Biomedical subjects

John Whyte

Publications and source records attributed to John Whyte.

42 records · Page 3Linked to original sources

PubMedDate not supplied

Community outcomes following traumatic brain injury: impact of race and preinjury status.

OBJECTIVE: To investigate the contribution of preinjury differences and potential biases in outcome measurement in explaining outcome differences between white and African American persons with moderate and severe traumatic brain injury (TBI). DESIGN: Prospective, 2 group longitudinal study with retrospective self-assessment of preinjury status. SETTING: Inpatient and outpatient TBI rehabilitation program. PARTICIPANTS: Ninety-four persons with moderate and severe TBI (55 whites and 39 African Americans) who provided data on both preinjury status and 1-year outcome. MEASURES: Community Integration Questionnaire, aggression and depression subscales of Neurobehavioral Functioning Inventory-Revised, Satisfaction With Life Scale, other questions on demographic and social status; all measures were selected by a biracial focus group. RESULTS: Whites and African Americans did not differ significantly on demographic factors except gender; nor on retrospective, self-reported preinjury status on any of the outcome measures. At 1 year post-TBI, African Americans reported significantly lower social integration subscale scores than whites. African Americans may also have lost more income than did whites. All other outcome measures were comparable between groups and showed declines in community productivity, increases in depression symptoms, and lower satisfaction with life for both whites and African Americans compared to preinjury. A higher rate of change in living situation post-TBI may partially account for lower levels of social integration for African Americans. CONCLUSION: Whites and African Americans who are comparable prior to injury may experience generally similar outcomes, but differences in social and financial outcomes require further investigation.

Adolescent↗

PubMedDate not supplied

Neuroanatomic basis of impaired self-awareness after traumatic brain injury: findings from early computed tomography.

BACKGROUND: Impaired self-awareness (ISA) is common among patients with severe traumatic brain injury (TBI) and contributes to poorer functional outcome. There is keen interest in improving the understanding of this disorder as the neuroanatomic substrate of posttraumatic ISA is poorly understood. OBJECTIVE: Determine whether (1) greater number of brain lesions, (2) greater volume of right hemisphere lesions, or (3) greater volume of frontal lesions is associated with greater levels of ISA after TBI. DESIGN: Prospective, observational study. PARTICIPANTS: Ninety-one TBI admissions to one of 2 National Institute on Disability and Rehabilitation Research TBI Model System (TBIMS) programs. Subjects met TBIMS inclusion criteria plus (1) resolution of posttraumatic amnesia (PTA) prior to rehabilitation discharge and (2) initial postinjury computerized tomography (CT) scan available as a hard copy and as an electronic file. METHODS: CT scan lesions outlined by a board-certified neuroradiologist were measured using NIH Image, and resulting calculated lesion volumes/scan variables compared against demographic characteristics, TBI severity variables, and ISA variables measured by the Awareness Questionnaire (AQ) at the time of PTA resolution. RESULTS: Most subjects (78%) had at least 1 lesion on emergent CT, and contusion volumes varied in all regions of interest. Patients rated their functioning as more intact on the AQ than ratings of treating clinicians, consistent with ISA. Greater injury severity was associated with a greater degree of ISA. Multivariable linear regression revealed that, after adjustment for other predictors, the number of brain lesions was predictive of degree of ISA. Right hemisphere contusion or frontal lobe contusion volumes, however, were not predictive of degree of ISA. CONCLUSIONS: ISA was significantly associated with the number, but not with location or volume of focal lesions early after TBI. Posttraumatic ISA may reflect disruption in the integrated operation of broadly distributed neural networks, with lesion burden in any specific region being less relevant than disruption across multiple regions. Further imaging research is warranted to confirm these findings and to provide insight into the distributed networks required for self-awareness.

Adult↗

PubMedDate not supplied

Executive function and self-awareness of "real-world" behavior and attention deficits following traumatic brain injury.

