Hostname: page-component-cd9895bd7-hc48f Total loading time: 0 Render date: 2024-12-27T06:06:19.842Z Has data issue: false hasContentIssue false
  • English
  • Français

The neuropsychological impact of sports-related concussion: A meta-analysis

Published online by Cambridge University Press:  01 July 2005

HEATHER G. BELANGER  and
RODNEY D. VANDERPLOEG
HEATHER G. BELANGER
Affiliation:
James A. Haley Veterans' Hospital, Tampa, Florida Department of Psychology, University of South Florida, Tampa, Florida Defense and Veterans Brain Injury Center, Tampa, Florida
RODNEY D. VANDERPLOEG
Affiliation:
James A. Haley Veterans' Hospital, Tampa, Florida Department of Psychology, University of South Florida, Tampa, Florida Department of Psychiatry, University of South Florida, Tampa, Florida Defense and Veterans Brain Injury Center, Tampa, Florida
Get access Rights & Permissions [Opens in a new window]

Abstract

There is increasing interest in the potential neuropsychological impact of sports-related concussion. A meta-analysis of the relevant literature was conducted to determine the impact of sports-related concussion across six cognitive domains. The analysis was based on 21 studies involving 790 cases of concussion and 2014 control cases. The overall effect of concussion (d = 0.49) was comparable to the effect found in the non-sports-related mild traumatic brain injury population (d = 0.54; Belanger et al., 2005). Using sports-concussed participants with a history of prior head injury appears to inflate the effect sizes associated with the current sports-related concussion. Acute effects (within 24 hr of injury) of concussion were greatest for delayed memory, memory acquisition, and global cognitive functioning (d = 1.00, 1.03, and 1.42, respectively). However, no residual neuropsychological impairments were found when testing was completed beyond 7 days postinjury. These findings were moderated by cognitive domain and comparison group (control group versus preconcussion self-control). Specifically, delayed memory in studies utilizing a control group remained problematic at 7 days. The implications and limitations of these findings are discussed. (JINS, 2005, 11, 345–357.)

Keywords

Brain concussionHead injuryMild concussionSequelaeTraumatic brain injuryFootballSoccer
Type
Research Article
Information
Journal of the International Neuropsychological Society , Volume 11 , Issue 4 , July 2005 , pp. 345 - 357
Copyright
© 2005 The International Neuropsychological Society

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

#Abreau, F., Templer, D.I., Schuyler, B.A., & Hutchison, H.T. (2000). Neuropsychological assessment of soccer players. Neuropsychology, 4, 175–181.Google Scholar
Alexander, M.P. (1992). Neuropsychiatric correlates of persistant postconcussive syndrome. Journal of Head Trauma Rehabilitation, 8, 60–69.CrossRefGoogle Scholar
Alves, W., Macciocchi, S.N., & Barth, J.T. (1993). Postconcussive symptoms after uncomplicated mild head injury. Journal of Head Trauma Rehabilitation, 8, 48–59.Google Scholar
American Congress of Rehabilitation Medicine (1993). Report of the Mild Traumatic Brain Injury Committee of the Head Injury Interdisciplinary Special Interest Group. Journal of Head Trauma Rehabilitation, 8, 86–87.Google Scholar
Baddeley, A., Emslie, H., & Nimmo-Smith, I. (1992). The Speed and Capacity of Language Processing Test: Manual. Bury St. Edmunds: Thames Valley Test Company.
*Barr, W.B. & McCrea, M. (2001). Sensitivity and specificity of standardized neurocognitive testing immediately following sports concussion. Journal of the International Neuropsychological Society, 7, 693–702.Google Scholar
Barth, J.T., Macciocchi, S.N., Giordani, B., Rimel, R., Jane, J.A., & Boll, T.J. (1983). Neuropsychological sequelae of minor head injury. Neurosurgery, 13, 529–533.CrossRefGoogle Scholar
Belanger, H.G., Curtiss, G., Demery, J.A., Lebowitz, B.K., & Vanderploeg, R.D. (2005). Factors moderating neuropsychological outcome following mild traumatic brain injury: A meta-analysis. Journal of the International Neuropsychological Society, 11, 215–227.Google Scholar
Benedict, R.H., Schretlen, D.J., Groninger, L., & Brandt, J. (1998). Hopkins Verbal Learning Test–Revised: Normative data and analysis of inter-form and test–retest reliability. Clinical Neuropsychologist, 12, 43–55.CrossRefGoogle Scholar
Benton, A.L. (1974). The Revised Visual Retention Test: Clinical and experimental applications (4th ed.). New York: The Psychological Corporation.
