The Rise Slope of the Compound Sensory Nerve Action Potential in Normal and Pathological Human Nerves.

In spite of the diagnostic importance of the early phase of the sensory nerve action potential (SNAP), reliable electrodiagnostic metrics for this part of the recorded waveform are lacking. The average rise slope of the SNAP appreciates the steepness of the initial negative deflection of the waveform, which might be a useful metric for the first part of the potential. Sural nerve sensory neurography was performed in patients with various axonal neuropathies, and median nerve sensory studies were carried out in patients with carpal tunnel syndrome. Age-matched healthy individuals served as controls. The rise slope was compared to conventional SNAP parameters such as conduction velocity, latency, duration, and rise time. Overall, 537 sensory studies were prospectively analyzed. The rise slope of the sural SNAP demonstrated superior classification performance in terms of sensitivity (92.5%), specificity (97%), and area under the receiver operating characteristic curve (0.986), as compared to conventional SNAP parameters. Its diagnostic power was similarly excellent in median nerve studies, whereas here a slightly better classification performance was obtained by SNAP latency and conduction velocity. The average rise slope appears to do justice to the tight interplay between amplitude and rise time of the initial negative spike deflection, outperforming many conventional measures. This composite metric proved high diagnostic potency in particular with regard to axonal sensory nerve dysfunction.

Deep Characterization of a Greek Patient with Desmin-Related Myofibrillar Myopathy and Cardiomyopathy.

Desmin is a class III intermediate filament protein highly expressed in cardiac, smooth and striated muscle. Autosomal dominant or recessive mutations in the desmin gene (DES) result in a variety of diseases, including cardiomyopathies and myofibrillar myopathy, collectively called desminopathies. Here we describe the clinical, histological and radiological features of a Greek patient with a myofibrillar myopathy and cardiomyopathy linked to the c.734A>G,p.(Glu245Gly) heterozygous variant in the DES gene. Moreover, through ribonucleic acid sequencing analysis in skeletal muscle we show that this variant provokes a defect in exon 3 splicing and thus should be considered clearly pathogenic.

Adult-onset dominant muscular dystrophy in Greek families caused by Annexin A11.

OBJECTIVE: Mutations in the prion-like domain of RNA binding proteins cause dysfunctional stress responses and associated aggregate pathology in patients with neurogenic and myopathic phenotypes. Recently, mutations in ANXA11 have been reported in patients with amyotrophic lateral sclerosis and multisystem proteinopathy. Here we studied families with an autosomal dominant muscle disease caused by ANXA11:c.118G > T;p.D40Y. METHODS: We performed deep phenotyping and exome sequencing of patients from four large Greek families, including seven affected individuals with progressive muscle disease but no family history of multi-organ involvement or ALS. RESULTS: In our study, all patients presented with an autosomal dominant muscular dystrophy without any Paget disease of bone nor signs of frontotemporal dementia or Parkinson's disease. Histopathological analysis showed rimmed vacuoles with annexin A11 accumulations. Electron microscopy analysis showed myofibrillar abnormalities with disorganization of the sarcomeric structure and Z-disc dissolution, and subsarcolemmal autophagic material with myeloid formations. Molecular genetic analysis revealed ANXA11:c.118G > T;p.D40Y segregating with the phenotype. INTERPRETATION: Although the pathogenic mechanisms associated with p.D40Y mutation in the prion-like domain of Annexin A11 need to be further clarified, our study provides robust and clear genetic evidence to support the expansion of the phenotypic spectrum of ANXA11.

Preserved eye movements in adults with spinal muscular atrophy.

INTRODUCTION: Spinal muscular atrophy (SMA) most prominently affects proximal limb and bulbar muscles. Despite older case descriptions, ocular motor neuron palsies or other oculomotor abnormalities are not considered part of the phenotype. METHODS: We investigated oculomotor function by testing saccadic eye movements of 15 patients with SMA. Their performance was compared with that of age-matched healthy controls. Horizontal rightward and leftward saccades were recorded by means of video-oculography, whereas subjects looked at light-emitting diode targets placed at ±5°, ±10°, and ±15° eccentricities. RESULTS: No differences in saccade amplitude gains, peak velocities, peak velocity-to-amplitude ratios, or durations were observed between controls and patients. More specifically, for 5° target eccentricities, patients had a mean saccadic peak velocity of 153°/s, whereas for 10° and 15° these values were 268°/s and 298°/s, respectively. The corresponding mean peak velocities of the control group were 151°/s, 264°/s, and 291°/s. DISCUSSION: Our results indicate that patients with SMA perform fast and accurate horizontal saccades without evidence of extraocular muscle weakness. These quantitative oculomotor data corroborate clinical experience that neuro-ophthalmic symptoms in SMA are not common and, if present, should prompt suspicion for an alternative neuromuscular disorder.