OBJECTIVE: To investigate the relationship between executive function and awareness of real-world behavioral and attentional dysfunction in persons with moderate and severe traumatic brain injury (TBI) and uninjured controls. DESIGN: Observational 2-group study. PARTICIPANTS: Thirty-six persons with moderate to severe TBI and residual cognitive deficits, recruited from therapy programs and the community, and 30 uninjured control participants of similar age, education, gender, and race. MEASURES: Eight clinical measures of executive function were combined in a composite score, the Executive Composite (EC). Awareness of behavioral and attentional lapses in everyday life was estimated using Self and Significant Other (SO) ratings on the Dysexecutive (DEX) Questionnaire and the Cognitive Failures Questionnaire (CFQ). RESULTS: Participants with TBI scored significantly worse on the EC than control participants and exhibited impaired self-awareness (ISA) compared to controls. Control participants agreed closely with their SOs on both the DEX and CFQ scales, whereas the SOs of TBI participants reported significantly greater degrees of difficulty on both scales than was endorsed by participants with TBI. Low-EC scorers within the TBI group had significantly worse ISA than controls, lending support to the hypothesis that executive function is related to ISA in chronic, moderate to severe TBI. Executive function and discrepancy scores demonstrated a modest but statistically significant association across the sample. CONCLUSION: Although executive function was associated with ISA in this sample, further research is needed to determine whether executive function deficits contribute in a causal fashion to ISA, and which of the cognitive operations within executive function are responsible for supporting self-awareness.

Adolescent↗

PubMedDate not supplied

Using treatment theories to refine the designs of brain injury rehabilitation treatment effectiveness studies.

Many rehabilitation treatments are difficult to define, resulting in a lack of clarity about their essential "active ingredients." Treatment theories can narrow the scope of possible active ingredients, by clearly specifying how the treatment is believed to act. Efficacy studies of theory-defined treatments assess their clinical value, but also advance the science underlying the theory. In addition, treatment theories shape inclusion and exclusion criteria by suggesting what types of patients may benefit, and shape outcome measures by suggesting where the treatment impact should be seen. Finally, treatment theories can assist an investigator in the selection of an optimal study design.

Brain Injuries↗

PubMedDate not supplied

The accuracy of artificial neural networks in predicting long-term outcome after traumatic brain injury.

OBJECTIVE: This study compared the accuracy of artificial neural networks to multiple regression and classification and regression trees in predicting outcomes of 1,644 patients in the Traumatic Brain Injury Model Systems database 1 year after injury. METHODS: Data from rehabilitation admission were used to predict discharge scores on the Functional Independence Measure, the Disability Rating Scale, and the Community Integration Questionnaire. RESULTS: Artificial neural networks did not demonstrate greater accuracy in predicting outcomes than did the more widely used method of multiple regression. Both of these methods outperformed classification and regression trees. CONCLUSION: Because of the sophisticated form of multiple regression with splines that was used, firm conclusions are limited about the relative accuracy of artificial neural networks compared to more widely used forms of multiple regression.

Brain Injuries↗

PubMedDate not supplied

Vocational services for traumatic brain injury: treatment definition and diversity within model systems of care.

OBJECTIVE: To examine characteristics and diversity among vocational treatment services in model programs for traumatic brain injury (TBI) rehabilitation. SETTING: Vocational or postacute treatment components of 16 TBI Model System (TBIMS) centers. PARTICIPANTS: Vocational director/coordinator from each TBIMS surveyed in semistructured phone interview. MEASURE: Survey of vocational services for people with TBI, with about 100 closed and open-ended questions on vocational assessments; pre- and postjob placement treatments; program philosophies; funding; and integration of cognitive, behavioral, family, and medical rehabilitation interventions. RESULTS: Great diversity was found among the vocational services of the 16 TBIMS. Programs fell into 3 clusters emphasizing medical rehabilitation services, supported employment, or a combination of these with an emphasis on case management. Job coaching was identified as a key intervention, but there was great variability in intensity, availability, and funding of coaching services. CONCLUSION: Diversity in vocational services appears related to funding differences and "parallel evolution" rather than strong treatment philosophy or scientific evidence base. Multicenter research on effectiveness or establishment of best practices in vocational rehabilitation after TBI must deal with substantial existing variability in treatment models and specific interventions, and must examine the relationship of treatment variations to case-mix factors.

Brain Injuries↗