Benton, A.L. & Hamsher, K.D. (1976). Multilingual Aphasia Examination. Iowa City, Iowa: University of Iowa.
Benton, A.L. & Van Allen, M.W. (1968). Impairment in facial recognition in patients with cerebral disease. Cortex, 4, 344–358.Google Scholar
Binder, L.M., Rohling, M.L., & Larrabee, J. (1997). A review of mild head trauma. Part I: Meta-analytic review of neuropsychological studies. Journal of Clinical and Experimental Neuropsychology, 19, 421–431.Google Scholar
Bleiberg, J., Cernich, A.N., Cameron, K., Sun, W., Peck, K., Ecklund, L.P., Reeves, C.D., Uhorchak, C.J., Sparling, M.B., & Warden, D.L. (2004). Duration of cognitive impairment after sports concussion. Neurosurgery, 54, 1073–1080.Google Scholar
Bleiberg, J., Kane, R.L., Reeves, D.L., Garmoe, W.S., & Halpern, E. (2000). Factor analysis of computerized and traditional tests used in mild brain injury research. Clinical Neuropsychologist, 14, 287–294.CrossRefGoogle Scholar
Borg, J., Holm, L., Cassidy, J.D., Peloso, P.M., Carroll, L.J., von Holst, H., & Ericson, K. (2004). Diagnostic procedures in mild traumatic brain injury: Results of the WHO Collaborating Centre Task Force on Mild Traumatic Brain Injury. Journal of Rehabilitation Medicine, 43 (Suppl.), 61–75.CrossRefGoogle Scholar
Brandt, J. (1991). The Hopkins Verbal Learning Test: Development of a new verbal memory test with six equivalent forms. Clinical Neuropsychologist, 5, 125–142.CrossRefGoogle Scholar
#Brooks, N., Kupshik, G., Wilson, L., Galbraith, S., & Ward, R. (1987). A neuropsychological study of active amateur boxers. Journal of Neurology, Neurosurgery and Psychiatry, 50, 997–1000.Google Scholar
*Bruce, J.M. & Echemendia, R.J. (2003). Delayed-onset deficits in verbal encoding strategies among patients with mild traumatic brain injury. Neuropsychology, 17, 622–629.Google Scholar
Buschke, H. (1973). Selective reminding for analysis of memory and learning. Journal of Verbal Learning and Verbal Behavior, 12, 543–550.CrossRefGoogle Scholar
Cantu, R.C. (1991). Minor head injuries in sports. In P.G. Dyment (Ed.), Adolescent medicine: State of the art reviews (pp. 17–30). Philadelphia, Pennsylvania: Hanley & Belfus.
Capruso, D.X. & Levin, H.S. (1992). Cognitive impairment following closed head injury. Neurologic Clinics, 10, 879–893.Google Scholar
Claeson, L.E., Esbjörnsson, E., Carté, B.M., & Wahlbin, M. (1971). Manual to Claeson-Dahls learning test for clinical use. Stockholm: Psykologiförlaget ab.
Cohen, J. (1988). Statistical power analysis for the behavioral sciences (2nd ed.). New Jersey: Lawrence Erlbaum.
Collins, M.W., Grindel, S.H., Lovell, M.R., Dede, D.E., Moser, D.J., Phalin, B.R., Nogle, S., Wasik, M., Cordry, D., Daugherty, K.M., Sears, S.F., Nicolette, G., Indelicato, P., & McKeag, D.B. (1999). Relationship between concussion and neuropsychological performance in college football players. Journal of the American Medical Association, 282, 964–970.CrossRefGoogle Scholar
Colorado Medical Society (1991). Report of the Sports Medicine Committee: Guidelines for the management of concussion in sports (revised). Denver, Colorado: Colorado Medical Society.
Congress of Neurological Surgeons (1966). Committee on head injury nomenclature: Glossary of head injury. Clinical Neurosurgery, 12, 386–394.Google Scholar
Conners, C.K. (1995). Conners' Continuous Performance Test. Toronto, Canada: Multi-Health Systems.
