Cerebrovascular Autoregulation Monitoring in the Management of Adult Severe Traumatic Brain Injury: A Delphi Consensus of Clinicians.

BACKGROUND: Several methods have been proposed to measure cerebrovascular autoregulation (CA) in traumatic brain injury (TBI), but the lack of a gold standard and the absence of prospective clinical data on risks, impact on care and outcomes of implementation of CA-guided management lead to uncertainty. AIM: To formulate statements using a Delphi consensus approach employing a group of expert clinicians, that reflect current knowledge of CA, aspects that can be implemented in TBI management and CA research priorities. METHODS: A group of 25 international academic experts with clinical expertise in the management of adult severe TBI patients participated in this consensus process. Seventy-seven statements and multiple-choice questions were submitted to the group in two online surveys, followed by a face-to-face meeting and a third online survey. Participants received feedback on average scores and the rationale for resubmission or rephrasing of statements. Consensus on a statement was defined as agreement of more than 75% of participants. RESULTS: Consensus amongst participants was achieved on the importance of CA status in adult severe TBI pathophysiology, the dynamic non-binary nature of CA impairment, its association with outcome and the inadvisability of employing universal and absolute cerebral perfusion pressure targets. Consensus could not be reached on the accuracy, reliability and validation of any current CA assessment method. There was also no consensus on how to implement CA information in clinical management protocols, reflecting insufficient clinical evidence. CONCLUSION: The Delphi process resulted in 25 consensus statements addressing the pathophysiology of impaired CA, and its impact on cerebral perfusion pressure targets and outcome. A research agenda was proposed emphasizing the need for better validated CA assessment methods as well as the focused investigation of the application of CA-guided management in clinical care using prospective safety, feasibility and efficacy studies.

Visual agnosia without alexia.

A 41-year-old man presented with bilateral posterior cerebral artery infarcts. He had visual object agnosia and prosopagnosia with preservation of reading abilities. There was also defective visual memory, topographic orientation, and color perception, as well as simultanagnosia. From the clinical facts and CT findings, it was postulated that bilateral visual-limbic disconnection accounted for the patient's visual agnosia and related disturbances.

Neuropsychological changes following the neurosurgical treatment of normal pressure hydrocephalus.

Extracranial shunting of cerebrospinal fluid is a well-known neurosurgical procedure for the treatment of normal pressure hydrocephalus. Research indicating reasonable success using this technique has been based primarily on subjective and global neurosurgical opinion. Given that the treatment carries morbidity risks, and that decisions to shunt are related to increasing adaptive functioning, attention must be paid to adequate measurement of surgical outcome. As part of a larger study, we report pre and postsurgical neuropsychological, neuroradiological, and clinical data on hydrocephalic patients, as well as presurgical intracranial pressure data. Prior to shunting, increase in ventricular dilatation and cerebral atrophy were associated with decreased cognitive functioning, gait disturbance, and bladder dysfunction. Following shunting, there were significant improvements in neuropsychological functioning in terms of attention, concentration, verbal and nonverbal memory, language and communication skills, and constructional skills, as well as clinical improvement in gait and bladder functioning. Improvement was related to presurgical dilatation of the temporal horns of the lateral ventricles and mental status, particularly memory functions.

Management of anticoagulation following central nervous system hemorrhage in patients with high thromboembolic risk.

SUMMARY BACKGROUND: Patients who present with central nervous system (CNS) hemorrhage while on anticoagulation (AC) for thromboembolic (TE) risk factors are a challenge to manage. OBJECTIVE: We sought to inform decisions surrounding the timing and intensity of AC resumption by performing a systematic review. METHODS: Three reviewers screened publications from Medline and EMBASE and extracted data. Hemorrhagic and TE adverse events that occurred subsequent to the index hemorrhage were recorded, as was their timing relative to presentation and covariates that might influence their occurrence. RESULTS: Data were extracted from 63 publications detailing 492 patients; 7.7% of patients experienced hemorrhagic complications and 6.1% experienced TE complications. Hemorrhagic complications were more common within 72 h of presentation while TE complications were more common thereafter. Patients restarted on AC after 72 h were significantly more likely to have a TE complication (P = 0.006) and those restarted before 72 h were more likely to hemorrhage (P = 0.0727). Factors associated with re-hemorrhage included younger age, traumatic cause, subdural hematomas and failure to reverse AC. TE complications were more common in younger patients and those with spinal hemorrhage, multiple hemorrhages, and non-traumatic causes of the index hemorrhage. Re-initiation of AC at a lower intensity also significantly increased the risk of TE complications. INTERPRETATION: Our results suggest that it may be prudent to re-initiate AC earlier than previously thought, with the timing and intensity modified based on predictors of TE and hemorrhagic complications. These findings must be explored in a prospective study because of limitations inherent to the analyzed studies.

