Predictive ability of preinjury stressful life events and post-traumatic stress symptoms for outcomes following mild traumatic brain injury: analysis in a prospective emergency room sample.

BACKGROUND: A subset of persons with mild traumatic brain injury (mTBI) experience long-term difficulties. Preinjury stress has been hypothesised to play a role in long-term maintenance of symptoms. OBJECTIVE: To investigate the predictive ability of preinjury stressful life events and post-traumatic stress symptoms to health-related quality of life and emotional distress after mTBI. METHODS: Within 2 weeks of injury, 186 participants with mTBI who were admitted to an emergency centre completed an interview and questionnaires regarding preinjury functioning, including the Stressful Life Events Questionnaire and the Post-Traumatic Stress Disorder Checklist. Outcomes were assessed at 3 months after injury and included the depression and anxiety subscales of the Brief Symptom Inventory, and the physical and mental component scores of the 36-item Short-Form Health Survey (SF-36). The incidence and type of stressful life events were reported. Hierarchical regression analyses were used to determine the predictive utility of Stressful Life Events Questionnaire and Post-Traumatic Stress Disorder Checklist after controlling for age, injury severity (complicated versus uncomplicated mild) and preinjury depression. RESULTS: Several potentially life-altering stressful events were endorsed by at least 25% of participants as having been experienced prior to injury. The incidence of stressful life events was a significant predictor of all four outcome variables. History of post-traumatic stress symptoms was predictive of scores on the SF-36 mental health component. CONCLUSIONS: A history of stressful events may predispose persons with mTBI to have poor outcomes. History of stress should be assessed during the early stages after mTBI to help identify those who could benefit from therapies to assist with adjustment and maximise recovery.

Visual perception of line direction in patients with unilateral brain disease.

The accuracy of identifying the slope of briefly exposed lines was assessed in patients with lesions of the left or right hemisphere and in a group of control patients without history or evidence of brain disease. The frequency of impaired performance was remarkably high in the patients with right hemisphere lesions. In contrast, the patients with left hemisphere lesions did not perform differently from the control group. Visual field defect, aphasic disorder, and age were not related to performance level. The striking interhemispheric difference in performance on this visuospatial task suggests its further development for clinicodiagnostic purposes.

Verbal-performance IQ discrepancy and perception of Rhythm and Timbre.

The Seashore Rhythm Tests, Form A and Form B, and the Timbre Test, Form A were administered to 90 strongly right-handed subjects placed in one of three WAIS Verbal-Performance IQ discrepancy groups. Some dissociation of performance on these tests was expected. As predicted, for the Rhythm Test Form A the High Performance group obtained significantly lower scores than the Equal group, which in turn had reliably lower scores than the High Verbal group. Converse predictions of group differences on Rhythm Test Form B were not confirmed. However, the predicted superiority of the High Performance group over the High Verbal group on Timbre Test Form A was found though the Equal group performed as well as the High Performance group. Thirty per cent of the High Performance group obtained scores on Rhythm Test Form A below the clinical cutoff of this test as opposed to only 6% of the Equal group and 0% of the High Verbal group.

Age effects on focal cerebral blood flow changes produced by a test of right-left discrimination.

The effects of age on focal cerebral blood flow changes resulting from the cognitive processing during right-left discrimination were examined. The pattern and amount of cortical flow were comparable for young and middle-aged subjects and consisted of flow increases in bilateral frontal, parietal and occipital regions. Task performance was negatively related to activation from left parietal and occipital channels. The frontal activation and the parietal correlation were attributed to the middle-aged subjects experiencing increased emotional arousal and attention to the right-left discrimination task due to hypothesized differences in cognitive effort and style, and/or novelty of formal examination situations.

Focal right temporo-occipital blood flow changes associated with judgment of line orientation.

Focal cerebral blood flow changes for judgment of line orientation were determined using the 133Xe inhalation technique with 18 normal right-handed male subjects. Measurements were made during three conditions in the same session: a line orientation task, a sensorimotor control task, and normal rest. Blood flow changes attributable to the judgment of line orientation were found for the measure f1 at a detector centered over the right temporo-occipital region. For the measure IS this activation was significant in the temporo-occipital region in both hemispheres but significantly greater in the right hemisphere. For f1 the change in blood flow and for IS the percent change in blood flow in the right temporo-occipital region attributable to judgment of line orientation decreased as performance on the line orientation task improved.