*Cremona-Meteyard, S.L. & Geffen, G.M. (1994). Persistent visuospatial attention deficits following mild head injury in Australian Rules football players. Neuropsychologia, 32, 649–662.CrossRefGoogle Scholar
Deb, S., Lyons, I., & Koutzoukis, C. (1999). Neurobehavioural symptoms one year after a head injury. British Journal of Psychiatry, 174, 360–365.CrossRefGoogle Scholar
Delis, D.C., Kramer, J.H., Kaplan, E., & Ober, B.A. (1987). California Verbal Learning Test: Adult Version. San Antonio, TX: The Psychological Corporation.
Dikmen, S., Machamer, J., & Temkin, N. (2001). Mild head injury: Facts and artifacts. Journal of Clinical and Experimental Neuropsychology, 23, 729–738.Google Scholar
Dikmen, S., Machamer, J.E., Winn, H.R., & Temkin, N.R. (1995). Neuropsychological outcome at 1-year post head injury. Neuropsychology, 9, 80–90.CrossRefGoogle Scholar
Dikmen, S., McLean, A., & Temkin, N. (1986). Neuropsychological and psychosocial consequences of minor head injury. Journal of Neurology, Neurosurgery and Psychiatry, 49, 1227–1232.CrossRefGoogle Scholar
#Downs, D.S. & Abwender, D. (2002). Neuropsychological impairment in soccer athletes. Journal of Sports Medicine and Physical Fitness, 42, 103–107.Google Scholar
#Drew, R.H., Templer, D.I., Schuyler, B.A., Newell, T.G., & Cannon, W.G. (1986). Neuropsychological deficits in active licensed professional boxers. Journal of Clinical Psychology, 42, 520–525.Google Scholar
Dunlap, W.P., Cortina, J.M., Vaslow, J.B., & Burke, M.J. (1996). Meta-analysis of experiments with matched groups or repeated measures designs. Psychological Methods, 1, 170–177.CrossRefGoogle Scholar
*Echemendia, R.J., Putukian, M., Mackin, R.S., Julian, L., & Shoss, N. (2001). Neuropsychological test performance prior to and following sports-related mild traumatic brain injury. Clinical Journal of Sport Medicine, 11, 23–31.CrossRefGoogle Scholar
Egger, M., Davey Smith, G., Schneider, M., & Minder, C. (1997). Bias in meta-analysis detected by a simple, graphical test. British Medical Journal, 315, 629–634.Google Scholar
*Erlanger, D., Saliba, E., Barth, J., Almquist, J., Webright, W., & Freeman, J. (2001). Monitoring resolution of postconcussion symptoms in athletes: Preliminary results of a web-based neuropsychological test protocol. Journal of Athletic Training, 36, 280–287.Google Scholar
Erlanger, D.M., Feldman, D.J., & Kutner, K. (1999). Concussion Resolution Index. New York: Headminder, Inc.
Gentilini, M., Nichelli, P., Schoenhuber, R., Bortolotti, P., Tonelli, L., Falasca, A., & Merli, G.A. (1985). Neuropsychological evaluation of mild head injury. Journal of Neurology, Neurosurgery and Psychiatry, 48, 137–140.Google Scholar
Giza, C.C. & Hovda, D.A. (2001). The neurometabolic cascade of concussion. Journal of Athletic Training, 36, 228–235.Google Scholar
Golden, C. (1978). Stroop Color and Word Test: A manual for clinical and experimental use. Chicago, Illinois: Stoelting.