Lateralizing brain damage with the Luria-Nebraska Neuropsychological Battery: diagnostic effectiveness as compared to the Halstead-Reitan Neuropsychological Test Battery.

This investigation examined the ability of the Luria-Nebraska Neuropsychological Battery (LNNB) to lateralize brain damage, since substantial statistical and methodological issues have been raised regarding the initial LNNB lateralization validation study. A comparison was then made of the ability of the LNNB and the Halstead-Reitan Neuropsychological Test Battery to lateralize brain damage. Both neuropsychological batteries were administered to 30 predominantly left- or right-hemisphere-damaged subjects (15 in each group) with discriminant analysis classification procedures demonstrating similar, above chance, accuracy in lateralizing cerebral dysfunction. Cross-validation of objective clinical rules designed to aid in LNNB test interpretation resulted in classification of brain damage and lateralization at levels below reported values from the test developer's laboratory. The limited role such simplistic rules have in assessment is discussed, as is the need to evaluate dimensions of test usefulness other than those related to gross diagnostic decisions (e.g., presence or laterality of brain damage) in determining the instrument of choice for clinical neuropsychological practice. More research is recommended to fully define the limits of the clinical utility of the LNNB.

Selective forgetting of aversive memories cued in the right hemisphere.

Several writers have suggested that there is selective inhibition of aversive right hemisphere processes from reaching the left hemisphere, thus reducing reportable awareness, although the right hemisphere processes might still affect behavior. Two similar experiments are reported supporting this theory. In the first of three phases, subjects learned a paired associate list to a criterion of one perfect trial. Second, distant associates of some of the words learned in phase 1 were punished. Third, subjects attempted to recall the first word list, with recall cued sometimes in the left visual field and sometimes in the right. Associates of punished words were more likely to be forgotten than control words, when cued in the left visual field so they had to cross from right to left hemisphere to be vocalized. Surprisingly, associates of punished words were remembered better when cued in the right visual field.

Effects of mild, moderate and severe closed head injury on long-term vocational status.

Survival from significant closed head injury (CHI) is frequently associated with cognitive defects, physical impairment, personality change, interpersonal difficulty and, in general, some degree of social dependence. Here we report a multidimensional assessment of quality of life of a sample of 131 male head-injury patients suffering a range of severities of insult with specific emphasis on vocational outcome. Of those patients who sustained a severe injury and were employed full-time prior to the CHI, only 55% were able to return to this level of employment. No differences were found between the moderate and severe groups in pre- or post-CHI occupational status, as measured by the Blishen (1967) quantitative social economic index, although both groups declined from pre- to post-CHI. Lower post-CHI occupational status was associated with lower GCS on admission and longer lengths of post-traumatic amnesia, with patient self-report of physical, cognitive and psychosocial difficulties, including spousal reports of confusion, belligerance, verbal expansiveness and the decreased ability to perform socially-expected activities. Stepwise multiple regression analysis accounted for 38% of variance in post-injury vocational status, with lower pre-injury vocational status, greater age, high physical and psychological difficulties and lower admission Glasgow Coma Scale score variables forming the regression equation. Implications are discussed in terms of rehabilitation issues, including vocational programming and planning.

Early metabolic and neurologic predictors of long-term quality of life after closed head injury.

Research has begun to identify early markers that predict survival after traumatic brain injury. In this study, trauma and biochemical indicators of severity were used to predict quality of life in 61 adults with traumatic brain injury and no damage to other organ systems. Severity markers available within 24 hours of injury were predictive of later psychosocial, behavioural and social role functioning. Multiple regression analyses demonstrated that the Glasgow Coma Scale, plasma glucose levels, leukocyte cell count and serum potassium concentration accounted for 12% to 66% of variance in certain measures of later quality of life. The importance of health-care resource allocation and psychosocial and behavioural intervention to the outcome after moderate traumatic brain injury is discussed.