Relevance of sensorimotor task components to the interpretation of task related blood flow changes.

This study demonstrated the importance of documenting rCBF changes produced by the sensorimotor components of a cognitive task when making inferences regarding brain-behavior relations. Subjects were ten young, non-smoking adult, right-handed, normal male volunteers. They were administered two tasks having identical cognitive and similar sensory components but different response modalities (oral vs manual). The two tasks produced highly divergent rCBF landscapes. In conjunction with the results from a previous rCBF activation study, these data were used to illustrate the necessity of including sensorimotor control tasks in cognitive activation studies designed to elucidate brain-behavior relations.

The relation between acute physiological variables and outcome on the Glasgow Outcome Scale and Disability Rating Scale following severe traumatic brain injury.

The relation between outcome and duration of adverse physiological events was studied, using suggested critical physiological values. Subjects were 184 patients with severe traumatic brain injury who received continuous monitoring of intracranial pressure (ICP), mean arterial pressure (MAP), cerebral perfusion pressure (CPP), and jugular venous oxygen saturation. Longer durations of adverse physiological events were significantly related to Glasgow Outcome Scale (GOS) scores and Disability Rating Scale (DRS) scores for all variables at all timepoints postinjury. When analyses excluded patients who died, the relation between adverse physiological events and GOS was nonsignificant; however, duration of ICP, MAP, and CPP still accounted for a significant portion of the variance in DRS scalres. The relative sensitivity of the GOS and DRS is discussed.

Hyperglycemia increases neurological damage and behavioral deficits from post-traumatic secondary ischemic insults.

The effects of post-traumatic administration of glucose 2.0 g/kg was compared to saline infusion with and without control of brain temperature at 37 degrees C on behavioral and histological measures of brain injury after controlled cortical impact injury complicated by a secondary ischemic insult. The glucose infusion increased blood glucose concentration from 114 +/- 4 to 341 +/- 76 mg/dl prior to the secondary ischemic insult. The resulting outcome measures were significantly worse in the glucose infusion group than in either control group. Mortality rate was significantly increased by the glucose administration, from 0% to 55% (p < 0.001). The median contusion volume was increased from 7.9 to 64.2 by glucose administration (p < 0.001) and the neuronal loss in the CA1 and CA3 areas of the hippocampus were greater in the glucose infusion group. In the animals that survived for the 2 weeks of behavioral studies, the duration of beam balance was shorter; the percent of animals that could balance on the beam for at least 60 s was less, the percent of animals that could perform the beam-walking task was less, and the length of time required to find the platform in the Morris water maze task was longer in the glucose infusion group. These studies demonstrate that the infusion of glucose after the cortical impact injury significantly increases the damage caused by post-traumatic ischemic insults. The adverse effect on neurological outcome could not be explained by the temperature effects of glucose infusion.

Validation of a controlled cortical impact model of head injury in mice.

A controlled cortical impact model of head injury was validated with mice. Mice were randomly assigned to moderate head injury, mild head injury, and sham injury groups. Beam balancing, open field activity, slant board inclination, grasp strength, and motor coordination were assessed prior to the injury and on days 1-5 postinjury. Morris water maze performance was evaluated on days 11-15 postinjury. Moderately head-injured mice took a significantly longer time to complete the motor coordination task and to find the hidden platform on the Morris water maze and had significantly fewer successful trials on both tasks than the mildly head-injured and sham-injured mice. Mildly head-injured and sham-injured mice performed similarly on both tasks. Contusion volume at the site of impact varied with severity of injury. Moderately head-injured mice had significantly larger contusions than mice with a mild head injury, and these mice in turn had significantly larger contusions than the sham-injured mice. Both moderately and mildly head injured mice had significantly fewer surviving cells in CA1 than the sham-injured mice but did not differ from each other in this regard. Although there was a group effect, only the mildly head-injured mice had significantly fewer surviving cells in CA3.

Visual field recognition memory for right-handed females as a function of familial handedness.

