Visual neglect as a disconnection syndrome? A confirmatory case report

Visual neglect has classically been associated with right hemisphere injury in parietal, frontal, or temporal cortex, in the basal ganglia or in the thalamus. More recently, visual neglect has been associated with injury extended into fronto-parietal white matter tracts. However, in most published cases white and gray matter injuries were associated. We present the anatomo-clinical study of a patient presenting with severe acute left visual neglect due to ischemic infarct limited to the right cerebral hemisphere white matter. Magnetic resonance diffusion tensor imaging tractography was instrumental to accurately localize the injury to the right arcuate fasciculus that is a component of the large-scale networks controlling visuo-spatial attention. These results add to a growing appreciation that neglect may result from disruption of a distributed attentional network. Paolo Bartolomeo and Alberto Bizzi as senior authors equally contributed to this work

Aphasia induced by gliomas growing in the ventrolateral frontal region: assessment with diffusion MR tractography, functional MR imaging and neuropsychology

Introduction: Lesions in the ventrolateral region of the dominant frontal lobe have been historically associated with aphasia. Recent imaging results suggest that frontal language regions extend beyond classically defined Broca's area to include the ventral precentral gyms (VPCG) and the arcuate fasciculus (AF). Frontal gliomas offer a unique opportunity to identify structures that are essential for speech production. The aim of this prospective study was to investigate the correlation between language deficits and lesion location in patients with gliomas. Methods: Nineteen patients with glioma and 10 healthy subjects were evaluated with diffusion tensor imaging magnetic resonance (MR) tractography, functional MR (verb generation task) and the Aachener Aphasie Test. Patients were divided into two groups according to lesion location with respect to the ventral precentral sulcus: (i) anterior (n = 8) with glioma growing in the inferior frontal gyms (IFG) and underlying white matter; (ii) posterior (n = 11) with glioma growing in the VPCG and underlying white matter. Virtual dissection of the AF, frontal intralobar tract, uncinate fasciculus (UF) and inferior frontal occipital fasciculus (IFOF) was performed with a deterministic approach. Results: Seven posterior patients showed aphasia classified as conduction (4), Broca (1), transcortical motor (1) and an isolated deficit of semantic fluency; one anterior patient had transcortical mixed aphasia. All posterior patients had invasion of the VPCG, however only patients with aphasia had also lesion extension to the AF as demonstrated by tractography dissections. All patients with language deficits had high grade glioma. Groups did not differ regarding tumour volume. A functional pars opercularis was identified with functional MR imaging (fMRI) in 17 patients. Conclusions: Gliomas growing in the left VPCG are much more likely to cause speech deficits than gliomas infiltrating the IFG, including Broca's area. Lesion extension to the AF connecting frontal to parietal and temporal regions is an important mechanism for the appearance of aphasi

Different views about the nature of gender-related asymmetries in task based on biological or artefact categories

Sex-related asymmetries in the ability to process different semantic categories have been reported both in normal subjects and in brain-damaged patients, but the nature of these asymmetries is still controversial. Some authors suggest that these differences might be due to social-role related familiarity factors, whereas others attribute them to inborn neural differences rooted in evolution. Drawing in part on this second line of thought, some authors have suggested that gender-related asymmetries might be due to differences in stimulus processing between men and women, namely, to the tendency of females to focus mainly on perceptual features and of males to focus equally on both perceptual and functional features. To test this hypothesis, we asked 53 male and 65 female undergraduate students to evaluate the relevance of a number of perceptual and functional features in the representation of various kinds of biological and artefact categories. Contrary to the hypothesis, evaluation of the weight of different sources of knowledge in representing living and artefact categories was similar in males and females

Assessment of patients with disorder of consciousness: do different Coma Recovery Scale scoring correlate with different settings?

