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Factors moderating neuropsychological outcomes following mild traumatic brain injury: A meta-analysis

Published online by Cambridge University Press:  04 May 2005

HEATHER G. BELANGER
Affiliation:
James A. Haley Veterans' Hospital, Tampa, Florida University of South Florida Department of Psychology, Tampa, Florida Defense and Veterans Brain Injury Center, Tampa, Florida Henry M. Jackson Foundation, Rockville, Maryland
GLENN CURTISS
Affiliation:
James A. Haley Veterans' Hospital, Tampa, Florida University of South Florida Department of Psychiatry, Tampa, Florida Defense and Veterans Brain Injury Center, Tampa, Florida
JASON A. DEMERY
Affiliation:
James A. Haley Veterans' Hospital, Tampa, Florida University of Florida, Department of Clinical and Health Psychology, Gainesville, Florida
BRIAN K. LEBOWITZ
Affiliation:
James A. Haley Veterans' Hospital, Tampa, Florida University of Cincinnati, Department of Psychology, Cincinnati, Ohio
RODNEY D. VANDERPLOEG
Affiliation:
James A. Haley Veterans' Hospital, Tampa, Florida University of South Florida Department of Psychology, Tampa, Florida University of South Florida Department of Psychiatry, Tampa, Florida Defense and Veterans Brain Injury Center, Tampa, Florida

Abstract

There continues to be debate about the long-term neuropsychological impact of mild traumatic brain injury (MTBI). A meta-analysis of the relevant literature was conducted to determine the impact of MTBI across nine cognitive domains. The analysis was based on 39 studies involving 1463 cases of MTBI and 1191 control cases. The overall effect of MTBI on neuropsychological functioning was moderate (d = .54). However, findings were moderated by cognitive domain, time since injury, patient characteristics, and sampling methods. Acute effects (less than 3 months postinjury) of MTBI were greatest for delayed memory and fluency (d = 1.03 and .89, respectively). In unselected or prospective samples, the overall analysis revealed no residual neuropsychological impairment by 3 months postinjury (d = .04). In contrast, clinic-based samples and samples including participants in litigation were associated with greater cognitive sequelae of MTBI (d = .74 and .78, respectively at 3 months or greater). Indeed, litigation was associated with stable or worsening of cognitive functioning over time. The implications and limitations of these findings are discussed. (JINS, 2005, 11, 215–227.)

Type
Research Article
Copyright
© 2005 The International Neuropsychological Society

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References

REFERENCES (Note. References marked with an asterisk “*” indicate studies included in the meta-analysis.)

Alexander, M.P. (1992). Neuropsychiatric correlates of persistant postconcussive syndrome. Journal of Head Trauma Rehabilitation, 8, 6069.Google Scholar
Alexander, M.P. (1995). Mild traumatic brain injury: Pathophysiology, natural history, and clinical management. Neurology, 45, 12531260.Google Scholar
Alves, W., Macciocchi, S.N., & Barth, J.T. (1993). Postconcussive symptoms after uncomplicated mild head injury. Journal of Head Trauma Rehabilitation, 8, 4859.Google Scholar
American Congress of Rehabilitation Medicine. (1993). Definition of mild traumatic brain injury. Journal of Head Trauma Rehabilition, 8, 8687.Google Scholar
American Psychiatric Association. (1994). Diagnostic and Statistical Manual of Mental Disorders: DSM–IV (4th ed.). Washington, DC: American Psychiatric Association.
Andersson, E.H., Bjorklund, R., Emanuelson, I., & Stalhammar, D. (2003). Epidemiology of traumatic brain injury: A population based study in western Sweden. Acta Neurologica Scandinavica, 107, 256259.Google Scholar
Baddeley, A., Emslie, H., & Nimmo-Smith, I. (1992). The Speed and Capacity of Language Processing Test: Manual. Bury St. Edmunds, Suffolk: Thames Valley Test Company.
