The evolution of white matter microstructural changes after mild traumatic brain injury: A longitudinal DTI and NODDI study

Neuroimaging biomarkers that can detect white matter (WM) pathology after mild traumatic brain injury (mTBI) and predict long-term outcome are needed to improve care and develop therapies. We used diffusion tensor imaging (DTI) and neurite orientation dispersion and density imaging (NODDI) to investigate WM microstructure cross-sectionally and longitudinally after mTBI and correlate these with neuropsychological performance. Cross-sectionally, early decreases of fractional anisotropy and increases of mean diffusivity corresponded to WM regions with elevated free water fraction on NODDI. This elevated free water was more extensive in the patient subgroup reporting more early postconcussive symptoms. The longer-term longitudinal WM changes consisted of declining neurite density on NODDI, suggesting axonal degeneration from diffuse axonal injury for which NODDI is more sensitive than DTI. Therefore, NODDI is a more sensitive and specific biomarker than DTI for WM microstructural changes due to mTBI that merits further study for mTBI diagnosis, prognosis, and treatment monitoring.

Outcomes of ruptured intracranial aneurysms treated by microsurgical clipping and endovascular coiling in a high-volume center

BACKGROUND AND PURPOSE

The purpose of this study was to analyze the 3-month outcomes of patients with aneurysmal subarachnoid hemorrhage (SAH) treated from January 2005 to June 2006. This paper describes the outcomes after treatment of aneurysmal SAH and comparison between patients treated by clipping or coiling in a high volume center.

MATERIALS AND METHODS

A retrospective chart review was performed of records of 195 consecutive patients with SAH. The overall outcome and the pretreatment variables predicting outcomes and the difference between the clipping and coiling groups were analyzed by logistic regression analysis.

RESULTS

A total of 105 (55%) patients had microsurgical clipping and 87 (45%) had endovascular coiling. At 3 months, 69% of patients recovered with no or mild disability. The predictors of a 3-month modified Rankin Scale (mRS) were Hunt and Hess (HH) grade on admission and the presence of intracerebral hemorrhage (ICH). Patients in the coiling group had worse admission grades; they had worse 3-month mRS (2.28 vs 1.73), but this was not significant when the groups were matched (P = .38). Vasospasm rate was significantly higher in the clipping group (66% vs 52%). The immediate incomplete occlusion rate of aneurysms was higher (21.7% vs 7.6%) in the coiling group.

CONCLUSION

The overall results of treatment of aneurysmal SAH have improved. There is no significant difference in the outcomes between the patients in the clipping and coiling groups.

Mild head injury: facts and artifacts

While most would agree that mild traumatic brain injury (TBI) is associated with early neuropsychological problems, disagreement exists regarding their persistence and whether they are the cause of the disabilities experienced by some people. The aim of this study was to examine how the criteria used to define mild TBI and how the pre-injury characteristics of people affect their neuropsychological outcome. A total of 157 unselected hospitalized cases with Glasgow Coma Scale scores of 13-15 and 109 trauma controls were prospectively recruited and administered a number of cognitive measures at 1 month and 12 months after injury. The results indicated early impairments that decreased with time and the stringency of the definition of 'mild' TBI. The contribution of demographics was usually significant and often stronger than the mild TBI effect. Subtle variation of the demographics of the brain injured or the comparison subjects can be sufficient to mimic or mask mild brain injury effects.

Prediction of functional outcomes after traumatic brain injury: a comparison of 2 measures of duration of unconsciousness

OBJECTIVE

To compare the usefulness of time until motor localization occurs versus time until commands are followed in predicting outcome after traumatic brain injury (TBI).

DESIGN

A retrospective analysis of data from a prospective cohort study of subjects with severe TBI.

SETTING

Seventeen Traumatic Brain Injury Model System programs.

PARTICIPANTS

A total of 496 subjects, recruited through the TBI Model System programs, with loss of consciousness greater than 1 day, with no late neurosurgical complications, and complete data for all measures.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Time until Glasgow Coma Scale (GCS) motor score of 5 (time to motor localization) and time until GCS motor score of 6 (time until commands were followed) were abstracted from medical records. Functional outcomes were assessed at inpatient rehabilitation admission and discharge, along with acute and rehabilitation lengths of stay and charges.

RESULTS

Time until commands were followed was a better predictor of all of the outcomes assessed than time until motor localization occurred. In multiple regression models, time until motor localization did not add significantly to the prediction provided by time until commands were followed. The predictive power of time to command following was superior even in the subgroup with poor language comprehension as measured by the Token Test.