Graham, F.K. & Kendall, B.S. (1960). Memory-for-Designs Test: Revised general manual. Perceptual and Motor Skills, 11 (Monograph Suppl. No. 2-VII), 147–188.CrossRefGoogle Scholar
Gronwall, D. & Wrightson, P. (1974). Delayed recovery of intellectual function after minor head injury. Lancet, 2, 605–609.CrossRefGoogle Scholar
Gronwall, D.A. (1977). Paced Auditory Serial Addition Task: A measure of recovery from concussion. Perceptual and Motor Skills, 44, 367–373.CrossRefGoogle Scholar
Guskiewicz, K.M., McCrea, M., Marshall, S.W., Cantu, R.C., Randolph, C., Barr, W., Onate, J.A., & Kelly, J.P. (2003). Cumulative effects associated with recurrent concussion in collegiate football players: The NCAA Concussion Study. Journal of the American Medical Association, 290, 2549–2555.CrossRefGoogle Scholar
*Guskiewicz, K.M., Riemann, B.L., Perrin, D.H., & Nashner, L.M. (1997). Alternative approaches to the assessment of mild head injury in athletes. Medicine and Science in Sports and Exercise, 29, S213–S221.CrossRefGoogle Scholar
*Guskiewicz, K.M., Ross, S.E., & Marshall, S.W. (2001). Postural stability and neuropsychological deficits after concussion in collegiate athletes. Journal of Athletic Training, 36, 263–273.Google Scholar
Hartlage, L.C., Durant-Wilson, D., & Patch, P.C. (2001). Persistent neurobehavioral problems following mild traumatic brain injury. Archives of Clinical Neuropsychology, 16, 561–570.CrossRefGoogle Scholar
Heaton, R.K. (1981). Wisconsin Card Sorting Test Manual. Odessa, Florida: Psychological Assessment Resources.
Heaton, R.K., Chelune, G.J., Talley, J.L., Kay, G.G., & Curtiss, G. (1993). Wisconsin Card Sorting Test Manual: Revised and Expanded. Odessa, Florida: Psychological Assessment Resources.
*Hinton-Bayre, A.D., Geffen, G., & McFarland, K. (1997). Mild head injury and speed of information processing: A prospective study of professional rugby league players. Journal of Clinical and Experimental Neuropsychology, 19, 275–289.CrossRefGoogle Scholar
*Hinton-Bayre, A.D., Geffen, G.M., Geffen, L.B., McFarland, K.A., & Friis, P. (1999). Concussion in contact sports: Reliable change indices of impairment and recovery. Journal of Clinical and Experimental Neuropsychology, 21, 70–86.CrossRefGoogle Scholar
Hunter, J.E. & Schmidt, F.L. (1990). Methods of meta-analysis: Correcting error and bias in research findings. Newbury Park, California: Sage.
Hunter, J.E., Schmidt, F.L., & Jackson, G.B. (1982). Meta-analysis: Cumulating research findings across studies. Beverly Hills, California: Sage.
*Iverson, G.L., Lovell, M.R., & Collins, M.W. (2003). Interpreting change on ImPACT following sport concussion. Clinical Neuropsychologist, 17, 460–467.CrossRefGoogle Scholar
Jones-Gotman, M. & Milner, B. (1977). Design fluency: The invention of nonsense drawings after focal cortical lesions. Neuropsychologia, 15, 653–674.Google Scholar
Kelly, J.P. & Rosenberg, J. (1997). Practice parameter. The management of concussion in sports. Report of the Quality Standards Subcommittee. Neurology, 48, 581–585.Google Scholar
Lafayette Instrument Company (Undated). Instructions for the Grooved Pegboard. Lafayette, Indiana.
*Lavoie, M.E., Dupuis, F., Johnston, K.M., Leclerc, S., & Lassonde, M. (2004). Visual p300 effects beyond symptoms in concussed college athletes. Journal of Clinical and Experimental Neuropsychology, 26, 55–73.Google Scholar
Levin, H.S. (1983). The Paced Auditory Serial Addition Task–Revised: University of Texas at Galveston (unpublished).
#Levin, H.S., Lippold, S.C., Goldman, A., Handel, S., High, W.M., Jr., Eisenberg, H.M., & Zelitt, D. (1987). Neurobehavioral functioning and magnetic resonance imaging findings in young boxers. Journal of Neurosurgery, 67, 657–667.Google Scholar
Levin, H.S., Mattis, S., Ruff, R.M., Eisenberg, H.M., Marshall, L.F., Tabaddor, K., High, W.M., Jr., & Frankowski, R.F. (1987). Neurobehavioral outcome following minor head injury: A three-center study. Journal of Neurosurgy, 66, 234–243.CrossRefGoogle Scholar
Lezak, M.D. (1995). Neuropsychological assessment (3rd ed.). Oxford, UK: Oxford University Press.
