Cognitive deficits in presumed minor head-injured patients

Short-term DTI predictors of cognitive dysfunction in mild traumatic brain injury

PRIMARY OBJECTIVE

To explore whether baseline diffusion tensor imaging (DTI) metrics are predictive of cognitive functioning 6 months post-injury in patients with mild traumatic brain injury (MTBI).

RESEARCH DESIGN

Seventeen patients with MTBI and 29 sex- and age-matched healthy controls were studied.

METHODS AND PROCEDURES

Participants underwent an MRI protocol including DTI, at an average of 4.0 (range: 1-10) days post-injury. Mean diffusivity (MD) and fractional anisotropy (FA) were measured in the following white matter (WM) regions: centra semiovale, the genu and the splenium of the corpus callosum and the posterior limb of the internal capsule. Participants underwent neuropsychological (NP) testing at baseline and at 6-month follow-up. Least squares regression analysis was used to evaluate the association of MD and FA with each NP test score at baseline and follow-up.

MAIN OUTCOMES AND RESULTS

Compared to controls, average MD was significantly higher (p = 0.02) and average FA significantly lower (p = 0.0001) in MTBI patients. At the follow-up, there was a trend toward a significant association between baseline MD and response speed (r = -0.53, p = 0.087) and a positive correlation between baseline FA and Prioritization form B (r = 0.72, p = 0.003).

CONCLUSIONS

DTI may provide short-term non-invasive predictive markers of cognitive functioning in patients with MTBI.

Neuropsychological studies of mild traumatic brain injury: a meta-analytic review of research since 1995

A meta-analysis conducted by Binder, Rohling and Larrabee established a relationship between mild traumatic brain injury (TBI) and small reductions in cognitive functioning in individuals assessed more than 3 months post-injury. As a follow-up, this study summarized similar research that (1) was published since the previous meta-analysis, and (2) included data collected at any stage post-injury. An extensive literature search revealed 17 suitable studies from which effect sizes were aggregated. The overall effect size was g = 0.32, p < .001. Speed of processing measures had the largest effect, g = 0.47, p < .001. The merging of post-acute effect sizes with those reported in Binder et al.'s review yielded a nonsignificant result, g = 0.11. Time since injury was found to be a significant moderator variable, with effect sizes tending to zero with increasing time post injury.

Abnormalities on magnetic resonance imaging seen acutely following mild traumatic brain injury: correlation with neuropsychological tests and delayed recovery

Mild traumatic brain injury (MTBI) is a common reason for hospital attendance and is associated with significant delayed morbidity. We studied a series of 80 persons with MTBI. Magnetic resonance imaging (MRI) and neuropsychological testing were used in the acute phase and a questionnaire for post-concussion syndrome (PCS) and return to work status at 6 months. In 26 subjects abnormalities were seen on MRI, of which 5 were definitely traumatic. There was weak correlation with abnormal neuropsychological tests for attention in the acute period. There was no significant correlation with a questionnaire for PCS and return to work status. Although non-specific abnormalities are frequently seen, standard MRI techniques are not helpful in identifying patients with MTBI who are likely to have delayed recovery.

Prevalence of traumatic brain injury in an ED population

The objective of this study was to determine prevalence of traumatic brain injury (TBI) in an emergency department (ED) population. Questionnaires were administered to patients in an urban, university, trauma center ED. All respondents provided demographics; patients reporting TBI were asked age at injury, if they experienced loss of consciousness (LOC), mechanism, or if medical attention was sought. Five hundred one patients completed the survey. Forty-one percent reported TBI; 23% had TBI with LOC. Mean age at injury was 21.5 years. Mechanism was evenly distributed among sports, assaults, falls, and motor vehicle crashes (MVC). Medical attention was sought for 61% of injuries. Men were more likely to report TBI (P <.001). Medical attention was more likely if MVC or LOC and less likely in sports-injured patients (all P <.01). Twenty-five percent of patients with TBI sustained repeat injury by the same mechanism. Prevalence of TBI in this population is high. Many occur by mechanisms that potentially are preventable.

Intellectual and emotional functioning in college students following mild traumatic brain injury in childhood and adolescence

OBJECTIVE

To investigate whether college students with a history of mild traumatic brain injury (TBI) in childhood or adolescence show residual deficits in intellectual functioning, approaches to studying, or emotional stability.

DESIGN

Participants with a history of mild TBI and two control groups.

SETTING

Volunteers were recruited from students taking an introductory psychology course.

PARTICIPANTS

79 students with a history of mild TBI, 75 students with a history of general anesthesia, and 93 students with no history of either TBI or general anesthesia.