CONCLUSION

Despite the theoretical appeal of time to motor localization (eg, in persons with language comprehension problems), time to command following appears to be a more powerful predictor of outcome after severe brain injury.

Discharge disposition from acute care after traumatic brain injury: the effect of insurance type

OBJECTIVE

To determine if persons with traumatic brain injury (TBI) who are insured by Medicaid or health maintenance organizations (HMOs) are more likely to receive postacute care in skilled nursing facilities (SNFs) than in rehabilitation facilities, compared with persons insured by commercial fee-for-service (FFS) plans.

DESIGN

Retrospective cohort study.

SETTING

County hospital admitting 30% of all Washington State TBI patients.

PATIENTS

Patients with moderate to severe TBI discharged to rehabilitation facilities or SNFs between 1992 and 1997 (n = 1271); 56.3% were insured by Medicaid, 26.1% by FFS plans, and 17.6% by HMOs.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Disposition on discharge from acute care (rehabilitation facilities vs SNF); adjusted relative risk (RR) and confidence interval (CI) for different insurance types.

RESULTS

After accounting for confounding factors, Medicaid patients were 68% more likely (RR = 1.68, 95% CI = 1.34-2.11) and HMO patients were 23% more likely (RR = 1.23, 95% CI =.90-1.68) to go to a SNF than FFS patients. However, the latter difference was not statistically significant.

CONCLUSIONS

An association exists between insurance type and postacute care site. Efforts should be made to determine the effect this relationship has on the cost and outcomes for TBI patients.

Functional status examination: a new instrument for assessing outcome in traumatic brain injury

The Functional Status Examination (FSE) is a new measure designed to evaluate change in activities of everyday life as a function of an event or illness, including traumatic brain injury. The measure covers physical, social, and psychological domains. The FSE is based on a structured interview and includes levels of functioning that accommodate the full spectrum of possible outcomes, from death through recovery to preinjury functioning. Based on 133 prospectively studied patients with moderate to severe traumatic brain injury, the FSE has favorable psychometric properties including good test-retest reliability (r = 0.80) and close correspondence of assessments provided by the patient and their significant other (SO; r = 0.80). The FSE correlated significantly with each of three severity indices with closest relationships occurring between the FSE assessed by the SO and posttraumatic amnesia (r = 0.76). The FSE assessed by the SO was significantly (p < 0.05) more closely related to each severity index than the Glasgow Outcome Scale (GOS) or Sickness Impact Profile and, for two of the three indices, than the SF-36. All measures showed significant change from 1 to 6 months after injury with the FSE showing the largest effect sizes. The FSE is significantly related to important constructs such as family burden, SO depression, and sacrifices the family makes, as well as overall indices of recovery and satisfaction with level of functioning. The latter relationships are significantly stronger than for the GOS. The FSE has demonstrated good reliability, validity, and sensitivity, and appears to be a promising instrument for monitoring recovery and assessing functional status in clinical trials.

Detecting change: A comparison of three neuropsychological methods, using normal and clinical samples

Detecting change in individual patients is an important goal of neuropsychological testing. However, limited information is available about test-retest changes, and well-validated prediction methods are lacking. Using a large nonclinical subject group (N = 384), we recently investigated test-retest reliabilities and practice effects on the Wechsler Adult Intelligence Scale and Halstead-Reitan Battery. Data from this group also were used to develop models for predicting follow-up test scores and establish confidence intervals around them. In this article we review those findings, examine their generalizability to new nonclinical and clinical groups, and explore the sensitivity of the prediction models to real change. Despite similarities across samples in reliability coefficients and practice effects, limits to the generalizability of prediction methods were found. Also, when multiple test measures were considered together, one or more "significant" changes were common in all (including stable) subject groups. By employing normative cut-offs that correct for this, sensitivity of the models to neurological recovery and deterioration was modest to good. More complex regression models were not more accurate than the simpler Reliable Change Index with correction for practice effects when confidence intervals for all methods were adjusted for variations in level of baseline test performance.

Emotional and behavioral adjustment after traumatic brain injury

OBJECTIVES

To examine emotional and behavioral adjustment and recovery over 1 year after traumatic brain injury (TBI), and to determine whether the difficulties, if present, are due to neurologic insult.

DESIGN

Longitudinal evaluation of adjustment from 1 month to 1 year after injury.

SETTING

Level I trauma center at a university hospital.

PATIENTS

One hundred fifty-seven consecutively hospitalized adults with TBI and 125 trauma controls with other system injuries evaluated at 1 and 12 months after injury.

MAIN OUTCOME MEASURES

Katz Adjustment Scale (KAS).

