Comparing the influence of mixed reality, a 3D viewer, and MRI on the spatial understanding of brain tumours

Background: Multiple 3D visualization techniques are available that obviates the need for the surgeon to mentally transform the 2D planes from MRI to the 3D anatomy of the patient. We assessed the spatial understanding of a brain tumour when visualized with MRI, 3D models on a monitor or 3D models in mixed reality.Methods: Medical students, neurosurgical residents and neurosurgeons were divided into three groups based on the imaging modality used for preparation: MRI, 3D viewer and mixed reality. After preparation, the participants needed to position, scale, and rotate a virtual tumour inside a virtual head of the patient in the same orientation as the original tumour would be. Primary outcome was the amount of overlap between the placed tumour and the original tumour to evaluate accuracy. Secondary outcomes were the position, volume and rotation deviation compared to the original tumour.Results: A total of 12 medical students, 12 neurosurgical residents, and 12 neurosurgeons were included. For medical students, the mean amount of overlap for the MRI, 3D viewer and mixed reality group was 0.26 (0.22), 0.38 (0.20) and 0.48 (0.20) respectively. For residents 0.45 (0.23), 0.45 (0.19) and 0.68 (0.11) and for neurosurgeons 0.39 (0.20), 0.50 (0.27) and 0.67 (0.14). The amount of overlap for mixed reality was significantly higher on all expertise levels compared to MRI and on resident and neurosurgeon level also compared to the 3D viewer. Furthermore, mixed reality showed the lowest deviations in position, volume and rotation on all expertise levels.Conclusion: Mixed reality enhances the spatial understanding of brain tumours compared to MRI and 3D models on a monitor. The preoperative use of mixed reality may therefore support the surgeon to improve spatial 3D related surgical tasks such as patient positioning and planning surgical trajectories

A novel seven-octapeptide repeat insertion in the prion protein gene (PRNP) in a Dutch pedigree with Gerstmann–Sträussler–Scheinker disease phenotype: comparison with similar cases from the literature

Human prion diseases can be sporadic, inherited or acquired by infection and show considerable phenotypic heterogeneity. We describe the clinical, histopathological and pathological prion protein (PrPSc) characteristics of a Dutch family with a novel 7-octapeptide repeat insertion (7-OPRI) in PRNP, the gene encoding the prion protein (PrP). Clinical features were available in four, neuropathological features in three and biochemical characteristics in two members of this family. The clinical phenotype was characterized by slowly progressive cognitive decline, personality change, lethargy, depression with anxiety and panic attacks, apraxia and a hypokinetic-rigid syndrome. Neuropathological findings consisted of numerous multi- and unicentric amyloid plaques throughout the cerebrum and cerebellum with varying degrees of spongiform degeneration. Genetic and molecular studies were performed in two male family members. One of them was homozygous for valine and the other heterozygous for methionine and valine at codon 129 of PRNP. Sequence analysis identified a novel 168 bp insertion [R2–R2–R2–R2–R3g–R2–R2] in the octapeptide repeat region of PRNP. Both patients carried the mutation on the allele with valine at codon 129. Western blot analysis showed type 1 PrPSc in both patients and detected a smaller ~8 kDa PrPSc fragment in the cerebellum in one patient. The features of this Dutch kindred define an unusual neuropathological phenotype and a novel PRNP haplotype among the previously documented 7-OPRI mutations, further expanding the spectrum of genotype–phenotype correlations in inherited prion diseases

Guillain-Barré syndrome:multifactorial mechanisms versus defined subgroups

The clinical spectrum of Guillain-Barré syndrome (GBS) is summarized in relation to antecedent infections and anti-ganglioside antibodies. Associations exist between a pure motor form of GBS, diarrhea, Campylobacter jejuni infection, and anti-GM1 antibodies; between cranial nerve involvement and Miller Fisher syndrome, C. jejuni infection, and anti-GQ1b antibodies; and between variants, such as severe sensory involvement and cytomegalovirus infection. These three clinical variants are suggested to form the extremes of a continuous spectrum; they are discussed in relation to the more pathologically defined patterns of acute motor axonal neuropathy and acute motor-sensory axonal neuropathy. In particular, patients with a clinically pure motor variant of GBS, diarrhea, anti-GM1 antibodies, or C. jejuni infection seem to respond better to early treatment with high-dose immunoglobulins than to plasma exchange.</p