MAIN OUTCOME MEASURES

Participants carried out tests of verbal memory, nonverbal memory, verbal fluency, and nonverbal fluency; in addition, they completed a short form of the Approaches to Studying Inventory and the Symptom Checklist-90-Revised (SCL-90-R).

RESULTS

In comparison with the two control groups, the students with a history of mild TBI produced similar scores on the cognitive tests and similar orientations to studying. However, they showed a significantly higher level of emotional distress on the SCL-90-R.

CONCLUSION

College students with a history of mild TBI in childhood or adolescence are intellectually unimpaired and approach their studying in a similar manner to their uninjured classmates. Nevertheless, they report more severe distress in terms of their general personal and emotional functioning.

Minor head injury: predicting follow-up after discharge from the Emergency Department

BACKGROUND

Up to 50% of ED patients discharged within a minor head injury (MHI) will develop postconcussive syndrome (PCS) within 1 month of injury. The follow-up visit is an important opportunity to identify and treat PCS before it becomes persistent.

OBJECTIVE

To identify factors predictive of follow-up (FU) after ED discharge in patients presenting with MHI.

METHODS

Prospective, observational study of a convenience sample of 71 MHI presenting within 24 hours of injury to the ED of a university teaching hospital between February 1996 and October 1997. MHI defined as loss of consciousness not greater than 10 minutes or amnesia, GCS 15, no skull fracture on PE, no new focality to neurologic exam and no brain injury on CT if one was done. Neurobehavioural test scores, clinical information and demographic data collected via use of standardized patient encounter form. All patients were discharged with written instructions to FU with their private physician within 1-2 weeks. Patients without a follow-up physician were assigned one. At 1 month post-injury, all patients were telephoned to determine if they had followed-up.

ANALYSIS

Stepwise, multivariate, logistic regression.

RESULTS

Thirty one out of 71 (43.7%) reported FU with a physician within 1 month. Factors associated with FU were performance of a head CT in the ED (OR = 3.58, 95% CI = 1.12-11.37), associated laceration (OR = 8.84, 95% CI = 1.69-42.55), female gender (OR = 3.19, 95% CI = 1.04-9.82), and African-American race (OR = 0.36, 95% CI = 0.13-0.99).

CONCLUSIONS

Several factors predict FU after ED discharge for MHI. Patients unlikely to FU may benefit from an assessment of PCS risk before they leave the ED.

Mild head injury: a misnomer

Despite controversy surrounding the concept of mild head injury (MHI), it is becoming evident that even a head trauma termed 'mild' may result in significant behavioural sequelae. The present study was an attempt at documenting structural cerebral damage, by way of computerized tomography, in a group of patients having suffered a MHI as defined by the Glasgow Coma Scale (GCS) score. A 1-year retrospective chart review identified 80 MHI patients who presented to the Emergency department of a lead hospital for trauma. Sixty-six per cent of these MHI patients were scanned. Evidence of intracranial abnormalities was obtained in 31% of the overall sample. Patients with a lower GCS score had a higher percentage of abnormal scans than those with a GCS score of either 14 or 15. The present findings suggest that a MHI can be associated with significant morbidity, and that a MHI group does not constitute a homogeneous pool of patients.

Epidemiology and predictors of post-concussive syndrome after minor head injury in an emergency population

OBJECTIVE

To determine if clinical variables or neurobehavioural test (NBT) scores obtained in the ED within 24 hours of minor head injury (MHI) predict the development of postconcussive syndrome (PCS).

METHODS

Prospective, observational study of 71 MHI patients and 60 orthopaedic controls. MHI defined as loss of consciousness < 10 minutes or amnesia, GCS 15, no skull fracture or new neurologic focality on PE, and no brain injury on CT (if done). All patients received a seven part NBT battery in the ED. Telephone follow-up was done at 1, 3 and 6 months to determine if patients met the DSM IV definition of PCS.

ANALYSIS

Stepwise, multivariate, logistic regression.

RESULTS

Predictors of PCS at 1 month were female gender (OR = 7.8; 95% CI = 41.6, 1.98), presence of both retrograde and anterograde amnesia (OR = 0.055; CI = 0.002, 0.47), Digit Span Forward Scores (OR = 0.748; CI = 0.52, 1.03) and Hopkins Verbal Learning A scores (OR = 0.786; CI = 0.65, 0.91); at 3 months, presence of both retrograde and anterograde amnesia (OR = 0.13; CI = 0.0, 0.93), Digit Span Forward Scores (OR = 0.744; CI = 0.58, 0.94). No variables fit the model at 6 months. 92% of males scoring > 25 on Hopkins Verbal Learning A did not have PCS at 1 month, and 89% of females scoring < 9 on Digit Span Forward did have PCS at 1 month.

CONCLUSIONS

Gender and two NBTs can help predict PCS after MHI.