247 concussed high school and college athletes (age mean  = 16.65, sd = 1.87)Sport: mixedGSC; 20 itemsReliability: not reportedValidity: presence and severity of symptoms correlated with baseline headaches and post-traumatic headachesSerial use: symptom total score and symptom severity was used across post-injury testing times considered relative to headache at baseline
Piland (2006)32Evaluate the factorial validity of a self-reported measure of concussion symptom severityCross sectional study of normative cases1089 high school athletes (mean age  = 16.3, SD = 0.9)Sport: footballGSC; 20 itemsReliability: not reportedValidity: analysis showed 3-factor (eg, somatic, neurobehavioural and cognitive) fit for the 16 items; better 3 factor fit for a model comprised of 9 items. Single second-order factor deemed “concussion symptomotology” foundSerial use: not reported
McCrea (2003)33Prospectively measure immediate effects and natural recovery course relating to symptoms, cognitive functioning and postural stability following sport-related concussionProspective cohort with matched case controls.1631 college football players (94 injured and 56 controls). Concussion mean age  = 20, SD = 1.36, control mean age  = 19.20, SD = 1.45Sport: footballGSC; 17 itemsReliability: not reportedValidity: group differences between concussed and non-concussed controls (through 5 days post injury); average symptom resolution 7 days. Symptom recovery curves similar to recovery curves on balance and neurocognitive functionSerial use: GSC administered serially post-injury, with greater group differences persisting through day 5
McCrea (2005)34Use standard regression-based methods, with baseline and serial testing paradigm to measure individual rates of cognitive/functional impairment following concussionProspective study with matched case controls.150 college athletes (94 injured and 56 controls) Concussion mean age  = 20.04, SD = 1.36; control mean age  = 19.20, SD = 1.45Sport: footballGSC; 17 itemsReliability: not reportedValidity: sensitivity and specificity were reported on the GSC immediately following injury (0.89 and 1.00, respectively). Specificity remained at 1.00 through day 7 post-injury; sensitivity declined successively. Symptom recovery generally preceded recovery on balance and cognitive testingSerial use: immediate post-injury, day 7
Guskiewicz (2003)35Estimate the incidence of concussion and time to recovery after concussionProspective longitudinal cohort study;2905 college athletes (184 injured)Sport: footballGSC; 17 itemsReliability: not reportedValidity: GSC used serially post-injury, demonstrated linear recoverySerial use: baseline, 7 post-injury (3 hours to 90 days); no RCI
Iverson & Goetz, (2004)36Describe practical considerations for interpreting change following brain injuryBook chapter analying prospective cohort200 collegiate football playersPCS; 22 itemsReliability: good internal consistency (Cronbach α  = .87) and moderate reliability (test-retest  = 0.55) at beginning and end of seasonValidity: interpretation of post- concussion symptom scores must be based on baseline ratesSerial use: pre-season to post-season for test-retest; no RCI
Lovell (2006)37Present psychometric and clinical properties of the PCSCross-sectional study with normative and clinical samples1746 high school (n = 707) and college (n = 1,039) athletes (260 injured)Sport: unspecifiedPCS; 22 itemsReliability: high internal consistency in normal samples (Cronbach α range from 0.88 to 0.94) and for concussed sample (r = 0.93)Validity: demonstrated differences in symptoms between concussed and normalsSerial use: 52 concussed athletes endorsed decreasing levels of symptoms across 3 visits
McClincy (2006)36Serially assess cognitive and symptom-report of concussed athletesProspective cohort104 concussed high school and college athletes (age mean = 16.11, SD = 2.22)Sport: mixed (football n = 83)PCS; 22 itemsReliability: not reportedValidity: discriminated between baseline and post-injury on visits 1 and 2 but not 3 (day 14 on average). Symptom report and recovery pattern similar to neurocognitive performanceSerial use: day 2, 7, 14: demonstrated expected pattern of post-injury symptom resolution across visits
Collins (1999)39Prospectively assess premorbid variables with neuropsychological performance and to evaluate post-concussion recoveryProspective cohort with normative and clinical samples393 non-concussed collegiate athletes (age age mean = 20.4, SD = 1.7), with concussed sample of 16Sport: footballPCS; 20 itemsReliability: not reportedValidity: increase in symptom report related to number of previous concussionsSerial use: none