Differential diagnosis between Vegetative State and Minimally Conscious State is a challenging task that requires specific assessment scales, involvement of expert neuropsychologists or physicians and use of tailored stimuli for eliciting behavioural responses. Although misdiagnosis rate as high as 40\% has been reported, no clear guidelines are available in literature on the optimal setting for assessment. The present study aims to analyse score differences in behavioural assessments of persons with disorders of consciousness (DOC) with or without family members and to determine whether the presence of caregivers could improve clinical accuracy in diagnostic evaluation. The research was conducted on 92 adults with DOC among 153 consecutive patients enrolled in the Coma Research Centre of the Neurological Institute C. Besta of Milan between January 2011 and May 2013. The results indicate that in almost half of the sample the scoring, thus the performance, observed with caregivers was better than without them. Furthermore, in 16\% of the sample, when assessment was performed with caregivers there was a change in diagnosis, from Vegetative to Minimally Conscious State or from that to Severe Disability. Finally, statistical differences were found in relation to diagnosis between mean scores in the "visual function" Coma Recovery Scale revised's subscale obtained by raters plus caregiver and rates only assessment. This study demonstrates how the presence of caregivers can positively affect behavioural assessments of persons with DOC, thus contributing to the definition of the optimal setting for behavioural evaluation of patients, to decrease misdiagnosis rates

Reliability of SFEMG in diagnosing myasthenia gravis: Sensitivity and specificity calculated on 100 prospective cases.

Objective The study aimed to determine the utility of single-fibre electromyography (SFEMG) in the diagnosis of myasthenia gravis (MG) in subjects with a clinical suspicion of the disease. Methods We performed a prospective, single-blinded study on 100 consecutive patients. SFEMG was not considered a criterion in making the MG diagnosis. For all cases, a different physician than the one performing SFEMG made the diagnosis of MG. All subjects underwent standard SFEMG of a single muscle, the orbicularis oculi. Results SFEMG was abnormal in 67 of 100 patients. A final diagnosis of definite MG was made in 54 patients (30 men/24 women). SFEMG was positive in 53 of 54 patients diagnosed with MG. The sensitivity of SFEMG in diagnosing MG was 98% (95% CI: 0.94\u20131.02), while the specificity was 70% (95% CI: 0.54\u20130.86), with a positive predictive value of 79% (95% CI: 0.74\u20130.79) and a negative predictive value of 97% (95% CI: 0.94\u20130.99). Conclusions In this cohort of patients, normal SFEMG findings were unlikely to occur in patients with MG

Anti-MuSK antibodies: Correlation with myasthenia gravis severity

The authors measured anti\u2013muscle-specific tyrosine kinase (anti- MuSK) antibodies (Abs) in 83 serum samples from 40 patients and evaluated their correlation with myasthenia gravis severity and treatment response. Ab concentrations were often reduced by immunosuppression but not after thymectomy. Both in individual cases and in the whole population, a correlation between Ab levels and disease severity was found

SFEMG: A piece in the diagnostic puzzle of myasthenia

We very much thank Haran (2014) for his comments on our paper. We completely agree that interpretation of the results coming from a diagnostic test must be done with great caution and that only a comprehensive evaluation of the clinical picture and instrumental results will lead to correct diagnosis and proper management of our patients. This is always true, especially in a treatable disease such as myasthenia. Our view is clearly expressed in the very last sentence of the manuscript: “The results of SFEMG should not be interpreted in isolation from the clinical presentation and ancillary test results” (Padua et al., 2014); however, Haran’s reply gives us the opportunity to emphasize the concept even more, which is also the subject of a recent editorial (Caliandro et al., 2013). We know that myasthenia may be difficult to diagnose in individual cases and that we must use all available tools to reach the correct diagnosis (Caliandro et al., 2009), as Haran and coworkers did with their patient (Haran et al., 2013) who, although rare, is a paradigmatic myasthenic patient with antibodies to muscle-specific tyrosine kinase (MuSK-MG) (Evoli et al., 2003 and Evoli et al., 2012). In our work on the reliability of SFEMG in diagnosing myasthenia gravis, we concluded that patients with normal findings at SFEMG are unlikely to be affected by myasthenia gravis because the results from the sensitivity analysis underline that the positive likelihood ratio is always low in both evaluations and therefore, SFEMG has a small value as the confirmatory test for myasthenia gravis diagnosis. Meanwhile, the negative likelihood ratio, although with a wide range, has a low value in both analyses and, therefore, SFEMG has a moderate-to-large value as the test useful in identifying healthy subjects. All this means that normal findings at SFEMG are more meaningful than pathological findings, but of course, a normal SFEMG does not definitively exclude the diagnosis of myasthenia gravis