*Barrow, I.M., Hough, M., Rastatter, M.P., Walker, M., Holbert, D., & Rotondo, M.F. (2003). Can within-category naming identify subtle cognitive deficits in the mild traumatic brain-injured patient? Journal of Trauma, 54, 888895; discussion 895–887.Google Scholar
*Bassett, S.S. & Slater, E.J. (1990). Neuropsychological function in adolescents sustaining mild closed head injury. Journal of Pediatric Psychology, 15, 225236.Google Scholar
*Bell, B.D., Primeau, M., Sweet, J.J., & Lofland, K.R. (1999). Neuropsychological functioning in migraine headache, nonheadache chronic pain, and mild traumatic brain injury patients. Archives of Clinical Neuropsychology, 14, 389399.Google 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, IA: University of Iowa.
Binder, L.M. & Rohling, M.L. (1996). Money matters: A meta-analytic review of the effects of financial incentives on recovery after closed-head injury. American Journal of Psychiatry, 153, 710.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, 421431.Google Scholar
*Bohnen, L., Jolles, J., Twijnstra, A., Mellink, R., & Sulon, J. (1992a). Coping styles, cortisol reactivity, and performance on vigilance tasks of patients with persistant postconcussive symptoms after mild head injury. International Journal of Neuroscience, 64, 97105.Google Scholar
*Bohnen, N., Jolles, J., & Twijnstra, A. (1992b). Neuropsychological deficits in patients with persistent symptoms six months after mild head injury. Neurosurgery, 30, 692695; discussion 695–696.Google Scholar
*Bohnen, N.I., Jolles, J., Twijnstra, A., Mellink, R., & Wijnen, G. (1995). Late neurobehavioural symptoms after mild head injury. Brain Injury, 9, 2733.CrossRefGoogle Scholar
Borg, J., Holm, L., Cassidy, J.D., Peloso, P.M., Carroll, L.J., von Holst, H., Paniak, C., & Yates, D. (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, 43S, 6175.Google Scholar
*Borgaro, S.R., Prigatano, G.P., Kwasnica, C., & Rexer, J.L. (2003). Cognitive and affective sequelae in complicated and uncomplicated mild traumatic brain injury. Brain Injury, 17, 189198.Google Scholar
*Brooks, J., Fos, L.A., Greve, K.W., & Hammond, J.S. (1999). Assessment of executive function in patients with mild traumatic brain injury. Journal of Trauma, 46, 159163.Google Scholar
Bryant, R.A. & Harvey, A.G. (1999). Postconcussive symptoms and posttraumatic stress disorder after mild traumatic brain injury. Journal of Nervous and Mental Disease, 187, 302305.CrossRefGoogle Scholar
Buschke, H. (1973). Selective reminding for analysis of memory and learning. Journal of Verbal Learning and Verbal Behavior, 12, 543550.CrossRefGoogle Scholar
Capruso, D.X. & Levin, H.S. (1992). Cognitive impairment following closed head injury. Neurologic Clinics, 10, 879893.Google Scholar
Centers for Disease Control and Prevention. (2003). TBI report to Congress on mild traumatic brain injury in the United States: Steps to prevent a serious public health problem. National Center for Injury Prevention and Control. Atlanta, GA: National Center for Injury Prevention and Control.
*Chen, S.H., Kareken, D.A., Fastenau, P.S., Trexler, L.E., & Hutchins, G.D. (2003). A study of persistent post-concussion symptoms in mild head trauma using positron emission tomography. Journal of Neurology, Neurosurgery and Psychiatry, 74, 326332.Google Scholar
*Cicerone, K.D. (1997). Clinical sensitivity of four measures of attention to mild traumatic brain injury. The Clinical Neuropsychologist, 11, 266272.CrossRefGoogle Scholar
*Cicerone, K.D. & Azulay, J. (2002). Diagnostic utility of attention measures in postconcussion syndrome. Clinical Neuropsychologist, 16, 280289.CrossRefGoogle Scholar
Cohen, J. (1988). Statistical power analysis for the behavioral sciences (2nd ed.). New Jersey: Lawrence Erlbaum.