RESULTS

The TBI group at 1 year follow-up demonstrated significant emotional and behavioral maladjustment, but such difficulties did not appear to be mediated by the brain injury, since the KAS scores for the TBI and trauma control groups were not significantly different. Those with moderate TBI reported greater difficulties than those with mild or severe injuries. Changes in adjustment over 1 year were common for both groups. Within the TBI group there was differential recovery: improvement in cognitive clarity, dysphoric mood, and emotional stability, but increased difficulties with anger management, antisocial behaviors, and self-monitoring.

CONCLUSIONS

These results raise questions about commonly held beliefs that those with mild TBI report greater distress, and clarify some misconceptions regarding change in emotional and behavioral functioning over time.

Late cognitive effects of early treatment with phenobarbital

We previously reported that IQ was significantly lowered in a group of toddler-aged children randomly assigned to receive phenobarbital or placebo for febrile seizures and there was no difference in the febrile seizure recurrence rate. We retested these children 3-5 years later, after they had entered school, to determine whether those effects persisted over the longer term and whether later school performance might be affected. On follow-up testing of 139 (of the original n = 217) Western Washington children who had experienced febrile seizures, we found that the phenobarbital group scored significantly lower than the placebo group on the Wide Range Achievement Test (WRAT-R) reading achievement standard score (87.6 vs 95.6; p = 0.007). There was a nonsignificant mean difference of 3.71 IQ points on the Stanford-Binet, with the phenobarbital-treated group scoring lower (102.2 vs 105.7; p = 0.09). There were five children in our sample with afebrile seizures during the 5-year period after the end of the medication trial. Two had been assigned to phenobarbital, and three had been in the placebo group. We conclude there may be a long-term adverse cognitive effect of phenobarbital on the developmental skills (language/verbal) being acquired during the period of treatment and no beneficial effect on the rate of febrile seizure recurrences or later nonfebrile seizures.

Selective dorsal rhizotomy: efficacy and safety in an investigator-masked randomized clinical trial

The objective of this single-center investigator-masked randomized clinical trial was to investigate the efficacy and safety of selective dorsal rhizotomy (SDR) in children with spastic diplegia. Forty-three children with spastic diplegia were randomly assigned on an intention-to-treat basis to receive SDR plus physical therapy (PT), or PT alone. Thirty-eight children completed follow-up through 24 months. Twenty-one children received SDR (SDR+PT group) and 17 received PT (PT Only group). SDR was guided with electrophysiological monitoring and performed by one experienced neurosurgeon. All subjects received equivalent PT. Spasticity was quantified with an electromechanical torque measurement device (spasticity measurement system [SMS]). The Gross Motor Function Measure (GMFM) was used to document changes in functional mobility. Primary outcome measures were collected at baseline, 6, 12, and 24 months by evaluators masked to treatment. At 24 months, the SDR+PT group exceeded the PT Only group in mean reduction of spasticity by SMS measurement (-8.2 versus +5.1 newton meters/radian, P=0.02). The SDR+PT group and the PT Only group demonstrated similar improvements in independent mobility on the GMFM (7.0 versus 7.2 total percent score, P=0.94). Outcomes on secondary variables were consistent with primary outcomes. There were no serious adverse events. We conclude that SDR is safe and reduces spasticity in children with spastic diplegia. SDR plus PT and equivalent PT without SDR result in equal improvements in independent mobility at 24 months. SDR may not be an efficacious treatment for children with mild spastic diplegia.

Recovery of simple motor skills after head injury

The performance of 40 head-injured patients (HI) without peripheral upper body injuries and 88 normal controls were compared on finger tapping and grip strength 1 month and 1 year after injury. The HI group demonstrated deficits on both tasks 1 month after injury, but only finger tapping was impaired 1 year postinjury. While grip strength differentially improved in the HI group from 1 month to 1 year, finger tapping improved similarly in both groups. The pattern of results was similar when a subset of 25 HI patients without any evidence of focal lesions were examined. These results demonstrate (1) motor deficits are present 1 year after injury even in a sample of predominantly mild head-injury patients, (2) grip strength is more sensitive to recovery in the first year after head injury, and (3) finger tapping continues to be impaired 1 year after head injury possibly due to its speed requirements.

