Nerve Conduction Studies of Dorsal Sural Nerve: Normative Data and Its Potential Application in ATTRv Pre-Symptomatic Subjects.

The objective of the study is to provide age-related normative values for dorsal sural nerve (DSN) and to analyse its application during follow-up of hereditary transthyretin amyloidosis (ATTRv) pre-symptomatic subjects. We consecutively recruited ATTRv pre-symptomatic carriers in which clinical examination, cardiological evaluation, and nerve conduction studies of the sural nerve and DSN were performed. To provide normative data of DSN, neurophysiologic parameters from healthy controls referred to our service were entered into linear regression analyses to check the relative influence of age and height.

Long-Term Safety and Usefulness of Mexiletine in a Large Cohort of Patients Affected by Non-dystrophic Myotonias.

The aim of our study was to evaluate the long-term efficacy and safety of mexiletine in 112 patients affected by genetically confirmed non-dystrophic myotonias. The study was performed at the Neurophysiologic Division of Fondazione Policlinico Universitario A. Gemelli Istituto di Ricerca e Cura a Carattere Scientifico (IRCCS), Rome and the Children's Hospital Bambino Gesù, Rome.

Sodium Channel Myotonia Due to Novel Mutations in Domain I of Na1.4.

Sodium channel myotonia is a form of muscle channelopathy due to mutations that affect the Na1.4 channel. We describe seven families with a series of symptoms ranging from asymptomatic to clearly myotonic signs that have in common two novel mutations, p.

Pharmacogenetics of myotonic hNav1.4 sodium channel variants situated near the fast inactivation gate.

Sodium channel myotonia and paramyotonia congenita are caused by gain-of-function mutations in the skeletal muscle voltage-gated sodium channel hNav1.4. The first-line drug is the sodium channel blocker mexiletine; however, some patients show side effects or limited responses.

The analysis of myotonia congenita mutations discloses functional clusters of amino acids within the CBS2 domain and the C-terminal peptide of the ClC-1 channel.

Myotonia congenita (MC) is a skeletal-muscle hyperexcitability disorder caused by loss-of-function mutations in the ClC-1 chloride channel. Mutations are scattered over the entire sequence of the channel protein, with more than 30 mutations located in the poorly characterized cytosolic C-terminal domain. In this study, we characterized, through patch clamp, seven ClC-1 mutations identified in patients affected by MC of various severities and located in the C-terminal region.

Translational approach to address therapy in myotonia permanens due to a new SCN4A mutation.

Objective: We performed a clinical, functional, and pharmacologic characterization of the novel p.P1158L Nav1.4 mutation identified in a young girl presenting a severe myotonic phenotype.

Admission neurophysiological abnormalities in Guillain-Barré syndrome: A single-center experience.

Objective: Although patients with Guillain-Barré syndrome (GBS) are often hospitalized few days after symptoms onset, nerve conduction studies (NCS) abnormalities in early phases of the disease are not well characterized. Our aim was to report early neurophysiological abnormalities from a cohort of GBS patients.

Methods: In this single-center study, we retrospectively reviewed the NCS data of 71 consecutive GBS patients in whom neurophysiology was performed within two weeks after disease onset.

A Case of Hemiabdominal Myoclonus.

Myoclonus consists of sudden, brief, involuntary jerky muscular contractions. Central and peripheral nervous system lesions are involved in the pathogenesis of this movement disorder. Symptomatic or secondary spinal myoclonus is the most common form.

Effect of mexiletine on transitory depression of compound motor action potential in recessive myotonia congenita.

Objective: We aim to demonstrate the effect of mexiletine on the compound muscle action potential (CMAP) amplitude transitory depression (TD) in a cohort of patients with recessive myotonia congenita.

Methods: We evaluated 21 patients with recessive myotonia congenita referred to our institute from 1990 to 2013 and treated with mexiletine chlorhydrate. All patients underwent prolonged 3 Hz repetitive nerve stimulation (3 Hz-PLRS) before and after the beginning of treatment.

Clinical, neurophysiological and pathological findings of HNPP patients with 17p12 deletion: a single-centre experience.

Background: Classic clinical manifestations of HNPP are characterized by recurrent painless mononeuropathies, but a minority of patients present with an atypical clinical pattern, including CMT-like neuropathy, acute or chronic inflammatory demyelinating neuropathy-like polyneuropathy, and carpal tunnel syndrome. Electrophysiological examination plays a central role in the diagnosis of HNPP, disclosing a non-uniform conduction slowing, more pronounced at entrapment sites.

Patients And Methods: We report clinical, electrophysiological and pathological findings from 73 patients with HNPP, coming from 53 unrelated families, followed at our Institute of Neurology over a 20-year period.

MRI neurography findings in patients with idiopathic brachial plexopathy: correlations with clinical-neurophysiological data in eight consecutive cases.