Collins (2003)40Examine relationship between on-field markers of concussion severity and post-injury neuropsychological and symptom presentationCase control78 concussed high school and college athletes (ages  = 14–22)Sport: mixed (football n = 64)PCS; 22 itemsReliability: not reportedValidity: symptom scores similar to good versus poor outcome classification based on neurocognitive performanceSerial use: none
Field (2003)41Evaluate symptoms and neurocognitive recovery patternsCase control92 high school (ages 14–18) and college (ages 17–25) athletes (54 total injured)Sport: football and soccer (football)PCS (20 item version)Reliability: not reportedValidity: increased symptoms in concussed sample relative to baseline and controls at 24 hours and 3 days post-injury and at 5 days for the high school athletesSerial use: 1, 3, 5 days; increased symptoms immediately post-injury with gradual decline
Echemendia (2001) 42Evaluate neuropsychological test performance prior to and following mTBIProspective cohort with matched controls49 college athletes (29 injured)Sport: mixed (football n = 12)PCS; 22 itemsReliability: not reportedValidity: demonstrated group differences: symptoms reported higher in concussed athletes versus controls at 2 hours post-injury but not at 48 hours post-injury. Agreement with neuropsychological data at 2 hours but not at 48 hoursSerial use: significant differences were found between controls and injured at 2 hours post-injury but not at 48 hours
Schatz (2006)43Identify sensitivity and specificity of ImPACT (including symptom report) for identifying athletes with concussionCase control cohort138 high school athletes (72 injured). Concussed age mean  = 16.5 (SD = 2.3), control age mean  = 17.3 (SD = 1.7)Sport: mixed (football 73%)PCS; 22 itemsReliability: not reportedValidity: demonstrated group differences: significant differences between concussed and non-concussed samples. Good sensitivity (82%) and specificity (89%) for identifying individuals with concussion when combined with neurocognitive test composites on ImPACTSerial use: not reported
VanKampen (2006)44Evaluate the individual and combined sensitivity and specificity of player symptom reportingCase control192 high school and college athletes (122 injured age 12 to 27 and 70 controls age 14–22)Sport: mixed (68% football)PCS; 22 itemsReliability: not reportedValidity: limited change in symptoms post-injury (64% of sample). Neurocognitive testing resulted in a net increase in sensitivity of 19%; conclude that reliance on patients’ self-reported symptoms post-concussion is likely to result in under-diagnosis of concussionSerial use: 64% of concussed athletes reported post-injury an increased symptom score that exceeded reliable change compared with 9% in the control group
Iverson (2003)45Examine stability of test scores, calculate reliable change confidence intervals for test-retest difference scores on ImPACTProspective longitudinal cohort(1) 56 high school and college student-athletes; (2) 41 high school/college student-athletes post-injuryPCS; 22 itemsReliability: test-retest moderate (r = 0.65)Validity: group differences reportedSerial use: preseason, post-concussion. RCI calculated
Iverson & Goetz (2004)36Describe practical considerations for interpreting change following brain injuryBook chapter analysing prospective cohort113 athletes (age range 15–20)Sport: junior hockey leagueRPCSQ; 16 itemsReliability: good internal consistency (Cronbach α  = 0.89) and split-half reliability (r = 0.88). Low test-retest reliability (Pearson r = 0.24, Spearman = 0.23)Validity: interpretation of post- concussion scores must be considered relative to level of baseline reportingSerial use: one-year time period for test-retest
Wilde (2008)46Examine the association between self-reported concussion symptoms and neuroimaging techniques (diffusion tensor imaging tractography) in adolescents with GCS = 15 and normal CT scanCase control10 adolescents ages 14–17 years (mean  = 15.7)Sport: 70% of sample was from “low impact” (eg, sports-related, bicycle, fall or assault)RPCSQ; 16 itemsReliability: not reportedValidity: discriminated between concussed and non-concussed groups; higher post-concussion symptoms in concussed group versus control group (cohen’s d = 1.57). Group differences found on all three subscales (cognitive, affective and somatic) with large effect sizes. Imaging measures not significantly correlated with symptom measureSerial use: none
  • GSS, graded symptom scale; ImPACT, immediate post-concussion assessment and cognitive testing; mTBI, mild traumatic brain injury; PCS, post-concussion symptom scale; RPCSQ, Rivermead post-concussion symptom questionnaire; RCI, reliable change indices.