Clinical and advanced neurophysiology in the prognostic and diagnostic evaluation of disorders of consciousness: review of an IFCN-endorsed expert group

The analysis of spontaneous EEG activity and evoked potentialsis a cornerstone of the instrumental evaluation of patients with disorders of consciousness (DoC). Thepast few years have witnessed an unprecedented surge in EEG-related research applied to the prediction and detection of recovery of consciousness after severe brain injury,opening up the prospect that new concepts and tools may be available at the bedside. This paper provides a comprehensive, critical overview of bothconsolidated and investigational electrophysiological techniquesfor the prognostic and diagnostic assessment of DoC.We describe conventional clinical EEG approaches, then focus on evoked and event-related potentials, and finally we analyze the potential of novel research findings. In doing so, we (i) draw a distinction between acute, prolonged and chronic phases of DoC, (ii) attempt to relate both clinical and research findings to the underlying neuronal processes and (iii) discuss technical and conceptual caveats.The primary aim of this narrative review is to bridge the gap between standard and emerging electrophysiological measures for the detection and prediction of recovery of consciousness. The ultimate scope is to provide a reference and common ground for academic researchers active in the field of neurophysiology and clinicians engaged in intensive care unit and rehabilitation.

A frameshift variant in the COL5A1 gene in a cat with Ehlers-Danlos syndrome

Ehlers-Danlos syndrome (EDS) is a group of heritable connective tissue disorders caused by defective collagen synthesis or incorrect assembly of the collagen triple helical structure. EDS is characterised by joint hypermobility, skin hyperextensibility, abnormal scarring, poor wound healing and tissue friability. Human EDS may be caused by variants in several different genes including COL5A1, which encodes the collagen type V alpha 1 chain. For the present study we investigated a 1.5-year-old, spayed female, domestic shorthair cat with EDS. The affected cat showed multiple recurrent skin tears, hyperextensibility of the skin and joint abnormalities. We obtained whole genome sequencing data from the affected cat and searched for variants in candidate genes known to cause EDS. We detected a heterozygous single base-pair deletion in exon 43 of the COL5A1 gene, namely c.3420delG. The deletion was predicted to result in a frameshift and premature stop codon: p.(Leu1141SerfsTer134). Sanger sequencing confirmed that the variant was present in the affected cat and absent from 103 unaffected cats from different breeds. The variant was also absent from a Burmese cat with EDS. Based on knowledge about the functional impact of COL5A1 variants in other species, COL5A1:c.3420delG represents a compelling candidate causative variant for the observed EDS in the affected cat.

Comparing immediate-type food allergy in humans and companion animals-revealing unmet needs

Adverse food reactions occur in human as well as veterinary patients. Systematic comparison may lead to improved recommendations for prevention and treatment in both. In this position paper, we summarize the current knowledge on immediate-type food allergy vs other food adverse reactions in companion animals, and compare this to the human situation. While the prevalence of food allergy in humans has been well studied for some allergens, this remains to be investigated for animal patients, where owner-reported as well as veterinarian-diagnosed food adverse reactions are on the increase. The characteristics of the disease in humans vs dogs, cats, and horses are most often caused by similar, but sometimes species-dependent different pathophysiological mechanisms, prompting the specific clinical symptoms, diagnoses, and treatments. Furthermore, little is known about the allergen molecules causative for type I food allergy in animals, which, like in human patients, could represent predictive biomarkers for risk evaluation. The definite diagnosis of food allergy relies-as in humans-on elimination diet and provocation tests. Besides allergen avoidance in daily practice, novel treatment options and tolerization strategies are underway. Taken together, numerous knowledge gaps were identified in veterinary food allergy, which need to be filled by systematic comparative studies.

Prevalence of canine methicillin resistant Staphylococcus pseudintermedius in a veterinary diagnostic laboratory in Italy

The overall prevalence of methicillin-resistant Staphylococcus pseudintermedius (MRSP) was 2% (10/590) among 590 canine specimens submitted to an Italian veterinary diagnostic laboratory during a two-month period, and 21% (10/48) among Staphylococcus intermedius group (SIG) isolates. All methicillin-resistant strains exhibited additional resistance to fluoroquinolones, gentamicin, lincosamides, tetracyclines, and potentiated sulfonamides, belonged predominantly to spa type t02 and harboured SCCmec type II-III cassette.