Objective: Idiopathic brachial plexopathy is a non-progressive disorder characterized by the sudden onset of shoulder pain associated with weakness and sometimes paraesthesia of the arm. Clinical and electrophysiological examinations are the primary diagnostic tools and allow physicians to localize the site of damage. MRI neurography is rarely performed in this setting.

Persistence of abnormal electrophysiological findings after carpal tunnel release.

Practitioners may refer to experienced hand surgeons to differentiate a recurrence in carpal tunnel syndrome (CTS) from a failed carpal tunnel release. The patient may complain about the reappearance of symptoms, whatever is the cause. Nerve conduction studies (NCS) are often required by the practitioner to assist the final diagnosis.

Clinical-neurophysiological correlations in a series of patients with IgM-related neuropathy.

Objective: We aim to draw clinical-neurophysiological correlations in our cohort of patients affected by IgM-related neuropathy to investigate whether neurophysiological parameters may help differentiate the classical phenotype from atypical forms.

Methods: We retrospectively evaluated patients with IgM-related neuropathy referred to our Institute from 1990 to 2011. All patients underwent extensive laboratory, clinical and neurophysiological evaluation.

TTR-related amyloid neuropathy: clinical, electrophysiological and pathological findings in 15 unrelated patients.

Familial amyloid polyneuropathy (FAP) is a rare condition caused by mutations of the transthyretin (TTR) gene and it is generally characterized by a length-dependent polyneuropathy affecting prevalently the small fibers. We reviewed clinical, electrophysiological and pathological findings of 15 unrelated patients with genetically confirmed TTR-FAP. All patients presented a progressive sensory-motor polyneuropathy.

Prospective electromyographic evaluation of functional postthyroidectomy voice and swallowing symptoms.

Background: Voice and swallowing symptoms following thyroidectomy in the absence of any demonstration of laryngeal nerves injury are usually considered a functional outcome of uncomplicated operations, mainly related to scar formation and emotional reaction. They could be related to unapparent laryngeal nerve or cricothyroid (CT) muscle injuries detectable only by laryngeal electromyography (LEMG). We correlated such symptoms with LEMG patterns.

Uncovering amyotrophic lateral sclerosis phenotypes: clinical features and long-term follow-up of upper motor neuron-dominant ALS.

The aim of our study was to analyse the natural history and clinical features of upper motor neuron- dominant (UMN-D) ALS. We studied a large series of sporadic ALS patients admitted in a single referral centre over a 23-year period. UMN-D phenotype was compared with other ALS forms, including classic ALS, flail arm and progressive muscular atrophy.

Low-rate repetitive nerve stimulation protocol in an Italian cohort of patients affected by recessive myotonia congenita.

Transitory depression of the compound muscle action potential during repetitive nerve stimulation is a well-documented neurophysiologic finding in recessive myotonia congenita. It represents the neurophysiologic counterpart of the transitory weakness often impairing patients at the beginning of a movement after rest, and it is usually better induced using high-rate nerve stimulations. The authors examined 30 patients with recessive myotonia congenita and carried out a 3 Hz nerve stimulation study to ascertain to what extent this protocol was able to detect the occurrence of transitory depression.

Polymorphism of CAG motif of SK3 gene is associated with acute oxaliplatin neurotoxicity.

Purpose: There is no agreement on which channel is involved in oxaliplatin neurotoxicity, most investigators favouring voltage-gated sodium channels. However, the small conductance Ca(++) activated K(+) channels, encoded by the SK1-3 genes, are also involved in membrane excitability, playing a role in after-hyperpolarization at the motor nerve terminal. As the SK3 gene is characterized in Caucasians by a highly polymorphic CAG motif within the exon 1, we hypothesize that SK3 gene polymorphism may influence the development of acute nerve hyperexcitability in oxaliplatin-treated patients.

Rippling muscle disease and cardiomyopathy associated with a mutation in the CAV3 gene.

Caveolin-3, the myocyte-specific isoform of caveolins, is preferentially expressed in skeletal, cardiac and smooth muscles. Mutations in the CAV3 gene cause clinically heterogeneous neuromuscular disorders, including rippling muscle disease, or cardiopathies. The same mutation may lead to different phenotypes, but cardiac and muscle involvement rarely coexists suggesting that the molecular network acting with caveolin-3 in skeletal muscle and heart may differ.

Clinical correlates with anti-MuSK antibodies in generalized seronegative myasthenia gravis.

The term seronegative myasthenia gravis (SNMG) refers to the generalized disease without detectable anti-acetylcholine receptor (anti-AChR) antibodies. In these patients, IgG antibodies against the muscle-specific kinase (MuSK) have been described, which reduced agrin-induced AChR clustering in vitro. We have assayed anti-MuSK antibodies in 78 patients with SNMG, who have been followed for many years in our Institution.