Recognition memory for nonsense words presented vertically and unilaterally in the left and right visual fields was investigated in right-handed females as a function of the memory interval and familial handedness. The subject decided whether another nonsense word presented in central vision after memory intervals of 0, 5, or 10 sec. was the same as the stimulus word. The exposure duration producing a recognition accuracy of about 75% for each subject was employed and ranged from 5 to 28 msec. Right-handed females with only right-handed family members demonstrated right visual field superiorities indicative of a slight left hemisphere specialization for memory but not for reception of verbal material. Field superiorities obtained for right-handed females with a left-handed parent or sibling were not significant. In general, less complete lateralization of linguistic function in females was indicated and the importance of familial handedness in cerebral asymmetry of function was confirmed.

Individual differences and asymmetry effects in memory for unfamiliar faces.

Visual field effects for recognition of unfamiliar faces was investigated using memory intervals of 0, 10, and 20 sec. and 8 stimuli in a same-different comparison paradigm. In Experiment I, 24 male and 24 female familial righthanders, half of whom had high and the other half, low Block Design (BD) scaled scores participated. Faces were recognized significantly more often in the LVF. A visual field x memory interval interaction resulted from reliable LVF superiorities with the 0 and 10 sec. memory intervals and a non-significant RVF superiority with the 20 sec. memory interval. Performance decreased significantly as the duration of the memory interval increased. No sex differences were found. Subjects with high and low BD scores performed similarly. In Experiment II, 16 stimuli were employed and the task repeated. Twenty-four male and 24 female familial righthanderds were given the BD and Vocabulary subtests of the WAIS as well as a brightness discrimination task. Field effects were non-significant. Performance decreased with longer memory intervals. For males, field effects for the 0 sec. memory interval were positively related to brightness discrimination scores.

Impaired recognition memory after head injury.

A continuous recognition memory task employing 120 line drawings of familiar stimuli was administered to patients recovering from closed head injury of varying severity and control patients. Mildly injured patients obtained significantly more correct responses, and higher memory sensitivity (d') values than moderately and severely injured patients who performed similarly. The measure of response criterion, c, was significantly lower in patients with injury of moderate severity when compared to mildly injured cases and control patients. Controls and mildly injured patients did not differ in their performance. In general, the total correct responses most impressively differentiated head injured patients with measurable coma duration as more than two-thirds had scores below the control group. Group differences in hits, false alarms and misses were examined also. Age and education, skull fracture, and hematoma were generally unrelated to any of the measures, whereas coma duration was significantly related to most measures of mnemonic efficiency.

rCBF for middle-aged males and females during right-left discrimination.

rCBF was measured in 10 male and 10 female normal righthanders with an average age of 44.2 years. For the measures f1 and IS significant occipital lobe activation was produced bilaterally and for the measure IS significant left hemisphere parietal activation was produced also by a visually presented right-left discrimination cognitive activation task over and above the activation produced by a sensorimotor control task. The amount and pattern of blood flow changes were similar for both sexes. Performance of males on the cognitive task was not significantly better than that of females. However, an inverse relationship was found for males but not females between cognitive task performance and percentage increase in IS for all regions showing significant cognitive activation.

Corpus callosum damage and interhemispheric transfer of information following closed head injury in children.

We evaluated the relationship of corpus callosum atrophy and/or lesions on magnetic resonance imaging (MRI) to functional hemispheric disconnection following closed head injury (CHI) in 51 pediatric patients, including mild CHI, moderate to severe CHI with extracallosal lesions, and moderate to severe CHI with callosal atrophy and/or lesions. Interhemispheric transfer of information was assessed using auditory, motor, tactile, and visual tests in patients and in 16 uninjured children. Total and regional callosal areas were measured from the midsagittal MRI slice by morphometry. The corpus callosum lesion group demonstrated a greater right ear advantage on verbal dichotic listening than all other groups. Areas of the posterior corpus callosum were negatively correlated with laterality indices of verbal dichotic listening performance and tachistoscopic identification of verbal material. The relationship of corpus callosum atrophy and/or lesions to asymmetry in dichotic listening is consistent with previous investigation of posttraumatic hemispheric disconnection effects in adults.

Adult respiratory distress syndrome: a complication of induced hypertension after severe head injury.