*Comerford, V.E., Geffen, G.M., May, C., Medland, S.E., & Geffen, L.B. (2002). A rapid screen of the severity of mild traumatic brain injury. Journal of Clinical and Experimental Neuropsychology, 24, 409419.Google Scholar
Conners, C.K. (1995). Conners' Continuous Performance Test. Toronto, Canada: Multi-Health Systems.
Deb, S., Lyons, I., & Koutzoukis, C. (1999). Neurobehavioural symptoms one year after a head injury. British Journal of Psychiatry, 174, 360365.Google 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, 729738.Google Scholar
*Dikmen, S., Machamer, J.E., Winn, H.R., & Temkin, N.R. (1995). Neuropsychological outcome at 1-year post head injury. Neuropsychology, 9, 8090.Google Scholar
Dikmen, S., McLean, A., & Temkin, N. (1986). Neuropsychological and psychosocial consequences of minor head injury. Journal of Neurology, Neurosurgery and Psychiatry, 49, 12271232.Google Scholar
Dikmen, S., Reitan, R.M., Temkin, N.R., & Machamer, J.E. (1992). Minor and severe head injury emotional sequelae. Brain Injury, 6, 477478.Google Scholar
Duus, B.R., Kruse, K.V., Nielsen, K.B., & Boesen, T. (1991). Minor head injuries in a Copenhagen district. 1. Epidemiology. Ugeskr Laeger, 153, 21112113.Google Scholar
Eisenberg, H.M. & Levin, H.S. (1989). Computed tomography and magnetic resonance imaging in mild to moderate head injury. In H.S. Levin, H.M. Eisenberg, & A.L. Benton (Eds.), Mild head injury (pp. 133141). New York: Oxford University Press.
Evans, R.W. (1992). The postconcussion syndrome and the sequelae of mild head injury. Neurologic Clinics, 10, 815847.Google Scholar
Evans, R.W., Ruff, R.M., & Gualtieri, C.T. (1985). Verbal fluency and figural fluency in bright children. Perceptual and Motor Skills, 61, 699709.Google Scholar
*Gentilini, M., Nichelli, P., & Schoenhuber, R. (1989). Assessment of attention in mild head injury. In H.S. Levin, H.M. Eisenberg, & A.L. Benton (Eds.), Mild head injury (pp. 163175). New York: Oxford University Press.
*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, 137140.Google Scholar
Golden, C. (1978). Stroop Color and Word Test: A manual for clinical and experimental use. Chicago, Illinois: Stoelting.
*Goldstein, F.C. & Levin, H.S. (2001). Cognitive outcome after mild and moderate traumatic brain injury in older adults. Journal of Clinical and Experimental Neuropsychology, 23, 739753.Google Scholar
Goodglass, H. & Kaplan, E. (1972). Assessment of aphasia and related disorders. Philadelphia, Pennsylvania: Lea & Febiger.
Gronwall, D. & Wrightson, P. (1974). Delayed recovery of intellectual function after minor head injury. Lancet, 2, 605609.Google Scholar
Gronwall, D.A. (1977). Paced Auditory Serial Addition Task: A measure of recovery from concussion. Perceptual and Motor Skills, 44, 367373.Google Scholar
Hannay, H.J. & Levin, H.S. (1988). The Continuous Recognition Memory Test. Houston, Texas: Neuropsychological Resources.
Hartlage, L.C., Durant-Wilson, D., & Patch, P.C. (2001). Persistent neurobehavioral problems following mild traumatic brain injury. Archives of Clinical Neuropsychology, 16, 561570.Google Scholar
Hayes, R.L. & Dixon, C.E. (1994). Neurochemical changes in mild head injury. Seminars in Neurology, 14, 2531.Google 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.
*Hugenholtz, H., Stuss, D.T., Stethem, L.L., & Richard, M.T. (1988). How long does it take to recover from a mild concussion? Neurosurgery, 22, 853858.Google 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.