Effect of long term enzyme replacement therapy in late onset Pompe disease: A single-centre experience.

Late onset Pompe disease (LOPD) is a slowly progressive metabolic myopathy with variable clinical severity. The advent of enzyme replacement therapy (ERT) has modified the natural course of the disease, though the treatment effect on adult patients is modest compared to infants with the classic form. This study aims to describe the long-term clinical outcome of the Greek LOPD cohort, as assessed by 6 min walk test, muscle strength using MRC grading scale and spirometry. ERT efficacy was estimated using statistical methodology that is novel in the context of Pompe disease, which at the same time is well-suited to longitudinal studies with small samples and missing data (local non-linear regression analysis). Improvement over baseline was significant at 1 year for motor performance and muscle strength (p < 0.05), and at 2 years for FVC-U and FVC-S (p < 0.05). A subgroup analysis showed that the onset of the disease before adulthood (18 years), a male gender, and a latency of more than 2 years between the onset of symptoms and ERT administration are unfavorable prognostic factors. Conclusively, this study presents longitudinal data from the Greek LOPD cohort supporting previous observations, that therapeutic delay is related to worse prognosis and treatment effects may decline after several years of ERT.

Effect of exercise training on functional capacity and body composition in myotonic dystrophy type 2 patients.

BACKGROUND: Myotonic dystrophy type 2 (DM2) is a neuromuscular disorder characterized by myotonia and muscle weakness, with no medical treatment to prevent a decline in decline. It is unknown whether exercise training is effective in DM2. The aim of this study was to investigate the effect of exercise training on functional capacity and body composition in these patients. METHODS: Body composition and functional capacity were evaluated at the beginning (T1) and end (T2) of a 12 wk control period, and again after 16 wk of exercise training (T3) in 10 patients. RESULTS: No changes were recorded after the control period. Handgrip strength, 5× sit to stand, timed up and go, 6 min walk distance, lean body mass (LBM), and bone mineral density (BMD) increased while arterial pressure decreased after training. CONCLUSIONS: These results suggest that supervised exercise training improves functional capacity, LBM, and BMD in ambulatory DM2 patients.

Vibratory testing with the 64 Hz Rydel-Seiffer tuning fork and its relation to the sural nerve action potential.

Despite its widespread use, little is known regarding the ability of the semi-quantitative Rydel-Seiffer tuning fork to designate peripheral nerve function. We sought to determine in a large sample of normal and abnormal nerves the relationship between vibration sense and compound sensory nerve action potential (SNAP) parameters recorded in a corresponding innervation area. Vibratory thresholds were determined on a scale of 0 to 8 with a 64 Hz Rydel-Seiffer tuning fork placed on the lateral malleolus of 303 subjects. Sural nerve sensory neurography was employed to derive SNAP parameters, which were related to vibration sense by means of multiple linear regression. ROC curve analysis was performed to determine the classification efficacy of the tuning fork in distinguishing normal from abnormal sural nerve responses. SNAP amplitude was the most significant predictor in the whole subjects group and in the subgroup of subjects with normal SNAPs, whereas conduction velocity played a major role in subjects with abnormal SNAPs. Age was significantly associated with vibration perception, particularly in subjects with normal SNAPs. With an area under the curve of 0.730, vibration sense was a fair classifier for decreased SNAP amplitudes. The optimal vibratory cutoff was 4.2. Age is a major determinant of vibratory test results, highlighting the importance of aging of central and peripheral pathways in mediating vibration sense. Hence, neurophysiological testing cannot be omitted in the context of polyneuropathy work-up, since even at the optimal cutoff threshold, vibratory examination still displays 40% false negative test results.

Update on Congenital Myopathies in Adulthood.