Ventricular entry during resection of malignant gliomas: effect on intracranial cerebrospinal fluid tumor dissemination

The ventricular system is not infrequently entered during the course of maximum cytoreductive surgery for high-grade supratentorial gliomas. It is unclear if ventricular entry during surgery and/or proximity of the tumor to the ventricular system affects cerebrospinal fluid (CSF) tumor dissemination or the patients' overall survival rate. The authors retrospectively reviewed hospital records and neuroradiological studies of 51 patients operated on at the University of Washington between 1987 and 1991. Inclusion in this study necessitated a pathological diagnosis of malignant glioma and the availability of preoperative and postoperative computerized tomography scans or magnetic resonance images. Patients were excluded from the study if they had radiographic evidence of ventricular entry or CSF tumor dissemination prior to referral to the authors' institution. The index operation was defined as the first operation at the University of Washington or (in those patients with ventricular entry) the operation in which the ventricle was entered. Patients were followed until time of death or, in the case of survivors, until February, 1992. The effect of both ventricular entry and the proximity of the tumor to the ventricular system on CSF tumor dissemination and survival rate was assessed using statistical survival methodology. There was no significant difference in time from diagnosis to the index operation between groups compared (Mann-Whitney U-test, p > 0.40). Cerebrospinal fluid dissemination was radiographically documented in 18 patients (35%) following the index operation. This occurrence was not significantly influenced by either ventricular entry during surgery (Mantel-Cox test, p = 0.13), the proximity of the tumor to the ventricular system (p = 0.63), or these two variables combined (p = 0.28). Survival rate following the index operation was not significantly affected by ventricular entry (p = 0.66), proximity of the tumor to the ventricular system (p = 0.61), or these two variable considered in combination (p = 0.44). However, survival rate was significantly decreased once CSF tumor dissemination had occurred (Cox model, p = 0.03).

Psychosocial outcome in patients with moderate to severe head injury: 2-year follow-up

Psychosocial outcome and recovery of a group of 31 consecutive adult patients with moderate to severe head injuries were prospectively investigated over a 2-year period. A friend control group was used for comparison purposes. We conclude that moderate and severe head injuries have a significant long-term impact on psychosocial functioning. More specifically, although there is an increase over time in the number of subjects who resume former levels of activity, many moderate to severely head-injured people remain unable to work, support themselves financially, live independently and participate in pre-injury leisure activities at least up to 2 years post-injury. Initially, self-perceived limitations in everyday functioning are widespread, with physical functioning being of primary concern. Over time, there is improvement in both physical and psychosocial areas. However, in spite of improvement, difficulties in psychosocial functioning become dominant later due to greater improvement in the physical area. This study gives no evidence of general increase in emotional distress with increasing time since injury.

Relative effects of brain and non-brain injuries on neuropsychological and psychosocial outcome

Based on the 242 consecutive surviving head injury cases and 132 general trauma cases, this study examined the contribution of brain and non-brain injuries to cognitive and psychosocial outcome 1 month postinjury. The study also examined the relationships among various head injury severity indices. The head injury severity indices were all correlated but patients with Glasgow Coma Scale scores in the mild range had broadly ranging scores on the other head injury severity indices (Abbreviated Injury Scale and time to follow commands). Neuropsychological outcome was related to brain injury severity, but was not independently influenced by severity of other systems injuries. Psychosocial outcome related to both brain and non-brain injuries independently. When evaluating trauma outcome, it is important to consider the contributions of both brain and other system injuries.

Neuropsychological recovery in patients with moderate to severe head injury: 2 year follow-up

Neuropsychological outcome and recovery of a group of 31 consecutive adult patients with moderate to severe head injuries were prospectively investigated over a 2-year period. A friend control group was used for comparison purposes. Based on the results we conclude: (1) there is marked impairment of a broad spectrum of neuropsychological functions at 1, 12, and 24 months postinjury; (2) coma length is significantly related to neuropsychological status at all three time periods, although the relationship is weaker at 12 and 24 months; (3) marked improvement in all functions occurs in the first year, while recovery in the second year appears more specific and may depend on the severity of the injury and type of function; (4) practice effects and variability over repeated measures cause difficulties in determining recovery and need to be addressed with larger samples.

Development and evaluation of modifications to the Sickness Impact Profile for head injury

Three modifications were made to the Sickness Impact Profile, a behavior-based measure of health status, to improve its sensitivity to the effects of head injury. (1) Additional items were included to capture head injury sequelae and behaviors typical of young adults, the age group to which head injury most frequently occurs. (2) Subjects individually excluded behaviors irrelevant to them, thus allowing the score to better reflect injury-related changes. (3) The different areas of functioning on the Sickness Impact Profile were reweighted to reflect global judgments of the construct's contribution to overall functioning rather than the sum of the item contributions. Only the first modification is head-injury specific. The others, are relevant to any disease or injury. The performance of the modifications was evaluated in a longitudinal study of 102 head injured and 102 comparison subjects tested at 1 and 12 months after injury. The evaluation of the modifications was based on their ability to distinguish head injury from comparison subjects and on the strength of their relationship with measures of brain dysfunction. Despite a few statistically significant improvements in discrimination, differences of a practical degree were not obtained. The standard Sickness Impact Profile performed well and is recommended for evaluation of day-to-day functioning in head injury studies.