*Lovell, M.R., Collins, M.W., Iverson, G.L., Field, M., Maroon, J.C., Cantu, R., Podell, K., Powell, J.W., Belza, M., & Fu, F.H. (2003). Recovery from mild concussion in high school athletes. Journal of Neurosurgery, 98, 296–301.CrossRefGoogle Scholar
*Lovell, M.R., Collins, M.W., Iverson, G.L., Johnston, K.M., & Bradley, J.P. (2004). Grade 1 or “ding” concussions in high school athletes. American Journal of Sports Medicine, 32, 47–54.CrossRefGoogle Scholar
*Macciocchi, S.N., Barth, J.T., Alves, W., Rimel, R.W., & Jane, J.A. (1996). Neuropsychological functioning and recovery after mild head injury in collegiate athletes. Neurosurgery, 39, 510–514.Google Scholar
*Maddocks, D.L., Dicker, G.D., & Saling, M.M. (1995). The assessment of orientation following concussion in athletes. Clinical Journal of Sport Medicine, 5, 32–35.CrossRefGoogle Scholar
*Makdissi, M., Collie, A., Maruff, P., Darby, D.G., Bush, A., McCrory, P., & Bennell, K. (2001). Computerised cognitive assessment of concussed Australian Rules footballers. British Journal of Sports Medicine, 35, 354–360.CrossRefGoogle Scholar
Maroon, J.C., Lovell, M.R., Norwig, J., Podell, K., Powell, J.W., & Hartl, R. (2000). Cerebral concussion in athletes: Evaluation and neuropsychological testing. Neurosurgery, 47, 659–669; discussion 669–672.Google Scholar
Mattis, S. & Kovner, R. (1978). Different patterns of mnemonic deficits in two organic amnestic syndromes. Brain and Language, 6, 179–191.CrossRefGoogle Scholar
*McCrea, M. (2001). Standardized mental status testing on the sideline after sport-related concussion. Journal of Athletic Training, 36, 274–279.Google Scholar
McCrea, M., Guskiewicz, K.M., Marshall, S.W., Barr, W., Randolph, C., Cantu, R.C., Onate, J.A., Yang, J., & Kelly, J.P. (2003). Acute effects and recovery time following concussion in collegiate football players: The NCAA Concussion Study. Journal of the American Medical Association, 290, 2556–2563.Google Scholar
*McCrea, M., Kelly, J.P., Kluge, J., Ackley, B., & Randolph, C. (1997). Standardized assessment of concussion in football players. Neurology, 48, 586–588.Google Scholar
*McCrea, M., Kelly, J.P., Randolph, C., Cisler, R., & Berger, L. (2002). Immediate neurocognitive effects of concussion. Neurosurgery, 50, 1032–1040; discussion 1040–1032.Google Scholar
McCrea, M., Randolph, C., & Kelly, J.P. (2000). The Standardized Assessment of Concussion (SAC): Manual for administration, scoring and interpretation. Waukesha: CNS, Inc.
Moran, L.J. & Mefferd, P.B. (1959). Repetitive psychometric measures. Psychological Reports, 5, 269–275.Google Scholar
*Moser, R.S. & Schatz, P. (2002). Enduring effects of concussion in youth athletes. Archives of Clinical Neuropsychology, 17, 91–100.Google Scholar
#Murelius, O. & Haglund, Y. (1991). Does Swedish amateur boxing lead to chronic brain damage? 4. A retrospective neuropsychological study. Acta Neurologica Scandinavica, 83, 9–13.Google Scholar
National Health and Medical Research Council (1994). Football injuries of the head and neck. Canberra: Sports Medicine Australia.
Osterrieth, P.A. (1944). Le test de copie d'une figure complex: Contribution a l'etude de la perception et de la memoire. Archives de Psychologie, 30, 286–356.Google Scholar
Pellman, E.J., Powell, J.W., Viano, D.C., Casson, I.R., Tucker, A.M., Feuer, H., Lovell, M., Waeckerle, J.F., & Robertson, D.W. (2004). Concussion in professional football: epidemiological features of game injuries and review of the literature—part 3. Neurosurgery, 54, 81–94; discussion 94–86.Google Scholar
Powell, J.W. & Barber-Foss, K.D. (1999). Traumatic brain injury in high school athletes. Journal of the American Medical Association, 282, 958–963.CrossRefGoogle Scholar
Powell, T.J., Collin, C., & Sutton, K. (1996). A follow-up study of patients hospitalized after minor head injury. Disability and Rehabilitation, 18, 231–237.CrossRefGoogle Scholar
Randolph, C. (1998). Repeatable battery for the assessment of neuropsychological status. San Antonio, TX: The Psychological Corporation.