OBJECT: The factors involved in the development of adult respiratory distress syndrome (ARDS) after severe head injury were studied. The presence of ARDS complicates the treatment of patients with severe head injury, both because hypoxia causes additional injury to the brain and because therapies that are used to protect the lungs and improve oxygenation in patients with ARDS can reduce cerebral blood flow (CBF) and increase intracranial pressure (ICP). In a recent randomized trial of two head-injury management strategies (ICP-targeted and CBF-targeted), a fivefold increase in the incidence of ARDS was observed in the CBF-targeted group. METHODS: Injury severity, physiological data, and treatment data in 18 patients in whom ARDS had developed were compared with the remaining 171 patients in the randomized trial in whom it had not developed. Logistic regression analysis was used to study the interaction of the factors that were related to the development of ARDS. In the final exact logistic regression model, several factors were found to be significantly associated with an increased risk of ARDS: administration of epinephrine (5.7-fold increased risk), administration of dopamine in a larger than median dose (10.8-fold increased risk), and a history of drug abuse (3.1-fold increased risk). CONCLUSIONS: Although this clinical trial was not designed to study the association of management strategy and the occurrence of ARDS, the data strongly indicated that induced hypertension in this high-risk group of patients is associated with the development of symptomatic ARDS.

The neuropsychology of trichotillomania.

The pathophysiology of trichotillomania (TM) is not well understood. Overlap with obsessive compulsive disorder (OCD) has been proposed, although extant data are inconsistent in this regard. In the neuropsychological domain, some data have supported the proposed TM-OCD overlap. However, the available studies are limited in number, and they typically have sampled a restricted range of performance domains. To examine further neuropsychological functioning in TM, the present study compared performance of 21 patients with TM and 17 normal control (NC) participants on a broad battery of tests assessing intellectual functioning, auditory perception and language, visual perception, somatosensory function, motor ability, memory, concept formation, attention and information processing speed, impulsivity, and cerebral dominance. The TM group demonstrated poorer performance on all measures of divided, but not focused, attention. Correlational data suggested the potentially important role of negative affect in TM. Implications of the data for the conceptualization of TM are discussed.

Dichhaptic perception of forms by normal adults.

Dichhaptic perception of nonsense forms was examined in familial righthanders. In Exp. 1, 15 males and 15 females performed similarly, obtaining a non-significant right-hand superiority with a 5-sec. memory interval between presentation of stimuli and their choice-recognition response. Individual differences in Block Design scaled scores but not State or Trait anxiety were related to hand performance for both sexes. One strategy on a questionnaire was related to performance of males. Exp. 2 was a replication with the memory interval removed. A significant right-hand superiority was obtained and different strategies were related to performance of males and females.

Relationships among anxiety, defensiveness, sex, task difficulty, and performance on various neuropsychological tasks.

The relationships between sex, personality differences, task difficulty, and the performance on neuropsychological tests were investigated. On the basis of trait anxiety and defensiveness, 120 college students were divided into three groups by coping style: high anxious, true low anxious, and repressor groups. As predicted, women obtained significantly higher scores than men on Digit Symbol and word fluency tests, while the opposite sex difference was found for Block Design and Finger Tapping tests. Performance did not vary with trait anxiety. However, on Block Design and one-word fluency test, rated by subjects as the most difficult tests, high state anxiety was associated with significantly poorer performance.

Simulation of a memory deficit on the Continuous Recognition Memory Test.

Simulation of a memory deficit on the Continuous Recognition Memory Test was studied, with 20 male and 20 female normal undergraduates assigned to each of two conditions. Simulation with prior test experience was studied by comparing performance following standard and then simulation instructions. A significant increase in false alarms was associated with a significant decrease in correct responses, d', c, and a slight decrease in hits. For studying simulation without prior test experience, the test was administered once with instructions to simulate. Performance was similar to simulation with test experience. Comparisons with the performance of closed head-injured patients were made.

Sex differences in hemispheric asymmetry revisited.

56 male and 56 female familial right-handers were given a tachistoscopic task requiring recognition of trigrams presented binocularly and vertically in the right or left visual field for individuality determined brief durations. Both males and females obtained a significant superiority in the right visual field and significant laterality coefficients indicative of processing by the left hemisphere. Implications for research on sex differences in hemispheric asymmetry are discussed.