Subcortical language and non-language mapping in awake brain surgery: the use of multimodal tests.

BACKGROUND: Awake craniotomy is currently considered the gold standard to maximise the extent of resection and to minimise postoperative deficits in patients with supratentorial tumours near eloquent areas. In addition to direct electrical stimulation (DES) of the cortex, intraoperative subcortical mapping is increasingly used as it optimises the benefit-to-risk ratio by decreasing (permanent) postoperative neurological deficits. However, only little attention has been paid to subcortical mapping procedures and especially the tasks to be used. METHODS: In this article, language and non-language testing at the subcortical level is described and discussed by means of three right-handed cases with a glioma in the left hemisphere. To assess subcortical functions, a multimodal test named the Quick Mixed Test was developed (QMT). Pre-, intra- and postoperative test results are described and discussed in detail. RESULTS: Based on the analysis of these preliminary observations, a number of clinical recommendations for intraoperative subcortical mapping may be made: (1) the selection of a set of language and non-language tests needs to be tailored according to the functional corticosubcortical regions affected by the tumoral lesion and the patient's characteristics (job/hobby/daily life activities); (2) language and non-language tests should be presented in a multimodal and alternating way during subcortical stimulation since this approach enables screening various functions simultaneously or in a very short period of time and (3) spontaneous speech is a useful adjunct to standardised tests since it most resembles daily life conversation. CONCLUSION: Administration of multimodal tests during subcortical DES such as the experimental QMT may facilitate identification of eloquent pathways leading to avoidance of permanent neurological impairments.

The Dutch Linguistic Intraoperative Protocol: a valid linguistic approach to awake brain surgery.

Intraoperative direct electrical stimulation (DES) is increasingly used in patients operated on for tumours in eloquent areas. Although a positive impact of DES on postoperative linguistic outcome is generally advocated, information about the neurolinguistic methods applied in awake surgery is scarce. We developed for the first time a standardised Dutch linguistic test battery (measuring phonology, semantics, syntax) to reliably identify the critical language zones in detail. A normative study was carried out in a control group of 250 native Dutch-speaking healthy adults. In addition, the clinical application of the Dutch Linguistic Intraoperative Protocol (DuLIP) was demonstrated by means of anatomo-functional models and five case studies. A set of DuLIP tests was selected for each patient depending on the tumour location and degree of linguistic impairment. DuLIP is a valid test battery for pre-, intraoperative and postoperative language testing and facilitates intraoperative mapping of eloquent language regions that are variably located.

Double trade-off curves with different cognitive processing combinations: testing the cancellation axiom of mental workload measurement theory.

The accomplishment model of average mental workload--a formal axiomatic measurement theory--was used as a basis for developing and testing secondary task indices of mental workload (H. A. Colle & G. B. Reid, 1997). Its cancellation axiom implies global sensitivity, which is an important theoretical and practical criterion for mental workload indices. Performance levels of different secondary tasks were empirically equated in mental workload and then used to test the cancellation axiom. Cognitive processing similarity--including orthographic, phonemic, and semantic processing of pairs of operator and secondary tasks--was manipulated in three experiments. Equivalencies between secondary tasks were independent of secondary-operator task similarity, consistent with the cancellation axiom and the global sensitivity of these secondary tasks. The results suggest that standardized secondary task techniques can be developed for the practical measurement of mental workload. Actual or potential applications of this research include the development of functionally useful and realistic secondary task measures of mental workload.

Context effects in subjective mental workload ratings.

The impact of performance context on subjective mental workload ratings was assessed with the Subjective Workload Assessment Technique (SWAT) and the NASA Task Load Index (TLX). In Experiment 1, a strong context effect was demonstrated. A low range of task difficulty produced considerably higher ratings on a common set of difficulty levels than did a high range of task difficulty. In Experiment 2, increasing the participants' range of experiences during practice eliminated the context effect. We recommend that methods for standardizing context, such as providing experience with the complete difficulty range, be developed for subjective mental workload evaluations. Actual or potential applications of this research include providing methodologies for controlling context effects in practical assessments of mental workload to increase the validity of subjective measures.

Modulation of the HLA class II antigen at a molecular level by maternal serum among cord blood cells and unrelated lymphocytes.