Kaplan, E., Goodglass, H., & Weintraub, S. (1983). The Boston Naming Test (2nd ed.). Philadelphia, Pennsylvania: Lea and Febiger.
Kraus, J.F. & Nourjah, P. (1988). The epidemiology of mild, uncomplicated brain injury. Journal of Trauma, 28, 16371643.Google Scholar
*Leininger, B.E., Gramling, S.E., Farrell, A.D., Kreutzer, J.S., & Peck, E.A., III (1990). Neuropsychological deficits in symptomatic minor head injury patients after concussion and mild concussion. Journal of Neurology, Neurosurgery and Psychiatry, 53, 293296.Google Scholar
Levin, H.S. (1983). The Paced Auditory Serial Addition Task–Revised. University of Texas at Galveston (unpublished).
Levin, H.S., Brown, S.A., Song, J.X., McCauley, S.R., Boake, C., Contant, C.F., Goodman, H., & Kotrla, K.J. (2001). Depression and posttraumatic stress disorder at three months after mild to moderate traumatic brain injury. Journal of Clinical and Experimental Neuropsychology, 23, 754769.CrossRefGoogle Scholar
*Levin, H.S., Mattis, S., Ruff, R.M., Eisenberg, H.M., Marshall, L.F., Tabaddor, K., High, W.M., & Frankowski, R.F. (1987). Neurobehavioral outcome following minor head injury: A three-center study. Journal of Neurosurgery, 66, 234243.Google Scholar
Levine, B., Stuss, D.T., Milberg, W.P., Alexander, M.P., Schwartz, M., & Macdonald, R. (1998). The effects of focal and diffuse brain damage on strategy application: Evidence from focal lesions, traumatic brain injury and normal aging. Journal of the International Neuropsychological Society, 4, 247264.Google Scholar
Lezak, M.D. (1995). Neuropsychological assessment (3rd ed.). Oxford, UK: Oxford University Press.
*MacFlynn, G., Montgomery, E.A., Fenton, G.W., & Rutherford, W. (1984). Measurement of reaction time following minor head injury. Journal of Neurology, Neurosurgery and Psychiatry, 47, 13261331.Google 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, 354360.CrossRefGoogle Scholar
*Mangels, J.A., Craik, F.I., Levine, B., Schwartz, M.L., & Stuss, D.T. (2002). Effects of divided attention on episodic memory in chronic traumatic brain injury: A function of severity and strategy. Neuropsychologia, 40, 23692385.Google Scholar
Marsh, H.V. & Smith, M.D. (1995). Post-concussion syndrome and the coping hypothesis. Brain Injury, 9, 553562.Google Scholar
*Mathias, J.L., Beall, J.A., & Bigler, E.D. (2004). Neuropsychological and information processing deficits following mild traumatic brain injury. Journal of the International Neuropsychological Society, 10, 286297.Google Scholar
*Mathias, J.L. & Coats, J.L. (1999). Emotional and cognitive sequelae to mild traumatic brain injury. Journal of Clinical and Experimental Neuropsychology, 21, 200215.Google Scholar
Mattis, S. & Kovner, R. (1978). Different patterns of mnemonic deficits in two organic amnestic syndromes. Brain and Language, 6, 179191.Google Scholar
*McAllister, T.W., Saykin, A.J., Flashman, L.A., Sparling, M.B., Johnson, S.C., Guerin, S.J., Mamourian, A.C., Weaver, J.B., & Yanofsky, N. (1999). Brain activation during working memory 1 month after mild traumatic brain injury: A functional MRI study. Neurology, 53, 13001308.Google Scholar
*McAllister, T.W., Sparling, M.B., Flashman, L.A., Guerin, S.J., Mamourian, A.C., & Saykin, A.J. (2001). Differential working memory load effects after mild traumatic brain injury. Neuroimage, 14, 10041012.Google Scholar