Diffusion tensor MRI-based estimation of the influence of brain tissue anisotropy on the effects of transcranial magnetic stimulation

We evaluate and discuss the relevance of fiber anisotropy in estimating the effect of transcranial magnetic stimulation (TMS) on the human brain. Finite element simulations were carried out on a three-dimensional model of the head that included anisotropic conductivity information derived from diffusion tensor imaging (DTI). The results show that anisotropy has minor effects both on the position of the main locus of activation and on its intensity. It has considerably more effect on the spatial distribution of the induced electric field, yielding differences of the order of 10% of the maximum induced field. Moreover the area affected by magnetic stimulation is slightly larger when we include fiber anisotropy in the calculations than in an isotropic model. We also show that the induced field observed in the anisotropic model does not always align with the local fiber orientation but rather follows specific patterns of parallelity. These findings will help to improve the estimation of the areas involved in magnetic stimulation.

Topological approach to neural complexity

Considerable effort in modern statistical physics is devoted to the study of networked systems. One of the most important example of them is the brain, which creates and continuously develops complex networks of correlated dynamics. An important quantity which captures fundamental aspects of brain network organization is the neural complexity C(X) introduced by Tononi et al. [Proc. Natl. Acad. Sci. USA 91, 5033 (1994)]. This work addresses the dependence of this measure on the topological features of a network in the case of a Gaussian stationary process. Both analytical and numerical results show that the degree of complexity has a clear and simple meaning from a topological point of view. Moreover, the analytical result offers a straightforward and faster algorithm to compute the complexity of a graph than the standard one.

[Results of elective open surgery for juxtarenal aortic aneurysms]

Review of the most significant surveys (data base: Pub Med on September 2003) of elective open surgery for Juxtarenal aneurysms and personal results of 106 cases (9.3% of AAA consecutively operated in the last 11 yrs.) are reported. Mortality and morbidity are discussed related to: technique of aortic cross-clamping; protective measures on splanchnic and renal perfusion; risks from previous CAD and chronic renal failure. Over all, the main predictive factor is the accuracy of the selected technique, without any difference among different approaches, and the same results of infrarenal aneurysms can be obtained.

Combined surgical approach for carotid and coronary stenosis. Sixty-four patients and review of literature

BACKGROUND

The proper role of combined carotid endarterectomy (CEA) and coronary bypass (CABG) is still controversial. We contribute to the discussion through the critical evaluation of 64 consecutive patients, whose data have been collected in a prospective way.

METHODS

Between 1990 and 1999, 64 patients presenting a critical coronary disease (unemendable by PTA) associated with severe carotid stenosis (= or >70% if symptomatic, = or >80% if asymptomatic), underwent combined CEA-CABG. Cardiological symptoms were evident in 90.6% of cases. Thirty-five patients (54.7%) had a three-vessel coronaropathy, 18 (28.1%) a two-vessel disease and 11 (17.2%) severe stenosis of the common trunk; furthermore 7 patients (10.9%) had a low ejection fraction (<50%). A positive neurologic history was present in 22 (44%) patients. Thirty-four patients (55%) had a carotid stenosis >90%; a significant disease of the contralateral carotid axis was observed in 53% of cases: stenosis >50% in 30 patients and thrombosis in 4. CEA was performed with somato-sensorial evoked potential monitoring.

RESULTS

The hospital mortality rate was 6.2% (4 patients). The cause of death was cardiac in 2 cases (1 early bypass thrombosis and 1 irreversible coronary spasm) and related to a multiorgan failure in 2. The neurologic morbidity rate was 0%.

CONCLUSIONS

Our data highlight that in these high-risk patients the combined approach dramatically reduces the stroke risk although the mortality rate is still higher than that observed after CEA or CABG.

Suprarenal aortic cross-clamping in elective abdominal aortic aneurysm surgery

INTRODUCTION

this retrospective study was undertaken to evaluate whether suprarenal aortic cross-clamping increased the perioperative mortality and morbidity as compared to infrarenal clamping, in order to create the rationale for a more extensive application of this apparently more traumatic manoeuvre.

MATERIALS AND METHODS

in a series of 734 elective aortic substitutions for abdominal aneurysm (AA), performed consecutively from January 1992 to June 1999, aortic cross-clamping was performed at a suprarenal level in 56 juxtarenal aneurysms, i.e. aneurysms extending to the lower edge of the renal arteries (8%, Group 1), and at an infrarenal level in 634 subrenal aneurysms (92%, Group 2). When analysing preoperative data, the diameter of aneurysms was larger in Group 1 than in Group 2 (p<0. 005). No significant differences were found between the two groups as regards age, sex, postinfarction cardiomyopathy, chronic obstructive pulmonary disease, chronic renal insufficiency and ASA classification of operative risks.