Congenital myopathies (CMs) constitute a group of heterogenous rare inherited muscle diseases with different incidences. They are traditionally grouped based on characteristic histopathological findings revealed on muscle biopsy. In recent decades, the ever-increasing application of modern genetic technologies has not just improved our understanding of their pathophysiology, but also expanded their phenotypic spectrum and contributed to a more genetically based approach for their classification. Later onset forms of CMs are increasingly recognised. They are often considered milder with slower progression, variable clinical presentations and different modes of inheritance. We reviewed the key features and genetic basis of late onset CMs with a special emphasis on those forms that may first manifest in adulthood.

Polymyositis with mitochondrial pathology or atypical form of sporadic inclusion body myositis: case series and review of the literature.

Polymyositis with mitochondrial pathology (PM-Mito) is a rare form of idiopathic inflammatory myopathy with no definite diagnostic criteria and similarities to both PM and sporadic inclusion body myositis (s-IBM). The aim of this study is to address the dilemma of whether PM-Mito is a subtype of inflammatory myopathy or represents a disease falling into the spectrum of s-IBM. Herein, we report four female patients diagnosed with PM-Mito, highlighting their rather atypical clinical and histopathological characteristics that seem to indicate a diagnosis away from s-IBM. Muscle weakness was rather proximal and symmetrical and lacked the selective pattern observed in s-IBM. Patients had large-scale deletions in mtDNA, reflecting the mitochondrial component in the pathology of the disease. Conclusively, our study adds to the limited data in the literature on whether PM-Mito is a distinct form of myositis or represents a prodromal stage of s-IBM. Although the latter seems to be supported by a substantial body of evidence, there are, however, important differences, such as the different patterns of muscle weakness, and the good response to treatment observed in some patients. Larger-scale studies are certainly needed to clarify pathogenesis and clinical characteristics of PM-Mito patients, especially in therapeutic and prognostic terms.

Motor and extra-motor gray matter integrity may underlie neurophysiologic parameters of motor function in amyotrophic lateral sclerosis: a combined voxel-based morphometry and transcranial stimulation study.

The association between gray matter (GM) density and neurophysiologic changes is still unclear in amyotrophic lateral sclerosis (ALS). We evaluated the relationship between GM density and motor system integrity combining voxel-based morphometry (VBM) and transcranial magnetic stimulation (TMS) in ALS. We included 17 ALS patients and 22 healthy controls (HC) who underwent 3D-T1-weighted imaging. Among the ALS group, we applied left motor cortex single-pulse TMS. We used whole-brain VBM comparing ALS and HC in GM density. We also conducted regression analysis to examine correlations between GM density and the following TMS parameters: motor evoked potential (MEP)/M ratio and central motor conduction time (CMCT). We found significantly decreased GM density in ALS patients in several frontal, temporal, parietal/occipital and cerebellar regions (p < 0.001 uncorrected; cluster-extent threshold k = 100 voxels per cluster). With regards to TMS parameters, ALS patients showed mostly increased MEP/M ratio and modest prolongation of CMCT. MEP/M ratio was associated with GM density in (a) rolandic operculum/inferior frontal gyrus/precentral gyrus; anterior cingulate gyrus; inferior temporal gyrus; superior parietal lobule; cuneus; superior occipital gyrus and cerebellum (positive association) and (b) paracentral lobule/supplementary motor area (negative association). CMCT was associated with GM density in (a) inferior frontal gyrus and middle cingulated gyrus (positive association) and (b) superior parietal lobule; cuneus and cerebellum (negative association). Our findings support a significant interaction between motor and extra-motor structural and functional changes and highlight that motor and extra-motor GM integrity may underlie TMS parameters of motor function in ALS patients.

Gray matter and white matter changes in non-demented amyotrophic lateral sclerosis patients with or without cognitive impairment: A combined voxel-based morphometry and tract-based spatial statistics whole-brain analysis.