McCrea, M., Kelly, J.P., Kluge, J., Ackley, B., & Randolph, C. (1997). Standardized assessment of concussion in football players. Neurology, 48, 586588.Google Scholar
Meyers, J.E., Morrison, A.L., & Miller, J.C. (2001). How low is too low, revisited: Sentence repetition and AVLT-recognition in the detection of malingering. Applied Neuropsychology, 8, 234241.Google Scholar
Meyers, J.E., Volkert, K., & Diep, A. (2000). Sentence Repetition Test: Updated norms and clinical utility. Applied Neuropsychology, 7, 154159.CrossRefGoogle Scholar
Miller, L. (1996). Neuropsychology and pathophysiology of mild head injury and the postconcussion syndrome: Clinical and forensic considerations. The Journal of Cognitive Rehabilitation, 14, 823.Google Scholar
Mittenberg, W., DiGiulio, D.V., Perrin, S., & Bass, A.E. (1992). Symptoms following mild head injury: Expectation as aetiology. Journal of Neurology, Neurosurgery and Psychiatry, 55, 200204.CrossRefGoogle Scholar
*Mutter, S.A., Howard, J.H., Jr., & Howard, D.V. (1994). Serial pattern learning after head injury. Journal of Clinical and Experimental Neuropsychology, 16, 271288.Google Scholar
Nelson, H.E. & Willison, J.R. (1991). National Adult Reading Test (NART): Test manual (2nd ed.). Windsor, UK: NFER-Nelson.
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, 286356.Google Scholar
*Parasuraman, R., Mutter, S.A., & Molloy, R. (1991). Sustained attention following mild closed-head injury. Journal of Clinical and Experimental Neuropsychology, 13, 789811.CrossRefGoogle Scholar
Peterson, L. & Peterson, M. (1959). Short-term retention of the individual verbal items. Journal of Experimental Psychology, 58, 193198.Google Scholar
*Ponsford, J., Willmott, C., Rothwell, A., Cameron, P., Kelly, A.M., Nelms, R., Curran, C., & Ng, K. (2000). Factors influencing outcome following mild traumatic brain injury in adults. Journal of the International Neuropsychological Society, 6, 568579.CrossRefGoogle Scholar
*Potter, D.D., Jory, S.H., Bassett, M.R., Barrett, K., & Mychalkiw, W. (2002). Effect of mild head injury on event-related potential correlates of Stroop task performance. Journal of the International Neuropsychological Society, 8, 828837.Google Scholar
Povlishock, J.T. & Coburn, T.H. (1989). Morphopathological change associated with mild head injury. In H.S. Levin, H.M. Eisenberg, & A.L. Benton (Eds.), Mild head injury (pp. 3753). New York: Oxford University Press.
Powell, T.J., Collin, C., & Sutton, K. (1996). A follow-up study of patients hospitalized after minor head injury. Disability and Rehabilitation: An International Multidisciplinary Journal, 18, 231237.Google Scholar
Prigatano, G.P., Amin, K., & Rosenstein, L. (1995). Validity studies on the BNI screen for higher cerebral functions. BNI Quarterly, 9, 29.Google Scholar
*Raskin, S.A. (1997). The relationship between sexual abuse and mild traumatic brain injury. Brain Injury, 11, 587603.Google Scholar
*Raskin, S.A. & Rearick, E. (1996). Verbal fluency in individuals with mild traumatic brain injury. Neuropsychology, 10, 416422.Google Scholar
Reitan, R.M. & Wolfson, D. (1985). The Halstead-Reitan Neuropsychological Test Battery. Tucson, Arizona: Neuropsychology Press.
Reitan, R.M. & Wolfson, D. (1993). The Halstead-Reitan Neuropsychological Test Battery: Theory and clinical interpretation (2nd ed.). Tucson, Arizona: Neuropsychology Press.