RESULTS

the average time of renal exclusion in the juxtarenal aneurysms was 20 min (range 12-35 min). There is no difference between the two groups as regards the time of aortic clamping (mean 50 vs. 60 min) or the need for homologous blood transfusion (7% vs. 11% of patients). Perioperative (30 days) mortality did not differ: 3.6% vs. 1.9% (n.s.); nor did the incidence of acute myocardial infarction (3.6% vs. 2.3%). Renal function deteriorated in 8 (14%) vs. 0 (0%) (p<0.001) and 1 patient (2%) required permanent dialysis, as compared to 0% in Group 2. The incidence of ischaemic colitis was also significantly higher in Group 1 (7%) than in Group 2 (2%, p<0.01).

CONCLUSION

this data shows that suprarenal clamping, which is necessary for the radical treatment of juxtarenal aortic aneurysms, can be performed with a low risk.

[Carotid endarterectomy in patients with neurological non-side related (NSRS) symptoms]

Out of 970 carotid endarterectomies (CE) performed for high-grade (> 80%) stenosis of the internal carotid artery (ICA) until 1995, 147 patients with neurological non side-related symptoms (NSRS) and without any cardiac, ocular or vestibular significant pathology have been evaluated, analyzing the medium and long-term functional results (mean follow-up 37.6 months) related to the morphological status of the ICA contralateral and the vertebral arteries. NSRS disappeared in 126 pts (85.71%): contralateral ICA was non-stenotic in 32 cases (25.39%), stenotic < 75% in 68 cases (53.96%), stenotic > 75% in 7 cases (5.55%) and occluded in 19 cases (15.09%); vertebral arteries were pathological in only 6 cases (4.75%), among which 4 were on the same side and 2 on the opposite side of CE. NSRS persisted in 20 pts (13.6%): contralateral ICA was non-stenotic in 5 cases (25%), with a stenosis < 75% in 11 cases (55%) and with stenosis > 75% in 4 cases (20%); vertebral obliterative lesions were 3 (15.78%), among which 1 on the same and 2 on the opposite side of CE. No one statistical comparison among the groups of cases obtained on the ground of the status of ICA and vertebral arteries were significant (p always > 0.05 at chi-square analysis). Authors' data confirmed that high grade stenoses of ICA can cause NSRS and that CE--always performed at the aim to prevent major neurological attacks--can relieve also these functional disorders in the most of cases, independently from the status of the contralateral ICA and the vertebral arteries.

Immediate detection of postreconstructive ischaemia by intra-operative Doppler ankle pressure index monitoring during aortic reconstructions

From March 1980 to February 1988, 368 aorto-iliac or aorto-femoral bilateral reconstructions were performed for aneurysmal or occlusive disease. In order to demonstrate early postreconstructive ischaemic complications, the intra-operative Doppler Ankle Pressure Index (API) was measured immediately before reconstruction (PRE), just after declamping (DEC) and 5, 15, 30 and 45 min thereafter. Each limb of the reconstruction (736) was considered individually and subdivided as follows: Group (A) 705 immediately successful (96% of limbs and 92% of patients); Group (B) 22 (3% of limbs and 5% of patients) in which, on the grounds of API data, an ischaemic complication was regarded as imminent and treated by graft revision or a peripheral thromboembolectomy (intra-operative corrections); Group (C) 9 (1% of limbs and 2% of patients) in which the diagnosis of ischaemic complications was made postoperatively when the patients underwent successful reoperation. All 736 reconstructions were patent and functional at discharge of the patient. By a retrospective analysis the intra-operative APIs were studied and the features (single or associated) suggesting an ischaemic complication examined. These were: (1) no flow at the time of declamping or its disappearance during the operation (10 cases, 1.25% of limbs) all detected and successfully corrected intra-operatively.(ABSTRACT TRUNCATED AT 250 WORDS)

[Connective tissue diseases and HEp-2 antinuclear antibodies]

Some characteristics of antinuclear antibodies that might be of use for diagnostic and/or prognostic purposed were studied using indirect immunofluorescence on HEp-2 cells in 55 cases of various types of connective tissue disease. For each nuclear (homogeneous, speckled, granular, dotted, pulverulent and centromeric) and nucleolar fluorescence pattern (homogeneous, conglutinated and dotted), the following parameters were observed; C3 fixing capacity, degree of antibody affinity and sensitivity to RNAse, DNAse and trypsin. The results were very interesting, especially in relation to the diagnosis of progressive systemic sclerosis and of the related subsets, but were insufficient for reliable, conclusive prognostic evaluation.