A retroplacental serum factor responsible for the downregulation of the MHC class II antigen expression has been described [1]. We found that maternal serum had the same property. The HLA class II modulating activity is however diminished in the presence of maternal serum as compared to retroplacental serum suggesting that the IA like inhibiting factor is released at the fetomaternal interface. After a 3-day incubation period of unrelated lymphocytes and mononuclear cord blood cells in a maternal serum pool, it was shown that the HLA Dr, the HLADp, and more significantly, the HLADq molecules were modulated. This phenomenon was more pronounced among cord blood cells. When third party lymphocytes and mononuclear cord blood cells were stimulated by Candidine or unrelated mononuclear cells in the presence of retroplacental serum, only the cellular subpopulation belonging to the CD4+ subset showed an HLADq downregulation. The molecular constituents of the MHC class II antigen expression characterizing cells belonging to other subsets remained unchanged. When the same stimulation assay was performed in the presence of a control medium (nulliparous serum), we found no changes in the MHC class II molecular constituents. When unrelated mononuclear cells and mononuclear cord blood cells were PHA stimulated in the presence of maternal and nulliparous serum, the HLADq expression of the CD8+ subset showed a significant downregulation in the maternal serum mediated stimulation assay as compared to the control stimulation test. The molecular expression of the HLA class II antigen related to the other subpopulation (CD4+, CD3+) stimulated by a mitogenic lectin remained unchanged. It is suggested that these molecular MHC class II modulations are due to a factor included in the maternal IgG reaction. Retroplacental IgG contains the highest concentration of this factor.

Paraplegia due to epidural infiltration in a case of chronic lymphocytic leukemia.

A case of chronic lymphocytic leukemia (CLL) is described during the course of which paraplegia appeared caused by epidural compression of the tissue by leukemic cells. This complication in CLL is rare. The disorders of the nervous system during the course of leukemia are summarized, and, in particular, the circumstances pertaining to the occurrence of paraplegia during chronic lymphocytic leukemia.

[Diagnostic and microsurgical aspects of brachial plexus tumors]. / Aspects diagnostiques et microchirurgicaux des tumeurs du plexus brachial.

Brachial plexus tumors are rare. Important progress in the diagnosis of these tumors has been realized, by means of CT-scan and angiography. The nature of the tumour, benign or malignant, plays a determining part in the results. Microsurgical technique allows large excisions with minimal sequelae.

Status of spatial location in auditory sensory memory: evidence from rapidly presented lists.

Letters presented rapidly to separate spatial locations were used to test the precategorical acoustic storage (PAS) model's assumptions that memory information can be stored and masked selectively at separate spatial locations in auditory space and that spatial location can act as a retrieval cue in PAS. The suffix effect was present at the end of the list, even at a presentation rate of six per second. The data from three other experiments suggested that spatial locations do not act as memory repositories and that spatial location cannot be used as a retrieval cue at fast rates of presentation.

[Ultrasonic diagnosis and control of an amebic obscess of the liver (author's transl)]. / Sonografische Diagnose und Verlaufskontrolle eines Amöbenab-szesses der Leber.

A case report is given of a patient, who suffered from relapsing fever, loss of weight, and right-sided upper abdominal colicky pain. A tentative diagnosis of amebic abscess was established on clinical grounds and after ultrasonography. Metronidazol was given and body temperature normalized within 24 hours; 6 weeks later only scarring of the liver remained. Sonographic controls were performed once weekly during the course of the disease, showing that the central parts of the abscess were liquified increasingly; at the same time a marginal zone about 1 cm broad was formed. This type of marginal zone could be demonstrated in another patient with amebic abscess of the liver as well by ultrasonography, whereas it could never be shown in patients with purulant abscesses of the liver.

[The effect of 15-methyl-prostaglandin F2 alpha administered intramuscularly to induce abortion in the first half of pregnancy (proceedings)]. / Wirkung von intramuskulär appliziertem 15-Methyl-Prostaglandin F2alpha zur Abortinduktion in der 1. Schwangerschaftshälfte.

PIP: 18 women ranging in age from 17-45 years receiving intramuscular injections of 250 mcg of 15-methyl-prostaglandin F2alpha (15-methyl-PGF2alpha) averaged 17 hours +or- 7 hours to delivery. Injections were repeated after 2 hours and every 5 hours thereafter. The cumulative abortion rate for the substance was intermediate between the very favorable results obtained using intraamniotic applications of E2 prostaglandins on the 1 hand and the somewhat unfavorable results with intraamniotic and retroamniotic applications of F2 alpha on the other hand. A comparison of side effects of intramuscular injection of 15-methyl-PGF2alpha with those of PGF2alpha injected intraamniotically or retroamniotically indicates that the occurrence of vomiting was slightly greater with it but the occurrence of diarrhea was almost the same. The dynamics of labor with 15-methyl PG were found to be similar to labor after injection of PGs intraamniotically and retroamniotically. The results suggest that 15-methyl-PGF2alpha is a safe and practical substance for inducing labor between the 10th and 20th week of pregnancy.^ieng