Memory and head injury severity

One hundred and two consecutive head injured patients were studied at 1 and 12 months after injury. Their performances were compared with a group of uninjured friends. The results indicate that impairment in memory depends on the type of task used, time from injury to testing, and on the severity of head injury (that is, degree of impaired consciousness). Head injury severity indices are more closely related to behavioural outcome early as compared with later after injury. At 1 year, only those with deep or prolonged impaired consciousness (as represented by greater than 1 day of coma, Glasgow Coma Scale of 8 or less, and post traumatic amnesia of 2 weeks or greater) are performing significantly worse than comparison subjects.

Neuropsychological and psychosocial consequences of minor head injury

Twenty subjects with minor head injury were compared to an uninjured group at 1 and 12 months after injury on a battery of neuropsychological and psychosocial measures. The results indicate that single minor head injury in persons with no prior compromising condition is associated with mild but probably clinically non-significant difficulties at 1 month after injury. Disruptions of everyday activities, however, are extensive with other system injuries significantly contributing to these problems. Recent reports in the literature may represent overestimation of head injury related losses due to lack of control for the effects of pre-injury characteristics and other system injuries.

Rationing of intensive care unit services. An everyday occurrence

We investigated the extent to which bed availability affects decision making in an intensive care unit (ICU). For 1,151 ICU patients, we determined the number of empty ICU beds available at times of admission and discharge and the outcome for those patients. For a randomly chosen group we assessed severity of illness. Patients admitted during times of bed shortage were, on average, more severely ill than those admitted when many beds were unoccupied. Patients discharged under crowded conditions were sicker and had a shorter stay than patients discharged when more beds were available. The relative risk of discharge was inversely related to empty bed availability, illness severity, and age. Bed availability had no effect on rates of death in the ICU, death after discharge, or readmission to the ICU. We conclude that physicians can effectively ration intensive care beds on a regular basis by altering admission and discharge decision making.

Behavioral effects of anticonvulsant prophylaxis: no effect or artifact?

We examined the effects that may be attributable to current use of anticonvulsants in patients with traumatic head injury. The performances of 15 head-injured matched pairs were compared on a comprehensive battery of neuropsychological and psychosocial measures 1 year post injury. The members of both groups were placed on anticonvulsants, principally phenytoin, immediately after the head injury. The members of one of the groups were still taking the drug at 1 year; the others had discontinued prior to that time. Although the results provided no evidence for appreciable side effects of anticonvulsants on formal neuropsychological or psychosocial measures, some methodological issues need to be considered in the interpretation of results and future studies of drug side effects.

Psychosocial functioning at 1 month after head injury

The authors examined the psychosocial sequelae of head trauma at 1 month after injury in a group of 102 adult head-injured patients representing a broad range of severity of trauma. One hundred two control subjects selected from friends of the head-injured patients were used for comparison purposes. Outcome was determined with a battery of psychosocial measures assessing a number of different areas of daily functioning. The results support the following conclusions: (a) at 1 month after injury, head-injured patients experience difficulties in a number of areas of psychosocial functioning, especially the resumption of major role activities (i.e., work, school, and home management) and leisure/recreational activities; (b) the relationship between head injury severity level and the adequacy of psychosocial functional differs for the various measures; and (c) in determining the psychosocial consequences of head trauma, the use of an appropriate control group is essential.

Head injury in the Pacific Northwest

This report describes 451 consecutive patients admitted to a regional trauma center with head injury over 1 year's time. Our results replicate findings from other hospital- and population-based studies of head trauma. Males exceeded females by 3 to 1; the most frequent age of patients was between 15 and 24 years; and motor vehicles were the most common cause of injuries. Mortality was related inversely to Glasgow coma scale (GCS) scores and directly to age. This study also points out two current problems in head trauma research. One is the difficulty in using the GCS in a community with highly sophisticated emergency medical services. In 38% of the patients, one or more GCS components could not be assessed directly. In 17% of cases, GCS scores could not be confidently assigned. This was principally because endotracheal tubes were in place before arrival at the hospital, precluding determination of the verbal response. A second problem is the influence of chronic pre-existing central nervous system conditions on head outcome. Twenty-nine per cent of our patients had one or more such conditions at the time of their injury. Minimal estimates of prevalence ranged from 1% (mental retardation) to 18% (alcoholism).