Reaction Time Indicators of Attention Deficits in Closed Head Injury

The nature of deficits in attention in closed head injury (CHI) was studied by three reaction time (RT) paradigms given to 20 patients who had a CHI 2 or more years previously and to 25 controls. We studied the effects of temporal uncertainty by varying the length and regularity of the preparatory interval, the effects of stimulus modality uncertainty on simple RT to tones and lights, and the effects of response selection in choice RT. The CHI group showed slower and more variable RT than controls under all conditions. In addition, a long preparatory interval on the preceding trial retarded RT more in the CHI group, and they showed greater effects of stimulus modality uncertainty. Both of these findings suggest a difficulty in shifting attention to unexpected stimuli. These greater effects on RT of variations of attention or preparation in CHI may account for their greater within-subject variability possibly due to frontal lobe damage.     

Recovery Versus Retest Effects in Attention after Closed Head Injury

Recovery in 60 patients with a closed-head injury (CHI) in the first year posttrauma was assessed repeatedly with a series of attention tests. A matched group of healthy subjects was tested at the same intervals to allow us to control for practice effects. The results of a multilevel analysis for longitudinal data show retest effects in all but one of the tests. Patients performed more poorly on all tests, but their results on each test appeared to show recovery over time. The indicator of recovery was an improvement in test performance that was greater than the retest effect shown by the controls. On most tests, the performance of the more severely injured patients was initially worse, but showed more recovery over time. Test results differed with respect to changes over time, sensitivity to severity of injury, and subject specific characteristics like age and vocational level. Recovery rate was not related to age or vocational status. Despite their recovery, the patient group was still impaired 1 year posttrauma on all tests sensitive to mental slowness. Outcome after 1 year, scored on a modified Glasgow Outcome Scale, was predicted to a small extent by PTA duration and initial performance on the RT-Distraction task. Return to work 2 to 5 years posttrauma was predicted by initial performance and improvement over time on the Stroop Color Word Test.     

Long-Term Consequences of Severe Closed Head Injury on Episodic Memory

This is the first systematic investigation of the very long-term effects of severe closed head injury (CHI) on objective measures of memory, and the first to employ both a normal control group and an other injury control group consisting of spinal cord injury (SCI) patients. The CHI group displayed significantly poorer performance on every memory measure, and the effect sizes were large. This impairment in episodic memory is neither due to pre-injury nor post-injury differences between CHI and normal control subjects because the same differences were found when the CHI group was compared to a group of SCI patients. The findings demonstrate severe impairment in learning and retention many years after sustaining a severe CHI, which is likely in part due to the bilateral hippocampal damage shown in neuropathological studies. This life-long memory impairment needs to be addressed by community service programs.     

Distribution of Forebrain Diffuse Axonal Injury Following Inertial Closed Head Injury in Miniature Swine

Diffuse axonal injury (DAI) is one of the most frequently encountered types of brain damage resulting from closed head injury. This study was designed to verify whether DAI could be produced in miniature swine by rapid acceleration and deceleration of the head in the coronal plane. Hanford miniature swine (16-19 kg) were anesthetized with 3% isoflurane and their heads accelerated rapidly once through a 60-105° arc in the coronal plane, producing only transient post-traumatic unconsciousness without prolonged coma. All animals made a good recovery and were sacrificed between 6 h and 10 days after injury. The response of forebrain projection systems to this injury was studied using neurofilament immunohistochemistry with antisera to nonphosphorylated (SMI-32) and phosphorylated (SMI-31) epitopes common to heavy (200 kDa) and medium (160 kDa) neurofilament proteins. In 9 of 12 animals, lesions characterized by foci of SMI-32 positive axonal retraction balls were present at the white matter/gray matter junction at the crests of gyri in the dorsolateral regions of the frontal, parietal, and temporal cortices and along margins of the lateral ventricles. A high density of pyramidal neuron perikarya in layers III and V within cortical gyri associated with subcortical DAI were intensely positive for SMI-31 immunohistochemistry. These results validate the use of miniature swine in studies of axonal injury and demonstrate that axonal injury analogous to that seen in the mildest form of DAI (grade I) can be produced in these animals without producing prolonged coma.     

Topographical Brain Mapping in Depression Following Mild Closed Head Injury:

No abstract available for this article.     

Brief Report: Anosmia and Remote Outcome in Closed Head Injury

The value of posttraumatic anosmia as a predictor of late social outcomes was examined in a sample of closed head injury (CHI) patients. Unemployment rates were equally high in both the anosmic and nonanosmic closed head injury patients. The groups also did not differ in psychiatric or neuropsychological status. Anosmic patients had longer initial hospital stays and deeper initial comatose/confusional states. Anosmia does not appear to add incrementally to disability status and it does not automatically imply the presence of basal-frontal damage.     

Denial inside Out: Subjective Experience with Anosognosia in Closed Head Injury

Abstract

Male genital self-mutilation has been known to occur in psychotic patients. We report a case of premeditated autocastration in the absence of clinical disorder, both at the time of the mutilation and upon follow-up. Coming from a strict Slavic family, this patient repressed gender identity issues for decades. After migrating to Western Europe, his sexual ambiguity became actuated. His motives can be understood in the light of his personal and cultural background. This case shows that cultural factors may contribute to explaining male genital self-mutilation behaviors.     