*Reitan, R.M. & Wolfson, D. (1999). The two faces of mild head injury. Archives of Clinical Neuropsychology, 14, 191202.Google Scholar
Rimel, R.W., Giordani, B., Barth, J.T., Boll, T.J., & Jane, J.A. (1981). Disability caused by minor head injury. Neurosurgery, 9, 221228.Google Scholar
Robertson, I.H., Ward, T., Ridgeway, V., & Nimmo-Smith, I. (1994). The test of everyday attention. Bury St. Edmonds, Suffolk, UK: Thames Valley Test Company.
Rosenthal, R. (1979). The “file drawer problem” and tolerance for null results. Psychological Bulletin, 85, 188193.Google Scholar
*Ruffolo, L.F., Guilmette, T.J., & Willis, G.W. (2000). Comparison of time and error rates on the trail making test among patients with head injuries, experimental malingerers, patients with suspect effort on testing, and normal controls. Clinical Neuropsychologist, 14, 223230.Google Scholar
Rutherford, W.H., Merrett, J.D., & McDonald, J.R. (1979). Symptoms at one year following concussion from minor head injuries. Injury, 10, 225230.Google Scholar
Schmidt, F.L. & Hunter, J.E. (2003). Meta-analysis. In J.S. Schinka & W.F. Velicer (Eds.), Handbook of psychology, Vol. 2 (pp. 533554). 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, 341349.Google Scholar
*Shum, D.H., McFarland, K., Bain, J.D., & Humphreys, M.S. (1990). Effects of closed-head injury on attentional processes: An information-processing stage analysis. Journal of Clinical and Experimental Neuropsychology, 12, 247264.Google Scholar
Sosin, D.M., Sniezek, J.E., & Thurman, D.J. (1996). Incidence of mild and moderate brain injury in the United States, 1991. Brain Injury, 10, 4754.Google Scholar
Spreen, O. & Strauss, E. (1998). A compendium of neuropsychological tests (2nd ed.). London, UK: Oxford University Press.
*Stuss, D.T., Stethem, L.L., Hugenholtz, H., Picton, T., Pivik, J., & Richard, M.T. (1989). Reaction time after head injury: Fatigue, divided and focused attention, and consistency of performance. Journal of Neurology, Neurosurgery and Psychiatry, 52, 742748.Google Scholar
Suhr, J.A. & Gunstad, J. (2002). “Diagnosis Threat”: The effect of negative expectations on cognitive performance in head injury. Journal of Clinical and Experimental Neuropsychology, 24, 448457.CrossRefGoogle Scholar
Thornhill, S., Teasdale, G.M., Murray, G.D., McEwen, J., Roy, C.W., & Penny, K.I. (2000). Disability in young people and adults one year after head injury: Prospective cohort study. British Medical Journal, 320, 16311635.Google Scholar
Thurman, D.J. (2001). The epidemiology and economics of head trauma. In L. Miller & R. Hayes (Eds.), Head trauma: Basic, preclinical, and clinical directions (pp. 327348). New York: John Wiley & Sons.
*Tiersky, L.A., Cicerone, K.D., Natelson, B.H., & DeLuca, J. (1998). Neuropsychological functioning in chronic fatigue syndrome and mild traumatic brain injury: A comparison. The Clinical Neuropsychologist, 12, 503512.Google Scholar
*Voller, B., Benke, T., Benedetto, K., Schnider, P., Auff, E., & Aichner, F. (1999). Neuropsychological, MRI and EEG findings after very mild traumatic brain injury. Brain Injury, 13, 821827.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, Texas: The Psychological Corporation.
Wechsler, D. (1997a). Wechsler Adult Intelligence Scale–Third Edition: Administration and Scoring Manual. San Antonio, Texas: Harcourt Brace.
Wechsler, D. (1997b). Wechsler Memory Scale–III Administration and Scoring Manual. San Antonio, Texas: The Psychological Corporation.
Zakzanis, K.K., Leach, L., & Kaplan, E. (1999). Mild traumatic brain injury. In Neuropsychological differential diagnosis (pp. 163171). Exton, Pennsylvania: Swets & Zeitlinger.