[Clinical significance of antinuclear antibodies in progressive systemic sclerosis]

Indirect immunofluorescence (IIF) was used to detect antinuclear antibodies (ANA) in 42 clinical cases. In each case cryostatic rat kidney slices and cultivated HEp-2 cells were used as substrates. Clinical diagnoses were as follow: Progressive Systemic Sclerosis (PSS) 25 cases, of which 8 were acrosclerotic, 8 diffuse, 5 CREST syndrome, 1 overlap PSS + Systemic Lupus Erythematosus (SLE) and 3 PSS + myopathy; Localised scleroderma (morphea): 3 cases; Mixed Connective Tissue Disease (MCTD): 3 cases; "Idiopathic" Raynaud's Disease (RD): 4 cases; Dermatomyositis (DM): 2 cases (1 paraneoplastic); SLE: 1 case; Unclassifiable Connective Tissue Disease (UCTD): 4 cases. The ANA-positive cases identified by the traditional technique were divided according to pattern into 4 categories: homogeneous, peripheral, speckled, nucleolar. In contrast those identified using HEp-2 cells were divided into 9 pattern groups: (nuclear type) centromere, fine speckled, coarse speckled, diffusely grainy, homogeneous: (nucleolar type) speckled, clumpy, homogeneous. The results demonstrated a higher general incidence of positivity with HEp-2 cells and confirmed the close connection between Anticentromere ANA and CREST syndrome. A similarly close connection was noted between MCTD and both nuclear diffusely grainy and nucleolar speckled patterns. A fairly clear connection was also noted between acrosclerotic or diffuse SSP and a fine speckled nuclear pattern. It is felt that ANA tests using IFI on HEp-2 cells should lead to significant progress in the field of diagnosis and prognosis and the study of PSS subsets.

[Immuno-histological findings on Sjögren's syndrome]

Six cases of SS, 12 cases of SS in association with other diseases (AR, LES, MCTD, SSP) and 14 cases of various diseases with no clinical signs of SS (AR, UCTD, LES, MCTD, PM, cutaneous PAN, Scheuermann's disease, ankylosing spondylitis) have been examined. Examination of the patients included general clinical, stomatological and ophthalmological examinations, slit lamp and Schirmer I test, labial biopsy direct immunofluorescence on labial biopsy, indirect immunofluorescence on labial biopsy of a healthy subject scialography and salivary scintiscan. Various seroimmunological tests were also performed--in the hope of identifying LE, ANA, anti-ENA and anti-dsDNA factors. The results of these clinical, immunological, bioptic and instrumental tests were studied with a view to clarifying the diagnostic and nosographic problems of the syndrome. The diagnostic importance of immunological and instrumental tests is emphasized. Labial biopsy in particular also makes it possible to quantify the glandular lesion to some extent as well as providing other histological data regarding any associated disease. Nosographically, it is suggested that SS be definitively included among the connective tissue diseases in recognition of its polymorphism and variety of clinical forms which cover a wide range from definite SS, whether in pure form or associated with other diseases, to "subclinical" SS in systemic diseases.

[Serological diagnosis of systemic connective tissue inflammation; a new immunofluorescence method for demonstrating antinuclear antibodies]

Two methods for the demonstration of antinuclear antibodies by means of indirect immunofluorescence were employed on 83 serum samples from 80 patients, with rat liver as the substrate. The first method (the classic ANA-test) uses cryostatic slices fixed in acetone; the second (ANA-Bp-test) is based on fixation of the substrate with Bouin's fluid and embedding in paraffin. The series was composed of 25 cases of lupus erythematosus (28 serum samples), 10 of rheumatoid arthritis, 1 of dermatomyositis, 8 of progressive systemic sclerosis, 4 of unclassifiable systemic connective tissues diseases, and 28 various internal and rheumatological forms. The undiluted sera that proved positive were subsequently tested for Ig typing and ANA titration. The ANA-Bp-test was found to be more sensitive, safer, more practical and less expensive than the ANA-test.