Validity Testing in Dually Diagnosed Post-Traumatic Stress Disorder and Mild Closed Head Injury

Prospects for the coexistence of post-traumatic stress syndrome (PTSS) and mild traumatic brain injury (mTBI) rely exclusively on subjective evidence, increasing the risk of response bias in a compensatable social context. Using a priori specificities derived from genuine brain disorder groups, we examined validity failure rates in three domains (symptom, cognitive, motor) in 799 persons reporting persistent subjective disability long after mild neurological injury. Validity tests included the Test of Memory Malingering, MMPI-2 Fake Bad Scale, and Infrequency (F) scales, reliable digit span, and Halstead-Reitan finger tapping. Analyses showed invalidity signs in large excess of actuarial expectations, with rising invalidity risk conditional on post-traumatic complexity; the highest failure rates were produced by the 95 persons reporting both neurogenic amnesia and re-experiencing symptoms. We propose an “over-endorsement continuum” hypothesis: The more complex the post-traumatic presentation after mild neurological injury, the stronger the association with response bias. Late-appearing dual diagnosis is a litigation phenomenon so intertwined with secondary gain as to be a byproduct of it.     

Cerebrovascular Pressure Reactivity and Cerebral Oxygen Regulation After Severe Head Injury

Background

To investigate the relationship between cerebrovascular pressure reactivity and cerebral oxygen regulation after head injury.

Methods

Continuous monitoring of the partial pressure of brain tissue oxygen (P_brO₂), mean arterial blood pressure (MAP), and intracranial pressure (ICP) in 11 patients. The cerebrovascular pressure reactivity index (PRx) was calculated as the moving correlation coefficient between MAP and ICP. For assessment of the cerebral oxygen regulation system a brain tissue oxygen response (TOR) was calculated, where the response of P_brO₂ to an increase of the arterial oxygen through ventilation with 100 % oxygen for 15 min is tested. Arterial blood gas analysis was performed before and after changing ventilator settings.

Results

Arterial oxygen increased from 108 ± 6 mmHg to 494 ± 68 mmHg during ventilation with 100 % oxygen. P_brO₂ increased from 28 ± 7 mmHg to 78 ± 29 mmHg, resulting in a mean TOR of 0.48 ± 0.24. Mean PRx was 0.05 ± 0.22. The correlation between PRx and TOR was r = 0.69, P = 0.019. The correlation of PRx and TOR with the Glasgow outcome scale at 6 months was r = 0.47, P = 0.142; and r = ?0.33, P = 0.32, respectively.

Conclusions

The results suggest a strong link between cerebrovascular pressure reactivity and the brain’s ability to control for its extracellular oxygen content. Their simultaneous impairment indicates that their common actuating element for cerebral blood flow control, the cerebral resistance vessels, are equally impaired in their ability to regulate for MAP fluctuations and changes in brain oxygen.     

Patient-Informant Agreement on Personality Ratings and Self-Awareness after Head Injury

To address concerns about self-awareness deficits and the validity of self-ratings by patients with head injury (HI), the current study examines mean differences and correlations between self-ratings from 52 patients with HI and ratings of the patient by informants using the revised NEO Personality Inventory (NEO-PI-R). Patient self-ratings were significantly lower than informant ratings on neuroticism and extraversion and significantly higher on conscientiousness. Patient-informant correlations ranged from .42 for conscientiousness to .67 for agreeableness, and these agreement correlations compare favorably with those obtained from normal adult samples. Hierarchical multiple regression equations for each of the five NEO-PI-R trait domains showed that more severe injuries were associated with higher agreement for extraversion. For all five traits, the strongest predictors of informant personality ratings were the patients' self-ratings. The implications of these findings for clinical assessment and improved research on self-awareness deficits after HI are discussed.     

Alteration of Astrocytes in Non-Gliotic Lesions after Protracted Non-Missile Head Injury

Morphological and immunohistochemical observations of a pathologic from of astrocytes, called “clasmatodendritic astrocytes (CAs)”, are described for descrived for two cases of protracted non-missile head injury. CAs were moderately swollen and characterized by disintegration of their processes which were clearly demonstrated by Cajal staining of the astrocytes. In both cases, CAs appeared not in astrogliotic scar lesions but in non-astrogliotic rarefied white matter lesions. Immunohistochemically, almost all CAs reacted weakly with glial fibrillary acidic protein. Also, a number of CAs (approximately 75%) strongly reacted with laminin and alphal-antichymotrypsin. These observations provide suggestive evidence that CAs do not produce fibrillary astrogliosis, which is considered to interfere with neurite regeneration, but play other roles after brain injuries. The possible altered nature of CAs is discussed.     

Outcome Measurement in a Community Head Injury Service

This paper seeks to illustrate the variety of outcome measures used in the provision of an open-ended, wide-ranging community head injury service with separate assessment, general rehabilitation, vocational rehabilitation, and family programmes. The heterogeneity of clients referred to the service and the structure of assessment, rehabilitation, and family services are outlined. The nature and implementation of six selected outcome scales are described: two for general rehabilitation (measuring functional independence and self-concept/personality change); two for vocational rehabilitation (measuring vocational limitations and work attitude, performance, and behaviour); and two for our family services (intimacy in relationships and family roles).     

Fatal Rhabdomyolysis in a Patient with Head Injury

Rhabdomyolysis is a rare but potentially life-threatening disorder caused by the release of injured skeletal muscle components into the circulation. The authors report a case of severe head injury, in which a hyperosmolar state and continuous seizure complicated by severe rhabdomyolysis and acute renal failure evolved during the course of treatment resulted in a fatal outcome despite intensive supportive treatment. Our bitter experience suggests that rhabdomyolysis should be born in mind in patients with severe head injury who may develop hyperosmolar state and continuous seizure.