The phenotypic heterogeneity in amyotrophic lateral sclerosis (ALS) implies that patients show structural changes within but also beyond the motor cortex and corticospinal tract and furthermore outside the frontal lobes, even if frank dementia is not detected. The aim of the present study was to investigate both gray matter (GM) and white matter (WM) changes in non-demented amyotrophic lateral sclerosis (ALS) patients with or without cognitive impairment (ALS-motor and ALS-plus, respectively). Nineteen ALS-motor, 31 ALS-plus and 25 healthy controls (HC) underwent 3D-T1-weighted and 30-directional diffusion-weighted imaging on a 3 T MRI scanner. Voxel-based morphometry and tract-based spatial-statistics analysis were performed to examine GM volume (GMV) changes and WM differences in fractional anisotropy (FA), axial and radial diffusivity (AD, RD, respectively). Compared to HC, ALS-motor patients showed decreased GMV in frontal and cerebellar areas and increased GMV in right supplementary motor area, while ALS-plus patients showed diffuse GMV reduction in primary motor cortex bilaterally, frontotemporal areas, cerebellum and basal ganglia. ALS-motor patients had increased GMV in left precuneus compared to ALS-plus patients. We also found decreased FA and increased RD in the corticospinal tract bilaterally, the corpus callosum and extra-motor tracts in ALS-motor patients, and decreased FA and increased AD and RD in motor and several WM tracts in ALS-plus patients, compared to HC. Multimodal neuroimaging confirms motor and extra-motor GM and WM abnormalities in non-demented cognitively-impaired ALS patients (ALS-plus) and identifies early extra-motor brain pathology in ALS patients without cognitive impairment (ALS-motor).

Investigating the neuroanatomical substrate of pathological laughing and crying in amyotrophic lateral sclerosis with multimodal neuroimaging techniques.

OBJECTIVE: Pathological laughing and crying (PLC) is common in several neurological and psychiatric diseases and is associated with a distributed network involving the frontal cortex, the brainstem and cortico-pontine-cerebellar circuits. By applying multimodal neuroimaging approach, we examined the neuroanatomical substrate of PLC in a sample of patients with amyotrophic lateral sclerosis (ALS). METHODS: We studied 56 non-demented ALS patients and 25 healthy controls (HC). PLC was measured in ALS using the Center of Neurologic Study Lability Scale (CNS-LS; cutoff score: 13). All participants underwent 3D-T1-weighted and 30-directional diffusion-weighted imaging at 3T. Voxel-based morphometry and tract-based spatial-statistics analysis was used to examine gray matter (GM) and white matter (WM) differences between ALS patients with and without PLC (ALS-PLC and ALS-nonPLC, respectively). Comparisons were restricted to regions with detected differences between ALS and HC, controlling for age, gender, total intracranial volume and depressive symptoms. RESULTS: In regions with significant differences between ALS and HC, ALS-PLC patients showed decreased GM volume in left orbitofrontal cortex, frontal operculum, and putamen and bilateral frontal poles, compared to ALS-nonPLC. They also had decreased fractional anisotropy in left cingulum bundle and posterior corona radiata. WM abnormalities were additionally detected in WM associative and ponto-cerebellar tracts (using a more liberal threshold). CONCLUSIONS: PLC in ALS is driven by both GM and WM abnormalities which highlight the role of circuits rather than isolated centers in the emergence of this condition. ALS is suggested as a useful natural experimental model to study PLC.

Memory-related white matter tract integrity in amyotrophic lateral sclerosis: an advanced neuroimaging and neuropsychological study.

We aimed to investigate structural changes in vivo in memory-related white matter tracts (i.e., perforant pathway zone [PPZ]; uncinate fasciculus [UF]; fornix) using diffusion tensor tractography and evaluate possible associations with memory performance in nondemented patients with amyotrophic lateral sclerosis (ALS). Forty-two ALS patients and 25 healthy controls (HCs) underwent a 30-directional diffusion-weighted imaging on a 3T MR scanner, followed by tractography of PPZ, UF, and fornix and analysis of fractional anisotropy (FA), axial diffusivity and radial diffusivity (Dr). Patients were administered neuropsychological measures of verbal (list learning via Rey Auditory Verbal Learning Test [RAVLT] and prose memory via Babcock Story Recall Test) and nonverbal (Rey's Complex Figure Test) episodic memory. After correcting for multiple comparisons, ALS patients showed increased Dr in the left PPZ compared to HC. We then fitted a multivariate general linear model within ALS patients with neuropsychological measures as dependent variables and age, age2, gender, verbal IQ, and diffusion tensor tractography metrics with at least medium effect size differences between ALS and HC as independent variables. We found that (1) left PPZ FA, gender, and verbal IQ contributed to RAVLT-Total Learning; (2) left PPZ FA, left UF Dr, and gender contributed to RAVLT-Immediate Recall; and (3) left PPZ FA and left UF axial diffusivity contributed to Babcock Story Recall Test-Immediate and Delayed Recall. Advanced neuroimaging techniques verified in this study previously reported neuropathological findings regarding PPZ degeneration in ALS. We also detected a unique contribution of microstructural changes in hippocampal and frontotemporal white matter tracts on patients' memory profile.

