John D. Corrigan

The epidemiology of traumatic brain injury

ObjectiveTo describe the most recent estimates of the incidence and prevalence of traumatic brain injury (TBI) and review current issues related to measurement and use of these data. DesignState of the science literature for the United States and abroad was analyzed and issues were identified for (1) incidence of TBI, (2) prevalence of lifetime history of TBI, and (3) incidence and prevalence of disability associated with TBI. ResultsThe most recent estimates indicate that each year 235 000 Americans are hospitalized for nonfatal TBI, 1.1 million are treated in emergency departments, and 50 000 die. The northern Finland birth cohort found that 3.8% of the population had experienced at least 1 hospitalization due to TBI by 35 years of age. The Christchurch New Zealand birth cohort found that by 25 years of age 31.6% of the population had experienced at least 1 TBI, requiring medical attention (hospitalization, emergency department, or physician office). An estimated 43.3% of Americans have residual disability 1 year after injury. The most recent estimate of the prevalence of US civilian residents living with disability following hospitalization with TBI is 3.2 million. ConclusionEstimates of the incidence and prevalence of TBI are based on varying sources of data, methods of calculation, and assumptions. Informed users should be cognizant of the limitations of these estimates when determining their applicability.

Relationships between Parts A and B of the Trail Making Test.

Two measures of relationship between Parts A and B of the Trail Making Test (TMT) were examined in a large, acute rehabilitation population (N = 497). A difference (B-A) and a ratio (B/A) score were calculated and compared to other neuropsychological measures. The difference score was found to be correlated highly with intelligence and severity of impairment and, to a lesser degree, with age, education, and memory functioning. The ratio measure was correlated moderately or showed no significant relationship with other variables. This finding supported the curvilinear nature of the relationship between the ratio measure and cerebral impairment, as suggested by Golden, Osmon, Moses, and Berg (1981). Both measures were examined for their ability to distinguish between right and left cerebral damage. Only a trend toward differentiating lateralized damage was found; the ratio measure and a geometric transformation of the ratio showed greater sensitivity than did the difference measure. Results are discussed in terms of the potential usefulness of TMT relationship measures in neuropsychological inference.

Substance abuse as a mediating factor in outcome from traumatic brain injury

A review of recent research addressed two questions: how common are problems of substance abuse in traumatic brain injury (TBI), and to what extent does alcohol and other drug use mediate outcome? Studies showed alcohol intoxication present in one third to one half of hospitalizations; data for other drug intoxication were not available. Nearly two thirds of rehabilitation patients may have a history of substance abuse that preceded their injuries. Intoxication was related to acute complications, longer hospital stays, and poorer discharge status; however, these relationships may have been caused by colinearity with history. History of substance abuse showed the same morbidity, and was further associated with higher mortality rates, poorer neuropsychological outcome, and greater likelihood of repeat injuries and late deterioration. The effect of history may be caused by subgroups with more severe substance abuse problems. Implications for rehabilitation are discussed, including the potential negative impact of untreated substance abuse on the ability to document efficacy of rehabilitation efforts.

Cognitive outcome following traumatic brain injury

ObjectiveTo determine whether an association exists between traumatic brain injury (TBI) sustained in adulthood and cognitive impairment 6 months or longer after injury. DesignSystematic review of the published, peer-reviewed literature. ResultsFrom 430 articles, we identified 11 primary and 22 secondary studies that examined cognitive impairment by using performance measures for adults who were at least 6 months post-TBI. There was clear evidence of an association between penetrating brain injury and impaired cognitive function. Factors that modified this association included preinjury intelligence, volume of brain tissue lost, and brain region injured. There was also suggestive evidence that penetrating brain injury may exacerbate the cognitive effects of normal aging. We found clear evidence for long-term cognitive deficits associated with severe TBI. There was suggestive evidence that moderately severe brain injuries are associated with cognitive impairments. There was inadequate/insufficient evidence to determine whether an association exists between a single, mild TBI and cognitive deficits 6 months or longer postinjury. ConclusionIn adults, penetrating, moderate, and severe TBIs are associated with cognitive deficits 6 months or longer postinjury. There is insufficient evidence to determine whether mild TBI is associated with cognitive deficits 6 months or longer postinjury.

Conducting statewide needs assessments for persons with traumatic brain injury.

The Traumatic Brain Injury Act of 1996 (Public Law 104-166) gave new authority to the Health Resources and Services Administration (HRSA) in the United States Department of Health and Human Services (DHHS) to establish a grant program for states to assist in addressing the needs of persons with traumatic brain injury (TBI). The resulting State Demonstration Grant Program has made available two categories of grants: planning and implementation. Planning grants are awarded to assist states in building infrastructure through the development of four core components. One of the core components is a statewide needs and resource assessment encompassing the full spectrum of services, from initial acute treatment through rehabilitation and long-term community supports. In 1999, assessments completed in 11 states were subjected to a comparative analysis to identify trends across states and to extract salient issues for the State Demonstration Grant Program. This article summarizes the context of the HRSA-funded needs assessments and contrasts the methods of needs assessment utilized. Over-arching issues are discussed, including exemplary qualitative and quantitative methods, and the diversity of theoretical models employed in designing assessments and interpreting findings. Several limitations in approaches were also identified, including shortcomings of convenience samples for conducting mail surveys and the unlikely validity of using a needs and resource discrepancy approach to identify gaps in services.