Flumazenil therapy for hepatic encephalopathy. A double-blind cross over study

Objectives and methods. Thirty-one patients with acute or chronic liver disease were included in the study to investigate the effect of flumazenil on hepatic encephalopathy. After screening for recent benzodiazepine use or non-hepatic causes of encephalopathy, 18 patients entered a double-blind cross-over study. The 13 remaining patients, most of them with renal failure or recent use of benzodiazepines, were given flumazenil in an open study. In the controlled study, flumazenil (1.0 mg) or placebo was given in a single injection on two separate days to study the immediate effect; half the patients received a continuous infusion of flumazenil (0.25 mg/h) or placebo for two 3-day periods to study a potential steady state effect. In the open study, a single bolus of flumazenil (1.0 mg) was given. Results. In the controlled study, fifteen minutes after bolus injection, the clinical grade of hepatic encephalopathy decreased in 6 patients after injection of flumazenil, whereas a decrease was found in 2 after the placebo (P = 0.06). However, the EEG grade did not change in any of the patients, and the changes in the mean dominant frequency as measured by spectral analysis did not differ between flumazenil and the placebo. Furthermore, patients on flumazenil did not differ significantly from those on placebo during the infusion period. Subgroup analysis of underlying liver disease and the causes of encephalopathy revealed a trend for clinical improvement only in the patients with chronic liver disease, but without significant changes in the mean dominant frequency. In the open study, the clinical grade of encephalopathy decreased in 3 patients and, in contrast to the controlled study, the EEG also improved in 2 patients and the mean dominant frequency increased significantly. Responders had previously used benzodiazepines. Conclusion. Our study does not support a major therapeutic effect of flumazenil on hepatic encephalopathy.</p

Validation of the Dutch version of the Boston Carpal Tunnel Questionnaire

The Boston Carpal Tunnel Questionnaire (BCTQ) is a scale that has been developed specifically for carpal tunnel syndrome (CTS). It consists of the Functional Status Scale (FSS) and the Symptom Severity Scale (SSS). It is the most widely used patient reported outcome measure in CTS and has been validated in many languages. Although already widely used, psychometric properties of the Dutch version of the BCTQ are yet unknown. The aim of this study was to assess the validity, reliability, responsiveness, and acceptability of the Dutch version. Moreover, this paper focuses the longitudinal validity (the use after an intervention) of the BCTQ, which has not been investigated before. A total of 180 patients completed the BCTQ in addition to a six-point Likert scale for perceived improvement, before and about 6-8 months after carpal tunnel release (CTR). Principal factor analysis revealed that the FSS is unidimensional, consisting of a single latent factor ("functionality") and has a high internal consistency (Cronbach's alpha = 0.825). However, the SSS has three dimensions, which are all highly internally consistent: "daytime symptoms" (Cronbach's alpha = 0.805), "nighttime symptoms" (Cronbach's alpha = 0.835), and "operational capacity" (Cronbach's alpha = 0.723). Post-treatment, the FSS still consisted of one factor, but the SSS changed in dimensionality, as it had only two factors left post-treatment. The Delta FSS and Delta SSS had good correlation with the six-point Likert scale for perceived improvement (r = 0.524; p <0.01 and r = 0.574; p <0.01, respectively), a moderate correlation between FSS and pinch grip (r = 0.259; p <0.01) was found, and a weak correlation between SSS and pinch grip (r = 0.231; p <0.01) was found. Standard Response Mean for FSS and SSS was 0.76 and 1.49, respectively. Effect size was 0.92 and 1.96, respectively, both indicating a good responsiveness. Response rate was high (82-84%). We concluded that the Dutch version of the BCTQ has a proper reliability, validity, responsiveness, and acceptability to assess the symptom severity and functional disabilities of CTS patients. Because of multidimensionality, we would recommend to create sum scores of the four different dimensions instead of two. Caution is required when interpreting the results postoperatively, due to the insufficient longitudinal validity of the SSS

Nasolabial shape and aesthetics in unilateral cleft lip and palate: an analysis of nasolabial shape using a mean 3D facial template.

The aim of this study was to determine the amount of deviation in nasolabial shape in patients with a cleft compared with an average non-cleft face, and to assess whether this difference is related to nasolabial aesthetics. Three-dimensional stereophotogrammetric images of 60 patients with a unilateral cleft were used. To quantify shape differences, four average non-cleft faces were constructed from stereophotogrammetric images of 141 girls and 60 boys. Three-dimensional shape differences were calculated between superimposed cleft faces and the average non-cleft face for the same sex and age group. Nasolabial aesthetics were rated with the modified Asher-McDade Aesthetic Index using a visual analogue scale (VAS). Mean VAS scores ranged from 51.44 to 60.21 for clefts, with lower aesthetic ratings associated with increasing cleft severity. Shape differences were found between cleft faces and the average non-cleft face. No relationship was found for the VAS, age, and sex, except that a lower VAS was related to a higher nose and lip distance between the superimposed cleft and average non-cleft faces for nasal profile (P= 0.02), but the explained variance was low (R2=0.066). In conclusion, except for nasal profile, nasolabial aesthetics were not influenced by the extent of shape differences from the average non-cleft face

Changes in functional coupling between neural networks in the brain during maturation revealed by omega complexity

To study age-dependent changes in coupling between cortical neural networks we applied a new method (omega complexity) to determine overall coherence of EEGs of 34 subjects ranging in age from 3 months to 16 years. We found that the functional coupling between different brain regions is low at birth and increases significantly in the first two decades of life. We suggest that this coupling depends critically upon the system of associational and callosal fibers which is unmyelinated at birth, and which only finishes myelinization in the second or third decade. Thus age-dependant changes in omega complexity may reflect maturation of brain structures underlying higher cerebral functions. If these results can be replicated, preferably in prospective, cohort rather than transectional type studies, omega complexity might prove to be clinically useful as an objective, quantitative measure of brain maturation