Understanding of headache patterns modification in an emergency department during the economic crisis of Greece.

Very few neurological research is published regarding health effects of global economic crisis. Our aim was to assess the impact of economic recession on frequency and severity of headaches. We also tested if depression, anxiety and experiences associated with crisis, such as unemployment, were reflected in headaches. This is a retrospective observational study in the Emergency setting of tertiary Clinic from 1 January 2008 until 31 December 2009 and from 1 January 2010 until 31 December 2011. Demographic data were collected of 1094 consecutive adult patients with headache. Multinomial logistic regression performed to examine if hospital anxiety depression (HAD), HAD anxiety, experience of serious life events, year of survey had influence on type of headache. The total number of headache cases increased significantly from 2008 to 2011 (p < 0.001). Tension type and medication overuse headaches remained unchanged over time (p > 0.05), while migraines decreased. Secondary and not otherwise specified (NOS) increased significantly (p < 0.05). The most common, overtime, was Tension type headache, followed by migraines (in 2008, 2011) and NOS (2010). Chi square test showed significant correlation between type of headache and year, as well medication type and year (p < 0.05). Common analgesics, the most common medication, increased five times during survey period (77 % 2008 to 87.6 % 2011). Multivariate analysis revealed stronger association for experience serious events with NOS vs. tension type headache [odds ratio (OR) 0.13; 95 % confidence interval (CI) 0.03, 0.7]. This is the first study showing that the prolonged economic crisis affected headache frequency accompanied by a higher use of analgesics.

Residency Training: Determinants of burnout of neurology trainees in Attica, Greece.

OBJECTIVE: The purpose of our cross-sectional study was to estimate the rate of burnout and identify its determinants among neurology residents in Attica, Greece. METHODS: In total, 131 placements for neurology training over 18 hospitals were available. All residents were approached and were asked to participate in the study by anonymously completing a questionnaire. Job demands and resources (JD-R) were examined via a 31-item questionnaire assessing 8 factors based on the JD-R model. Burnout was measured with the Maslach Burnout Inventory (MBI). The emotional exhaustion + 1 criterion was used to distinguish respondents with and without burnout. RESULTS: A total of 116 residents participated in the study (response rate 88.5%). In total, 18.1% of the participants were experiencing burnout. Multivariate analysis showed that each increased point in the total score of the factor regarding opportunities for professional development was associated with lowering the odds of burnout by 28.7%. CONCLUSIONS: Burnout among neurology residents is associated with decreased professional development. Educators and program directors need to identify those residents at high risk of burnout and design interventions to promote residents' resilience and mental health.

Rapid Screening for Carpal Tunnel Syndrome: A Novel Method and Comparison With Established Others.

PURPOSE: The authors have observed that in healthy people, the Ulnar wrist-to-first dorsal interosseous distal motor latency does not differ significantly compared with median wrist-to-abductor pollicis brevis distal motor latency. The aim of our study was to investigate whether the difference between these two latencies can be used as a screening tool for diagnosing carpal tunnel syndrome and how this technique compares with other established techniques. METHODS: The study was set up as a prospective observational study. As gold standard for the clinical diagnosis of carpal tunnel syndrome, the authors used the opinion of two neurologists who independently examined the patients. A third neurologist, also independently, performed the electrophysiological study. RESULTS: Eighty-four subjects, 42 patients and 42 age- and sex-matched controls, participated in the study. Among all subjects using a receiver operating characteristic curve analysis, the area under the curve was 0.924 (95% CI, 0.857-0.991; SE, 0.034; P < 0.001). To detect carpal tunnel syndrome, at a cutoff score of equal to or greater than 0.575 milliseconds, our technique showed a sensitivity of 91%, a specificity of 93%, a positive predictive value of 93%, and a negative predictive value of 91%. Compared with other "classical" techniques, our technique showed better area under the receiver operating characteristic curve and better Youden index. CONCLUSIONS: The median wrist-to-abductor pollicis brevis motor latency minus ulnar wrist-to-first dorsal interosseous motor latency may be used as a novel rapid screening tool of patients suffering from carpal tunnel syndrome.