Outcomes in the first 5 years after traumatic brain injury

OBJECTIVE To examine the extent to which outcomes from traumatic brain injury differ as a function of time and can be predicted at discharge from inpatient rehabilitation. DESIGN Survey method employing cross-sectional analyses. SETTING An inpatient brain injury rehabilitation unit in a large midwestern academic medical center. SUBJECTS Ninety-five adults with traumatic brain injuries, 6 months to 5 years after inpatient rehabilitation, stratified by time postdischarge. MAIN OUTCOME MEASURES Functional Independence Measure (FIM), Sickness Impact Profile (SIP), Medical Outcomes Survey SF-36, Community Integration Questionnaire (CIQ), Craig Handicap Assessment and Reporting Technique (CHART), Brief Symptom Inventory (BSI), Satisfaction With Life Scale (SWLS), and indices of current psychosocial functioning. RESULTS Substance abuse, need for supervision, life satisfaction, and selected subscales of the CIQ and CHART differed over the period 6 months to 5 years after discharge. Approximately 75% of the variance in current FIM scores, and 40% to 50% of CHART, CIQ, and SIP total scores, could be predicted at time of discharge. CONCLUSIONS Outcomes over the first 5 years after discharge were dynamic, with most change being improvement, at least after the first 2 years. Important aspects of outcome could not be predicted based on premorbid characteristics, injury severity, and initial functional abilities.

Initial reliability and validity of the Ohio State University TBI Identification Method.

ObjectivesEvaluate the psychometric properties of indices of a lifetime history of traumatic brain injury (TBI). ParticipantsConvenience samples recruited from 2 treatment programs for persons with substance use disorders: N = 119 (study 1) and N = 103 (study 2) DesignTest interrater reliability (study 1) and predictive validity (Study 2). MeasuresSummary indices of the number, severity, timing, and effects of lifetime TBIs calculated from data elicited via a structured interview. ResultsInterrater reliability was high. Factor analysis showed indices could be characterized by severity weighted counts of the number of injuries, both lifetime and in childhood, number of symptoms persisting, worst injury, time since last TBI with loss of consciousness, and age at first TBI with loss of consciousness. Age at injury and symptoms persisting contributed independently to the prediction of common cognitive and behavioral consequences of TBI. ConclusionThese results provide preliminary support for the reliability and validity of summary indices of lifetime history of TBI elicited via a structured interview.

Development of a scale for assessment of agitation following traumatic brain injury

Development and initial validation of a scale for assessment of agitation in traumatic brain-injured individuals is described. Items were selected from an initial 39-item pool based on their testability, differentiation of agitation, frequency of occurrence, and representation of the full domain of the construct. The resulting 14-item instrument, called the Agitated Behavior Scale (ABS), was subsequently tested on an independent sample of 35 head-injured subjects. Reliability was examined via measures of internal consistency and qualitative evaluation of principal components factor analysis. Cronbachs alpha exceeded .80 for all rates. Comparable values of theta were found and qualitative criteria of internal consistency were met. The ABS score accounted for between 36% and 62% of the variance in 15 of 16 correlations with simultaneous, independent observations of agitation. Results of initial validation are discussed in light of classic test theory and research necessary for determination of construct validity.

Validity of the functional independence measure for persons with traumatic brain injury.

OBJECTIVE Replicate and extend studies of the construct validity of the Functional Independence Measure (FIM) for persons with traumatic brain injury (TBI). DESIGN A cross-sectional study of admissions to acute rehabilitation evaluated 6 months to 5 years after discharge. SETTING An inpatient brain injury rehabilitation unit in a large, academic medical center. SUBJECTS Ninety-five patients with primary diagnosis of TBI stratified by time postdischarge. MAIN OUTCOME MEASURES Prediction of (1) average daily minutes of assistance and (2) supervision required in comparison to the Sickness Impact Profile (SIP) and SF-36. RESULTS The FIM was highly predictive of minutes of assistance (83% accuracy), supervision (82% accuracy), and the need for either type of assistance (78% accuracy). Prediction was only minimally improved by measures of neurobehavioral impairment. The accuracy of the FIM was superior to the SIP and SF-36. CONCLUSIONS Results provided substantial support for the validity of the FIM as a measure of functional independence for persons with TBI. The importance of supervision as a type of assistance required after TBI was evident, with the FIM highly predictive of this need, as well.

Perceived needs following traumatic brain injury.

Objectives:(1) Provide population-based estimates of perceived needs following traumatic brain injury (TBI) and the prevalence of unmet needs 1 year postinjury; (2) identify relations among needs that define unique clusters of individuals; and (3) identify risk factors for experiencing selected needs. Design:Telephone survey 1 year after injury of a prospective cohort of all people hospitalized with TBI in the state of Colorado during 2000. Measures:Self-reported need for assistance in 13 areas of functioning. Results:A total of 58.8% of persons hospitalized with TBI experienced at least 1 need during the year following injury; 40.2% will experience at least 1 unmet need 1 year after injury. Most frequently experienced needs were “improving your memory, solving problems better” (34.1%), “managing stress, emotional upsets” (27.9%), and “managing your money, paying bills” (23.3%). Cluster analysis revealed 8 distinctive groupings of subjects. If a need existed, those least likely to be met involved cognitive abilities, employment, and alcohol and/or drug use. Conclusions:Results were consistent with findings from previous assessments of need for services based on surveys of convenience samples; however, the prevalence of unmet needs 1 year after injury may be higher than previously suspected. More post-hospital services addressing cognitive and emotional problems appear needed. Risk factors for experiencing needs suggest potential avenues for clinical intervention.