Randt, C.T. & Brown, E.R. (1983). Randt Memory Test. Bayport, New York: Life Science Associates.
Raven, J.E. (1960). Guide to the standard progressive matrices. London, UK: Lewis.
Reitan, R.M. & Wolfson, D. (1985). The Halstead-Reitan Neuropsychological Test Battery. Tucson, AZ: Neuropsychology Press.
Reitan, R.M. & Wolfson, D. (1993). The Halstead-Reitan Neuropsychological Test Battery: Theory and clinical interpretation (2nd ed.). Tucson, AZ: Neuropsychology Press.
Rimel, R.W., Giordani, B., Barth, J.T., Boll, T.J., & Jane, J.A. (1981). Disability caused by minor head injury. Neurosurgery, 9, 221–228.Google Scholar
Schatz, P. & Zillmer, E.A. (2003). Computer-based assessment of sports-related concussion. Applied Neuropsychology, 10, 42–47.Google Scholar
Schmidt, F.L. & Hunter, J.E. (2003). Meta-analysis. In J.S. Schinka & W.F. Velicer (Eds.), Handbook of psychology (pp. 533–554). Hoboken, New Jersey: John Wiley & Sons.
Schmidt, M. (1996). Rey Auditory Verbal Learning Test: A Handbook. Los Angeles, California: Western Psychological Services.
Schretlen, D.J. & Shapiro, A.M. (2003). A quantitative review of the effects of traumatic brain injury on cognitive functioning. International Review of Psychiatry, 15, 341–349.CrossRefGoogle Scholar
Shipley, W.C. (1940). A self-administered scale for measuring intellectual impairment and deterioration. Journal of Psychology, 9, 371–377.CrossRefGoogle Scholar
Spreen, O. & Strauss, E. (1998). A compendium of neuropsychological tests (2nd ed.). London, UK: Oxford University Press.
The Psychological Corporation (1994). Vigil/W Continuous Performance Test. San Antonio, TX: The Psychological Corporation.
#Tysvaer, A.T. & Lochen, E.A. (1991). Soccer injuries to the brain. A neuropsychologic study of former soccer players. American Journal of Sports Medicine, 19, 56–60.Google Scholar
*Warden, D.L., Bleiberg, J., Cameron, K.L., Ecklund, J., Walter, J., Sparling, M.B., Reeves, D., Reynolds, K.Y., & Arciero, R. (2001). Persistent prolongation of simple reaction time in sports concussion. Neurology, 57, 524–526.Google Scholar
#Webbe, F.M. & Ochs, S.R. (2003). Recency and frequency of soccer heading interact to decrease neurocognitive performance. Applied Neuropsychology, 10, 31–41.Google Scholar
Wechsler, D. (1974). WISC–R manual, Wechsler Intelligence Scale for Children–Revised. New York: The Psychological Corporation.
Wechsler, D. (1987a). Wechsler Adult Intelligence Scale–Revised. New York: The Psychological Corporation.
Wechsler, D. (1987b). Wechsler Memory Scale–Revised. San Antonio, TX: Psychological Corporation.
Wechsler, D. (1997a). Wechsler Adult Intelligence Scale–Third Edition: Administration and Scoring Manual. San Antonio, TX: Harcourt Brace.
Wechsler, D. (1997b). Wechsler Memory Scale–III Administration and Scoring Manual. San Antonio, TX: The Psychological Corporation.
Westerman, R., Darby, D.G., Maruff, P., & Collie, A. (2001). Computerised cognitive function testing of pilots. Australian Defense Forces Health Services Journal, 2, 29–36.Google Scholar
Wilson, B.A., Watson, P.C., Baddeley, A.D., Emslie, H., & Evans, J.J. (2000). Improvement or simply practice? The effects of twenty repeated assessments on people with and without brain injury. Journal of the International Neuropsychological Society, 6, 469–479.Google Scholar
#Witol, A.D. & Webbe, F.M. (2003). Soccer heading frequency predicts neuropsychological deficits. Archives of Clinical Neuropsychology, 18, 397–417.Google Scholar
Zakzanis, K.K., Leach, L., & Kaplan, E. (1999). Mild traumatic brain injury. In L.A. Bieliauskas (series Ed.), Neuropsychological differential diagnosis: Studies on Neuropsychology, Development, and Cognition (pp. 163–171). Exton, Pennsylvania: Swets & Zeitlinger.